NUTR 251 Exam 3
thermic effect of food TEF
energy to process food, digestion and absorption
In the past 4 decades, obesity ______ in every state.
increased
Which of the following is NOT a good source of vitamin E in the American diet? A) Vegetable oils B) Potato C) Green leafy vegetables D) Seed and nuts
B) Potato Potato is an OK source of Vitamin C
Why is BMI not a perfect indicator of health risks?
BMI does not take into account: -variation in fitness (body composition) - body composition - fat distribution -BIOMARKERS
Another surgical procedure besides Gastric Bypass and Gastric Banding is _________. How does it work? What are the health benefits (are there any??)
Liposuction: surgical procedure removes fat deposits from certain areas of the body and can alter the body shape in specific areas. Liposuction does not provide health benefits.
Describe indirect calorimetry in measuring energy expenditure in humans.
Indirect calorimetry: measuring the oxygen the body consumed and carbon dioxide expelled
Why is there no pantothenic acid deficiency in the US? What is the role of pantothenic acids? That is, describe the importance of pantothenic acid in the conversion of pyruvate to acetyl CoA.
Pantothenic acid is relatively abundant in U.S. foods. Pantothenic acid is a part of coenzyme A aka CoA which forms acetyl CoA, a key compound in several metabolic pathways.
Who is at risk for hemolytic anemia, ie. which vitamin E can help? A) premature infants B) elders C) teenagers who exercise a lot D) babies who do not get enough sunlight
A) premature infants
Which of the following provides the LEAST amount of precursor vitamin A? A) Corn B) Spinach C) Carrots D) Cantaloupe
A) Corn
Many health experts describe our environment here in the U.S. as "obesogenic." Why?
An obesogenic environment includes all of the circumstances that we encounter daily that push us toward fatness. Over the past 4 decades, the demand for physical activity has decreased as the abundance of food as increased. Food is available everywhere, all the time, and for cheap prices and in large portions. Physical inactivity is promoted by technology such as cars, escalators, tv remotes, computers and video games.
In your own words, describe the role of vitamin E as an antioxidant. Now list all the other antioxidants in your diet which are mentioned in Lesson 9. Do carotenoids function as antioxidants? Does vitamin A? What is the role of good vitamin E status in heart disease?
Antioxidants scavenge free radicals that would otherwise damage cells. Vitamin C, Carotenoids and Flavonoids act as antioxidants Vitamin A does NOT act as an antioxidant Vitamin E may reduce risk of heart disease by protecting LDLs against oxidation and reducing inflammation
What are major food sources of vitamin E? One tablespoon of corn oil contains 2-3 mg of vitamin E. How much corn oil is needed to give you your RDA?
Best food sources: vegetable oils, seeds, nuts, green leafy vegs One tablespoon TBS of corn oil contains 3 mg of Vitamin E RDA = 15 mg/day (5 tbs corn oil)
In what tissue(s) must a molecule of vitamin D be chemically altered to yield a compound that is fully active? A) Liver only B) Kidney only C) Liver and kidney D) Liver and intestines
C) Liver and kidney
Vitamin K is A) an antioxidant. B) important in calcium reabsorption in the kidney. C) a coenzyme. D) important in the synthesis of opsin. E) C and D are both true.
C) a coenzyme
Why are elders at risk for marginal vitamin D deficiency? A) With aging, adults decrease their abilities to convert vitamin D to the hormone form. B) Elders typically drink little milk. C) Elders only absorb about half of the vitamin D in milk because of low Intrinsic Factor. D) A and B are both true, but not C. E) A, B, and C are all true.
D) A and B are both true, but not C.
Which statement is FALSE regarding the active, hormone form of vitamin D when blood calcium is low? A) It acts on the kidney to decrease the urinary excretion of calcium. B) It acts on small intestinal cells to increase absorption of calcium. C) It acts on bone to increase mobilization of calcium out of bone and into blood. D) It acts on bone to increase calcium into bone.
D) It acts on bone to increase calcium into bone. ***FROM bone, not into bone
Free radicals are A) reduced in the presence of vitamin E. B) produced during normal metabolism when oxygen is needed. C) good in small amounts for killing bacteria in the body. D) Only A and B are true. E) A, B, and C are all true.
E) A, B, and C are all true.
What is the misconception in this student quote? "The less dietary fat I take in, the less body fat I will have.
Excess body fat is a result of environmental factors, cultural factors, behavioral factors, socioeconomic, psychological, genetic and metabolic factors.
What variables are accounted for in the DRI equation for calculating Total Energy Expenditure?
Gender, Age, weight, height, physical activity
What is the connection between homocysteine and folate? Some hypothesize that the rate of heart disease may go down now that there is more folate in the food supply. Why? What other vitamins are connected to homocysteine metabolism?
Homocysteine is an amino acid degradation product that has been found to be elevated in people with heart disease. Folate, B6 and B12 are important in the degradation of homocysteine from the body. Increasing amounts of these vitamins can lower blood levels of homocysteine.
Briefly, what is the difference between hunger, satiation, satiety, and appetite? Does the phrase "feeling fuller for longer" refers to satiety or satiation?
