Nutrition 251 Exam 3
discuss the process of vitamin D activation:
-UV light will trigger endogenous synthesis in the skin (7-dehydrocholesterol to D3 or ergocalciferol) -it is converted to its active form in the liver (25-hyroxyvitamin D aka calcidol) -the circulating form is converted to the active form in the kidneys. the active form of Vitamin D is called 1,25-dihydroxyvitamin D aka calcitriol
strength and limitation of each measure of body composition?
-calibers: cheap to use, but lot of training required and error in measurement -BMI: cheap and easy and fairly accurate, but not always accurate in fat compared to muscle -Bodpod: very expensive, but very accurate -underwater weighing: very accurate, but have to find someone willing to be submerged in water -BIA: accurate depending, can be cheap and can do it at the gym some places, lack of conduciveness, making sure fluid status is appropriate in oder to accurate measurements -DXA: very accurate and gives location of fat, but very expensive
what strategies are common among individuals who are successful at maintaining weight loss?
-exercise regularly (60-90 min daily) -make small and comfortable changes in diet -eat breakfast -eat smaller, more frequent meals -choose low-fat foods -keep track of their weight, intake, and physical activity -emphasize low energy dense foods in diet -drink lots of water
what percent of energy expenditure comes from thermic effect of food?
10%
what is the RDA for children and adults for vitamin D
15 micrograms/day of 600 IU/day
BMI cut-off for healthy weight:
18.5-24.9
One tablespoon of corn oil contains 2-3 mg of vitamin E. How much corn oil is needed to give you your RDA? (See front cover of text for RDA.) Why are vitamin E deficiencies rare?
2-3 mg=2000-3000 micrograms. Since the RDA for adults, males and females, is 900 and 700 micrograms respectively, this is over the RDA. Vitamin E deficiencies are rare because it is present in many foods
BMI cut-off for overweight:
25-29.9
what percent of energy expenditure comes from physical activity
30-50%
what percent of energy expenditure comes from basal metabolism?
50-60%
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?
60 mg of tryptophan=1 mg of niacin 1 niacin equivalent = 1 mg of niacin -300 mg of tryptophan/ 6 mg = 5 niacin equivalents
approximate prevalence of adult overweight and obesity combined in the US adults:
70.7% of US adults are either overweight or obese
where is excess vitamin A stored in the body?
90% of vitamin A stored are in the liver
BMI cut-off for underweight:
<18.5
how many adults are underweight in U.S.?
<2%
folic acid toxicity can mask a ___________ deficiency
B12
which vitamin plays a critical role in the formation of myelin?
B12
why does it take years to develop B12 deficiency and only weeks or months to produce folate deficiency?
B12 is a fat soluble vitamin and folate is a water soluble vitamin
what are the roles of gastric acid and intrinsic factor in B12 absorption?
B12 is attached to protein. in the stomach, HCL and pepsin cleaves release it from protein. Intrinsic factor is released from the stomach and is required for B12 absorption. it attached to B12 and in the small intestine, IF is recognized by a receptor and B12 is absorbed.
why are vegans/vegetarians at risk for low B12 nutritional status?
B12 is naturally found in animal foods (meat, fish, eggs, and milk)
how does a vitamin B12 deficiency cause a folate deficiency?
B12 removes a methyl group to activate the folate coenzyme. when folate gives up its methyl group, the vitamin B12, coenzyme becomes activated. so it causes deficiency because without B12, folate cannot be activated
what are the 3 indicators of risks to health from obesity?
BMI (25-29.9; >30) waist circumference (>30;>40) disease risk profile
rate at which body expends energy for life sustaining activities
BMR
when you eat a very low kcal intake from your usual kcal intake for a few days, what happens to your BMR?
BMR decreases
which TEE is most variable?
EEPA
Is vitamin K's role in the body as a coenzyme? What is vitamin K's role in the clotting process?
It activates proteins required for blood clotting (prothrombin-> thrombin). It is required to make proteins that bind calcium to bone (osteocalcin)
describe in a brief sentence the roles of niacin and riboflavin in ATP production
NAD picks up a H+ in glycolysis and in different places in the TCA cycle. it carries it to the ETC where each NADH make 3 ATP. FAD picks up 2 H+ ions and their electrons in the TCA cycle and delivers them to ETC where 2 ATP are produce
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-they are born with sterile intestinal tract and their plasma prothrombin concentrations are low.
vitamin B6 facilitates the release of energy like other B vitamins, but from protein rather than carbohydrates and fats
PLP assists enzymes that cleave off the amino group on some amino acids making available the carbon part of the molecule for energy metabolism. amino acids are a component of carbs rather than proteins
B6- pyridoxine
PLP or pyridoxal phosphate : facilitate energy metabolism and amino acid metabolism
what is the deficiency of niacin called and what are the symptoms?
