p. 12CO, 1
Derived primarily from plant sources Produced by photosynthesis: energy from the sun stored chemically as carbohydrate in plants Composed of organic compounds (CHO): _______ _______ _______
CARBOHYDRATE
Carbohydrates
Functions
primary energy source
____ calories/gram
protein sparing effect source of dietary fiber sweetening agent
Acceptable Macronutrient Distribution Range (AMDR)
Carbohydrate Protein Fat 45-65% total calories 10-35% total calories 20-35% total calories
225-325 grams for 2000 calorie diet 50-175 grams for 2000 calorie diet 44-78 grams for 2000 calorie diet
2005 Food Guide Pyramid
Simple Sugar Facts
Simple sugars are small molecules Two types: monosaccharides and disaccharides 3 Monosaccharides: Glucose (blood sugar or dextrose) Fructose (fruit sugar)
________
3 Disaccharides consist of two linked molecules
Glucose + fructose = ________ ( table sugar) Glucose + glucose = ________ (malt sugar) Glucose + galactose = ________ (milk sugar)
Glucose Utilization
Immediate energy source to all cells Converted into glycogen (glycogenesis)
chains of linked glucose units stored in:
_______ (90 grams CHO or ~360 calories) _______ (150 grams CHO or ~600 calories)
Converted into fat
adipose tissue (unlimited storage capacity)
Fig. 12-3, p. 4
Controlling blood glucose levels
Insulin
functions to ______ blood glucose levels
required for glucose uptake into cells enhances conversion of excess glucose to glycogen (glycogenesis) enhances storage of excess glucose to fat in adipose tissue
Controlling blood glucose levels
Function to raise blood glucose levels Glucagon
liver glycogen to glucose
Somatostatin
inhibits insulin
Epinephrine
rapid conversion glycogen to glucose
Glycemic Index
Glycemic Index: a measure of the speed with
which the carbohydrates in food are broken down to glucose (sugar) and enter the blood stream, causing a rise in blood sugar
Glycemic Load: a measure of speed multiplied
by quantity, i.e., GI x number of grams of available carbohydrate in a typical or standard serving
1. Reduce intake of refined flours & processed foods. 2. Opt for whole grain & stone-ground breads & grains. 3. Include pumpernickel, sourdough, & other grainy, dense breads. 4. Limit use of foods containing significant amounts of sugar (sucrose, high fructose corn syrup, fructose, dextrose, honey, etc). 5. Eat more beans & legumes as a protein source or as a side dish. 6. Emphasize high fiber, low energy density foods including vegetables & fruits. 7. Keep portion sizes reasonable as per the Food Guide Pyramid & food labels. 8. Include at least one lower Glycemic Index (GI) food with each meal or snack. 9. Balance carbohydrates with protein and healthy fats. 10. Include 1-2 tablespoons of lemon juice, lime juice, or vinegar with each meal.
Ten Tips to Lower the Glycemic Index or Load of Your Diet
Wheres the Sugar?
Americans consume 84 grams of added sugar per day, about 17% of the average caloric intake Sugar consumption up 23% in past 30 years Biggest source for many is___________ Sucrose is added to other foods Sugar is common ingredient of breakfast cereals Simple sugars are in fruits and some vegetables Fruits and vegetables provide many nutrients Besides milk, animal products have no sugars
Fig. 1-11, p. 18
SUGAR In Our Food Supply
Sources: white sugar, brown sugar, dextrose, fructose, high fructose corn syrup (HFCS), glucose, corn sweetners, lactose, concentrated fruit juice, honey, maple syrup, molasses, sugar alcohols All chemically similar, provide 4 calories/gram and few other nutrients
Added Sugars
Sugar is added to food during food processing or preparation Nutrition labels list total amount of sugar per serving All simple sugars must be lumped together under sweeteners followed by a parenthetical list itemizing each type in order of weight Labels contain information on total sugars per serving and do not distinguish between sugars naturally present in foods and added sugars
Sugars in Food
Whats So Bad about Sugar?
Foods with simple sugars are generally poor sources of nutrients Simple sugars provide only calories Many foods high in sugars are also high in fat Likelihood that diets will be insufficient in vitamins and minerals increases with sugar intake Sweets consumption promotes___________
Sugar Fiction and Fact
Sugar has been falsely accused of: depleting the body of nutrients causing violent and criminal behavior producing diabetes causing hyperactivity in children Sugar actually: decreases kids activity level makes adults sleepy reduces appetite in the short-term
Advice on Sugar Intake
Enjoy sugars in limited amounts DRIs say limit intake to below 25% of total calories WHO and others recommend limiting added sugars to 10% of calories Brush your teeth after eating sticky sweets Replace regular soft drinks with water
Carbohydrates and Teeth
Sugar and tooth decay (dental caries) related exposure time important variable stickier sweets more apt to promote decay
Decay declined during WW I and II Rebounded when sugar became available Highest rates where sugar added to foods Simple sugars come from starchy foods Some countries have campaigns about cavitypromoting foods
Table 12-7, p. 15
Water Fluoridation
Declines in tooth decay in U.S. from fluoride supplements, toothpastes, rinses and gels, protective sealants, and improved dental hygiene and care Lower rates of dental caries with reduced intake of sugars and sticky carbohydrates Fluoridation is safe, effective, and cheap
Baby Bottle Caries
Infants who fall asleep with a bottle (sugar water, milk, or formula) may develop severe decay Fluid collects, bathing teeth in sweet fluid for as long as the child sleeps Foods with little carbohydrate protein or and high dietary fiber inhibit tooth decay
Sugar Alcohols
Sugar alcohols (reduced energy sweeteners)
contain 4 calories per gram reduced absorption causes less dental caries may cause gas or diarrhea sorbitol mannitol xylitol
types:
Alternative Sweeteners
Nonnutritive sweeteners
aspartame (brand name = Nutrasweet)
bonding of amino acids phenylalanine & aspartame used by over 100 million worldwide FDA approved in 1981 180 to 200 times sweeter than sucrose Does not promote tooth decay Not stable under prolonged heat PKU (Phenylketonuria)
genetic disorder cannot metabolize phenylalanine hould not use aspartame
Is Aspartame Safe?
