Nutrition and health exam 2

Carbohydrates

Provides energy, primary fuel source for the brain, nerve tissues, and red blood cells, promotes healthy gut function. DRI 130g/day, different than AMDR. Carbs are essential nutrients coming from the diet

Monosaccharides

Simple, glucose, fructose, galactose.

Disaccharides

2 monosaccharides together, maltose, sucrose, lactose

Maltose

Starch, glucose + glucose

Sucrose

table sugar, fructose + glucose

Lactose

Sugar in milk and yogurt, galactose + glucose

Lactose Intolerance

Insufficient production of lactose. 65-75% people lose ability to produce lactose, more than 1/3 of the US has this. Food sources can be milk and yogurt. Symptoms include nausea, pain, diarrhea, excessive gas.

High fructose corn syrup

Found in many processed products, inexpensive sweeteners or desserts and sodas. 55% fructose generally, the remainder is glucose. Hormonal response may be different, ghrelin (appetite stimulating hormone) not as suppressed by HFCS, meaning you don’t feel full when eating HFCS. Adverse effect on certain blood lipids (triglycerides) has been confirmed

Non-sugar sweeteners

Aspartame, stevia, sucralose (splenda). World helath organization reccomends against using them to control body weight or reduce risk of noncommunicable disease. Aspartame ‘limited evidence’ for cancer in humans, specifically liver cancer, acceptable level is 40mg/kg body weight. American heart association reccomends replacing sugary & diet drinks with plain, carbonated, or unsweetened water.

Starch

Complex, occasionally-branched glucose chains. Plants store glucose as this, which we then consume. Some easily digested (white flour); others take longer (beans) while some aren’t digested (resistant starch-technically a type of fiber)

Wheat bran

Protective coating

Wheat endosperm

Stores protein

Wheat germ

Grows in fat

Enriched

Adds things that woudl’ve been there if the whole grain was kept.

Glycogen

Doesn’t come from food, highly branched glucose chains (cellulose), body’s storage form of glucose, structure is ideal for rapid release of glucose

Dietary fiber

Cannot break down, an example is cellulose, long strands of glucose. Provides structure to plant cell walls, bonds can’t be broken. Large intestine feeds off this fiber. Reccomended fiber intake is 14 grams per 1000 kcal

Water insoluble fiber

Make up cell walls and tough structures of plants (skin, heavy portion). EX: cellulose, hemicellulose, and lignin. Seem to make development of certain types of cancer less likely. Improves digestive function. Resistant to fermentation > easier to use bathroom

Water soluble fiber

Viscous fibers that can make a gel, occur in various watery compartments of plant tissue. EX: pectins, gums, and mucilages (oat, barely, citrus fruit). Lower blood cholesterol

Strategies for increasing fiber

Choose high fiber cereals and breads, eat legumes, choose fruits and veggies with edible skins or seeds, add fiber gradually and maintain a high fluid intake

Benefits of fiber

Lowers cholesterol through soluble fibers such as fruits, veggies, oat bran, and legumes, it regulates blood glucose levels, encourages healthy bowel function through insoluble fibers which are the bulk of stool such as wheat bran, skins, and seeds, it also helps with weight management

Carbohydrate digestion

Beginning in the mouth, chewing and grinding is occuring and salivary amylase is breaking down starch. In the esophagus, peristalsis is occuring. In the stomach, gastric juices including hydrochloric acid which stops digestion. The stomach also is very acidic so it denatures proteins. The pyloric valve turns food into chyme. In the liver, delivered monosacharrides are converted into glucose when glucagon tells it to and then enters the circulatory system to be used. In the pancreas, enzymes are produced such as sucrase, maltase, lactase, amylase, insulin (glycogen) and glucagon. In the small intestine enzymes are working from the pancreas and in the large intestine insoluble fiber remains

Lipid digestion

In the mouth, lingual lipase is in babies only. In the stomach, fats are delaying gastric emptying which moves slower into the small intestine. In the liver, it is producing bile then giving it to the gallbladder to store along with the CCK hormone. The pancreas produces lipase to work on lipids.

Celiac disease

Not an allergy, but an autoimmune disease. Sensitivity to proteins (gluten) in wheat, rye, and barley. Consumption triggers an immune response and the small intestine villi and microvilli are damaged which affects the absorption of nutrients and causes bloating, gas, and diarrhea and long term consequences. Needs to be diagnosed by a health care professional. Individuals can consume quinoa, rice, soy, and corn but no oats due to cross contamination.

