Food Nutrition Exam 2 Preparation (copy)
Chapter 4: Carbohydrates
Spotlight A: Nutrition and Diabetes
1. What are the functions of carbohydrates?
Carbohydrates are the body’s main source of energy. They are used for energy production, energy storage as glycogen, and they help spare protein from being broken down for energy. The brain and red blood cells rely on glucose as their primary fuel source.
2. List the three monosaccharides.
Glucose, fructose, and galactose
i. Which monosaccharide gives the intense sweetness to fruit?
Fructose gives fruit its intense sweetness
ii. Which disaccharide is known as table sugar?
Sucrose is known as table sugar
3. List the 3 disaccharides and their food sources.
Sucrose, lactose, maltose
Sucrose: found in sugarcane, sugar beets, maple syrup, honey, fruits, and vegetables
Lactose: found in milk and other dairy products
Maltose: found in germinating grains and malted beverages
4. What are oligosaccharides?
Short chains of 3-10 sugar units. They are considered complex carbs and act as prebiotics, or food for beneficial gut bacteria.
5. What are the 3 polysaccharides?
Starch: foods rich in starch include grains, potatoes, rice, and pasta
Glycogen: storage form of carbs in animals and humans, primarily in the liver and muscles; it is not a food source
Fiber: found in plant-based foods such as whole grains, vegetables, fruits, and legumes
i. What foods contain these polysaccharides?
ii. Note: Glycogen is a storage form of carbohydrate. There is not a food source of glycogen.
6. List the health benefits of fiber.
A high fiber-diet can lower LDL (“bad”) cholesterol, stabilize blood sugar levels, promote healthy digestion and prevent constipation, and is associated with a reduced risk of cardiovascular disease, certain cancers, and type 2 diabetes
7. List the dietary recommendations for carbohydrates, fiber and added sugars.
Carbohydrates: The acceptable macronutrient distribution range (AMDR) for carbs is 45-65% of total calories. The recommended dietary allowance (RDA) is 130 grams per day to provide the brain with adequate glucose and prevent ketosis.
Fiber: The adequate intake (AI) for fiber is 25 g/day for women and 38 g/day for men under 50 years old
Added sugars: The recommended limit for added sugars is less than 10% of total calories
8. What foods and food groups could increase your fiber intake?
Whole grains, bran cereals, beans, lentils, peas, nuts, seeds, berries, broccoli, leafy greens
9. List food sources of soluble fiber and food sources of insoluble fiber.
Soluble fiber: found in foods such as oat bran, barley, nuts, seeds, beans, lentils, peas, and some fruits
Insoluble fiber: Found in foods such as wheat bran, whole grains, and many vegetables
10. Name and describe:
i. Whole grains: grains that contain all three parts of the kernel: the bran, the endosperm, and the germ
ii. Refined grains: grains that have been processed to remove the bran and germ, leaving only the starchy endosperm. This results in a loss of fiber and several vitamins and minerals.
iii. Enriched grains: Refined grains that have some nutrients, such as B vitamins and iron, added back after milling.
11. What percent of the grains we eat should be whole grains per the Dietary Guidelines for Americans?
The dietary guidelines for the Americans recommend that at least half of the grains consumed should be whole grains.
12. Name and describe the 3 edible parts of a whole grain.
The three edile parts are the bran, the endosperm, and the germ
i. Which part contains fiber? The bran contains the majority of the fiber
13. Processed, enriched flour and grains are made from only one part that is mostly made of starch. Which part is it? The endosperm
14. What is the storage form of glucose in the body? Glycogen
15. Describe the body's use of glucose to provide energy.
The body breaks down most of the carbs we eat into glucose, which is then released into the bloodstream. Cells, particularly the brain and red blood cells, take up this glucose to produce ATP, which is the chemical energy they use to function.
16. Describe the way excess glucose can be used to make glycogen or to make body fat.
After meeting immediate energy needs, excess glucose is stored as glycogen in the liver and muscles. Once glycogen stores are full, any additional excess glucose can be converted into fat and stored in adipose tissue.
17. Discuss:
i. Lactose intolerance: This condition occurs when the body does not produce enough of the enzyme lactase to properly digest lactose, the sugar found in milk. This leads to the lactose being fermented by bacteria in the colon, causing symptoms like gas and discomfort.
ii. Hypoglycemia: A condition characterized by abnormally low blood glucose (sugar) level
18. List the 2 hormones released by the pancreas. When are they released and how do they work to regulate blood glucose?
Insulin and Glucagon
I. What they do:
Insulin: released when blood glucose levels are high (after a meal)
It signals cells to take up glucose from the blood for energy or storage. It stimulates the liver and muscles to store glucose as glycogen.
Glucagon: released when blood glucose levels are low (between meals or during fasting)
It signals the liver to break down stored glycogen and release glucose into the blood. It also promotes gluconeogenesis (making new glucose from non-carb sources like protein).
List the effects of insulin resistance:
In insulin resistance, the body’s cells do not respond effectively to insulin. This causes:
The pancreas produces more and more insulin to try and push glucose into the cells.
Blood glucose levels remain high, leading to hyperglycemia (pre-diabetes or Type 2 diabetes).
Metabolic abnormalities like high blood pressure, abnormal cholesterol/triglyceride levels, and increased risk of cardiovascular disease (CVD).
18. What is the definition of Diabetes Mellitus?
Diabetes Mellitus is a metabolic disease characterized by high blood glucose (hyperglycemia) resulting from defects in insulin secretion, insulin action, or both
19. List the three types of diabetes:
Type 1 Diabetes Mellitus
Type 2 Diabetes Mellitus
Gestational Diabetes (occurs during pregnancy)
20. What are the risk factors for Type 2 Diabetes?
Obesity
Physical inactivity
Family history of diabetes
Age (45 years or older)
Race/ethnicity
History of gestational diabetes or giving birth to a baby over 9 pounds
High blood pressure
High cholesterol/lipid levels
21. Name and describe the different treatments for each types of diabetes:
Nutrition
Type 1 Diabetes: Carbohydrate counting is essential for matching food intake to insulin doses. Focus on a balanced diet with consistent carbohydrate and protein intake
Type 2: Focus on lifestyle changes first, including a well-balanced diet emphasizing whole-grain/high-fiber starches and non-starchy vegetables. The goal is consistent, portion-controlled meals to manage blood glucose.
Physical Activity:
Type 1: Regular exercise is important but requires careful adjustment of insulin doses and/or carbohydrate intake to prevent hypoglycemia (low blood sugar), as exercise increases insulin sensitivity
Type 2: Regular aerobic exercise (at least 150 min/week) and strength training improves insulin sensitivity, lowers blood pressure, and reduces CVD risk.
Medication:
Type 1: Insulin therapy (injections or pump) is mandatory, as the pancreas produces little to no insulin.
Type 2: Often starts with metformin to improve insulin sensitivity and reduce liver glucose production. Other oral medications or injectable medications (including insulin) may be added if blood glucose targets are not met.
22. What is a safe blood glucose level for non-diabetes?
(for non-diabetes) is less than 100 mg/dL
23. How is a safe diagnosis of diabetes made (blood test numbers)?
Fasting plasma glucose (FPG): greater than or equal to 126 mg/dL
Oral Glucose Tolerance Test (OGTT): greater than or equal to 200 mg/dL (2 hours after drinking a glucose load)
Hemoglobin A1c (HbA1C): greater than or equal to 6.5%
Random Plasma Glucose: greater than or equal to 200 mg/dL
In a person with class symptoms of hyperglycemia
Chapter 5: Lipids
List the functions of fat.
