NUTR 2100- UGA Exam 2

Functions of Carbohydrates

ideal nutrients to meet your bodies energy needs, feed the brain and nervous system, and fuel physical activity

what is the difference between indigestible and digestible carbohydrates

indigestible carbohydrates, like fiber, wont get digested but provide other health benefits

digestible carbohydrates provide energy for the body

simple carbs

sugars

complex carbs

starch and fiber

how does the sun affect carbohydrates?

carbs contain the suns radiant energy due to it fueling the process of photosynthesis in plants. Light is converted into chemical energy in the form of glucose. Plants don't use all the energy stored in their sugars, so it remains available for use by animals and humans who consume the plants

monosaccharide and examples

single molecule sugars that can be directly absorbed into the blood

glucose

fructose

galactose

glucose

the most important monosaccharide in the human body and is absorbed directly into the blood

fructose

rearrangement of glucose molecules. it is taken in mostly via foods and drinks wiht added sugars

galactose

same number/atoms as glucose and fructose, but in another arrangement. when bound with glucose, it forms lactose, which is the sugar found in milk

disaccharides and expamples

double sugars that must be broken down into monomers to be digested

lactose

maltose

and sucrose

sucrose and which monomers comprise it

table sugar- made from refining juice from sugar cane/beets

glucose linked to fructose makes sucrose

lactose and which monomers comprise it

milk sugars

glucose linked to galactose makes lactose

maltose

malt sugar-appears wherever starch is being broken down in geminating seeds and digestion of starch in the body

glucose linked to glucose makes maltose

function of glucose

primary energy source

function of fructose

used for fuel by the liver or the building blocks of fat

function of galactose

converted to glucose by the liver

polysaccharides and examples

long strands of glucose units

starch

glycogen

fiber

starch

a plants storage form of glucose

- for its own needs

- stores energy in its seeds for the next generation

- insoluble

glycogen

- animal storage form of glucose

- chains are longer and more highly branched than starch

- nearly undetectable in meats because it breaks down rapidly when the animal is slaughtered

fiber

glucose bound in a distinct patter that is different from that of starch

pass through the human digestive tract mostly intact

its function in a plant is to support the structure of leaves, stens and seeds while additionally retaining water and protexts the seeds from drying out

do proteins provide energy advantages over carbohydrates?

no

what macro nutrient is used as fuel for the CNS?

carbohydrates (glucose)

what functions does glucose have in the body

energy

alter shape and function of certain proteins

maintains consistency of mucus

binds to the outside of membranes, which it facilitates cell to cell communication and normal nerve functions

guidelines for carb intake

increase intakes of fiber rich whole foods

reduce their intakes of foods high in refined grains and added sugars

reccomendations for total carb and added sugar in ercentages of total calories

- 45-65% of daily cals be from carbs

soluble fiber

readily dissolves in water

adds viscosity to jelly and salad dressing

best known for modulating blood glucose levels, lowering blood cholesterol levels, and promoting colon health

many kinds are readily fermented by colonic bacteria, supporting immunity and reducing inflammation

insoluble fibers

do not dissolve in water

not viscous and do not form gels

resists fermentation

retain shape and texture, even after hours of cooking

health benefits of fiber rich food

reduced risk of heart disease and stroke

reduced risk of diabetes

- soluble fibers help reg blood glucose after a carb rich meal

improves digestive tract health

- support the population of beneficial bacteria

-give weight to fecal matter, which eases constipation

-insoluble fibers promote colon lining to secrete mucus and water that enlage and soften stools

reduced the risk of hemorrhoids

reduce risk of colon and rectal cancer

helps promote a healthy body weight due to an increased feeling of fullness

hemmorrhoids

swollen, hardened veins in the rectum, usually caused by pressure from constipation

appendicitis and how fiber affects it

inflammation and/or infection of the appendix

feces can block or infect appendix, which causes it to swell and possibly burst

diverticula

sacs or pouches that balloon out of the intestinal wall, caused by weakening of the muscle layers that encase the intestine

can tear, casueing inflammation and infection

can lead to abscess, blockage, or peritonitis

DRI recommendations for fiber

25g/day for women

38g/day for men

fiber as a binding agent

act as a chelating agent: molecules that attract or bind with other molecules and are therefore useful in either preventing or promoting movement of substances from place to place

can bind to important minerals

carries minerals out of the body

can have positive uses: treating lead poisoning

why did people start enriching refined grains

in turning to refined grains, many people suffered deficiencies of nutrients previously found in whole grains

what nutrients were added in 1942 and 1996 in the US enrichment act

1942: iron, thiamin, riboflavin, and niacin

1996: folate

health effects of whole grains

three daily servings of whole grains often have healthier body weights and less body fat that others

- fills stomach

- slow digesting

- promote longger lasting feelings of fullness

- lower risk of heart disease, type 2 diabetes, cancer, and health

what is the path of carbs to glucose (i hate you glycolysis)