Pellagra, diarrhea, dermatitis, and dementia, and death
critical to recent food and physical activity are not as strict (usually higher than BMR)
RMR
describe the role of vitamin E as an antioxidant:
Vitamin E halts the chain reaction of free radicals. It protects membranes and cells from oxidation. It also protects LDL from oxidation of the polyunsaturated fatty acids in their membranes.
Some vitamin K is from a non-dietary source. Explain. What foods are rich in vitamin K?
Vitamin k can also come from bacteria in the GI tract Vitamin k is stored in the liver Green vegetables, and vegetable oils
fat cells are called
adipocytes
adipose tissue produces _____________ which are metabolic changes like insulin resistance that indicate disease risk
adipokines
the condition of having less than the normal number of RBC or less than the normal quantity of hemoglobin in the blood
anemia
self-starvation, excessive weight loss and fear of gaining weight or being "too fat"
anorexia (usually shown as underweight)
a molecule capable of inhibiting the oxidation of other molecules
antioxidant
integrated response to sight, smell. thought, or taste of food
appetite
vitamin c
ascorbic acid
energy needed to maintain life when a body is at complete digestive, physical, and emotional rest
basal metabolism
does leptin increase or decrease in obesity ? does it become more or less efficient?
because it is made in adipose tissue the amount increases in obesity but become less efficient with obesity.
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 4kcal/g. why are these values different?
because the human body is not as efficient as the bomb calorimeter, some kcals have to be subtracts to account for digestibility and nitrogen
getting support from family and friends, identifying triggers to overeating, keeping a food record, and reducing stimuli are all what kind of strategies
behavior modification strategies
menstrual irregularities, infertility, increased risk of miscarriage, osteoporosis, and bone fractures, anemia, hair loss, irregular heartbeat, impaired nerve function, low bone density and others related to nutrient deficiencies. very hard to survive life-threatening diseases developed (reduced immune defenses) ALL of these are associated with what?
being underweight
involved compulsive overeating. includes episodes of binge eating without purging like in bulimia
binge eating disorder (overweight)
the rate at and the extent to which a nutrient is absorbed and used
bioavailability
biotin
biotin
what is neural tube defects?
birth defects of the spine, brain, or spinal chord. there are two types, anencephaly and spina bifida. in spina bifida, the spinal chord does not form completely. in anencephaly the brain and skull does not develop.
body fat high, leptin ______ = ________________
body fat high= leptin high=suppresses appetite
body fat low, leptin _________=______________
body fat low=leptin low= stimulates appetite and suppresses expenditure
involved cycles of binge eating and purging
bulimia (usually shown as a healthy weight)
what are the phsiological fuel values or carb, protein, fat, and alcohol:
cab: 4kcals/gram protein: 4 kcals/gram fat: 9 kcals/gram alcohol: 7 kcals/gram
excess fat around trunk of body; abdomen fat or upper body fat
central obesity
what is the hormone that signals satiety
cholecystokinin (CCK)
what food sources provide vitamin c?
citrus fruits, green peppers, strawberries, tomatoes, broccoli, and sweet and white potatoes
B12
cobalamin
what is the chemical name for vitamin B12. what does cobalt have to do with vitamin B12?
cobalamin- this reflects the presence of cobalt. cobalt is a trace mineral in the center of the chemical structure of vitamin B12
pantothenic acid
coenzyme A
the strong protein that is the matrix on which teeth and bone form
collagen
folate deficiency = ____________ =______________
decrease in cell division, megaloblastic anemia
when you lose weight, leptin _____________ causing satiation to _____________ as well which makes someone feel hungry ____________ between meals and challenges weight loss
decreases; reduce; faster
how does fiber impact satiety and satiation?
delays absorption so they are more satiating
how do you get from lbs --> kg?
divide by 2.2
why are elderly at risk for B12 deficiency (pernicious anemia)?
elderly are at risk because they may suffer from atrophic gastritis (thinning of the stomach lining). this reduces the amount of B12 absorbed by the SI and results in pernicious anemia.
negative energy balance =
energy intake < energy expenditure. results in the use of stored energy from glycogen, fat, and muscle (lose weight)
positive energy balance =
energy intake > energy expenditure. results in the storage of excess energy as adipose tissue (weight gain)
complications of bulimia:
erosion of teeth, gum disease, tears and burning of esophagus, electrolyte inbalance
what macronutrient provides highest level of satiety?
fat
how does the body shape of an individual influence health?
fat distribution around the abdomen (apple shape) increases the risks of diseases because all the organs are around the abdomen. central obesity is associated with increased risks of heart disease, stroke, diabetes, gallstones, cancer, sleep apnea, osteoarthritis, and liver disease.
dissolved into fat, not directly excreted, excess intake stored in body, deficiency symptoms develop slowly, not needed daily in diet, toxicity is possible because they are stored in body
fat-soluble vitamin
B2-riboflavin
flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN)
explain the roles of folate and B12 in blood health. what is B12's second role in the body?
folate and B12 facilitates the formation of RBC. B12 is a coenzyme for an enzyme in the production of nerve tissue myelin.