Energy storage (as triglycerides in adipose tissue)
Insulation and padding (protecting internal organs)
A component of all cell membranes
Aiding absorption of fat-soluble vitamins (A,D,E,K)
Providing essential fatty acids
Adding texture and flavor to foods
Describe the structure of:
Triglycerides:
The most common form of fat in the body and food. They are composed of one glycerol molecule and three fatty acid molecules
Phospholipids:
A glycerol backbone with two fatty acid molecules and one phosphate group. The phosphate group makes the head water-soluble (hydrophilic), while the fatty acid tails are fat-soluble (hydrophobic)
Sterols:
Compounds whose chemical structure consists of a four-ring carbon structure. Cholesterol is the most well-known example in the body.
List the functions of phospholipids.
They are a major component of all cell membranes
They act as emulsifiers in the body and in food, allowing fat and water to mix
List the functions of cholesterol.
Part of cell membranes
Used to make bile acids (for digestion)
Used to make steroid hormones (e.g., sex hormones like estrogen and testosterone)
Used to make Vitamin D
Describe the process of fat digestion and absorption.
Mouth: Lingual lipase begins to break down some short-chain triglycerides
Stomach: Gastric lipase acts on some triglycerides
Small Intestine (Major Site):
Bile (an emulsifier from liver/gallbladder) breaks large fat globules into smaller droplets
Pancreatic lipase hydrolyzes the triglycerides into monoglycerides and free fatty acids
Micelles (small clusters of bile, monoglycerides, and free fatty acids) transport the lipids to the intestinal cells for absorption
Absorption:
Short and medium chain fatty acids are absorbed directly into the bloodstream
Long-chain fatty acids and monoglycerides are reassembled into triglycerides inside the intestinal cells and packaged into chylomicrons
What is the difference between a chylomicron and other lipoproteins?
Chylomicrons are the largest and least dense of the lipoproteins. They are made in the small intestine and function to transport dietary (exogenous) fat from the intestine to the rest of the body
Other lipoproteins (VLDL, LDL, HDL) are mainly made by the liver and transport fat that was synthesized or recycled within the body (endogenous fat)
List and describe the 4 types of lipoproteins.
Chylomicrons: Transport dietary triglycerides from the small intestine into the body cells
Very-Low-Density Lipoproteins (VLDL): Transport endogenous triglycerides (made by the liver) from the liver to the body cells.
Low-Density Lipoproteins (LDL): Formed from VLDL remnants. They transported cholesterol to the body’s cells (bad cholesterol).
Why is HDL good and why is LDL bad?
LDL (bad): delivers cholesterol to the body cells, and high levels can deposit cholesterol in artery walls, contributing to the formation of plaque and atherosclerosis (hardening of the arteries)
HDL (good): because it scavenges excess cholesterol from the body’s cells and artery walls and returns it to the liver (a process called reverse cholesterol transport), which helps to clear plaque and is protective against cardiovascular disease
Describe the process of plaque formation that leads to atherosclerosis
Damage occurs to the artery lining
Due to high LDL, high blood pressure, or smoking
LDL cholesterol particles slip under the artery’s inner layer and become oxidized
Immune cells engulf these oxidized LDL particles
Forming foam cells
Plaque is formed by foam cells, cholesterol, etc
Plaque is a fatty deposit
Narrows the artery and stiffens the walls
Impedes blood flow and increases risk of heart attack or stroke
List the 2 Dietary Reference Intakes for essential fatty acids
Linoleic acid (omega-6)
Linolenic acid (omega-3)
List the food sources of:
Monounsaturated fats: olives/olive oil, canola oil, peanuts/peanut oil, avocados, most nuts
Polyunsaturated fat: corn oil, sunflower oil, soybean oil, safflower oil, walnuts
Omega 3’s: Fatty fish (salmon, tuna, mackerel, sardines), flaxseeds/flaxseel oil, walnuts, soybean oil
Saturated fat: animal products (fatty cuts of meat, butter, whole milk/cream, cheese), coconut oil, palm oil
Trans fat: Historically in hydrogenated oils (margarine, vegetable shortening), and foods made with them (baked goods, deep-fried foods). Naturally occurs in small amounts in some meat and dairy
Health benefits of Omega-3 Fatty acids:
Reduced risk of cardiovascular disease
Lowers blood triglycerides
Reduces blood clotting
Lowers blood pressure
Brain health
Especially during infant development
Reduced inflammation
List the acceptable blood lipid levels for decreased CVD risk:
Total blood cholesterol: <200 mg/dl
LDL cholesterol: < 100 mg/dl
HDL cholesterol: > 60 mg/dl (for maximum protection)
Triglycerides: < 150 mg/dl
What is the health concern with Coconut Oil?
Very high content of saturated fat (80-90%), which can raise LDL levels in some people
Process of hydrogenation:
Chemical process that adds hydrogen atoms to unsaturated fatty acids (oil)
Makes liquid more solid and stable
Less prone to rancidity
Changes the double bonds from a cis to a trans configuration
Creates trans fatty acids
What % of ingredients need to be organic for a product to be organic?
Must contain 95% organically produced ingredients
NUMBERS TO KNOW
A muffin has 10g of fat and 180 total calories
Multiply grams of fat by 9 calories per gram: 10g fat x 9 calories/gram = 90 calories
Divide calories from fat by total calories: 90 calories / 180 calories = 0.50
Multiply by 100: 0.50 x 100 = 50% of calories in the muffin are from fat
Chapter 6: Protein Spotlight C: Plant-Based Diets
Protein Structure, Composition, and Function
Structure and Composition: Proteins are large, complex molecules composed of one or more long chains of amino acids linked together.
Each amino acid contains an amino group, an acid group (carboxyl group) and a unique side chain (R-group). The protein structure has 4 levels:
Primary Structure: linear sequence of AA linked by peptide bonds
Secondary structure: local folding into alpha helices or beta pleated sheets, stabilized by hydrogen bonds
Tertiary structure: protein’s unique, overall three-dimensional shape, formed by interactions between the AA side chains
Quaternary structure: arrangement of two or more polypeptide chains (subunits) into a larger protein complex
What makes the structure of each protein different?
The unique sequence and # of amino acids (primary structure) determines the final 3D shape, or conformation, of the protein. This specific sequence dictates how the chemically different side chains interact to form the secondary, tertiary, and quaternary structures
How are amino acids linked together to form proteins?
Joined by a peptide bond
Covalent bond formed between the carboxyl group (C-terminus) of one amino acid and the amino group (N-terminus) of the next amino acid (AA)
What are the functions of protein?
Known as ‘workhorses’ of the cell, including:
Enzymes: acting as biological catalysts to speed up chemical reactions
Structure: forming supporting structures like collagen (in bones, tendons, and skin) and keratin (in hair and nails)
Movement: building muscles (actin and myosin) for movement
Transport: moving substances (hemoglobin transports oxygen in the blood)
Hormones: serving as chemical messengers (insulin)
Immunity: producing antibodies to fight disease
Fluid and pH balance: helping maintain the body’s acid-base balance and fluid distribution
Energy: providing energy or glucose if needed
Protein Synthesis and Metabolism
Protein synthesis is an ‘all-or-nothing’ process. To build a specific protein, the body must have an adequate supply of all required amino acids available in the amino acid pool. If an essential AA (one the body cannot produce) is missing or in short supply, it becomes a limiting amino acid, halting or severely limiting the synthesis of that particular protein.
How many essential amino acids exist?
9 essential (indispensable) AA’s
What is protein turnover?
Continuous, dynamic process in which body proteins are constantly being broken down (protein degradation) and rebuilt (protein synthesis)
This recycling allows the body to maintain protein quality, adjust to physiological changes, and re-utilize AA’s
What is protein denaturation?
Irreversible process where a protein loses its specfic three-dimensional shape, and thus its biological function, due to exposure to destructive forces such as heat (cooking an egg), strong acids (stomach acid), high salt concentrations, or mechanical agitation.