- saliva contains enzymes that split starch into shorter units

- salivary enzyme (protein) is deactivated by the stomach acid

- digestion cesases in the stomach but resumes in the small intestine due to enzyme provided by the pancreas

resistant starch definition

the fraction of starch in a food that is digested slowly or not at all, by human enzymes, technically a fiber

what are fibers fermented by

colon bacteria

what is lactose intolerance

impaired ability to digest lactose due to reduced amounts of the enzyme lactase

what percentage of people lose the ability to produce lactase in adulthood

65-75%

symptoms of lactose intolerance and what is it caused by

nausea, pain, diarrhea, and gas

caused by intestinal bacteria utilizing undigested lactose

endosperm

soft white inside part of the kernal of wheat that has starch and protein

germ

part of wheat that grows into a new plant, contains concentrated food ot support new life

Husk

par tof wheat that is the dry outermost layer that is inedible to humans, but can be digested by many animals

bran

protective coating of wheat that is similar in function to the shell of a nut. Rich in nutrients and fiber

uses of glucose

basic carb used for energy

the body handles glucose judiciously and maintains internal store to be used when needed and tightly controls blood glucose concentration to ensure steady supply

brain use of glucose

the brain stores in tiny fraction of the total amount of glucose as an emergency reserve to fuel the brain for an hour or two in severe glucose deprivation

splitting of glucose for energy

glucose is split for energy in the body

it is first broken in half to release energy (glycolysis) and can be reassembled (gluconeogenesis)

used as raw material to make certain amino acids or fat

glucose and fat relationship

glucose can be converted into fat, but cannot be converted into glucose to feed the brain adequately

what happens when the body faces a severe carb shortage

it must turn to protein to make some glucose, deriving protein from its own critical functions. protein is taken from blood, organ, or muscle proteins because there are no protein store of this purpose

ketosis

an undesirably high cncentration of ketone bodies, such as acetone, in the blood or urine caused by too little carbs flowing to the brain, so the body turns fat into ketone bodies for energy

side affects of ketosis

can disrupt acid-base balance in blood, a rare but life threatening situation. overtime, ketosis can cause deficiencies of vitamins and minerals, loss of bone minerals, elevated blood cholesterol

DRI values of carbs

130 g of carbs per day

much more is recommended to maintain health and glycogen stores

how is glucose regulated in the body

Siphoning off excess blood glucose

- into the liver and muscles for storage as glycogen or into the adipose tissue for stage as body fat

Insulin

stimulates glucose storage as glycogen

glucagon

helps release glucose from storage

how does the pancreas regulate blood glucose

after a meal, as blood glucose rises, the pancreas releases insulin which signals to the body tissues to remove glucose from the blood. this stimulates glucose uptake by muscle and adipose which increases glucose uptake and glycogen production by the liver

when blood glucose starts to fall too low, the pancreas release glucagon which triggers the breakdown of liver glycogen to single glucose molecules. enzymes in liver cells attack the many branches of the glycogen molecule

two ways to handle excess glucose

body tissue burn more glycose

- fat is left to circulate and be stored

liver breaks down glucose into smaller molecules and assembles them into fat

- newly made fat travels in the blood to the adipose tissues for storage

- fat can also build up in the liver so monitor carb intake because it can lead to fatty liver

glycemic index

a method of classifying foods according to their potential for raising blood glucose

type 1 diabetes

Diabetes of a form that usually develops during childhood or adolescence and is characterized by a severe deficiency of insulin, leading to high blood glucose levels.

type 2 diabetes

Diabetes of a form that develops especially in adults and most often obese individuals and that is characterized by high blood glucose resulting from impaired insulin utilization coupled with the body's inability to compensate with increased insulin production.

Hypoglycemia

abnormally low level of sugar in the blood

symptoms

- weakness, irreg heartbeats, sweating, anxiety, hunger, trembling, and rarely, seizure and loss of conciousness

causes

- poorly managed diabetes, too much insulin, too much strenuous physical activity, inadequate food intake, and illness

treatments

- treat wiht fruit juice, hard candies, or glucose tablets

do added sugars cause diabetes

added sugars may raise blood pressure, which plays a critical role in cardiovascular health. some important metabolic links exist among added sugars, obesity and chronic diseases

3 main classes of lipids

triglycerides (95%)

phospholipids such as lecithin

sterols such as cholesterol

how is fat physiologically active

secretes homrones that regulate appetite and also secretes homrones that regulate other body functions

efficiency of fat sores

glycogen isnt as efficient for the major form of stored energy due to it holding water, so adipose tissue is more efficient because it can pack much tighter together

additionally, gram for gram, fat provides twice the energy of carbs or protein

How are fats useful in food

concentrated energy source

- for a person engaging in strenuous activity, fat-rich foods provide max energy in the smallest package