Hunger: signals a physiological need for food Satiation: you stop eating DURING a meal because of satiation due to signals from your stomach and hormones Satiety: refers to the time between meals, continued feeling of fullness and satisfaction that inhibits your eating until the next meal "feeling fuller for longer" Appetite: appetite influences the amount of food you eat and is independent of physiological signals of hunger and fullness
What nutrients are added to enriched grains? (Recommend rereading pages 45-53 describing differences between refined (and enriched) vs. whole grains.)
Iron, Niacin, Riboflavin, Thiamin and Folate
Is there risk of low vitamin K status in any human populations in the U.S.? Explain. What has been done in the U.S. to alleviate this problem?
Newborns in the U.S. are given injections of Vitamin K because they are born with a sterile GI tract and it can take several weeks to develop GI bacteria that produce vitamin K on their own.
Did supplements of beta-carotene reduce or increase incidence of lung cancer in the clinical trial with smokers?
No ***but eating fruits and vegetables that contain carotenoids poses no risk
List the physiological fuel values for carbohydrate, protein, fat, and alcohol?
Protein = 4 kcal/g Carbohydrates = 4 Fat = 9 Alcohol = 7
Compare the RDA and UL for vitamin B6? Why is there a UL? Would you suggest a supplement of 100 mg/day of B6 to your sister who has PMS? Why or why not?
RDA = 1.3 mg/day vs UL = 100 mg/day Treatment of PMS via B6 has never been scientifically proven, and in some cases there have been women who have experienced irreversible nerve damage after taking large doses of B6 for months or years.
Some vitamin K is from a non-dietary source. Explain. Does this non-food source typically meet all of an individual's need for vitamin K? What foods are rich in vitamin K?
The GI tract bacteria produces Vitamin K, but NOT enough to meet the body's needs. Food sources: leafy green veg, kale, avocado, kiwi, vegetable and bean oils.
Describe the role of retinal in the visual cycle by listing the steps in the process of vitamin's A role in the visual cycle. The first symptom of vitamin A deficiency is night blindness. What is night blindness and why does low vitamin A status cause it?
The cells of the retina contain rhodopsin, a molecule composed of opsin (a protein) and cis-retinal (vitamin A). As rhodopsin absorbs light, retinal changes from cis to trans, which triggers an electrical impulse that carries visual information to the brain through the optic nerve. Night blindness is caused by lack of vitamin A at the back of the retina, which results in there not being enough retinal to recycle rhodopsin. A night-blind person loses their ability to recover promptly from the temporary blinding that follows a flash of bright light at night or to see after dark.
What is the chemical name for vitamin B12. What does cobalt have to do with vitamin B12?
The chemical name for vitamin B12 is cobalamin. B12 is an organic molecule containing cobalt.
Vitamin B6 facilitates the release of energy like other B vitamins, but from protein rather than carbohydrates and fats. Explain.
The coenzyme for Vitamin B6 is pyridoxal phosphate aka PLP. Because PLP can transfer amino groups from an amino acid o a keto acid, the body can make nonessential amino acids. The ability to add and remove amino groups makes PLP valuable in protein metabolism.
Explain the statement: Vitamin B12 deficiency causes a folate deficiency. What distinguishes pernicious anemia from megaloblastic anemia (i.e. folate deficiency)? Explain the roles of folate and B12 in blood health. Now describe vitamin B12's second role in the body.
To activate folate, the methyl group must be removed by an enzyme that requires the help of vitamin B12. Megaloblastic anemia = a symptom of of B12 deficiency (pernicious anemia) that is caused by folate depletion Pernicious anemia = B12 deficiency - In the blood: B12 combines with an intrinsic factor secreted by the stomach and transports this IF to the small intestine via the bloodstream. Folate circulates as a part of a monoglutamate-methyl group form to be delivered to cells. - B12's second role in the body is to serve as a coenzyme in the production of nerve tissue myelin.
what are the cutoffs/ranges for the BMI?
Underweight = 18 Healthy weight = 19-24 Overweight = 25-29 Obese = 30 +
What are the roles of gastric acid (HCl) and Intrinsic Factor (IF) in B12 absorption? Why are elderly at risk for B12 deficiency (pernicious anemia)? What is atrophic gastritis? What are some options on treating pernicious anemia in the elderly population?
HCl in the stomach releases B12 from the proteins to which it is attached in foods. Then as B12 passes from the stomach to the small intestine, it binds with a stomach secretion called intrinsic factor. Bound together, intrinsic factor and vitamin B12 travel to the end of the small intestine where receptors recognize the complex and absorb the B12 into the bloodstream. Vitamin B12 deficiency is common among elderly because most older adults develop atrophic gastritis, a condition that damages the cells of the stomach, which in turn damages production of HCl and Intrinsic factor. Treatment: periodic injections of B12, B12 nasal sprays, and taking very high doses to overcompensate for absorption impairment.
What is hemolytic anemia and who is at risk for developing it?
Hemolytic anemia results from low vitamin E status and fragile red blood cells which may rupture. Babies born prematurely are at risk because vitamin E does not cross the placenta until the late weeks of pregnancy.
Why are the World Health Organization and United Nations providing large doses of vitamin A to children throughout the developing world? Describe the connection of vitamin A status and infectious diseases.
Vitamin A supports immune function and inhibits the replication of the measles virus, which is correlated with symptoms of vitamin A deficiency such as diarrhea or pneumonia. Vitamin A supplements may protect against complications of other major diseases such as HIV or malaria.