_________ ___________ is the synthetic form of folate used in supplements and fortified foods
folic acid
is folic acid or folate easier to absorb?
folic acid because monoglutamate is more easily absorbed
retinoic acid
functions in growth, cell differentiation, and immunity
gastric band to create small stomach pouch. the size of opening can be adjusted by inflating or deflating band by way of a port placed in the abdomen just beneath skin
gastric banding
small stomach pouch and creates an outlet directly to small intestine, bypassing most of stomach, the entire duodenum, and some of jejunum
gastric bypass
a protein produced by stomach cells that enhances appetite and decrease energy expenditure
ghrelin
hormone that acts as opposition to leptin:
ghrelin
BMI cut-off for obese:
greater than or equal to 30
what variables are accounted for in the DRI equation for calculating total energy expenditure?
height, weight, age, and sex
negative energy balance= ________ ghrelin
high
lack of sleep = ________ ghrelin and _________ leptin
high ghrelin, low leptin (THATS WHY YOU GAIN WEIGHT FROM LACK OF SLEEP)
explain how energy density could be useful in weight management
higher volume foods with lower energy density can increase satiety and replace high calorie foods; protein and healthy fat can help increase satiety as well; and high fiber. the less energy dense meal you have the more nutrient dense meal you have. it will still make you feel full providing you with more nutrients and less calories.
painful sensation caused by look of food
hunger
control center; energy intake, expenditure, storage from other parts of brain, GI tract, and liver
hypothalamus
leptin is primarily in the
hypothalamus
what organ monitors conditions to maintain homeostasis?
hypothalamus
explain how in the case of alcohol abuse, an individual can rapidly develop folate deficiency
if GI tract cells are damaged, folate is lost. in alcohol abuse, GI tract cells become damaged over time meaning folate deficiency rapidly develops and further damages the GI tract
describe the role of retinoic acid in the body? what would happen to a lab animal who only received retinoic acid and no other form of vitamin A?
if a lab animal were to only receive retinoic acid, and no other form of Vitamin A, they could see issues with birth defects, liver abnormalities, and decreased bone mineral density. they may also see problems with eyesight and reproduction
how do you get from inches to centimeters?
inches*2.54=cm cm/100=meters
what is the role of CCK in intake?
increases satiety which means it decreases our intake
vitamin D as 1,25 dihydroxy vitamin D has 3 target tissues. Name those tissues. what is the physicological response when calcium is low in the blood and vitamin D is activated.
intestines: vitamin D enhances Ca absorption kidneys: vitamin D promotes Ca reabsorption Bones: vitamin D will mobilize calcium from the bones
what nutrients are added to enriches grains?
iron, niacin, thiamin, riboflavin, folate, vitamin B6, mg, zinc, and fiber
what is night blindness and why does low Vitamin A status cause it?
is when there is not enough retinal (comes from Vitamin A) to recycle the trans form of retinal
if someone consumes a large dose of niacin, what is the resulting reaction called? note that the UL quantity in a supplement rather than niacin in food
it causes vasodilation. when there is a large amount in your blood, it has a pharmacological effect. it dilates the capillaries and causes a tingling effect known as the niacin flush.
why is there no pantothenic acid deficiency in the US?
it is found in a variety of food (beef, poultry, whole grains, potatoes, broccoli)
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.
it is part of the chemical structure of coenzyme A-the CoA that form acetyl CoA. it is therefore, involved in many steps in the synthesis of lipid, neurotransmitters, steroid hormones and hemoglobin.
where was beri beri first observed? why is it a potential problem in populations that consume most of their kcals from "polished" rice?
it was first observed in Indonesia when they started to polish rice. a good source of thiamin comes from the whole, fortified or enriched grains. polished rice has the outer bran layer removed so there is no thiamin. Americans consume a lot of products that are enriches, grains in particular. pork and legumes are also other sources of thiamin.
what is lean body mass and what is its role in weight management?
lean body mass raises BMR which makes your need for more energy to increase. higher BMR makes it easier to lose weight
protein produced by fat cells under direction of "ob"gene that decreases appetite and increases energy expenditure
leptin
what hormone decreases intake?
leptin
how does fat impact satiety and satiation?
