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what are the healthiest sources of carbohydrates?
- grains that are intact and are unprocessed
- ex: whole wheat bread, brown rice, whole grain pasta, whole oats, bulgur, kasha, quinoa
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how do the effects of a high carb diet depend on the body weight and physical activbity of the individual consuming that diet?
- carb diets have different effects on lean active people than they do on overweight sedentary people due to the lack of exercise which ultimately leads to:
- increased refined carbs-> increased weight, increased fatigue, decreased energy from food
-
what are the effects of a diet high in refined catbs on serum lipid values such as triglycerides and HDL cholesterol?
- increase insulin
- increase triglycerides
- decrease HDL
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in contrast to the old system of classifying carbs as either simple or complex, what is a better way of distinguishing healthy from unhealthy carbs?
- high vs low glycemic index foods
- whether they come from refined or whole grains
-
list the seven most common carb sources in the average american diet
- cake/donuts/pastries
- pizza
- potato chips/popcorn
- rice
- beer
- french fries
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explain how a meal rich in easily-digested catbs can eventually result in low blood sugar levels and an early return of hunger
- the resulting flood of insulin can drive glucose levels way down. if there is not anymore digestable carbs in the stomach or the intestines your gut and brain send out hunger signals to make you grab more food even though your liver is releasing stored glucose
- increase glucose=> increase insulin=> decrease blood glucose
-
explain how insulin resistance affects pancreastic function
- resistance to insulni keeps blood glucose at high levels for longer periods of time and forces the pancreas to produce extra insulin in order to jam glucose into cells
- the insulin making cells in the pancrease may wear out from this abuse and eventually they may stop producing insulin all together (type 2 DM)
-
list the important contributors to the development of insulin resistance
- obesity
- inactivity
- dietary fats
- genetics
-
what health problems other than blood sugar disorders have been associated with insulin resistance
- hypertension
- increased triglycerides
- decreased HDL
- CVD
- cancer
-
what do measurmentfs of the glycemic index of different sources of carbs tell us about the similarities and differences between sugars and complex carbs?
- simple sugars increase glycemic index
- complex sugars increase and decrease glycemic index
-
which complex carb foods have a very high glycemic index
- pancakes
- total cereal
- grape nuts
- raisin bran
- cheerios
- shredded wheat
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what is the difference between glycemic index and glycemic load and which one appears to be a more accurate indicator of the effects of a food on blood sugar?
- glycemic load= GIXCarbs in grams/100
- glycemic load is more accurate
-
when calculating the glycemic index, a control or reference food is given the value of 100 for comparison. what are the two foods used in different tables as the reference food
-
what characteristics of a carb containing food determines it glycemic index or load?
- amount of gelatin starch
- how processed it is
- fiber content
- fat content
-
which micronutrients are depleted by more than 50% when whole wheat flour is refined into unenriched white flour
- vitamin E
- B6
- magnesium
- riboflavin
- niacin
- fiber
- zinc
- potassium
- iron
- copper
-
risk for which disease can be lowered with a diet hig hin whole or intact grains
- CVD
- GI problems such as diverticulosis
- diabetes
- speculated that it can lower risk of come cancers
-
list all the possible mechanisms that may explain the role of whole grains in preventing disease
- delays absorption of glucose
- eases the workload of the insulin producing cells in the pancrease
- lowers blood cholesterol levels
- increases the bodies natural anticoagulants -> decreased clot formation
- antioxidants such as vit E prevent LDLs from reacting with oxygen
- phytoestrogens -> protection from some cancers
- bran layer contains essential minerals -> decreaseing the risk of CVD and DM
-
what terms may be used in an ingredients label of a food product to indicate that refine flour was used in that product?