You just ate 2 slices of a medium pizza for lunch. Here is the nutrient analysis: 21 g of protein, 75 g of carbohydrates, 18 g of fat, and 4 g of fiber. Estimate how many kcals is in this meal? Calculate the percent kcals coming from fat.
21 x 4 = 84 75 x 4 = 300 18 x 9 = 162 (there is no physiological fuel value for dietary fiber) total k cal = 546 k cals from fat = 162/546 = 29%
What is the recent recommendation for physical activity for weight maintenance or weight loss?
35 minutes of moderately physical activity in addition to activity of daily life
Which of the following food substances can be converted to vitamin A in the body? A) Tryptophan B) Chlorophyll C) Xanthophyll D) Beta-carotene
D) Beta-carotene tryptophan --> Niacin
Which of the following is not a fat-soluble vitamin? A) Retinol B) Tocopherol C) Phylloquinone D) Cobalamin
D) Cobalamin aka B12, water-soluble retinol = Vitamin A tocopherol = Vitamin E Phylloquinone = Vitamin K
True or false and explain? There are no health risks associated with being underweight (BMI<18.5), especially in women.
FALSE. An underweight person, especially an older adult, may be unable to preserve lean tissue during the fight against a wasting disease such as cancer or a digestive disorder. Without adequate nutrient and energy reserves, an underweight person will have an increased risk of mortality following surgeries. Underweight women develop menstrual irregularities and become infertile. Underweight and significant weight loss in women are also associated with osteoporosis and bone fractures.
How are fat-soluble vitamins absorbed into the body? Contrast this to water-soluble vitamins.
Fat soluble vitamins are insoluble in watery juices of the GI tract, so instead they require bile for their digestion and absorption. Upon absorption, they travel through the lymphatic system within chylomicrons before entering the bloodstream (where many of them still require protein carriers for transport.) Water soluble vitamins move directly into the blood.
The heat generated in a bomb calorimeter for protein is 5.6 kcal/g, yet on a food label it tells me that protein is 4 kcal/gram. Why are these values different? (Hint: 2 factors are subtracted)
Two factors are subtracted: (1) digestibility factor: this is a small adjustment for the fact that not all nutrients are digested and absorbed (2) nitrogen factor: unlike the bomb calorimeter, the body cannot use nitrogen bonds for energy. Therefore, a nitrogen factor is subtracted from the heat of combustion for protein only
Sonia consumed ~2800 µg of vitamin A (~400% of her RDA) as vegetables and one daily vitamin yesterday. Is she at risk of toxicity? If she ate a pound of carrots on a fad weight loss diet, would she be at risk of hypervitaminosis A? Recall the definition of UL.
UL for Vitamin A = 3,000 micrograms of RAE/day Toxic symptoms can develop after large amounts of retinoids are consumed in supplements over a short period of time. Sonia is very close to the UL and may start to develop symptoms if she takes any more. Because she ate a pound of carrots, she is not at risk for hypervitaminosis A because this is caused by high levels of retinoids- carrots contain carotenoids. High intakes of provitamin carotenoids are not associated with toxicity symptoms, but may cause the skin to temporarily turn yellow. Definition UL: the maximum daily amount of a nutrient that appears safe for most healthy people and beyond which there is risk of adverse health effects
To meet one's need for vitamin A, rich sources of carotenoid-containing vegetables only need to be consumed a few times each month. Why? Compare plant and animal sources of vitamin A. How many carrots would it take to fulfill your RDA for vitamin A? Is milk a good source of vitamin A?
Vitamin A is stored in large amounts in the liver. Plant sources contain carotenoids, not retinoids: dark, leafy greens, rich yellow or orange vegetables Animal sources (richest source of retinoids): liver, fish liver oils, milk and milk products, butter and eggs RDA = 700 micrograms for women, 900 micrograms for men 2 handfuls of carrots would fulfill your RDA Reduced-fat, low-fat, and fat free milk are fortified with vitamin A to contain the same amount as whole milk.
Why are vegan vegetarians at risk for low B12 nutritional status?
Vitamin B12 is naturally found in animal foods such as meat, fish, eggs and milk. A person can get adequate amounts of B12 from other supplements, but a person on a vegan/vegetarian diet who is not getting these supplements would develop a deficiency within a couple of years after B12 stored in the liver has run out.
3 components of energy expenditure and their associated percentages. For the average semi-sedentary American, what category is responsible for the most calorie expenditure?
basal metabolism 60-65% physical activity (percent varies, 25-50%) food consumption 10%
Describe components of the Weight Maintenance Wheel (3)
behavior modification, physical activity, healthy eating plan
Describe the difference between a coenzyme and an enzyme.
coenzyme: organic molecule that works with an enzyme to perform a catalytic job enzyme: protein that facilitates chemical reaction without being changed in the process; protein catalysts
What is a reasonable reduction in kcals/day (either from food or exercise) for a healthy weight loss diet?
deficit of 500-750 kcalories/day
"Don't count ________," "The goal is not simply weight loss, but __________."
kcalories, health gains
Describe the two bariatric surgeries used to treat severe obesity in adults. List the 4 criteria for approving an adult for gastric bypass surgery. List some possible complications due to this procedure. The success of long term effectiveness of gastric surgery depends on ___________________.