Small intestine digestion

Digestive enzymes from pancreas assist in digestion and absorption. Lactase, maltase, sucrase, and amylase digest starch, starch digests to disaccharides then enzymes split into monosaccharides. Monosaccharides delivered to liver and here, galactose and fructose are converted to glucose. From liver glucose enters the circulatory system to transport cells

Blood glucose regulation

Hormones from the pancreas help control it, insulin opens the door for glucose to enter and signals the body to uptake glucose. Glucagon is a pancreatic hormone that prevents blood sugar from dropping too low by signaling the liver to release stored glucose into the bloodstream (triggers the breakdown of liver glycogen)

Glycemic index (GI)

Ranks CHO foods on how quickly they enter bloodstream and elevate blood sugar. Based on 50 grams of CHO (food) and compared to score of standard food (glucose or white bread). High GI foods are quickly digested and the blood sugar response is fast and high. Low GI foods are slowly digested and blood sugar response is slow and steady. You should choose low GI foods if it is eaten alone, and high GI foods after exercise

Usefulness of fats

Fats in body: Energy stores (80% of energy), muscle fuel, padding (fat pads within bones, protection), insulation (warmth), emergency reserve (body feeds off fat when hungry). Fats in food: Nutrient, energy, transportation, sensory appeal, satiety, texture

Lipids AMDR

20-35%, 9kcal/g

Triglycerides

glycerol, food fat and body fat is stored fat. 3 Fatty acids: saturated, trans, and unsaturated. Unsaturated can be mono or poly. Most common lipid in foods, sources of fat in the US diet are fats and oils; red meats, poultry, fish, and dairy products. Body fat is composed mainly of these, and they consist of glycerol + 3 fatty acids.

Saturated fats

<10% RDA, Single bonds, the #1 food is sandwiches, then it can also come from tropical oils like coconut or palm, and dessert foods due to high levels of butter. Animal products can be saturated if they are full fat dairy like whole milk, cheese, butter, or ice cream. A diet too high in sat. fat can lead to high LDL levels.

Trans fat

Produced by making liquid fats more solid and makes the product more shelf stable (hydrogenating unsaturated fats). Increases LDL cholesterol.

Unsaturated

Can be mono or poly, mono is one degree of unsaturation and poly is multiple degrees of unsaturation

Monounsaturated fats

1 double bond, oleic acid in olive, avocado, peanut, and canola oil. Hydrogens are missing which causes a point of unsaturation.

Polyunsaturated fats

Multiple double bonds, Omega-3 (alpha linolenic) > essential, DHA, EPA. Can come from oils like flaxeed, walnut or canola oil. Omega 3 can come from fatty fishes like salmon, sardines, and tuna. Omega 6 (linoleic) > essential, coming from vegetable oils. DRI established the omegas to possibly reduce total cholesterol

Phospholipids

emulsifiers. EX: lectin in eggs helps oil and water stay together in mayo. glycerol + 2 fatty acids

Sterols (cholesterol)

This produces the cholesterol needed. In food, it can be found in animal products (the actual flesh and what comes from them) and in the body can be found as vitamin D, testosterone, and bile.

Lipoproteins

Endogenous or exogenerous

Endogenous lipoproteins

Inside the body (liver). VLDL or HDL proteins.

Exogenerous lipoproteins

Outside body, comes from diet, goes through small intestine, then into chylomicron and then into the lymphatic system.

VLDL lipoprotein

Endogenous, primarily triglycerides. LDL is “bad cholesterol'“, so the lower level the better. Can be accumulated in circulation and cause problems like clogged arteries (saturated fat). Half triglyceride: carry TG from liver to body tissues and shrink after triglycerides removed and eventually gather cholesterol to form LDL

HDL protein

Remaining cholesterol from cells > liver. High protein content compared to LDL and VDL. Physical activity impacts this and the higher the amount of this the better. Transport cholesterol back to the liver from peripheral cells which reduces buildup of cholesterol.

chylomicrons

Transport lipids from intestinal cells to the liver and other tissues. Highest fat content.

LDL protein

Found in something like blood, bad cholesterol. Derived from VLDLs as cells removed TG from them. Circulate through the body making their contents available to cells of all tissues.

How to limit saturated fats

Choose meats that are loin or round cuts, and prepare them by baking or grilling. Choose low fat dairy products such as 1% or skim milk, reduced fat or low fat cheeses, and avoid tropical oils commonly found in processed foods (coconut, palm, palm kennel)

Protein digestion

Hydrochloric acid denatures proteins in the stomach, and the proteins become strands of amino acids that break down further. In the small intestine, amino acids are absorbed. The enzymes split peptide strands into tripeptides and dipeptides and the enzymes on the surface of the small intestine further break down di and tripeptides into amino acids which are then absorbed into the bloodstream

Amino acids

Building blocks of proteins, containn nitrogen. Each amino acid has a backbone made of an amine group and an acid group, then a side chain.

Nonessential amino acids

Body produces these amino acids

Conditionally essential amino acids

Obtain from diet if insufficient amount produced

Essential amino acids

Body cannot produce them, omega 3 and omega 6

Structure of amino acids

Same basic structure, central carbon with an amino group and an acid group, side group differs from one amino acid to the next. Chains are amino acids linked together, and they form a strand of amino acids, which is part of a protein. There is only one correct sequence of amino acids for each kind of protein, and that is determined by genetics.

Step 1 of building proteins

The first shape of a strand of amino acids is a chain, which can be very long.