- for a person at rest, htose same high fat foods deliver many unneded cals in only a few bites

aide in nutrient absorption and transport

- soem essential nutrients are lipid in nature and therefore soluble in fat

- fat is necessary for their absorbtion

-ex: vitamin a,d,e, and k along wiht some phytochemicals

sensory and satiety

- fat carries wiht it many dissolved compounds with enticing aromas and flavors

- gives crispness to fried foods and tenderness to meats and baked goods

- fat use incereases as they become less expensive and more available

- contributes to satiety, the satisfaction of feeling full after a meal

Triglycerides

major form of lipid found in food and in the body

most fatty acids are incorporated into trigylcerides

composed of 3 fatty acids and a glycerol

is saturated or unsaturated fats softer

unsaturated

saturated fat

is every available bond from the carbons is holding a carbon

no double bonds

unsaturated fats

contains one or more points of unsaturation

c=c double bonds

healthier

sources of fatty acids

vegetable and fish oils along with animal fats

what type of fatty caids are found in fish and vegetables

polyunsaturated fattu acids and some are rich in monounsaturated fats

what type of fatty acids are found in meat

saturated fats

phospholipids

like a triglyceride, consists of a molecule of glycerol with fatty acids attached

2 fatty acid chains rather than 3

phosphate is soluble in water and the fatty acid chains are soluble in fat

Fat Emulsion

having both water and fat soluble poprtions that allows it to mix wiht both fat and water, permanently dispersing fat in water

sterols

interconnected rings of carbon with side chains of carbon hydrogen and oxygen

cholesterol

the most prominent sterol

the raw materials to make bile and gives cells structure

can be made by the body, so unnecessary to consume

how are fats digested in the mouth

gland at the base of the tongue plays a role in digestting milk fat in infants

very little happens in the mouth of adults

how are fats digested in the small intestine

compounds made from cholesterol that works as emilsifiers

one end of each molecule that ttracts and holds fat, while the other end attracts and hold water

made by liver and stored in gal bladder

released into a duct that leads to the small intestine when it is needed for fat digestion

how does fat digest in the stomach

droplets of fat separate from the wtaery components and tend to float as a layer on top and little digestion occurs here

transportation of fats

glycerol and shorter fatty acid chains pass directly thoughj intestinal cells into the bloodstream- and then travel unassisted to the liver

larger lipids are moved by lipoproteins that are assembled packages of lipid and protein molecules that cluster together to form triglycerides that clump to form chylomicrons that are then relaesed into the lymph vessles

where does the body store fat molecules not immediately needed for energy in fat stores?

subcutaneous layer of fat that pads the abdomen

the body pulls from these stores when the body starts to run out of available fuel from food

how do fat cells respoind to the call for energy

dismantle stored trigylcerides and release fatty acids into the blood

how do carbs aide in fat breakdown

without fats, products of incomplete fat breakdown (ketones) build up into the tissues and blood spills into the urine

recommendations for lipid intake

20-35% of daily energy is from fat which eves out to 400-700 cals per 2000 cal diet

as little trans fat intake as possible

US fat intakes

about 35% of total energy from fat and 11% daily energy from saturated fat

purpose of lipoproteins

provide a blood transport system for triacylglycerols

why? because they're insoluble in water

Chylomicrons

very low desnity lipoproteins that transport trilycerides and other lipids made in the liver for the body to use

amount of lipids or proteins or chylomicrons in relation to densities

the more lipids, the less dense

the more proteins, the more dense

chylomicrons are the least dense

very low density lipoproteins (VLDL)

transport triglycerides and other lipids from the liver to various tissues in the body

low density lipoproteins

transport cholesterol and other lipids to the other tissues for their use. it is what is left after VLDL have honated many of their triglycerides to the body cells.

rich in cholesterol and high levels trigger inflammation and heart disesase

High-Desnity Lipoproteins

pick up cholesterol from body cells and carry it to the liver for disposal. they are smaller, denser and packaged wiht more protein

high levels oppose heart disease and vice versa

major risk factors for cardiovascular disease are

high blood LDL cholesterol

low blood HDL cholesterol

food cholesterol effect on blood cholesterol

most saturated and trans fats in food raise harmful blood cholesterol but food cholesterol has little effect on blood cholesterol

what is a major indicatior of CVD risk

high blood LDL cholesterol

good lipids are associate with raising LDL cholesterol such as saturated fat and trans fat in excess amounts

what percent of adults still test too high for LDL

more than 25% of adults

how to lower LDL

trim saturated and trans fat from diet and replace them with monounsaturated and polyunsaturated fats along with keeping calories reasnoable

How to raise HDL

physical activity (most effective), no smoking, eat regularly, less total fat, moderate alcohol intake.

what is linoleic the parent member of

omega 6 fatty acid family

arachidonic acid