Safe level defined as 50 mg/kg body weight per day in U.S. and 40 mg/kg body weight per day in Canada U.S. limit equals 20 aspartame-sweetened soft drinks or 55 desserts per day Average intake in U.S., Canada, Germany, and Finland from 2 to 10 mg per day, safely low Claims of headaches, dizziness, or anxiety from small amounts not confirmed
Alternative Sweeteners
Nonnutritive sweeteners
Saccharin (Sweet n Low)
been in use for over a century 300 to 700 times sweeter than sucrose
Acesulfame K (Sunette, Sweet One)
FDA approved in 1988 200 times sweeter than sucrose synthetic product; nondigestible used in chewing gums, nondairy creamers heat stable
Alternative Sweeteners
Nonnutritive sweeteners
Sucralose
derived from sugar FDA approved in 1998 600 times sweeter than sucrose poorly absorbed; excreted in urine stable in baking and cooking does not promote tooth decay over 100 studies demonstrate safety
Guide to Popular Sweeteners
Substance "aka" FDA approval vs. sugar Heat stable? Found in
Sucralose
Splenda
1998
600Xsweeter
yes
> 3,500 foods
Aspartame
Equal
1981
200Xsweeter
no
>6,000 foods
Saccharin
Sweet'N Low
2000*
300Xsweeter
yes
toothpaste,gum
Acesulfame K
Sweet One
1988 sold as supplement
200Xsweeter
yes
cookies,soda
Stevia
Stevia
300Xsweeter
yes
not approved
Stevia
http://en.wikipedia.org/wiki/Stevia From sweet tasting leaves of the Stevia shrub Extracts 300 times the sweetness of sugar Has been sold in the US as a supplement rather than a nonnutritive sweetener GRAS status with FDA being sought so can be used as dietary ingredient
Alternative Sweeteners
Nonnutritive sweeteners
Cyclamate
under ban by FDA since 1970 evidence of causing bladder cancer in animals used in Canada ban under appeal
Dietary Carbohydrates
SIMPLE CARBOHYDRATES
Monosaccarides glucose, fructose, galactose Disaccharides sucrose, lactose, maltose
COMPLEX CARBOHYDRATES Polysaccharides starches, FIBER glycogen
Dietary Fiber Facts
Fiber intake in U.S. below the amount recommended People get recommended amount from whole-grain breads, highfiber cereal, and dried beans and five servings of vegetables and fruits daily Food sources same cooked, or raw Fast foods are poor sources of fiber
Types of Fiber
Classification system for edible fibers is based on source Fiber is not digested by human digestive enzymes Fibers are classified as
functional fiber dietary fiber total fiber
Types of Fiber
Functional fibers have beneficial functions in the body
INSOLUBLE functional fibers: decrease food intake by a feeling of fullness reduce post-meal rises in blood glucose levels prevent constipation SOLUBLE functional fibers: decrease fat and cholesterol absorption
Functional fiber is produced to fortify foods Psyllium, pectin, gels, seed and plant gums, and meat connective tissues are functional fibers
Diagram of a Grain of Wheat
Diagram of a grain of wheat showing the bran that is a rich source of dietary fiber The germ contains protein, unsaturated fats, thiamin, niacin, riboflavin, iron, and other nutrients The bran and germ are removed in the refining process The endosperm primarily contains starch, the storage form of glucose in plants
Dietary Fibers & Food Sources
________ fibers (cellulose)
whole grains, unrefined cereals, vegetables, seeds, popcorn, nuts
________ fibers (pectin, gums)
beans, peas, lentils, fruits, oat bran, oatmeal, barley, corn, carrots, white potatoes
Fiber and Health
helps body function more efficiently lowers risk heart disease, colon cancer, obesity, constipation, hemorrhoids, diverticular disease lower blood cholesterol assists in blood glucose control ___ to ___ grams fiber/day recommended
p. 14
Tips to Boost Fiber Intake
Opt for whole grain breads and cereals
Choose cereals that contain at least 3 grams of fiber per serving or mix high fiber cereal, like All Bran or Fiber One with lower fiber cereal Look for breads that have at least 2 grams of fiber per slice
Eat at least five servings of vegetables and fruits each day Include dried beans and peas regularly Minimize use of processed, refined foods Increase fiber intake gradually Increase fluid intake along with increase in fiber
High Protein Diets
Are not recommended for people with liver or kidney problems May promote heart disease and prostate cancer May leave glycogen stores nearly empty May cause nausea, headache, decreased stamina, and a reduced ability to concentrate
High-Protein Low-Carbohydrate Diet Health Concerns
increases in LDL-cholesterol increases losses of urinary calcium & osteoporosis increased protein load may alter kidney function dehydration & electrolyte imbalances intolerance to intensive physical activity side effects of ketosis may include: headache, bad breath, fatigue, nervousness, diarrhea, hair loss, leg cramps, hypotension
Protein Diet Limitations
They dont work in the long run People revert to more pleasurable, usual diets As soon as carbohydrates are returned to the diet in normal amounts, appetite returns and weight gain follows