This process does not break the peptide bonds, only the weaker bonds that maintain the protein’s fold
Describe enzymes:
Special class of proteins that act as catalysts
Accelerate chemical reactions in the body w/out being permanently changed or consumed themselves
Almost all metabolic processes depend on enzymes
Protein Quality, Digestibility, and Comparison
Protein Quality is determined by a protein’s amino acid profile and its digestibility (how easily it is broken down and absorbed)
Protein Digestibility and Absorption refers to the efficiency with which the body breaks down protein into AA’s and absorbs them into the bloodstream
Compare animal sources of protein to plant sources of protein:
Animal sources (meat, eggs, dairy): considered complete proteins because they contain all 9 essential AA’s in proportion the human body needs. They have high digestibility (approximately 90-99%)
Plant sources (grains, legumes, nuts): generally considered incomplete proteins because they are often low in one or more essential AA’s. Lower digestibility (approximately 70-90%) than animal sources
How does the body use excess AA’s?
The body does NOT store excess amino acids for later protein building
Instead, they are degraded (deamination)
The amino group (nitrogen) is removed, converted to ammonia, and then to urea in the liver for excretion by the kidneys
The remaining carbon skeleton (keto acid) is used for energy or converted into glucose or fat for storage
Define complementary proteins
Two or more incomplete plant proteins that, when eaten together, supply all 9 essential AA’s
They complement each other because the AA limiting in one food is supplied by the other
Rice, which is low in lysine, combined with beans, which are rich in lysine
DO NOT need to be eaten at the same meal
Vegetarianism and Complete Plant Proteins
Lacto-ovoz: excludes meat, poultry, and fish, but includes dairy products (lacto) and eggs (ovo). Most common type of vegetarian diet
Pescetarian: excludes meat and poultry, but includes fish and seafood, as well as dairy and eggs (classified to be semi-vegetarian or flexitarian diet)
Vegan: excludes all animal-derived products, including meat, poultry, fish, eggs, dairy, and often honey
Flexitarian: follows a primarily plant-based diet but occasionally includes small amounts of meat or fish (flexible vegetarian)
What health benefits occur with vegetarian diets?
Associated with reduced risk of several chronic diseases
Obesity
Heart disease (lower cholesterol and blood pressure)
Type 2 diabetes
Some types of cancer
Why do people follow a vegetarian diet?
Health: to reduce the risk of chronic diseases
Environmental/Sustainability: to reduce the consumption of resource-intensive foods
Ethical/Animal Welfare: concern over animal treatment in farming
Religious or Cultural: Dietary restrictions mandated by faith or tradition
List the nutrients that may not be included in a vegetarian diet:
Vitamin B12 (only found in animal products)
Iron (non-heme iron from plants is less absorbed than heme iron from meat)
Zinc (also less bioavailable in plant foods)
Calcium and Vitamin D (especially in vegan plants, without fortified foods)
Omega-3 Fatty acids (EPA and DHA, unless from algae or fortified foods)
What type of plant-based foods are complete proteins (high quality)?
Soybeans (tofu, tempeh, edamame)
Quinoa
Amaranth
Buckwheat
Hempseed
Protein DRI calculation and nitrogen balance
Calculate the DRI for protein for an adult (0.8 g/kg of body weight for adults)
Identify sources of protein in the diet
Protein foods (meat, poultry, fish, eggs, nuts, seeds, legumes/beans)
Dairy (milk, cheese, yogurt)
Grains (whole grains, bread, pasta contain smaller amounts)
Vegetables (legume and certain vegetables contain smaller amounts)
Nitrogen balance:
Composition of nitrogen (protein) intake versus nitrogen excretion in the body
Equilibrium: Nitrogen Intake = Nitrogen loss. Health adults who are maintaining their weight and muscle mass are in this state
Negative: Nitrogen loss > nitrogen intake. This body is breaking down more protein (muscle) that is synthesizing. This occurs during illness, injury, starvation, or when the diet is too low in protein
Positive: Nitrogen intake > nitrogen loss. The body is building more protein than is breaking down. This occurs during periods of growth, pregnancy, and recovery from illness
Describe 3 conditions that must be present for protein synthesis:
Sufficient All-Amino Acid Supply: the availability of all necessary AA’s, especially all 9 essential AA’s, in the amino acid pool
Adequate Energy Intake: sufficient calories must be consumed so that dietary protein is NOT diverted from its synthetic role and used for energy instead
Genetic/Cellular Machinery: presence of the correct DNA template, mRNA, and ribosomes to read the code and assemble the AA chain
Kwashiorkor:
A form of severe protein-energy malnutrition (PEM) resulting primarily from a protein deficiency with relatively adequate, though often marginal, calorie intake.
Characterized by edema (swelling, often of the belly) and a fatty liver
Marasmus:
A form of severe PEM resulting from a severe, long-term deficiency of both calories and protein. It is characterized by severe wasting of muscle and body fat, giving the individual a starved, skeletal appearance
Describe a Mediterranean Diet:
A dietary pattern characterized by high intake of vegetables, fruits, whole grains, legumes, nuts, and olive oil (main source of fat)
Includes moderate amounts of fish and wine, and low consumption of red meat and high-fat dairy products
Benefits: strongly associated with numerous health benefits, including reduced risk of CVD, lower incidence of certain cancers, better blood glucose control, and increased overall longevity
Examples of polyphenols and sources
Group of chemical compounds found in plants that act as powerful antioxidants
Resveratrol: a polyphenol found in the skin of grapes, red wine, peanuts, and some berries
Carotenoids: a class of red, yellow, and orange plant pigments. Examples include beta-carotene (carrots, sweet potatoes), lycopene (tomatoes, watermelon), and Lutein (spinach, kale)
Chapter 14: Global Nutrition: Food Security and Sustainability
What is food security?
State of a household or individual having limited for uncertain access to sufficient, safe, and nutritious food required to maintain an active and healthy life due to a lack of resources
Describe outcomes related to food insecurity
Poor overall dietary quality
Nutrient deficiencies
Higher rates of diet-related chronic diseases
Diabetes, CVD
Poorer academic performance in children
In the U.S. and developed countries, what is the main reason for hunger?
Economic inequality and poverty
Lack of financial resources or access to nutritious food, rather than a lack of food availability overall
Describe poverty and obesity existing together
Individuals with limited resources often rely on less expensive, energy dense foods (high in sugar and unhealthy fats) that are filling but low in essential nutrients.
This poor diet quality contributes to both nutrient deficiencies and weight gain
Increases risk of obesity and related chronic disease
What is SNAP?
Benefitting in a way that it can be used to buy food and non-alcoholic beverages for household consumption, as well as seeds and plants that produce food
They cannot be used to buy alcohol, vitamins, medicines, hot foods, or nonfood items
Describe the WIC program
The Special Supplemental Nutrition Program for Women, Infants, and Children is a federal assistance program that provides highly nutritious supplemental foods, nutrition education (including breastfeeding support), and referrals to health and social services for pregnant women
Which includes: breastfeeding, non-breastfeeding postpartum women, and infants and children up to age 5 who are found to be at nutritional risk
What is the NSLP?
The National School Lunch Program is a federally assisted meal program that operates in public and non-profit private schools and residential childcare institutions
It provides balanced, low cost or free lunches to children each school day, with meals required to meet federal nutrition standards
What is a sustainable food system?
One that delivers food security and nutrition for all in a way that it is profitable throughout (economic)
Has broad benefits for society (social)
Has positive or neutral impact on the environment (environmental) for current and future generations
What is a sustainable diet?
Dietary pattern that promotes optimal health and well-being
Low environmental impact
Accessible, affordable, and culturally acceptable
Provides all necessary nutrients
What food takes the most resources to produce?
