NS 1325 Exam 2- TTU

Carbohydrate metabolism

cells can "burn" basic units of carbs

-AKA monosaccharides

Monosaccharides

Simple carbohydrates

-glucose (good)

-galactose (grief)

-fructose (freaking)

Monosaccharides: Glucose

-blood sugar (dextrose)

-fuel source for: muscle cells, RBC's and nervous system cells

Sources: fruits & veggies

Monosaccharides: Galactose

glucose + galactose= lactose

-joins with glucose to make lactose, "milksugar"

-uncommon in foods

-not found free in nature

Monosaccharides: Fructose

-fruit sugar; levulose

-sweetest of all

-naturally occurs in fruit, honey, and some veggies

-converted to glucose in the body

-used to sweeten several foods (high fructose corn syrup)

Disaccharides

-lactose

-maltose

-sucrose

Disaccharide: Lactose

-"milk sugar'

-milk and some products made from milk

Disaccharide: Sucrose

-table sugar

-comprimes glucose and fructose molecules

-naturally occurring in honey, maple syrup, carrots, pineapples

-glucose+fructose

-major source in american diet

Sweeteners

nutritive

alternative

artificial

Artificial Sweetener (Nonnutritive)

-manufactured

-ex: sucralose

-provides 0 kcal/g

Sucralose

-splenda- artificial sweetner

-tiny amount digested

-heat stable

Aspartame

-composed of phenylalanine, aspartic acid, and methanol

- trace amount needed for food, 4 kcal/g

-side effects: headaches, dizziness, seizures, nausea

Starch

-storage form in plants

-GI digests to glucose

-seeds, roots, and tubers

-wheat, rice, oats

- bread and cereals, vegetables

Soluble fibers

-dissolve in water, are viscous and gel-forming

-associated with risk reduction of cardiovascular disease and T2D.

-found in fruits, berries, oats, legumes, and beans

Insoluble fibers

-do not dissolve in water, are nonviscous

-promote regular bowel movements

-found in whole grains, seeds, legumes, fruits, and veggies

Carbohydrate Digestion

-All monosaccharides are converted to glucose by the liver

-glucose circulating in the blood is our primary source of energy

-excess glucose is converted to glycogen by the liver

Blood Glucose Regulation

-hormones control blood glucose levels:

-insulin (after a meal)

-glucagon (haven't eaten yet)

-normal glucose levels are 70 to 110mg/dl

Insulin

-produced by beta cells of the pancreas

-stimulates glucose uptake by cells and the liver

Glucagon

-produced by alpha cells of the pancreas

-stimulates: liver- breaks down glycogen to glucose, and glucongenius

Storing glucose as Glycogen

-takes place in both the liver and muscle tissue

-synthesis of glycogen is stimulated by the pancreatic hormone insulin. Insulin is released in response to elevated blood glucose

When returning glucose to the blood...

muscle tissue does not respond to glucagon

ketone bodies

chemicals that result from incomplete metabolism of fat

-alternative energy source

-low carb diet

-sufficient energy from CHO prevents ketones, aka protein sparing

low dietary carbohydrate ketosis:

-process of fat breakdown during fasting states

-results in ketone bodies

Fiber

is not an essential nutrient

-you can live w/o it but may live better with it

dietary sources of carbohydrates

fiber rich foods

unrefined starches

whole grains

Type 1 diabetes

-insulin dependent, do not produce enough insulin

-causes high blood sugar

-typical onset is 10-14 years

-may be an autoimmune disease: genetic susceptibility, evironmental factors, viral intestinal infections

-if poorly controlled: increased appetite with weight loss, breath that smells like fruit, fatigue, and confusion

Type 2 Diabetes

-insulin resistant, less responsive to insulin

-cause is unclear but increased risk if: inactive, overweight, genetics

Hypoclycemia

-blood glucose is low, less than 70 mg/dl

-in response, body secretes epinephrine: which can cause restlessness, shaking, confusion, sweating

reactive hypoglycemia

too much insulin produced after a meal

-occurs 2-4 hours after eating

-shakiness, sweating, anxiety

fasting hypoglycemia

too much insulin produced even when patient hasn't eaten

People who are lactose intolerant...