- low carb
- made with whole flour
-
what terms must only be used when a whole grain flour product is used
- whole wheat
- whole oats
- whole rye
- whole grain
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why is the glycemic index an improvement over other ways of classifying carbs>
becuase blood glucose response to complex carbs has been found to vary considerably. a more accurate indicator of the relative glycemic response to dietary carbs is the glycemic index
-
how does a high glycemic index food increase the liklihood of hypoglycemia after a meal
- repid increase in blood glucose -> incrase insulin released from the pancreas
- over the next few hours the high insulin levels induced by consumption of high glycemic index foods may cause a sharp decrease in blood glucose levels
-
what measurment is used along with the glycemic index to arrive at the glycemic load of a food
the amount of carbs in grams
-
how does a high glycemic load diet influcence the development of diabetes
increased secretion of insulin overtime adds insult to the insulin producing cells in the pancrease and can lead to deceased pancreas function
-
in large prospective studies of nurses and male health professionals, which foods were most consistently associated with increased risk of DM
- potatoes
- white rice
- white bread
- carbonated sweet beverages
-
what are the benefits of low glycemic load diets in the treatment of existing diabetes
increased control of blood glucose -> decreased episodes of hypoglycemia
-
what lipid abnormalitites and other cardiovascular risk factors are associated with a high glycemic load diet
- decreased HDL
- increased triglycerides
- increased C-reactive proteins (systemic inflammatory marker)
-
what type of individual of individual is likely to be most susceptible to the adverse cardiovascular effects of a high glycemic load diet?
overweight females
-
what are the probably mechanisms by which a low glycemic load diet improves the results of weight loss
feeling of feeling full for longer periods of time -> decreased food comsumption
-
what changes from a typical western diet would still allow consumption of foods high in carbs while lowering the overall glycemic load of the diet
- increaseing the consumption of : whole grains, nuts, legumes, fruits, constarchy vegetables
- decreasing the comsumption of : potatoes, white rice, white bread, sugary foods like cookies, cakes, candy and soft drinks
-
name the types of compunds that share many of the characteristics of dietary fiber but have not typically been included in the definition of dietary fiber
- indigestable carbs from animal sources
- synthetic indigestible carbs that are inaccesable to human digestive enzymes
-
contrast the way observational research has typically studied fiber from the way intervention research has typically studied fiver
- observational studies looked at fiber rich foods
- interventional studies have isolated pure fiber
-
what is meant by the term functional fiber
isolated or synthetic fibers that may be added to foods or used as supplements
-
what health-promoting properties are associated with viscous fiber
- ability to delay stomach emptying
- delaying nutrient absorption
- decreased serum cholesterol
-
what health promoting properties are associated with fermentable fiber
- increased amount of bacteria in colon
- formation of short chained fatty acids which are used for energy
-
what fiber containing foods and fiber supplements lower LDLs
- legumes
- oat products
- supplements: pectin, guar gum, psyllium
-
what is the effect of adding viscous fiber to a meal on subsequent blood glucose and insulin levels, compare to a meal lacking viscous fiber
shows a significant positive change in the glucose/insulin response which leads to smaller but more sustained increases in blood glucose and significantly lower insulin levels
-
what fiber containing foods and fiver supplements consistently increase stool bulk, shorten transit time, and effectively treat constipation
- wheat bran
- fruits
- veggies
- cellulose
- psyllium
-
what is the clinical significance of diverticular disease and what type of fiber appears to provide the strongest protection from this disease
- causes pockets/pouches in the colon which can become inflammed when food particles become trapped
- non-viscous dietary fiber (cellulose)
-
based on research on women consuming high fiber, low fat diets, how might these diets play a role in breast cancer prevention
by decreasing circulating estrogen levels by increasing the excretion of estrogens and promoting the metabolism of estrogens to less estrogenic forms NO SOLID EVIDENCE ON THIS THOUGHT
-
by what mechanism might a high fiber diet help prevent weight gain or promote weight loss
- probides less energy
- extending the feeling of fullness after a meal
-
what are the best food sources of soluble/viscous fiver
-
what are the best food sources of insoluble/nonviscous fiber