Red meat (especially beef) is generally considered the most resource-intensive food to produce
It requires significantly more land, water, and generating the highest greenhouse gas emissions per gram of protein compared to other food groups
Describe GMO and its pros and cons
GMO (Genetically Modified Organism): An organism such as a plant or an animal whose DNA has been altered in a way that does not occur naturally
By adding or deleting a gene
This process is known as genetic engineering
Pros:
Increased crop yield: can lead to higher output by incorporating resistance to pests, diseases, or environmental stressors (like drought)
Reduced Pesticide Use: crops engineered with pest resistance (Bt-corn) require less chemical insecticide spraying
Enhance nutrition: can improve the nutritional value (e.g., golden rice engineered with beta-carotene to increase vitamin A)
Cons:
Potential Allergenicity: concern that transferring genes from one food to another could introduce new allergens
Herbicide Resistance/Use: Widespread use of herbicide-tolerant crops has led to increased use of herbicides (like glyphosate) and development of superweeds
Gene Flow: concerns about engineered genes migrating to conventional crops or wild relatives
Describe the requirements for a food to be labeled 100% organic
The product must contain 100% organically produced ingredients (excluding water and salt) and cannot contain any non-organic ingredients or additives
May be displayed with the USDA organic seal
What percentage of ingredients need to be organic anyway?
95%
ADDITIONAL NOTES:
Glucagon is released when blood glucose levels are low
Type 1 Diabetes requires insulin therapy for management
Type 2 Diabetes is often associated with obesity and insulin resistance
Gestational Diabetes occurs during pregnancy
LADA is the slow progression resembling type 2 but with autoimmune component
Prediabetes is when blood glucose levels are elevated without meeting full criteria for diabetes
Insoluble fiber does not play a role in the absorption of fat-soluble vitamins. Instead, it aids in digestive health by adding bulk to stool and promotes regular bowel movements
Soluble fiber dissolves in water to form a gel-like substance in the digestive tract which slows down digestion and absorption of carbs (leading to MORE glucose being released in the bloodstream)
Cholesterol (lipids like sterol) plays a crucial role in the body by serving as a building block for steroid hormones such as cortisol, testosterone, and estrogen (which are all important for physiological process like metabolism and immune response)
Phospholipids form a bilayer that provides structural integrity and fluidity to cell membranes
Omega-3 Fatty acids are crucial for heart and brain health, and reducing inflammation. They cannot be synthesized by the body, making fish, flaxseeds and walnuts vital for health.
Lipogenesis is the metabolic pathway that converts excess carbs, particularly glucose, into fatty acids for energy storage in adipose tissue (this occurs in the liver and adipose tissue, where enzymes facilitate the conversion of glucose to triglycerides)
Translation is the process where ribosomes read mRNA sequences to synthesize polypeptides, forming the primary structure of proteins
DNA is converted into mRNA during transcription, which ensures that genetic information is accurately conveyed for protein synthesis
Translation involves tRNA molecules bringing specific amino acids to the ribosome, matching them to mRNA codons to build the polypeptide chain
The reason for including a variety of protein in a vegetarian diet is to ensure adequate intake of all essential amino acids
Fats are energy-dense macronutrients (9 calories per gram)
The body metabolizes fats through beta-oxidation, producing acetyl-CoA, which enters the Krebs cycle to generate ATP efficiently
Dietary fiber passes through the upper gastrointestinal tract largely intact and is fermented by gut bacteria in the large intestine. This fermentation process produces short-chain fatty acids and gases, but the fiber itself is not absorbed, emphasizing its role in digestive health rather than as a source of energy.
Oligosaccharides acts as a prebiotic for gut health
Unsaturated fats have one or more double bonds in their carbon chains, which creates kinks, preventing tight packing and solidification
Saturated fats have no double bonds, allowing their carbon chains to pack closely together, resulting in a solid state at room temperature
Bile, produced by the liver and stored in the gallbladder, contains bile salts that break down large globules into smaller droplets. This emulsification process increases the SA of fats, allowing digestive enzymes, like lipase, to effectively break down triglycerides into fatty acids
The glycemic index (GI) categorizes foods based on their impact on blood sugar, influencing dietary choices for better health management
Foods with high GI can cause rapid spikes in blood glucose, potentially leading to insulin resistance and increased risk of diabetes
The role of insulin in blood glucose regulation signals cells to take up glucose from blood
Kwashiorkor is a severe protein-deficiency disease, in which there is swelling of the abdomen due to fluid retention, often seen in children who are weaned from breast milk and do not receive adequate protein intake thereafter
Insulin and glucagon work together to regulate blood glucose levels in which insulin lowers blood glucose while glucagon raises them (to maintain homeostasis)
The body needs to have a sufficient amount of essential amino acids because they are required for synthesizing proteins that perform various functions in the body, including building and repairing tissues, producing hormones and enzymes, and supporting immune function.
Lipid digestion occurs in the small intestine, where bile salts from the liver emulsify fats, enhancing their absorption
Cholesterol is essential for the absorption of fat-soluble vitamins (A, D, E, and K) because it aids in the formation of micelles in the intestines
Micelles facilitate the transport of these vitamins across the intestinal wall into the bloodstream, ensuring that the body can utilize them effectively
Polyunsaturated fats have two or more double bonds in their structure, allowing for more fluidity in their physical form
HDL has the highest protein content and lowest triglyceride content, making it crucial for reverse cholesterol transport, which helps remove excess cholesterol from tissues
Chylomicron is the largest lipoprotein and is formed in the intestines to transport dietary triglycerides, containing the largest percentage of triglycerides
White bread is typically low in fiber due to its refining process that removes the bran and germ from the wheat, whereas bran cereal contains the highest amount of fiber since they are made from the outer layer of grains and are often fortified with additional fiber
The impact on emulsification on the lipid digestion process is that it facilitates the breakdown of large fat globules into smaller droplets, enhancing enzyme action on lipids, which increases the surface area of lipids
Smaller fat droplets formed during emulsification improve the solubility of lipids in the aqueous environment of the digestive tract, aiding absorption
Enriched grains are called enriched grains because vitamins and iron have been added back to the refined grain
What’s least likely to be directly improved by a diet high in soluble fiber is low stomach acid production (hypochlorhydria)
Starch is digestible by human enzymes due to its alpha-bonds, whereas cellulose is indigestible due to its beta-bonds
Hydrogenation is primarily used to convert cis-fatty acids into trans-fatty acids, increasing CVD
The lipoprotein responsible for transporting dietary fat (triglycerides) from the small intestine via the lymphatic system to the rest of the body is the Chylomicron
Amylase is not required for complete digestion and absorption of fat
“fatty acids” refer to a chain of carbons with a carboxyl group at the end
The final products of protein digestion that are absorbed into the intestinal cells are primarily: single amino acids, dipeptides, and tripeptides
Proteins help maintain balance of fluid and electrolytes since proteins attract water into the blood, preventing fluid accumulation in the tissues (edema)
Branched-Chain Amino Acids are the most metabolically active, fueling muscles during intense exercise
Lactase breaking down lactose in the small intestine is an example of a protein acting as an enzyme
The R-group on an amino acid determines its unique characteristics, such as size, polarity, and electrical charge
The Large Intestine, functioning in terms of Protein Metabolism, excretes unabsorbed protein waste
Spotlight B Notes (since the FRQ is over this)
75% of deaths due to CVD worldwide occur in low to middle income families
1/3 of Americans have some form of CVD
There is one death of CVD every 36 seconds, equating to 2300 deaths per day in America
46% of adults in the US have high blood pressure
31% of deaths in the US are from CVD
9% have strokes, heart disease, heart failure
12% of adults in the US have high blood cholesterol
CVD strikes the blood vessels— veins and arteries— as well (although often called “heart disease”)
Long-term narrowing and loss of elasticity in blood vessels are caused by ahterosclerosis
Atherosclerosis is an inflammatory disease characterized by the accumulation of fatty plaque in the walls of arteries and blood vessels that generally develops over the course of several decades
process caused by the presence of LDLs in the blood
as LDLs rise, they infiltrate the artery wall, where the LDLs are likely to become oxidized
“oxidized” in this case means reacting with unstable oxygen-containing molecules
oxidized LDLs cause injury to cells that line the vessel wall, and this initiates an inflammatory process that attracts white blood cells called macrophages inside the arterial lining
Macrophages take up the oxidized LDLs in a rapid and uncontrolled fashion (now called foam cells) which further promotes inflammation
As a result of artery wall inflammation, the lining of blood vessel becomes more prone to develop a waxy accumulation of cholesterol and triglycerides, known as plaque
increases formation of blood clots that blocks blood flow and causes tissue damage and death
LDLs must be located in the subendothelial space of the arterial wall to promote the development of atherosclerosis
space located between the endothelium, the innermost layer of cells lining the blood vessel, and the media, the smooth muscle layer
Blood vessels are tubes that deliver blood with oxygen and nutrients to the tissues of the body
Healthy blood vessels are an open tube with smooth arterial lining and lots of room for blood to flow through
Cholesterol is delivered to the cells via LDLs flowing through healthy blood vessels
Atherosclerosis can contribute to dementia by reducing blood flow to the brain, starving it of oxygen and nutrients, which can lead to brain tissue damage and loss of mental function
A healthy range of triglyceride levels (for adults) is below 150 mg/dL, but lower than 90 mg/dL for children and teens (ages 10-19)
Replacing saturated and trans fats with unsaturated (polyunsaturated fats from fish, nuts, and seeds, and carbs from whole grains) is probably the best thing you can do to lower risk of coronary heart disease and possibly CVD
Learning Objectives:
Identify the primary functions of carbohydrates in food and in the body (Infographic 4.1)
They serve as the body’s main energy source and are classified into monosaccharides, oligosaccharides, and polysaccharides based on their chemical composition. They are synthesized through photosynthesis in plants and regulated through complex metabolic processes in animals, while whole grains, unlike refined grains, retain all their original components.
