Nutrition

nutrients

Substances essential for health that the body cannot make or makes in quantities too small to support life

essential nutrients

Has a specific biological function

Absence from the diet leads to decline in biological function

Adding missing substance back to the diet before permanent damage occurs restores normal biological function

macronutrients

Needed in large amounts

* Carbohydrates
* Lipids
* Proteins
* Water

micronutrients

Needed in small amounts

* Vitamins
* Minerals

undernutrition

* Nutrient intake does not meet needs
* Nutrient stores are depleted

over nutrition

* Consumption of more nutrients than the body needs
* Most common type in industrialized nations: excess energy intake

Where to look for credible sources of nutrition information

FDA, Food and Nutrition Board

Food Desert

* Geographic areas where fresh, affordable, healthy foods cannot be purchased easily

Qualities of Healthy Diet

Nutrient dense

foods high in nutrients but relatively low in calories

Energy dense

foods high in calories but lacking nutrients

American Diet

* 16% of energy intake as proteins
* 50% as carbohydrates
* 33% as fats
* Too many calories are being consumed
* Too much protein from animal sources; too little from plants
* Too many carbohydrates from simple sugars; too few from complex carbohydrates
* Too much fat from animal sources; too little from plants

Food label

Health consequences of malnutrition and food insecurity for children and adults

* Report more asthma, stomachaches, headaches, and colds
* May not grow normally
* Are more likely to have behavioral problems in school and lower educational achievement
* Report higher rates of depression and suicidal symptoms and increased levels of psychological distress

Food security vs food insecurity

“access by all people at all times to enough food for an active, healthy life”

vs

* at fewer servings of nutrient-dense foods and consume poorer-quality diets
* linked with obesity, as individuals are more likely to overeat when food is more plentiful and purchase mostly inexpensive, high-energy-density foods

Major U.S. government programs designed to increase food security

* Supplemental Nutrition Assistance Program (SNAP)
* Special Supplemental Nutrition Program for Women, Infants, and Children (WIC)
* National School Lunch Program
* School Breakfast Program
* Child and Adult Care Food Program
* Programs for seniors: Meals on Wheels, Senior Farmers’ Market Nutrition Programs, congregate meal programs
* Food distribution programs: food banks and pantries

Factors of food insecurity

* Skipping meals
* Reducing the size of meals
* Not eating when hungry
* poverty guidelines:
* $25,750 annually for a family of 4

organic foods vs conventional foods

* Biological pest management
* Composting
* Manure applications
* Crop rotation to maintain healthy soil, water, crops, and animals

vs

* Synthetic pesticides
* Fertilizers
* Hormones
* Antibiotics
* Sewage sludge
* Genetic engineering
* Irradiation

Pros of GMO

1. GMOs improve the quality of the food that is grown. Genetically modified foods can be engineered to have a longer shelf life, which can limit food waste.


2. GMOs are easier for farmers to grow. \n Genetically modified foods can also be engineered to grow in specific, sometimes challenging environments.


3.  It increases the food yields that we can produce on existing croplands. \n By the year 2050, the human population on our planet is expected to top 10 billion people.
4. GMOs can be shipped to remote areas of the planet. Many non-GMO crops spoil when attempted to ship to remote areas of the world.
5. Herbicide use on GMO crops is lower than other crops. Many GMO crops are already resistant and don’t need extra herbicide.
6. The FDA requires GMO foods to meet the same requirements as all other foods.

Mechanical digestion

Begins in the mouth

– Teeth masticate \n – Food bolus

• Esophagus – Peristalsis

• Stomach

* –  Smooth muscle contractions
* –  Storage
* –  Chyme

• Smallintestine – Segmentation

Chemical digestion

• Enzymes

• Hormones

• Mouth

– Salivary glands

• Saliva

• Amylase

• Lipase

• Stomach

– Gastric juices

• Acid

• Proteases

• Lipase

• Liver \n – Bile is synthesized

• Small Intestine

– CCK

• Gallbladder \n – Bile is released

• Pancreas

– Pancreatic juices

• Bicarbonate

• Amylase \n • Proteases

• Lipase

Importance of bacteria in the gut

* Probiotics \n – Beneficial bacteria
* Prebiotics
* –  Food for the beneficial bacteria
* –  Chicory, whole-grain rye, oats, wheat , barley, leeks, onions, and garlic

digestive disorders

* Diverticulitis
* Gastritis
* Ulcers
* Acid Reflex
* Gastroesophageal reflux disease (GERD)
* Irritable bowel syndrome (IBS)


* Inflammatory bowel disease (IBD)
* Ulcerative colitis
* Crohn’s disease
* Gallstones
* Celiac Disease
* \

Calories per nutrient

Carbs: 4 kcal/g

Lipids: 9 kcal/g

Protein: 4 kcal/g

simple carbs

complex carbs

Starch, Fiber, Glycogen

storage form of carbs

stored as glucose, liver break down to give glucose to blood, muscles break down to do work

Lactose intolerence

Low lactase activity

• Lactose maldigestion

– Diarrhea

– Gas, cramps, abdominal pain

• Treatment

– Decrease dairy intake

– Lactase pills \n – Calcium-rich foods

components of whole grain

endosperm, bran, germ

types of grains

• Wholegrains

– Contain the endosperm, germ, and bran in original proportions

• Refined grains (white grain)