-may need to find alternate sources of calcium than dairy foods (try soy milk)

-sometimes yogurt is tolerated

-eat dairy with fat such as cheese and yogurt in moderation

Lipids role

-producing and storing energy

-cell membrane maintenance

-hormone production

-insulation, cushioning

Type of lipids

-triglycerides

-sterols

-phospholipids

Functions of Triglycerides (TGs)

energy- long hyrdocarbon chains of fa's are efficient for energy storage

heat production- fa's are oxidized to provide instant heat

insulation

buoyancy

TG: Numbering and Shape

-carbons can be numbered

carboxyl end (COOH)

methyl end (CH3)

Shape: the hydrogen atoms at the unsaturated part can arranged in different positions

-cis: same side of the carbon chain

-trans: opposite side of the chain

Saturation

-saturated fatty acids- hydrogen atoms surrounding every carbon in the chain, no double bonds

-monounsaturated fatty acids- lack hydrogen atoms in one part, one double bond

-polyunsaturated fatty acids- lacy hydrogen atoms in multiple sites, more than one double bond

Saturated Fatty Acids (SFA) sources

-in large amounts in animal fats

-solid at room temperature

-vegetable oils- palm and coconut oil (richest source)

Monounsaturated Fatty Acids (MUFA) sources

-canola oil, olive oil, peanuts, peanut oil

-nuts

-avocado

Essential Fatty Acids (EFAs)

-type of PUFA

-cannot be synthesized in human cells, must come from food

-linoleic acid (omega 6 FA)- found in vegetable and nut oils, arachidonic acid

-alpha-linolenic acid (omega 3 FA)- found in vegetables, fish, and fish oils, eicosapentaenoic acid, docosahexaenoic acid

Omega 3 fatty acid

sources- primarily fish oils...canola oils... flaxseed and nuts

-recommend of 2 servings of fish a week

Trans Fatty Acids

processed foods: crackers, cakes, and other baked goods

-straight unsaturated fatty acids

Hydrogenation

-adding H atoms to unsaturated fatty acids

- converts liquid oils into a more solid form

- used to create margarine from plant oil

- creates trans fatty acids and SFAs

- increased risk of CVD

Dietary Cholestrol

-found only in animal products

*plants do not contain cholesterol

-recommended limit to 200-300 mg/day

Sources: egg yolk, meat, fish and shell fish, poultry, dairy products

Phospholipids

-soluble in water

-Choline: vitamin like compound in lecithin (major phospholipid in food: egg yolks, liver, wheat germ, peanut butter, soybeans)

Function of Fat

1. energy

-9 kcal/gram

-major energy used during rest

- energy storage

2. carrier for fat soluble vitamins

3. Fat is essential to many body functions

- cell membrane structure, nerve cells transmission, protection of organs

4. provides flavor and texture to foods

5. makes us feel satiated

Lipid Digestion

-majority of it occurs in the small intestine

-bile contains bile salts that emulsify the lipids

-fats are not digested and absorbed easily

in the small intestine - absorptive cells remove monoglycerides, FAs, gylcerol, and cholesterol.... assemble triglycerides... form chylommicrons

Chylomicrons

-assembled in the small intestine

- travel through the lymphatic system via lacteal

- transferred to the blood stream

Atherosclerosis

-plaque builds up inside arterial walls

-clot formations

-can cause heart attack

-related diseases: stroke (brain attack, clot blocks artery in the brain)

Lipoproteins

Transportation of cholesterol and triglycerides

-types from biggest to smallest

chylomicrons (CM)

very low density lipoproteins (VLDL)

low density lipoproteins (LDL)- oxidized LDL cholesterol

high density lipoproteins (HDL)

Recommendations for Fat and Cholesterol Intakes:

AMDR: 20-30% of total calories

AHA: less than 25-35%

Dietary Guidelines

- less than 10% from SFAs

-trans fat low as possible

-less than 300 mg/day cholesterol

Increasing EFAs

recommendations for omega 6:

-5-10% of total energy intake

-corn oil, seeds, and nuts

recommendations for omega 3

-1% of total energy intake

-flaxseeds, soybeans, and walnuts

-fatty fish

Foods that lower cholesterol...

lean cuts of meat

moist cooking methods

steam meats and veggies

skim milk or 1% milk

less salad dressing

low fat foods

high fruit and veggie diet

fatty fish

cholesterol

Statins taken for health issues interfere with liver's metabolism of...