Describe the classifications of dietary carbohydrates and their chemical composition (Infographic 4.2)
Energy production, energy storage, sparing protein, and preventing ketosis. They are the main energy source for the body, providing fuel for all cells and bodily processes such as breathing. Carbs also play a role in building macromolecules. They are composed of CHO and are chemically defined as a polyhydroxyaldehydes (aldoses) or polyhydroxyketones (ketoses). They are classified into mono, oligo, and polysaccharides. Glucose, an aldohexose, is crucial monosaccharide used as fuel by human cells. Dietary carbs include essential nutrients like sugars, starches, and fiber, which the body converts into glucose for energy. The diverse group of dietary carbs possesses a range of chemical, physical, and physiological properties. Carbs can be categorized as either complex or simple, both providing energy by breaking down into glucose.
Explain how carbohydrates are synthesized in plants and animals (Infographic 4.2 and Infographic 4.4)
In plants, carbohydrates are synthesized through photosynthesis. This process captures energy from the sun and stores it in the carbon-carbon bonds of glucose. Carbohydrate biosynthesis in plants includes the creation of sucrose, starch, and cellulose. Animals synthesize carbohydrates through a process called gluconeogenesis, which creates glucose from non-carbohydrate precursors like amino acids, lactate, and glycerol. This occurs in the liver and kidneys, and is essential when dietary glucose is unavailable. The body also forms more complex carbs, like glycogen, from this synthesized glucose for storage.
Define “whole grain,” and explain what occurs when grain is refined (Infographic 4.5)
It’s considered a “whole grain” when all three of its original parts–the bran, germ, and endosperm– are still present in their natural proportions. Whole grains offer a complete package of health benefits because they retain valuable nutrients. In contrast, when a grain is refined, the bran and germ are removed during the milling process. This refining process results in a finer texture and longer shell life but strips away many valuable nutrients.
Endosperm: most starch is contained in this part of a “whole grain.” So if a seed is planted, it will provide energy to the growing plant embryo, or germ. The endosperm is surrounded by nondigestible fibrous bran coating.
Outline the steps in carbohydrate digestion (Infographic 4.6)
The mechanical and chemical digestion of carbohydrates begins in the mouth. Chewing or mastication, breaks down carbohydrate-containing foods into smaller pieces. Salivary amylase, released from the parotid and submandibular salivary glands, then starts the chemical breakdown of carbohydrates. The digestion process continues as carbohydrates move through the digestive system, with various enzymes playing a role.
Describe how blood glucose is regulated (Infographic 4.7) Identify sources of added sugar in the U.S. diet (Infographic 4.8)
Blood glucose regulation is a complex process involving hormones, neurological mechanisms, hepatic autoregulation. Hormones like insulin play a significant role in controlling blood glucose levels. The liver’s primary function in glucose homeostasis is to store glucose as glycogen. When blood glucose levels are low, the hypothalamus senses this and activates the sympathetic nervous system to help maintain glucose levels. Glucose uptake by non-insulin-dependent tissues, which accounts for 80% of the body’s glucose uptake in physiological situations, is mediated by GLUT 1 to 3 transporters. Glucose uptake by insulin-dependent tissues is facilitated by insulin, which activates GLUT-4 transporters. Conditions such as diabetes mellitus can impair the body’s normal blood glucose regulation.
The leading sources of added sugars in the US diet are sugar-sweetened beverages, followed by desserts and sweet snacks such as ice cream, pastries, and cookies. Teenagers and young adults generally have the highest intakes of added sugars. Regular carbonated soft drinks are a significant contributor of added sugars, especially for individuals across most age and gender groups, with the exception of the very young and the elderly.
Describe the differences between nutritive and nonnutritive alternative sweeteners, and identify examples of each category (Infographic 4.9)
Nutritive sweeteners contain carbohydrates and provide energy. These can be found naturally in foods or added during food processing or by consumers. Examples of nutritive sweeteners include sorbitol and xylitol. Sorbitol has 60% of the sweetness of sucrose, while xylitol is as sweet as sucrose. Other natural sweeteners like fruit juice, honey, molasses, and maple syrup are also considered nutritive. Nonnutritive sweeteners (NNS) provide sweetness with few to no calories or energy. Examples are aspartame, acesulfame, potassium, monk fruit extract (luo han guo), neotame, saccharin, stevia, sucralose, and advantame. Stevioside and rebaudioside A, derived from natural sources, are also recognized as zero-calorie nonnutritive sweeteners.
Identify the types and sources of fiber, and describe the health benefits of fiber (Infographic 4.10 and Infographic 4.11)
Fiber is a type of carb that the body cannot digest. It is exclusively derived from plant-based foods, such as veggies, fruits, whole grains, and legumes, and is a crucial component of a healthy diet. Soluble corn fiber, for instance, can contain a high percentage of soluble dietary fiber. Good sources of insoluble fiber include most plant foods and wheat bran. Fruits like apples and berries, and vegetables such as broccoli, brussel sprouts, cabbage, corn, and dried beans are excellent sources of fiber. Whole-wheat products like chapati, roti, and tortillas are also providing good dietary fiber.
Improved gut health, blood sugar regulation, weight management, and heart health. Fiber can help manage diabetes by controlling blood sugar and preventing fat absorption. A high-fiber diet can also lower LDL, reducing the risk of CVD. Fiber also aids in preventing and mitigating type 2 diabetes and colon cancer. Additionally, fiber contributes to satiety, which can help with weight loss.
Identify sources of carbohydrates in foods, and describe the dietary recommendations for carbohydrate intake (Infographic 4.3 and Infographic 4.12)
Carbohydrates are found in a wide variety of foods, both healthy and unhealthy. Major food sources include vegetables, fruits, whole grains, milk, and milk products. Specific examples include grains, such as bread, beans, popcorn, and pasta; certain vegetables like corn and potatoes; and fruits. Breads, for example, can provide about 15 g of carbs per slice.