Step 2 of building proteins

coiling the strand. The strand of amino acids takes on a springlike shape as the side chains variously attract and repel each other

Step 3 of building proteins

Folding the coil. The coil then folds and flops over on itself to take a functional shape

Step 4 of building proteins

Once coiled and folded, the protein may be functional as is, or it may need to join with other proteins or to add a carbohydrate molecule or a vitamin or mineral, as the iron of the protein hemoglobin demonstrates

Complete protein

High quality proteins. Animal foods such as eggs, milk, meat and also includes soy. These contain all of the essential amino acids (9).

Incomplete protein

Plant foods such as corn

Complementary proteins

Combining two incomplete proteins. EX: legumes and grains

How much protein?

AMDR: 10-35% total calories

RDA: .8g per kg body weight (gxkg) kg=lb/2.2

Dietary guidelines: 1.2-1.6g/kg/day

Some individuals may require more than RDA. More protein alone doesn’t build more muscle. Populations: pregnancy, infants/children, older adults (avoid sarcopenia)

nitrogen balance

Positive: Intake > excretion (times of growth like pregnancy and childhood)

Negative: Excretion > intake (sick)

Equilibrium: intake = excretion (healthy)

Where protein comes from

Protein: 1 ounce of meat, 1 egg, ½ cup beans = 7g of protein

Dairy: 1 cup milk/yogurt, 1 ounce cheese = 8g protein

Grains: ½ cup cooked= 3 ish g of protein

Protein functions

Energy: protein can be used for energy and glucose. Blood clotting, the structure is a component of many body tissues, acid-base and fluid & electrolyte balance: act as buffers or maintain body fluids, hormones: messenger molecules, insulin is a protein. Transportation: carry nutrients, Enzymes: build up and break down all the compounds the body makes and uses- acts as a catalyst, Antibodies: giant proteins formed in response to body invaders

Protein metabolism (feasting)

Cannot store protein as is > excrete amino group > use to make glucose for storage as glycogen or fat for energy

protein metabolism (fasting)

Deplete glycogen stores > draw on triglycerides > draw on proteins from blood then muscles

How much carbohydrate?

AMDR: 45-65% total kcals

RDA: 130g

DRI: grams fiber: 14g per 1000 kcal

Dietary guidelines: added sugar limit: 10g or less/meal

AHA: <6% total kcals

How much fat?

AMDR: 20-35%

Dietary guidelines: saturated fat limit: <10% total kcals

AI for 2 fatty acids: alpha linolenic acid and linoleic acid

Metabolism

How the body obtains and uses energy from food

Anabolic/Anabolism reactions

Requires energy, build up: building of proteins from amino acids.

catabolism

Releases energy, Break down: break down of protein into amino acids

Enzymes

Catalysts of metabolic reactions. EX: lactase, lipase, amylase

Coenzymes

Organic, associate with enzymes, without coenzyme, an enzyme cannot function

Feasting metabolism

Metabolism favors fat formation, regardless whether excess kcal from protein, fat, or carbohydrates. Dietary fat to body fat is most direct and efficient conversion. Carbohydrate and protein have other roles to fufill before conversion to body fat/

Transition from feasting to fasting

Glucose, glycerol, and fatty acids are used then stored. Fasting state draws on these stores: glycogen first then fat are released, preventing ketosis because it is expensive and protein sparing is important. Fasting is in between meals or overnight, starving is more chronic

Factors influencing metabolic rate

age, body composition, height, growth, fever, physiological stress, environmental twmperature, thyroxine (hormone), Fasting/starving/malnutrition (role of popular diets)

Low carb diet

lowers insulin levels (carbs>glucose> glycogen> insulin production), burns stored fat for energy, typically < AMDR for carbs, South beach was a popular low carb diet, Short term: weight loss Long term: low CHO versus other diets = no difference in weight loss in a year

Low carb diet pros and cons

Pros: Short term weight loss, may reduce intake of refined carbohydrates, studies have shown reduction in triglyceride levels.

Cons: May lead to increased saturated fat intake > LDL levels rise leading to heart problems. May also lead to decreased fiber intake

Ketogenic diet

Severe carbohydrate restriction that induces ketosis, high fat (usually saturated fat) intake, moderate protein intake (Atkins is a popular keto diet). Forces the body to switch from using glucose to using fats, The body is in a state of ketosis (producing ketone bodies) due to glycogen depletion. Used to be used to treat epilepsy because the brain converts carbs into glucose which the brain prefers

Ketogenic diet pros and cons

Pros: Sezuire reduction, short term weight loss, water loss from loss of glycogen stores

Cons: constipation (not enough fiber), muscle cramps (water loss), weakness (drawing too much from protein stores), difficulty concentrating (glucose) , rashes, bad breath (ketone bodies), increased risk of kidney stones, increased LDL cholesterol (saturated fat), nutrient deficiencies (carb is primary source of vitamins and minerals), poor bone health, studies have shown loss in muscle mass on this diet

Dietfits

12 month healthy low fat vs healthy low carb diet. Both groups instructed to: maximize vegetable intake, minimize intake of refined fibers, added sugars, and trans fats, focus on whole foods that were minimally processed, nutrient dense, and prepared at home whenever possible. Results: no difference in mean weight loss between groups. LDL increased in healthy low carb group, triglyceride decreased less in healthy low fat group.