vegetables
-
what is meant by the term prebiotics and which fiber supplements are given this classification
- substances with the ability to stimulate the growth of bifidobactera in the colon
- insulins and oligofructoses
-
what health clain about psyllium is approved by the FDA
-
-
what strategies may hellp people avoid gastrointestinal side effets of increasing their fiber intake
increased water intake to 2 liters/day
-
what straegy will help avoid interactions between fiber and medications
- add intake of kaolin-pectin
- take medications 1 hour before or 2 hours after fiber intake
-
what component of cereal fiber is thought to be responsible for the effect of fiber on mineral absorption
phytate
-
list the beneficial compounds present in abundance in whole grains
- vitamins
- minerals
- phytochemicals
- lignans
- phytoesterols
- fiber
-
what changes in fasting insulin levels and other measures of insulin resistance occur on a diet low in whole grains and high in refined grains
increased insulin resistance
-
in prospecitve studies of coronary heart disease risk, what whole grain foods were associated with reduced risk
- dark bread
- whole grain cereal
- popcorn
- oatmeal
- brown rice
- bran
- barley
- bulgar
- kasha
-
fiber from which whole grains appears to improve total and LDL levels
oat fiber
-
how do phytosterols in whole grains cause a decrease in serum cholesterol
they interfere with intestinal adsorption of cholesterol
-
by what mechanisms may constituents of whole grains reduce the risk of some types of cancer
- accelerate the passage of poop thru the colon
- decrease contact time of carcinogens
- lignans in whole grain = phytoestrogens-> decreased hormone dependent cancer
- phenolic compounds modify signal transduction pathway- alters metal
-
other than cancer, what intestinal disorders may be prevented by diets rich in whole grains and what biochemical or physiological mechanisms are involved
- decreased constipation-> softens and adds bult to poop which speeds transit time out of the colon
- decreased diverticulosis risk
-
what strategies can be used to make sure whole grian foods are purchased when shoping
- items that list whole grain as #1 ingredient
- >>2 grams of fiber/serving
- beneficial health claims such as: 51% or greater whole grain by weight
-
list some other strategies for increasing whole grain intake
- whole grain (breakfast cereals, bread, crackers, pasta, flour)
- brown rice
- barley
-
which high protein foods are considered the healthiest choices
-
what is meant by an incomplete protein
- lacking one or more essential amino acids
- vegetable proteins are often incomplete
-
how does the typical protein intake on a western diet compare with daily protein requirements
typically have more protein than what is needed
-
which foods have the highest percentage of calories from protein
- water packed tuna
- roasted chicken
- low fat cottage cheese
- broiled top serloin
- salmon filet
-
what are the important differences between animal and vegetable sources of protein in terms of their effects on health and disease
alone they are the same but the packaging of animal sources of protein often includes incrased saturated fat
-
what type sof cooking may increase the risk of cancer from eating meat
- frying
- grilling to death can cause and incrase in carcinogens
-
list the possible mechanisms behind the cardio protective benefits of eating nut
- unsaturated fats lecreased LDL increase HDL
- omega-3 decrease blood clotting
-
what are the environmental arguments for making certain choices amoung different protein foods
- vegetable proteins are more efficient
- increased requirements to feed beef/meat sources
-
what were the findings of the nurses health study regarding the effects of protein intake on the risk of heart disease
an increase in protein intake leads to a 25% decrease in the likelihood to have a MI vs decreased protein intake
-
why might increased protin intake contribute to successful weight control
- chicken, beef, fish decrease stomach emptying and therefore you have longer satiety
- protein has a low glycemic index
-
how does protein intake affect calcium balace in teh bode
increased protein intake requires calcium to neutralize acids and this calcium is pulled from bone and this may have long term effects
-
extensive tissue loss may increase protein requirements by how much in relation to RDA
up to 2X of RDA
-
how do the protein requirements of athletes compare to non-athletes in terms of grams required per day
increased requirements ni athletes can be met by increased caloric intake with normal proportions of protein (10-15% of total calories)
-
how do the protein requirements of athletes compare to non-athletes in terms of percentage of total calories that should come from protein
- endurance exercises: 1.2-1.4 g protein/kg body mass per day (150% RDA)
- strength exervises: 1.7-1.8g protein/kg body mass per day (220%)