Dietary recommendations suggest that 45-65% of daily calories should come from carbohydrates, while the minimum RDA is 130 g/day for adults. If on a 2,000 calorie diet, the average adult should have 225-325 g/day of carbs, as there are 4 calories per gram of a carb. For women, aim up to 25 g/day, and for men, aim up to 38 g/day.
Describe global prevalence trends of diabetes (Infographic A.1)
The global prevalence of diabetes has been steadily increasing, leading to various health complications when poorly controlled. Prediabetes, a precursor to type 2 diabetes, involves elevated blood sugar levels that are not yet diagnostic of diabetes. Maintaining a balanced diet and understanding the role of different fats and proteins are crucial for managing and preventing these conditions.
The global prevalence of diabetes has shown a significant upward trend. The number of individuals living with diabetes increased from 200 million in 1990 to 830 million in 2022. Projections indicate that by 2050, approximately 853 million adults, or 1 in 8, will have diabetes, representing a 46% increase. Between 1990 and 2022, the age-standardized prevalence of diabetes rose in 131 countries for women and 155 countries for men. The global diabetes prevalence in adults increased from 7% to 14% during this period, with low- and middle-income countries experiencing the most significant increases. In 2021, 529 million people of all ages worldwide were living with diabetes, with a global age-standardized prevalence of 6.1%. By 2030, the global prevalence is expected to reach 643 million, with a 150% increase primarily due to type 2 diabetes.
Explain what happens when sensitivity to insulin is impaired (Infographic A.2)
When sensitivity to insulin is impaired, a condition known as insulin resistance occurs, making the hormone less effective in regulating blood sugar. As a result, the body requires more insulin to prompt fat and muscle cells to absorb glucose and to signal the liver to store it. Insulin resistance can lead to elevated blood glucose levels and weight gain. It is linked to a range of abnormalities, including type 2 diabetes, accelerated atherosclerosis, hypertension, and polycystic ovarian syndrome. Impaired insulin sensitivity can also affect muscle glycogen synthesis by reducing intracellular glucose translocation. The heart's ability to adjust to changing energy demands can be compromised due to increased fatty acid delivery and impaired insulin resistance. This condition is associated with various other health issues, such as obesity, metabolic dysfunction-associated fatty liver disease, cardiovascular disease, chronic kidney disease, fatigue, muscle pain, mood swings, and digestive problems.
Explain the difference between diabetes and prediabetes (Infographic A.3)
Prediabetes is a condition where blood sugar levels are higher than normal but not high enough to be diagnosed as type 2 diabetes. It represents an intermediate stage between normal blood glucose and diabetes. Individuals with prediabetes have a higher risk of developing heart disease, stroke, and type 2 diabetes. In many cases, prediabetes can be reversed. Diabetes, on the other hand, involves blood glucose levels that are definitively in the diabetic range. Before developing type 2 diabetes, individuals nearly always experience prediabetes.
List health issues that are common in people with poorly controlled diabetes (Infographic A.4)
Poorly controlled diabetes can lead to severe health complications across various bodily systems. These complications include heart disease, stroke, kidney problems (nephropathy), blindness (retinopathy), and nerve damage (neuropathy). Other issues can involve diabetic foot complications, reduced blood flow, cardiomyopathy, and periodontal disease. Uncontrolled diabetes also increases the risk of life-threatening complications such as diabetic ketoacidosis and hyperosmolar syndrome.
Describe how gestational diabetes differs from type 1 or type 2 diabetes (Infographic A.6)
Gestational diabetes occurs exclusively during pregnancy and is distinct from pre-existing type 1 or type 2 diabetes. Unlike type 1 diabetes, which is an autoimmune disorder preventing the pancreas from producing insulin, gestational diabetes is not caused by a lack of insulin. Instead, during gestational diabetes, the pancreas produces insulin, but the body does not utilize it effectively due to other hormones produced during pregnancy that reduce insulin's effectiveness.
Describe factors that increase risk for type 2 and gestational diabetes and factors that protect against these conditions and how these factors relate to the Dietary Guidelines for Americans recommendations (Infographic A.7)
Risk factors for type 2 diabetes and gestational diabetes can be categorized as non-modifiable and modifiable
Non-modifiable Risk Factors
Age: Increasing age elevates the risk for prediabetes and type 2 diabetes.
Previous Gestational Diabetes: Having had gestational diabetes significantly increases the risk for developing diabetes later.
Modifiable Risk Factors
Weight: Being overweight or obese is a key risk factor for developing diabetes. Losing 5% to 10% of body weight, combined with regular physical activity, can substantially reduce this risk.
Physical Activity: Physical inactivity is a major modifiable risk factor for prediabetes and type 2 diabetes.
Dietary Patterns: Excessive consumption of fats, simple sugars, and high-calorie foods can contribute to insulin resistance, a precursor to type 2 diabetes.
The Dietary Guidelines for Americans (DGA) provide food-based recommendations to promote health and prevent disease for individuals aged two and older. These guidelines are updated periodically, with the 2015-2020 DGA providing guidance on healthy eating. Specific dietary recommendations are reviewed for the primary prevention of chronic diseases, including diabetes.
Identify the four major categories of dietary lipids (Infographic 5.1)
The four major categories of dietary lipids include:
Saturated fats
Trans fats
Monounsaturated fats
Polyunsaturated fats. Additionally, lipids can be broadly classified into triglycerides (fats and oils), sterols (cholesterol), and phospholipids.
Describe the structural differences between saturated, monounsaturated, and polyunsaturated fats (Infographic 5.2)
Saturated fats: These fats have no double bonds between carbon atoms in their fatty acid chains, meaning they are "saturated" with hydrogen atoms. This results in straight chains that can pack tightly together.
Monounsaturated fats (MUFAs): These fatty acids contain one carbon-carbon double bond in their carbon chain. This double bond typically creates an L-shaped bend in the chain.
Polyunsaturated fats (PUFAs): These fatty acids have more than one carbon-carbon double bond in their structure. These multiple double bonds are spread throughout the acyl chain.
Identify the types of foods that are rich in monounsaturated fat, polyunsaturated fat, and saturated fat (Infographic 5.3)
Foods rich in monounsaturated fats include:
Oils: Olive, peanut, canola, safflower, and sunflower oils.
Avocados.
Nuts: Almonds, pecans, and other nuts.
Seeds: Pumpkin and sesame seeds.
Foods high in polyunsaturated fats include:
Fatty fish: Anchovies, herring, mackerel, black cod, salmon, sardines, bluefin tuna, whitefish, striped bass, and cobia.
Vegetable oils: Sunflower, corn, soybean, and flaxseed oils.
Nuts and seeds: Walnuts and flax seeds.
Foods rich in saturated fats include:
Fatty cuts of meat: Beef, lamb, pork, and poultry (especially with skin).
Meat products: Sausages, pies, bacon, salami, chorizo, and pancetta.
Dairy products: Butter, ghee, lard, cream, and cheese (especially hard cheese and full-fat dairy).
Tropical oils: Coconut oil and palm oil.
Baked goods: Cakes and biscuits.
Name two roles of phospholipids in the body (Infographic 5.4)
Major membrane lipids: Phospholipids form the lipid bilayers that are fundamental cellular structures. These bilayers act as barriers, protecting the cell from environmental insults and enabling cellular processes to occur within subcellular compartments.
Regulation of cellular processes: Beyond their barrier function, membrane lipids, particularly phospholipids, play critical roles in regulating various cellular processes, including signal transduction and organelle functions. They also contribute to the diversity of membranes through their acyl chain composition, affecting membrane fluidity and interactions with proteins.
Describe the process of lipid digestion, and explain how emulsification assists in the process (Infographic 5.5)
Lipids, proteins, and complex carbohydrates are primarily broken down into smaller, absorbable units in the small intestine. Emulsification is a key process that aids lipid digestion. It significantly increases the surface area of lipids, making them more accessible to digestive enzymes. This prepares the lipids for subsequent enzymatic breakdown into fatty acids and monoglycerides, which can then be absorbed by the body.
