exam 1 carbs Flashcards
carbohydrates are classified as simple or complex depending on
Number of sugar molecules—will have at least one, and sometimes hundreds
Whether it is a straight chain or branched
simple sugars include
monosaccharides and disaccharides
examples of monosaccharides
galactose
glucose
fructose
examples of disaccharides
sucrose
maltose
lactose
complex sugars includes
starches
glycogen
cellulose
fibers
starches
The storage form of energy in plants
Found in two forms:
amylose
amylopectin
glycogen
Form in which starch is stored in the liver and muscles
Accessed when glucose levels fall too low
glucose
Form of energy supplied by simple and complex carbohydrates –provides energy and spares protein for other function such as healing Preferred fuel source for: red blood cells the brain the central nervous system
gluconeogenesis
Synthesis of glucose from protein or glycogen
Response to Carbohydrate Intake in Excess of Body’s Need for Glucose
Glucose is stored as glycogen in muscles and liver.
Glucose in excess of the capacity to store glycogen is metabolized into triglycerides.
insulin
moves glucose out of blood stream when blood glucose levels rise
glucagon
stimulates conversion of stored glycogen into glucose when blood glucose levels are too low
glycemic index
Measure of rise in blood glucose during two hours after ingestion of 50 gm of carbohydrate
high glycemic index foods
quick elevation in blood glucose following intake
low glycemic index foods
blunted response following intake
better for diabetics
food sources of carbs
Plant-based foods-beans, legumes, corn, potatoes, peas
Milk and yogurt
Prepared and processed foods with added sugars
simple sugar food sources
include those with naturally occurring and added sugar sources
naturally occurring (intrinsic) sugars
Fructose- fruit sugar
Lactose-milk sugar
Sucrose- table sugar
added (extrinsic) sugars
sucrose
high-fructose corn syrup
nutritional facts on food labels do not
Does not differentiate between naturally occurring sugars and added sugars
May not be a clear indicator of overall nutritional value
complex carbohydrates
Foods that contain starches and fibers
starches
The form of carbohydrate stored in plants
whole grains
Not overly processed during milling
Retain the germ and bran
processed or refined grains
Removal of germ and bran cause loss of fiber and nutrients
enrichment
nutrients lost during processing are replaced
fortification
nutrients not originally present are added
recommended dietary allowance (RDA) for carbs
Daily minimum of 130 gm of carbohydrates
Range of 45–65% of daily calorie intake should come from carbohydrates
recommended intake of added sugars
Daily intake not to exceed 25% of total calories
World Health Organization: not to exceed 10% of total calories
factors that affect carbohydrate needs
Weight
Activity level
Pregnancy and lactation
Dietary Guidelines for Americans and Health Canada recommendations regarding sugar:
limit intake of foods and drinks with added sugars to:
promote dental health
avoid excessive calorie intake
Dietary Guidelines recommend sugar as discretionary calories
Dietary Guidelines for Americans and Health Canada recommendations regarding complex carbohydrates
Intake should come from a variety of food groups, including: fruits vegetables grains legumes
whole grains =
at least half of the recommended grain intake
which helps blood sugar control and satiety
fiber
A polysaccharide not digested by the body
Moves through digestive tract until partially fermented by bacteria in the colon – this may cause bloating
Is not absorbed by the small intestine
Promotes laxation
Controls cholesterol and blood glucose
categories of fiber
insoluble and soluble
insoluble fiber
includes cellulose, hemicelluloses, and lignins
gives plant food texture
adds bulk to stool and promotes laxation
Foods closer to original form have greater fiber content than processed or prepared foods
soluble fiber
Slows digestion, diminishing how quickly sugar is absorbed in the intestine
Binds fatty acids in the intestine, resulting in lower blood cholesterol
Interfere with enterohepatic recycling of bile -> reduction in blood cholesterol levels
Slow gastric emptying and absorption of glucose -> improved postmeal blood glucose levels in diabetics
recommended daily total fiber intake
Based on 14 gm fiber per 1,000 kcalories consumed:
25 gm for females
38 gm for males
~1gm/kg of body weight
increasing fiber in the diet
Increase gradually to avoid intestinal side effects
Take in adequate fluid to improve tolerance
excessive fiber intake
Self-limiting practice; you know when you’ve had too much fiber
No upper limit recommendations
fiber promotes intestinal health
Normalizes the transit time of substances through the intestinal tract and promotes laxation
Increases stool bulk and weight and relieves constipation
Can prevent the development of diverticula
May have a role in the prevention of colon cancer, but there is a lack of clear evidence
(high fiber for diverticular, low fiber for diverticulitis)
high fiber diets may help manage weight because they
have fewer calories than other foods of equal weight
create the feeling of fullness because of their volume
may delay gastric emptying
five non-nutritive sweeteners have been approved for use with guidelines given for Acceptable Daily Intake (ADI)
aspartame acesulfame potassium sucralose neotame and saccharin
aspartame
Marketed as Nutrasweet and Equal (blue packet)
Composed of aspartic acid and phenylalanine
Little caloric contribution
No confirmed links to negative health affects
Can cause migraines; if head injury, you should not take equal
Acesulfame Potassium (acesulfame-K)
Marketed as Sunette
All-purpose sweetener
Blended with other nonnutritive sweeteners because of intense sweetness
sucralose
Marketed as Splenda
Composed of a sucrose molecule chemically combined with chlorine
Poorly absorbed by intestines, no caloric value
Heat stable
No confirmed links to negative health effects
neotame
Not yet widely available in foods
Contains aspartic acid and phenylalanine
7,000 to 13,000 times sweeter than sucrose
stevia
Plant-derived, noncaloric sweetener
Not yet approved in the United States or Canada for use as a sweetener or food additive????
GRAS- generally recognized as safe
Possible link to infertility and mutagenic risks
saccharin
Marketed as Sweet’N Low and Sugar Twin
Made from synthetic chemicals
FDA approved for use in beverages, packaged sugar substitute, and some processed foods
sugar alcohols
Lower calorie sugar replacements that are derived from sugars
Absorbed more slowly and in lesser amounts than simple sugars
Average energy content of 2 kcalories/gm
Excessive intake may cause an extreme laxative effect/diarrhea
common sugar alcohols
sorbitol
mannitol
xylitol
Concerns and potential health effects related to carbohydrate intake include the following:
Increased risk of dental caries
Possible relationship between carbohydrate intake and weight gain
Side effects of low-carbohydrate diets:
changes in blood lipid levels
increased loss of urinary calcium
insufficient intake of nutrients found in fruits, vegetables, whole grains, and milk