(1) Gastric bypass: surgeon constructs a small stomach pouch and creates an outlet directly to the small intestine, bypassing most of the stomach. This suppresses hunger by changing production of gastrointestinal hormones. (2) Gastric banding: surgeon uses a gastric band to create a small stomach pouch. The size of the opening can be adjusted via a port in the abdomen. - Four criteria: unable to achieve adequate weight loss with diet and exercise, BMI > 40, no medical or psychological contraindication, understanding of risks and strong motivation to comply wit post-surgery treatment plan. - Complications: vitamin and mineral deficiencies, development of psychological problems "The success of long term effectiveness of gastric bypass surgery depends on compliance with dietary instructions."
4. Why are elderly at risk for marginal vitamin D deficiency?
(1) skin, liver and kidneys lose their ability to make and activate Vitamin D with age (2) older adults typically do not drink milk (3) older adults typically spend most of their time indoors and wear protective clothing
Active vitamin D as 1,25 dihydroxy vitamin D (also called calciferol) has 3 target tissues. Name those tissues (i.e. organs). Now describe what the physiological response is when calcium is low in the blood and vitamin D is activated
(1) small intestine: vitamin D stimulates Ca-binding proteins to aid in the absorption of Ca into the body. (2) kidney: If blood Ca level is low, the kidney is signaled by vitamin D to increase Ca reabsorption, drawing Ca back into the body (3) bone: as a last resort, if blood Ca levels are low, vitamin D promotes the release of Ca from bone storage back into blood
How many Calories (kcals) are equivalent to one pound of adipose tissue (fat tissue)? What are the limitations of weigh loss estimates based on these numbers?
- Adipose tissue is primarily fat (87%) Each pound of adipose tissue equals approx. 3,500 kcals. An individual who consumes 500 kcals beyond his/her energy needs each day will store the excess energy and have a net gain of about 1 lb of adipose tissue each week. (500x7 = 3500) and vise versa with losing weight. If a person is losing weight, basal metabolism is changing downward, so that weight loss slows with time, and may even plateau.
List and review the components of behavior modification strategies that can be used to assist in sustained behavior change in order to lose weight or maintain a healthy body weight.
- Become aware of the behavior that created the problem - Change behaviors - Cognitive skills: problem-solving and cognitive restructuring of thoughts to promote behavioral change - Personal Attitude: responding more appropriately to stressors - Support Groups
Leptin, neuropeptide Y, and cholecystokinin (CCK); From a purely speculative point of view, which of these might help each to either reduce or increase one's appetite and food intake, as wished?
- Cholecystokinin CCK is released from the small intestine when fat is present and sends a strong signal of satiety and inhibits food intake. - Neuropeptide Y is a chemical that is produced in the brain and has been shown to cause carbohydrate craving. - Leptin is a protein that acts as a hormone in the hypothalamus, maintaining homeostasis by regulating food intake and energy expenditure in response to adipose tissue. When body fat increases, leptin increases, which suppresses appetite. When mice are injected with leptin, their fat cells decrease in size and self-distruct. Leptin deficiencies have been tied to obesity in humans, and when given injections of leptin these humans lost substantial amounts of weight. Leptin injections effectively increase satiation after weight loss.
List the strong points and the weak points of the Dukan Diet, Wheat Belly, and The Zen Diet Revolution.
- Dukan diet: ☺ encourages daily exercise, moderate salt intake, and lifelong weight management. The Dukan diet follows a highly structured plan. ☹ reduces carbs to induce ketosis, not suited for vegetarians who prefer not to emphasize animal proteins. - The Wheat Belly: ☺ No wheat makes for a very low-calorie diet. ☹ This would likely be low in B vitamins, calcium and vitamin D. - The Zen Diet: ☺ Offers a basic nutrition approach that does no harm and reminds you to make food meaningful and treat your body with respect. ☹ Recommendations to use fat-burning herbs, supplements, and green tea to decrease fat cells are unsubstantiated and expensive.
Comment on the effects of nutrient composition of a meal on satiation and satiety. Contrast low energy density with high energy density. Which has the lowest energy density: an apple or a candy bar?
- Energy-dense foods have more kcals/g. The nutrient with the highest amount of kcals/g is fat, therefore foods with higher fat composition are more energy dense. - Foods low in energy density are more satiating. - Fat has a weak effect on satiation during a meal, but once it is in the small intestine, it produces strong satiety signals and triggers the release of cholecystokinin. - A candy bar has a higher energy density because it provides more kcals/g than an apple.
Explain the issue which prompted the Food and Drug Administration (FDA) in 1998 to approve the enrichment of flour (and other cereal products) with folic acid? What is neural tube defect? Why must women during their child bearing years (even before they are pregnant) be aware of their folate/folic acid intake? (Chpt 10 and p. 476-478) Since fortifying the food supply in the US, has the incidence of neural tube defect been reduced to zero? List foods rich in folate.