Proteins

Function:

-make, maintain and repair cells and body tissue

-build structures

-make certain hormones- insulin and glucagon (chemical messengers produced by glands and secreted into the blood to target a tissue)

-functions as enzymes

-provide energy

-maintenance of fluid and electrolyte balance

What are proteins?

-large complex molecules composed of amino acids

-found as essential components of all living cells

-contain C, H, O and N

- primary source of nitrogen in our diets

Amino Acids- AA

basic building blocks

- 20 different amino acids

structure includes the basic backbone and a side chain

essential and nonessential amino acids

essential: 9

cannot be produced by our bodies, must come from food

nonessential: 11

can be made by our bodies, still the diet must supply enough nitrogen to support synthesis on non essential AA

Branch chain amino acids (BCAAs)

Valine

Leucine

Isoleucine

- if unable to break down bcaa's you can get maple syrup urine disease, can lead to seizures, comas, and death

How are proteins made?

Amino Acids are joined to each other by peptide bonds

Protein Digestion

-begins in the stomach

- HCl breaks down protein structure and activates pepsin

- pepsin: is an enzyme that breaks down proteins into short polypeptides and amino acids

-digestion continues in the small intestine

The Central Dogma

DNA undergoes transcription into mRNA and then it is translated into protein

Sickle Cell Anemia

causes RBC to have a sickle shape (hard and sticky)

-end up blocking the vessels and depriving the nearby tissue of oxygen

Protein Needs

RDA: 0.8 g/kg of body weight

example: weight is 200lbs.. divide by 2.2 to get weight in kg...90.9 kg... multiply by 0.8g/kg= 72.72 g of protein RDA

Protein Intake

American Consumption: 80g protein/ day if 220lbs

-15% of energy intake

-AMDR 10-35% of calories

Protein in Foods

meat

fish

legumes- soybeans

tree nuts

eggs

some dairy

Incomplete and complete protein

incomplete: does not contain all essential AA's

- considered low quality protein

complete: contains sufficient amounts of all 9 essential AA's

- considered high quality protein: animal and soy protein

-highly digestible

*limiting protein- essential aa's found in dietary protein in the least amount relative to the amounts needed

complementary proteins

-2+ foods that together supply all 9 essential AA's for a complete protein

Vegetarianism

Semivegetarian- generally avoids meat

Lactovegetarian- consumes milk and milk products

Ovovegetarian- eggs

Lactoovovegetarian- milk and eggs

vegan- eats only plant products

Dangers of vegetarianism

-low energy

-lack high quality proteins

-lack omega-3 fatty acids

-lack vitamin b-12 and riboflavin

-lack minerals zinc, iron, and calcium

Food allergy

-immune response to one or more harmless substances in food

-allergen is typically a protein

-onset of symptoms within minutes

What is gluten?

group of related proteins in wheat, barley, and rye

-foods to avoid: barley, rye, wheat, triticale

-foods safe to eat: arrowroot, buckwheat, corn, flax, oats, nuts, rice, soy, quinoa

Celiac Disease

autoimmune response in the small intestine to gluten

-chronic disease

-villi are destroyed

-no cure

-make substitutions of food such as cornmeal instead of flour

During carbohydrate digestion...

the pancreas releases pancreatic amylase into the small intestine that continues the breakdown of starches into maltose molecules

Protein assumption

not recommended for normal, healthy adults to have excess protein intake.. causes: urinary loss of calcium (dehydration), liver and kidney issues