-
what are the pros and cons of a high protein diet for normalizing flucose intolerance, weight loss, and/or dyslipidemia
- normalizing glucose intolerance- substititing lean protein for carbohydrates with decreased glucose intolerance
- weight loss- substituting lean protein for carbs increases HDL and decreasing LDL
- dyslipidemia- need to watch which protein s you use! favor plants or animal proteins
-
what are the potential consequences of avery high meat protein diet
- increased risk of lung, colon, breat, nonhydgkin lymphoma (especially if over done)
- increased risk of kidney stones
- suggested upper limit of protein intake is no more than 2X RDA suggested intake
-
list the common foods that belong to the legume famil
- beans
- peas
- lentils
- soybeans
- peanuts
-
name the phytoestrogens family found in soybeans
isoflavoures
-
what are the mechanisms by which legume consumption decreases the risk of type 2 DM
legumes have a relatively low glycemic index
-
which cardiovascular risk factors are affected by legume consumption
it improves serum lipid and lipoprotein files
-
what health claims does the FDA allow on labels of foods containing soy
diest low in saturated fat and cholesterol with 25g soy protein a day may decrease CVD risk
-
which cancer appears to be reduced in risk by consumption of both soy and other legumes
- prostate cancer
- breast cancer
-
is soy protein considered a complete protein
yes soy protein is considered a complete protein becuase it contains all of the essential amino acids
-
which cardiovascular disease and risk factors are affected by fruit and vegetable intake
- decreased CVD
- decreased incidence of MI
- decreased hypertension
-
what nutritional components of fruits and veggies are likely to contribule to their health effects
- vit C
- folate
- potassium
- fiber
- phytochemicals
-
why are case control studies of the relationship between fruit/veggie intake and cancer less convincing than the results of prospective cohort studies
case control studies showed positive results of increased fruit/veggies with decreased cancer however, the study leaves room for bised sampling
-
what are some explanations proposed to accound for the disagreement between studeis of cancer risk and fruit/veggie consumption
- problems with population bias
- showed reduction in individual cancers
-
which specific vegetables have been associated with protection from which specific cancers
- increased fruit-> decreased lung cacner
- increased cruciferous vegetables -> decreased bladder cancer
- increased totatoes-> decreased prostate cancer
-
explain the mechanism by which fruit and vegetable consumption may protect against bone loss
fruit and vegetables are high in bicarbonate which can be used as a buffer to keep calcium levels high
-
increased fruit and vegetable consumption may prevent which disease of the eye
- cataracts
- macular degeneration
-
which foods are associated with protection agains chronic obstructive lung disease
higher fruit intakes, especially apple intakes, are associated with higher forced expiratory volume values, indicative of better lung function
-
name the six principal dietary carotenoids. which ones have vitamin A activity
- alpha carotene (A)
- beta carotene (A)
- beta cryptoxanthin (A)
- lutein
- zeaxanthin
- lycopene
-
list the potentially beneficial functions of carotenoids other than vitamin A activity
- antioxidant
- light filtering
- intercellular communication
- immune system activity
-
which carotenoid is not typically associated with protection from lung cancer according to recent studeis
beta carotene
-
which caroteinoid is associated with tomato consumption
lycopene
-
describe the conclusions of slinical trials of beta carotene supplementation for reducing the risk of various disease
- experts feel that the risks of high does beta carotene supplementation outweight any potential benefits for cancer prevention
- especially in smokers or other high risk populations
-
which arotenoids are concerntrated in the retina and lens of the eye
-
which carotenoid is the most abundant in the north american diet
- alpha carotene
- beta carotene
- beta cryptoxanthin
- lutein
- zeaxanthin
- lycopene
-
examples of alpha and beta carotene
-
examples of beta cryptoxanthin
- pumpkin
- red peppers
- oranges
-
examples of lycopenes
- tomatoes
- pink grapefruit
- watermelon
-
examples of lutein and zeaxanthin
-
what strategy for taking carotenoid supplements will allow for the best absorption
they are best absorbed with a meal containing fat
-
what is the difference between synthetic beta carotene and beta carotene extracted from natural sources
the supplmental form of beta carotene has higher vitamin A actibity
-
what methods of food preparation increase th ebioavailability of carotenoids
- chopping
- homogenizing
- cooking
- heating tomatoes in oil
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