- High folic acid supplementation to women prior to contraception and during early stages of pregnancy deceased the risk of some congenital malformations including neural tube defects of the spine (spina bifida) skull and brain. - Neural tube defect: malformations of the brain, spinal chord, or both during embryonic development that often results in lifelong disability or death. - Folate supplements taken 1 month before conception and continued through the first trimester (critical period) can prevent such defects. - Folic acid fortification has shown a 25-50% fall in the rates of neural tube defects. - Foods rich in folate: broccoli, tomato juice, pinto beans, lentils, asparagus
Why is beriberi a potential problem in populations which consume most of their kcals from "polished" rice? Americans eat lots of polished rice, yet do not get beriberi, why? What American subpopulation may be at risk for thiamin deficiency and why? Briefly describe the metabolic role of thiamin.
- Historically, beriberi was characterized in Indonesia in populations consuming polished rice (white rice.) This is because the bran and germ contain thiamin and are removed during processing to polish the rice. - Rice in the U.S. are fortified with Thiamin, and rice sold in the U.S. should not be washed prior to cooking. - Malnourished, homeless and recent immigrants may be at risk for thiamin deficiency. People who derive most of their energy from empty kcalories and beverages are at risk. Alcohol impairs thiamin absorption and enhances thiamin excretion in the urine, doubling the risk of deficiency. An estimated four out of 5 alcoholics are thiamin deficient. - Thiamin is used in energy metabolism, converting pyruvate to acetyl CoA.
Characterize leptin as to where it is synthesized, where does it go, and what does it do. Why was Theresa obese? What is the location and function of the MC4 receptor? How many people are affected by the genetic defect described in this video? What can scientists do with this information about the MC4 receptor in terms of helping people control their weight?
- Leptin is a hormone, synthesized in adipose fat tissue, that sends signals to your brain on whether or not you are starving or full. When humans lack the hormone leptin, they eat more and become obese. If you were to give a person leptin injections, they would eat less, lose weight, and their fat content would go down. - A central switching component in the leptin process is the melanocortin 4 receptor or MC4R, which receives and passes on the message to damp down hunger. If these receptors are altered by genetic mutation, their surface becomes malformed, unable to process the message to switch off appetite. - Theresa was obese because her MC4 receptor was malformed. - The hope is to create medications that help people who have these genes to manage their weight.
Your genetics and epigenetics for lipoprotein lipase (LPL) can affect body weight regulation. How? Where is LPL located in the body?
- People who are obese typically have more LPL in their adipose tissue than leaner people. - LPL is located on the cell membrane. When excess energy is consumed, adipose cells increase production of LPL, encouraging fat deposition/storage.
Pellagra was in epidemic proportions in this country around 1910-1930. What are the symptoms of this disease? What were the dietary conditions which precipitated this disease? What was the significance of a low protein diet? How did our public health officials resolve the situation so that pellagra is now eradicated in this country?
- Symptoms: diarrhea, darkening and flaking of the skin, dementia and sometimes death. - Causes: low socioeconomic populations during this time consumed most of their energy from corn products. Corn is low in protein, therefore low in tryptophan. - Public health resolution: In 1938, the U.S. mandated fortification of processed grains such as flour and rice with niacin, thiamin and riboflavin. Today there is no risk of niacin deficiency in the U.S. food supply because food is rich with fortified grain and high quality protein.
Is your body an apple or a pear? So what; why is this important? What are the cut-offs in terms of adult waist circumferences and risk for increased chronic diseases?
- apple shape = visceral fat: fat that is stored around the organs of the abdomen is also referred to as central obesity or upper body fat. This type of fat contributes to heart disease, cancers, diabetes, and related deaths. - pear shape = Subcutaneous fat: fat located primarily on the hips, buttocks, and thighs - In general, women with a waist circumference of 35 inches and men with a waist circumference of 40 inches have a high risk of central obesity-related health problems.
Describe the principles of the non-diet philosophy
- diversity - no ideal body size - self-esteem and body image are strongly linked - appearance stereotyping is inherently unfair and based on superficial factors - we respect the bodies of others - each person has a responsibility to take care of his or her own body - good health is not defined by body size; it is a state of physical, mental and social well-being - no matter what size you are you can always reduce your risk of poor health
List the benefits of physical activity for managing body weight. (discretionary calories? metabolism? body composition? appetite? psychological benefits?)
- increases lean body mass, increases basal metabolic rate, improves cardiovascular fitness, blood pressure, and decreases insulin resistance, increases feelings of self esteem. - Discretionary calories: Physical activity increases discretionary kcalories, because although energy needed to maintain weight increases with physical activity, energy needed to supply nutrients remains the same. This creates wiggle room in weight loss diets. - Metabolism: increased physical activity increases metabolism, both immediately after a workout and overall in the longrun to support weight loss or maintenance. - Body Composition: physical activity leads to less body fat and more lean body mass. - Appetite control: workouts suppress digestive functions and help to curb inappropriate appetite that results from boredom, anxiety, or depression. - Psychological benefits: physical activity helps to reduce stress, improve body image and separate the connections between body image and self-worth.
Explain the difference between dietary fat having a low satiation in the stomach, verses fat producing satiety signals when in the small intestine (think energy density). What nutrient is considered most satiating?
-Fat has a weak effect on satiation during a meal, but once it is in the small intestine, it produces strong satiety signals and triggers the release of cholecystokinin. - Of the three energy-yielding nutrients, protein is the most satiating (keeps you fuller, longer.)
What are two other criteria (besides BMI) which should be used to determine healthy body status in an individual?