List the four major lipoproteins, and describe their functions in the transport of lipids (Infographic 5.6 and Infographic 5.7)
Triacylglycerols: These transport saturated, monounsaturated, and trans fatty acids, which form a crystal phase.
Phospholipids and Cholesterol Esters: These transport polyunsaturated fatty acids in polar and crystal phases, respectively.
ApoB-48: Transports saturated fatty acids to hepatocytes in the form of chylomicrons.
ApoA-1: Transports polyunsaturated fatty acids directly to cells, including hepatocytes. It also plays a role in high-density lipoproteins (HDL) that transport polyunsaturated fatty acids for structural functions into cells via phospholipid re-esterification.
ApoA-100: Contains two lipid-binding domains and transports saturated fatty acids and their cholesterol esters
Identify the two essential fatty acids, their primary structural difference, and food sources of each in the diet (Infographic 5.8 and Infographic 5.9)
The two essential fatty acids are linoleic acid (LA) and alpha-linolenic acid (ALA). These are considered essential because the human body cannot synthesize them and they must be obtained through diet.
Essential fatty acids, being polyunsaturated fatty acids (PUFAs), have two or more double bonds in their structure. The primary structural difference between linoleic acid (omega-6) and alpha-linolenic acid (omega-3) lies in the position of the first double bond from the methyl end of the fatty acid chain. The human metabolism cannot introduce a double bond between carbon atoms 3 and 4 (for omega-3 fatty acids) or between carbon atoms 6 and 7 (for omega-6 fatty acids) from the methyl end.
Linoleic Acid (LA): Found in various food fats.
Alpha-Linolenic Acid (ALA): Rich sources include nuts, flaxseed, whole grains, legumes, and dark green leafy vegetables. It is also found in plant oils like canola oil and flaxseed oil.
Describe sources of saturated fat in the U.S. diet (Infographic 5.10)
Meat and Dairy Products: These are identified as the leading sources of saturated fat. Specific examples include beef, lamb, pork, and poultry with skin. Full-fat dairy products, butter, and cheese are also significant contributors.
Sandwiches: Many sandwiches, especially those combining meat and cheese like burgers and lunchmeat sandwiches, are a main source.
Desserts and Sweet Snacks: These items contribute to saturated fat intake.
Pizza, Ice Cream, Eggs and Omelets, Burritos and Tacos, and Chicken: These foods collectively account for 25% of total saturated fat in the diet.
Coconut Oil: This is another food high in saturated fat.
Describe the Acceptable Macronutrient Distribution Range for lipids and how to use a Nutrition Facts Panel to evaluate a food’s fat content (Infographic 5.11)
The Acceptable Macronutrient Distribution Range (AMDR) for total fat in adults suggests that 20% to 35% of total daily energy intake should come from fats. For saturated fat, the AMDR recommends less than 10% of total caloric intake.
To evaluate a food's fat content using a Nutrition Facts Panel:
Check Total Fat: The Nutrition Facts label on packaged foods and beverages shows the amount of total fat in grams (g) and its % Daily Value (%DV) per serving.
Saturated and Trans Fat: Total fat, saturated fat, and trans fat are always listed and required on the Nutrition Facts panel. Unsaturated fat may also be present.
Serving Information: Start by checking the serving information, including calories per serving and per container.
Limit Certain Nutrients: The label helps identify nutrients to limit, such as saturated and trans fats.
Summarize the events that lead to the development of atherosclerosis (Infographic B.2)
Accumulation of fats: Fats and cholesterol accumulate in the artery walls.
Plaque formation: This accumulation forms fatty material called plaque, which can block the arteries.
Inflammation: Atherosclerosis is a chronic inflammatory disease involving various cell types, including endothelial, smooth muscle, and immune cells. Bone marrow-derived immune cells play a role in atherogenesis.
Oxidative stress and mitochondrial dysfunction: Cardiolipin remodeling can exacerbate oxidative stress and mitochondrial dysfunction, which are linked to age-related diseases and can contribute to atherosclerosis.
Identify at least five risk factors that affect the initiation or progression of cardiovascular disease (Infographic B.4)
High blood pressure (hypertension).
High cholesterol (dyslipidemia).
Smoking/Tobacco use: Including vaping.
Obesity or overweight: Including unhealthy nutrition.
Diabetes/Hyperglycemia: Type 2 diabetes is a risk factor.Other contributing factors include physical inactivity, family history, age, and excessive alcohol use.
Describe how total cholesterol, low-density lipoproteins, and high-density lipoproteins interact to affect the risk of cardiovascular disease (Infographic B.5)
The interaction of total cholesterol, LDL, and HDL affects the risk of cardiovascular disease (CVD). The search results do not explicitly detail this interaction in the context of Infographic B.5, but they do refer to dietary changes and their effects on serum lipids. Linoleic acid in cholesterol esters was inversely associated with total cholesterol and triglycerides, while eicosapentaenoic acid was inversely associated with triglycerides and positively associated with HDL cholesterol.
A mixed diet rich in monounsaturated fat was as effective as a diet rich in polyunsaturated fat in lowering LDL cholesterol, and both diets lowered HDL cholesterol. Dyslipidemia in insulin resistance includes elevated plasma triglycerides, decreased HDL, and a predominance of small, dense LDL, which are metabolic consequences that can lead to atherosclerosis. The triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio is identified as a biomarker for metabolic syndrome and has been validated as a predictor of cardiovascular disease risk in the general population.
List the cluster of risk factors associated with metabolic syndrome (Infographic B.6)
Abdominal obesity / Central obesity / Increased waist circumference.
High blood pressure / Elevated blood pressure (hypertension).
Impaired fasting glucose / Raised fasting glucose / Insulin resistance.
High triglyceride levels / Increased triglycerides.
Low HDL cholesterol (high-density lipoprotein cholesterol).
Discuss the implications of and recommendations for intake of saturated fatty acids, trans fatty acids, and unsaturated fatty acids in relation to cardiovascular disease (Infographic B.7 and Infographic B.8)
Dietary fatty acid intake significantly influences the risk of cardiovascular disease (CVD)
Saturated Fatty Acids
Implications: High SFA intake may increase the risk of atherosclerosis due to proinflammatory effects. SFAs have been associated with an increased prevalence of CVD.
Recommendations: There is ongoing discussion regarding specific functions of individual SFAs, requiring further exploration to update dietary recommendations. Generally, recommendations suggest decreasing saturated fat intake.
Trans Fatty Acids
Implications: TFAs derived from industrial hydrogenation of oils have a well-demonstrated deleterious effect on CVD.
Recommendations: An international consensus sets a maximum accepted level of 1% of total energy intake for TFAs. The best alternatives to replace them in the diet are currently under discussion.
Unsaturated Fatty Acids (UFA)
Implications: Unsaturated fatty acids include monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). Dietary n-3 polyunsaturated fatty acids (such as marine eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) may reduce CVD risk by decreasing atherosclerosis, inflammation, and thrombotic processes.
Recommendations: Replacing saturated fat with polyunsaturated fat has been recommended.
Summarize the dietary strategies that reduce the risk of heart disease (Infographic B.9)
Limiting Trans Fats: Trans fats increase the risk of heart disease.
Healthy Fats: Opting for healthy fat sources.
Nutrition Optimization: Nutritional optimization is a lifestyle factor that can protect against heart disease.
Mediterranean Diet: A Mediterranean diet supplemented with nuts has been studied for its potential in preventing cardiovascular disease.
Avoiding Ultraprocessed Foods: Associations between ultraprocessed food consumption and cardiovascular disease have been noted.
Discuss at least four functions of protein in the body (Infographic 6.1)
Structural Support and Movement: Proteins provide structural and mechanical support, such as collagen in connective tissues. They also enable movement, with myosin playing a role in muscle contraction.