– Stripped of the germ and bran, leaving only the endosperm

• Enrichedgrains

– Some nutrients lost in processing are added back

carb digestion

• Mouth \n – Amylase

– Breaks starch into smaller links of glucose

• Small intestine

– Amylase \n – Continue digestion of starch into maltose and glucose

• Small intestinal cells

• Maltase

– Hydrolyzes maltose to produce two glucose monosaccharides

• Sucrase

– Hydrolyzes sucrose to produce one glucose and one fructose monosaccharide

• Lactase

– Hydrolyzes lactose to produce one glucose and one galactose monosaccharide

blood glucose levels

* Normal fasting blood glucose levels: 70-100 mg/dl
* Liver determines amount of glucose that is needed to enter the bloodstream after a meal
* Pancreas secretes:

• Insulin

• Glucagon

diabetes

* Above 126 mg/dl is classified as diabetes (hyperglycemic)

• Hunger \n • Thirst \n • Frequent urination

• Weight loss

added sugars

* Refined sugars are added to processed foods

– Add flavor

– Increase energy density

– Decrease nutrient density

– Contribute to obesity

nutritive sweeteners

– Provide calories, but fewer than sugars

– Have reduced absorption \n – Include sugar alcohols (polyols)

non-nutritive sweeteners

– Calorie free

types of fiber

* • Insoluble fiber
* – Softens stool and decreases constipation
* – Decreases hemorrhoids and diverticular disease
* • Soluble fiber
* – Slows stomach emptying
* –  Slows digestion and absorption
* –  Reduces the risk of coronary artery disease


* • Dietary fibers
* • Nondigestible carbohydrates
* • These fibers pass through the small intestine into the large intestine, where they may be partially or completely fermented by gut bacteria.
* • Functional fiber
* • Isolated or purified carbohydrates that are nondigestible
* • Absorbed in the small intestine, and have beneficial physiological effects in humans

categories of lipids

Fatty acids, triglycerides, sterols, phospholipids

types of fatty acids

Saturated, Monounsaturated, polyunsaturated, cis and trans

structure of triglyceride

* a three-carbon glycerol molecule with three fatty acids attached

structure of phospholipids

* a three-carbon glycerol molecule with two fatty acids and a phosphate group on the third carbon

lipid digestion and absorption

types of lipoproteins

* chylomicrons
* lipoproteins made in intestinal cells or enterocytes
* transport fat from the intestine to the body
* very low-density lipoprotein (VLDL)
* made in the liver
* transports fat from the liver to the body
* low-density lipoprotein (LDL)
* made in the liver
* transports cholesterol from the liver to the cells of the body
* "bad" cholesterol
* high-density lipoprotein (HDL)
* collects fat and cholesterol from the body to transport back to the liver (“reverse cholesterol transporter”)
* "good cholesterol"

essential fatty acids

* omega-3 fatty acids
* linolenic acid
* food sources: cold-water fish, flaxseed oil 
* omega-6 fatty acids
* linoleic acid
* food sources: walnuts, plant oils 

trans fat

* behave like saturated fats and raise LDL cholesterol
* increase risk of heart disease

roles of protein

protein structure

* Building blocks of protein are amino acids

protein denaturation

* Caused by heat, light, change in pH, alcohol, or motion
* Affects the protein’s ability to function

protein folding

* After translation, amino acid chains fold into a particular shape
* The shape determines the protein’s function
* A protein must be folded correctly to function

protein digestion

* Mouth
* Mechanical digestion
* Stomach
* Acidic juices
* Pepsin
* Small intestine
* Pancreatic proteases
* Absorption of amino acids

protein turnover

nitrogen balance

* Nitrogen can be used as a measure of protein
* Nin − Nout
* Nin
* Protein intake
* Nout
* Urine and feces
* Sweat and other secretions
* Skin, hair, and nails

Protein AMDR and RDAs for different groups of people

* Adults 50 to 65 years of age
* 0.7 to 0.8 g/kg of body weight/day is beneficial
* Adults older than 65 years of age
* 1.2 g/kg of body weight/day is beneficial

When should we consume protein? How much?

* 0.3-0.5g/kg/meal

Protein’s effect on fat mass

can cause loss fat mass

Diseases associated with Protein deficiency

* Edema (swollen belly)
* Proteins hold water and salt in the blood vessels
* Marasmas
* Protein energy malnutrition (PEM)
* Starvation
* “Skin and bones” appearance

processes of Transcription and Translation

Cons of GMOs

1. They may contribute to an increase in food-related allergies. Information from the CDC shows that food allergies in children have increased from 3.4% to 5.1% in the last decade.


2. Genetic engineering can trigger allergies from alternative foods. \n GMOs that contained proteins from Brazil nuts were found to trigger an allergic reaction in people who are allergic to them.


3. GMOs may contribute to antibiotic resistance. \n GMOs are often incorporated with antibiotic-resistant genes in order to strengthen the crops that will grow.
4. One research paper connects GMOs to cancer formation. A paper that was first published in 2013 linked the herbicide that is found in Roundup-tolerant crops to cancer development in rats. –since retracted.
5. Just 6 companies control almost the entire GMO seed market and 70% of the global pesticide market. Much of the negative energy which surrounds GMOs tends to involve Monsanto.
6. Herbicide resistance happens naturally without the need for genetic engineering. There are currently 64 different types of weeds which have been proven to be resistant to atrazine.
7. Independent research is not allowed with GMO seeds from half of today’s controlling organizations. User agreements with half of today’s leading GMO seed producers prohibit the use of independent research on the final product.