-body composition: how much of the weight is fat vs. lean body mass (muscle weighs more than fat!) - fat distribution: where the fat is located
what are the factors influencing energy expenditure for thermic effect of food
-meal size (larger meal = more energy to process) - composition (it takes more energy to process protein than it does to process carbs, more to process carbs than fat.)
How much orange juice must you drink to get your RDA for vitamin C?
1 cup of orange juice provides more than 100 mg (super tracker says 84 mg) RDA = 75-90 mg/day
Biotin is needed to keep the TCA cycle going by making oxaloacetate from pyruvate as well as for other metabolic needs such as fatty acid metabolism. We get biotin from two sources; explain.
1) widespread in food; liver, egg yolks, soybeans, fish, whole grains (2) produced by GI tract bacteria
There is 10 micrograms of vitamin D in 1 quart (4 cups) of milk. How does the level relate to the RDA for children and adults? The current RDA's assume no exposure to sun at all.) How much sunshine weekly and to how much skin surface would you recommend to people who consume no dairy products? How does this recommendation change with individuals with darker skin color? How does living north of 40° latitude (including central Pennsylvania) impact vitamin D needs throughout the year?
4 cups of milk provides 10 micrograms of vitamin D. The current RDA for adults is 15-20 ug and 15 for children, but this assumes NO sun exposure. Sun recommendation: 5-10 minutes 2-3 times a week Dark skinned people require as much as 4 to 6 times more sunlight exposure than light skinned people. Above 40 latitude, vitamin D synthesis ceases for 4 months of the winter. Some people may miss as much as 6 months of vitamin D production.
What weight would health experts set as a safe and reasonable goal for Sonia to attain from a weight loss diet? Sonia should lose about ___ % of her body weight over a 6 month period or ____ lbs/week.
5-10% or .5 to 2 lbs
How many kcals do you have to remove from your diet (and/or expend by exercise) to lose about 1 pound of body weight per week? Use the "3500 kcal rule." Describe the limitations of this 3500 kcal rule. Most probably, does this calculation overestimate or underestimate actual weight loss projections in humans?
500/day x 7 days = 3500 kcal or 1 lb per week This calculation OVERestimates weight loss. But, limitations: - When a person is losing weight, basal metabolism is moving downwards - Body composition (lean mass vs. fat)
Define a megadose of vitamin C? What is the bottom line on the effect of high doses of vitamin C on the common cold and cancer? List the side effects and negative consequences of chronically consuming high amounts of vitamin C as a daily supplement?
A megadose of vitamin C would exceed the UL Intake which is 2,000 mg/day There is no scientific evidence that excessive amounts of vitamin C prevent colds or prevent or cure cancer. Side effects of toxicity: gastrointestinal stress, diarrhea, false positives or negatives on urine tests testing for diabetes, counteraction of anticlotting medications, kidney stones.
It is July and we've been having sunny weather in State College. You are watching your friend's soccer matches wearing a short sleeve shirt and light weight long pants. You tend to go watch 2-3 times per week. How long will it take a fair skinned individual to meet his/her vitamin D needs? A) 5-10 minutes for each match B) 30-45 minutes for each match C) 60-90 minutes for the total of 3 matches D) 3-4 hours over the course of two matches E) Never could you get your vitamin D needs by sun exposure in State College.
A) 5-10 minutes for each match
Which of the following functions is shared by beta-carotene and vitamin E? A) Inhibition of oxidation B) Prevention of keratinization C) Inhibition of bone calcium loss D) Prevention of hemolytic anemia
A) Inhibition of oxidation
Which of the following describes an association of vitamin A and vision? A) Light causes retinal to shift from a cis to a trans configuration B) Retinoic acid is the form required for synthesis of retinoblasts. C) Pigment molecules in the retina are composed of a molecule of vitamin A bound to an omega-3 fatty acid. D) Retinoic acid is the form bound to rhodopsin in the membrane of the retina. E) A and D are both true.
A) Light causes retinal to shift from a cis to a trans configuration *** retinal, not retinoic acid, is the form bound to rhodopsin in the membrane of the retina
Which of the following describes an event in the visual response process? A) Light energy strikes the retina and excites pigments to release retinal. B) Light energy strikes the cornea and excites pigments to release retinoic acid. C) Visual pigments deep in the brain are excited by light transmitted through the retina. D) Epithelial cells on the surface of the eye respond to light energy by transmitting opsin molecules along nerve pathways to the brain.
A) Light energy strikes the retina and excites pigments to release retinal -When light strikes the retina, rhodopsin responds and opsin is released and retinal shifts from cis to trans.
Bo has just had a baby girl. When she brings the child home, she regales you with the details of her hospital stay. She mentions that shortly after the birth, the child received an intramuscular injection of vitamin K, and she wondered why this was done, as it made her cry. You explained that it A) Prevented possible bleeding events. B) Was needed to promote good bone growth. C) Protected the baby from lipid oxidation. D) Was needed to prevent eye disease.
A) Prevented possible bleeding events. Vitamin K is a coenzyme that activates proteins that help blood clotting.
Your sister Ellen has just joined the Peace Corps and will be working on ways to improve the nutritional status of children in Indonesia. Once there, she saw that many of the children and some adults suffer from night blindness. Which of the following foods should she recommend be incorporated into the Indonesian diet to help prevent future generations from developing this condition? A) Sweet potato. B) Peanut butter. C) Pork. D) Orange juice.