Enzymatic Activity (Biochemical Catalysts): Proteins catalyze virtually all chemical reactions in the body as enzymes.
Transport and Storage: Proteins transport molecules, such as oxygen (hemoglobin) and other substances like hormones, fatty acids, and vitamins, throughout the body. They also store certain substances.
Immune System Function: Proteins, specifically antibodies, protect the body from foreign pathogens and contribute to immune system strength.
Hormonal Regulation: Some proteins function as hormones, transmitting messages from cell to cell and regulating various bodily processes.
Maintenance of pH and Fluid Balance: Proteins help maintain the body's pH and fluid balance.
Tissue Repair and Building: Protein is essential for repairing and building body tissues
Distinguish between essential and nonessential amino acids (Infographic 6.2)
Essential Amino Acids (EAAs): These are amino acids that the human body cannot produce on its own and therefore must be obtained from food through the diet. There are nine essential amino acids. Examples include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Nonessential Amino Acids (NEAAs): These are amino acids that the human body can synthesize internally, either from other amino acids or from carbon skeletons provided by metabolic intermediates. There are 11 nonessential amino acids. Examples include alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine.
Describe the primary steps in protein synthesis and what determines the shape of a protein (Infographic 6.3 and Infographic 6.4)
Transcription: This is the first stage where genetic information from DNA is used to create messenger RNA (mRNA).
Translation: This is the second stage where the mRNA sequence is decoded to synthesize a protein. This process includes initiation, elongation, and termination phases.Post-translational modifications can also occur after the initial synthesis.
The three-dimensional shape or conformation of a protein is determined by its amino acid sequence.
Primary Structure: The specific sequence of amino acids is the primary determinant.
Noncovalent Interactions: The folded structure is stabilized by various noncovalent forces, including electrostatic forces.The way these amino acids are arranged dictates the protein's folding into its primary, secondary, tertiary, and quaternary structures. The ultimate shape of a protein directly influences its function.
Explain denaturation and how it may alter protein function (Infographic 6.5)
Denaturation is a process where a protein undergoes a structural change, leading to the loss of its unique three-dimensional conformation. This process involves the disruption of the bonds and forces that maintain the protein's secondary, tertiary, and quaternary structures. As a result, the polypeptide chain unfolds.
How it May Alter Protein Function
Denaturation typically results in the loss of a protein's biological properties and function. A denatured protein cannot perform its intended function because its specific shape is crucial for its activity, similar to a machine that cannot operate if its parts are warped. This loss of function can be permanent, especially if covalent modifications or aggregation of denatured proteins occur. Denaturation can be triggered by changes in environmental conditions such as pH or temperature.
Summarize protein digestion and absorption (Infographic 6.6)
Protein digestion and absorption involve breaking down dietary proteins into smaller units that the body can utilize. The digestive system breaks down dietary protein into individual amino acids, as well as di- and tri-peptides, primarily in the stomach and small intestine. These individual amino acids, di-peptides, and tri-peptides are then absorbed and used by cells to construct other proteins within the body.
Identify the Recommended Dietary Allowances and Acceptable Macronutrient Distribution Ranges for protein for adults (page 176)
The Recommended Dietary Allowance (RDA) for protein for adults aged 18 and older is 0.8 g/kg of body weight. This RDA has remained largely consistent for over 70 years and represents the minimum amount of protein required to prevent body nitrogen loss.
The Acceptable Macronutrient Distribution Range (AMDR) for protein for adults suggests that protein should constitute 10% to 35% of total daily calories. The lowest level of protein intake within the AMDR is higher than the RDA. Recent studies, particularly in older individuals, indicate that protein intake exceeding the RDA may offer specific health benefits.
Explain protein turnover and how amino acids may be used for energy (Infographic 6.7 and Infographic 6.8)
Protein turnover is the continuous process of protein synthesis and breakdown within the body. This dynamic process involves various energy-dependent steps associated with protein and amino acid metabolism.
Amino acids can be used for energy, particularly when consumed in surplus.
Oxidation to Glucose: The oxidation of amino acids in the liver can provide nearly two-thirds of the total energy available from their oxidation.
Energy-Yielding Pathways: A greater proportion of dietary amino acids may be directed toward energy-yielding pathways.
Specific Dynamic Action: Protein and amino acids exert the largest specific dynamic action, meaning they cause a significant increase in energy metabolism after ingestion.
Gluconeogenesis: Amino acids can be converted to glucose through gluconeogenesis, contributing to energy production.
Explain the concept of nitrogen balance and what factors are required to retain lean body mass (Infographic 6.9)
Nitrogen balance refers to the net difference between the nitrogen ingested (intake) and the nitrogen excreted (loss) by the body. It reflects whether the body is gaining or losing total body proteins.
Positive Nitrogen Balance: Indicates a net anabolic state, meaning the body is retaining nitrogen and building protein. This is desirable for growth, pregnancy, and muscle building.
Negative Nitrogen Balance: Indicates net protein catabolism, meaning the body is losing nitrogen and breaking down protein.
Identify at least three sources of protein in the U.S. diet and what factors to consider in choosing protein foods (Infographic 6.10 and Infographic 6.11)
Animal-based sources:
Seafood.
Meat and poultry: Lean meats are recommended.
Eggs.
Plant-based sources:
Beans, peas, and lentils.
Nuts and seeds.
Soy products.
Other plant-based proteins include broccoli, chickpeas, edamame, and oats.
Factors to Consider in Choosing Protein Foods
When selecting protein foods, several factors should be considered:
Source: Opt for healthy sources, predominantly plant-based proteins. Regularly include fish and seafood.
Fat Content: Choose lean or low-fat cuts of meat and poultry, and remove poultry skin. Drain fat from meat.
Variety: A variety of protein foods is key to ensure a diverse intake of nutrients.
Non-protein Components: Consider the amount and nature of fat, carbohydrate, fiber, and other nutrients present in the food source.
Dairy Choices: Select low-fat or fat-free dairy options.
Describe protein deficiency diseases, and identify regions in the world where this condition is prevalent (Infographic 6.12)
Kwashiorkor:
Caused by severe protein deficiency, often in children recently weaned.
Characterized by edema (swelling) in the feet and abdomen, poor skin health, growth retardation, low muscle mass, and liver malfunction.
Symptoms include diarrhea, fatigue, peeling skin, and irritability.
Results from inadequate albumin synthesis due to protein deficiency, leading to fluid retention.
Marasmus:
Caused by a deficiency in all macronutrients (protein, carbohydrates, and fats), primarily affecting infants and young children.
Characterized by extreme emaciation, poor skin health, growth retardation, acute fatigue, hunger, and diarrhea.
Children with Marasmus can have body weight up to 80% less than healthy children of the same age.
Marasmic Kwashiorkor:
A combined syndrome exhibiting features of both Kwashiorkor and Marasmus, including variable edema.
Undernutrition severely suppresses the immune system, making death often due to infection.
Regions with High Prevalence of Protein Deficiency
Asia:
Highest global prevalence of protein-energy malnutrition in 2019.
South Asia: Had the highest prevalence within Asia in 2019 and the highest age-standardized incidence rate (ASIR) in 2021. India recorded the highest total incidence and DALYs globally in 2021. Southern India, along with West Africa, shows high prevalence in children and infants.
East Asia and Southeast Asia: Also recorded significant numbers of cases in 2019.
Sub-Saharan Africa:
Consistently faces severe nutritional deficiencies, including protein-energy malnutrition.
Recorded the highest age-standardized death rate (ASDR) and age-standardized DALY rates in 2021.
Countries like Somalia, Niger, Chad, Sierra Leone, and South Sudan show particularly high rates.
Low-Income Regions:
Generally, areas with a low Socio-Demographic Index (SDI) and lower income levels bear a substantial burden of nutritional deficiencies.
Incidence, death, and DALY rates in low-income regions are over 10 times higher than in high-income regions.