A) Sweet potato Sweet potato is a deep yellow/orange vegetable that contains Vitamin A
A recent clinical trial found that smokers who were given supplements of beta-carotene had increased risk for lung cancer compared to those not given beta-carotene. A) True B) False
A) True
What type of person needs more body fat? Needs less body fat?
Athletes need less body fat. People living in very cold climates and women who are pregnant need MORE body fat.
Which of the following is NOT among the features of the fat-soluble vitamins? A) Can be stored in the liver and adipose tissue. B) Absorbed directly into the vascular (blood) system. C) Found in the fat and oily parts of foods. D) Pose a greater risk for developing a toxicity than water-soluble vitamins.
B) Absorbed directly into the vascular (blood) system. - require bile, enter the lymph, then blood
Your old friend from high school has just moved to Northern Canada to do full-time research on bats in caves. She typically works in the caves during the day when the bats are there and leaves at sundown when the bats are active. Since your friend only purchases organic and all natural foods, which of the following would you most likely advise she buy regularly at the grocery store? A) Whole-grain bread B) Vitamin D-fortified milk C) Vitamin A-fortified carrot juice D) Omega-3 fatty acid-fortified milk
B) Vitamin D-fortified milk because she is not getting enough sunlight!
Why does it take years to develop B12 deficiency and only weeks or months to produce folate deficiency?
B12 deficiency might take years to develop because B12 is stored in the liver and efficiently reabsorbed via enterohepatic circulation. The liver incorporates excess folate into bile. If the cells in the GI tract are damaged in any way, the folate is lost and deficiency rapidly develops (such as in alcohol abuse.)
What factors or characteristics can raise basal metabolic rate (BMR) and what factors can lower basal metabolic rate? When you eat a very low kcal intake (say, cut your calories in half) from your usual kcal intake for a few days, what happens to your BMR?
Body composition: leaner body mass = higher BMR Gender: male hormones lead to higher BMR than female Age: BMR decreases as we age Fever: raises BMR Environmental temperature: heat and cold raise BMR (think homeostasis) Fasting/starving or a low calorie diet: lowers BMR Hormones: both raise and lower BMR Smoking: raises BMR growth
Terry is trying to lose 10 pounds quick and is now following a fad diet she read about in a magazine. For 3 weeks now she eats a small breakfast, lunch is a half a pound of carrots, and supper is a salad. She is now panicking because her skin is turning an odd yellow. You would tell Terry: A) Well, you look like you have a sun tan. Enjoy it. B) Stop those carrots. Beta-carotene is toxic and you may already have liver damage. C) Stop those carrots. Your liver and skin is over storing beta-carotene, but don't worry because beta-carotene is not toxic. D) You are accumulating retinal in your liver and fat of your skin cells. This is not good, so don't get pregnant for 6 months until you can get rid of it. Stay off wacky diets.
C) Stop those carrots. Your liver and skin is over storing beta-carotene, but don't worry because beta-carotene is not toxic.
Why is there a UL for niacin? (Lesson 8 and Chpt 10) Note that the UL reflects quantity in a supplement rather than niacin in food.
Many vitamins that pose no risk of toxicity when consumed in food can reach toxic levels when taken as supplements. It is possible to experience Niacin toxicity. Vitamins in food have a physiological effect while vitamins in supplements have a pharmacological effect.
A group of rats were fed a diet with adequate amounts (about the RDA levels) of all essential nutrients except niacin (extremely low amounts). They grew just as well as the control rats that were fed all nutrients including niacin. Explain why (hint: protein was adequate). Niacin is still considered an essential nutrient for humans. Why?
Niacin can be obtained directly from foods AND can be synthesized in human cells from the amino acid tryptophan. In 1938, the U.S. mandated fortification of processed grains such as flour and rice with niacin, thiamin and riboflavin. Today there is no risk of niacin deficiency in the U.S. food supply because food is rich with fortified grain and high quality protein. Niacin is still considered an essential nutrient for humans because some humans do not have tryptophan and therefore cannot make Niacin on their own
Now list factors identified as important when developing eating plans for weight loss and maintenance of a healthy weight.
Nutritional adequacy - lose weight while still meeting nutrient needs Eat Small portions Slow down Lower Energy Density Remember Water - water fills the stomach, can replace sweetened beverages, and helps the GI tract adjust to a high-fiber diet. Focus on fiber Choose fats sensibly Select Carbohydrates carefully Watch for other empty kcalories
Experts recommend that weight reduction diets should not be below 1200 kcal per day. Why?
Nutritional adequacy is difficult to achieve on fewer than 1200 kcalories.
If you ate a nice lunch of steak and eggs, which provided 300 mg of tryptophan, how many milligrams of niacin equivalents did this meal provide? How does this compare to the RDA?
One needs to eat 60 mg of tryptophan for the production of 1 mg of niacin. 300/60 = 5 mg of Niacin. RDA for Niacin = 14-16 mg/day
Describe rickets versus osteomalacia. Who is most at risk for rickets now in U.S.? Why is this population at risk?
Osteomalacia occurs in adults and results in the bones to become increasingly soft, flexible, brittle and deformed. Rickets: bones fail to calcify normally, causing growth retardation and skeletal abnormalitites. The bones become so weak that they bend when they have to support the body's weight. Breast-fed infants are at risk for rickets because breast milk is low in vitamin D.
Sonia has struggled with overweight throughout her childhood and adult life. Zoom ahead 20 years and Sarah becomes obese in her 40's. Explain the differences between fat cell development between Sonia and Sarah. Explain why Sonia will likely have more difficulty losing weight than Sarah will. Compare hyperplastic vs hypertrophic obesity. (Chpt 9)
People with extra fat cells tend to regain lost weight rapidly, while people with an average number of enlarged fat cells may be more successful in maintaining weight loss. The number of fat cells increases most rapidly during childhood and this period sets the course for the rest of a person's life. - In hyper plastic obesity (Sonia), there is a greater-than-normal number of fat cells that are also larger than normal. This type of obesity is associated with massive obesity and begins at an early age. - Hypertrophic obesity (Sarah) results from normal number of fat cells that have increased in size. This type of obesity is more common, is associated with moderate obesity or "overweight," and typically develops in adults.
Describe in a brief sentence the roles of niacin (NADH) and riboflavin (FADH2) in ATP production.
Riboflavin coenzyme is FAD. FAD picks up H+ ions and their electrons in the TCA cycle and delivers them to the electron transport chain, where 2 ATP are produced. Niacin coenzyme is NAD, which also picks up H+ in glycolysis and in several places in the TCA cycle and carries it to the electron transport chain where 3 ATP are produced.
A person suffering from scurvy has pinpoint hemorrhaging in the skin and at points of the body where there is mechanical stress, like on the gums and joints. Why? Discuss the biological role of ascorbic acid and iron to explain this observation.
Scurvy reflects the role of vitamin C in collagen formation. Collagen is a strong protein that is the matrix on which teeth and bone form. It is necessary for skin, muscle, blood vessels, and wound repair. Vitamin C helps iron serve as a cofactor in the hydroxylation of proline to hydroxyproline. Without Vitamin C (aka absorbic acid) and iron, the collagen is weak which causes blood vessels to rupture, causing pinpoint hemorrhages, bruising, slow wound healing, bleeding gums and loose teeth.
Vitamin D has been described as both a vitamin and a hormone. Explain your answer. We can synthesize previtamin D in our liver from cholesterol. Why is vitamin D referred to as the sunshine vitamin?
Vitamin D is a hormone because it is produced in one part of the body (liver) and acts on other organs (small intestine, kidney, bone) Vitamin D is made in the body after skin is exposed to UV rays from sunlight.
Is vitamin K's role in the body as a coenzyme? What is vitamin K's role in the clotting process?
Vitamin K functions as a coenzyme which activates proteins required for the blood clotting process and binds minerals in bones.
Describe the Set-Point Theory. Does this mean that no one can ever lose weight and keep it off?
When weight decreases, energy expenditure via basal metabolism decreases, making weight loss harder. People easily regain weight after having lost it because they are battling against enzymes that want to store fat. Biological mechanisms seem to set a person's body weight or composition at a fixed point; the body will make adjustments to restore that set point if the person tries to change it.
What are the differences in LPL distribution between females and males and between lean and obese humans as reported by researchers that may explain genetic differences in risk for cardiovascular disease?
Women have increased production of LPL in the hip and thigh region, while men have increased LPL activity in the abdominal region. This explains the tendency of men to have more central obesity (apple shape) compared to women.
With severe vitamin A deficiency Xeropthalmia may result. What is Xeropthalmia? Describe retinoic acid's involvement in this form of irreversible blindness by explaining vitamin A's role in epithelial cell differentiation.
Xeropthalmia is complete and irreversible blindness. Xeropthalmia is caused by a lack of vitamin A at the front of the eye- the cornea. At first, the cornea becomes dry and hard because certain eye cells stop producing mucous and instead produce keratin, then progresses to softening of the cornea which leads to irreversible blindness.
What is a free radical? Are they normally produced in the body? Why must the body have controls over free radical production? What types of molecules are being protected and why? What is one positive role of free radicals in the body?
free radical: an unstable molecule with one or more unpaired electrons SOME free radicals are produced in the body Free radicals attack other molecules in the body because they are looking for electrons to take. Free radical attacks cause widespread damage: they damage polyunsaturated fatty acids in lipoproteins and in cell membranes, disrupting transport of substances in and out of cells. Free radicals also alter DNA and RNA, creating excesses and deficiencies of proteins which then impairs cell functions, contributes to disease progression and aging. Vitamin E protects: polyunsaturated fatty acids, LPL, DNA from damage Free radicals can be used in oxidative bursts by the body as an effort to demolish disease-causing bacteria and viruses.
What variable that could contribute to a teenager's Total Energy Expenditure (TEE), is not accounted for in the TEE for adults? Note that a body builder laying down lean body mass would also not account for this variable.
growth: the BMR is high in people who are growing. For this reason, pregnant women, children, and adolescents have their own sets of energy equations
What does a bomb calorimeter measure? Briefly describe how it works.
measures: potential energy. A bomb calorimeter measures the heat released from a food when the dried food is burned (aka its potential energy or heat of combustion)
basal metabolic rate BMR
textbook: the rate at which the body expends energy for life-sustaining functions lesson: energy required to maintain life when the body is at complete rest and fasting for 12 hrs
lean body mass is
the body minus its fat