little satiation BUT strong satiety signals (releases cholecystokinin-hormones that signals satiety)
positive energy balance = _________ ghrelin
low
what is the role of energy density in satiety and satiation?
low density food provides more satiation
folic acid = folate =
monoglutamate polyglutamate
how does carbohydrates impact satiety and satiation?
mostly satiation especially fiber because it slows absorption
how do each of the hormones and adipokines contribute to intake and weight?
neural peptide y (makes you crave carbs) and ghrelin increase obesity because they decrease satiety. leptin and CCK help decrease hunger which helps reduce obesity.
what is the significance of tryptophan in the diet in terms of niacin nutrition?
niacin can be synthesized in the body from tryptophan
B3-niacin
nicotinamide adenine dinucleotide (NAD) and NADP
all factors surrounding a person that promote weight gain, such as increased food intake, especially of unhealthy choices, and decrease activity
obesogenic environment
___________ ______________ is paying attention to hunger and satiety by restoring weight to a healthy level, while _____________ _____________ involves clinical evidence of eating disorder and misuse of eating functions
ordered eating, disordered eating
B12 deficiency = ________________
pernicious anemia
what are the health risks associated with obesity?
premature death, heart disease, diabetes mellitus, cancer, arthritis, quality of life issues
what macronutrient provides highest level of satiation?
protein
how does living north of 40 degree latitude impact vitamin D needs throughout the year?
reduces the amount of sunshine someone gets and vitamin D synthesis stops for 4 months
list the benefits of physical activity for managing body weight:
regular exercise increase BMR, helps control appetite, and has positive psychological benefits: increase lean body mass, increase BMR, imporves cardiovascual fitness, decreases blood pressure, decreases insulin resistance, increases feelings of well-being and self-esteem
what is the difference between rickets and osteomalacia?
rickets and osteomalacia are caused by vitamin D deficiency. rickets occurs in children, osteomalacia occurs in adults
feeling of satisfaction that occurs during a meal (determines how much food is consumed during a meal)
satiation
how does protein impact satiety and satiation?
satiation
"feeling fuller for longer" refers to what
satiety
feeling of fullness that occurs after meal (determines how much time has passed between meals)
satiety
what is a result of loss of collagen in the body
scurvy
lowing BMR=
sedentary adult, low levels of activity, lean body mass diminishing, body composition, poor nutritional state, gender
point at which controls are set and body tends to maintain a certain weight by means of its own internal controls
set-point
megaloblastic RBC are ____________ than normal red blood cells, and have an irregular shape
slightly larger
how would you explain the concept of internal regulation of eating to someone interested in losing weight?
start eating when you feeling like a 5 and stop eating around a 7. this prevents you from waiting too long before meals and settling for something unhealthy because you're hungry and also prevents you from overeating when you do decide to make yourself a meal
describe the role of retinal in the visual cycle by listing the steps in the process of Vitamin A's role in the visual cycle.
step 1: cis retinal will combine with opsin (a protein) to form Rhodopsin step 2: light will strike Rhodopsin (cis retinal opsin) and this will change cis retinal to trans retinal. trans retinal will break away from opsin step 3: trans retinal will need to be recycled into cis retinal (via Vitamin A intake) to keep this process moving
where is beta-carotene stored in the body?
stored in the skin. eat too many carrots you turn orange
fat stored directly under the skin
subcutaneous fat
why is vitamin D referred to as the sunshine vitamin?
sunshine activated previtamin D in the skin (7-dehydrocholesterol to D3 or ergocalciferol)
symptoms of Pellagra? what were the dietary conditions, which precipitated this disease? what was the significant 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, dermatitis, dementia, death. A lack of niacin causes pellagra. In the south, people were on a low-protein diet and they ate a lot of corn. Niacin is found in high protein foods. Public health officials ordered fortification of grain products.
folate
tetrahydrofolate : transfers one carbon units called methyl groups
how does the length of time one spends overweight/ obese influence ease of weight management?
the longer someone spends overweight, the more difficult it is to reduce their weight to a healthy level because they have more fat cells -adipocytes
Explain the issue that prompted the Food and Drug Administration (FDA) in 1998 to approve the enrichment of flour with folate?
there was a rise in the amount of neural tube defects
generation of heat; used as an index of how much energy that body is expending
thermogenesis
how do we measure energy expenditure in humans?
thermogenesis- generation of heat; used as an index of how much energy the body is expending
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?
they body needs to have controls because high levels of free radicals accelerate aging, lead to disease and cell damage. Polyunsaturated fatty acids, DNA and RNA and Protein are being protected. Polyunsaturated fatty acids can lead to lipid radicals, DNA and RNA can result in excess or too little proteins and proteins can be altered which leads to an impaired cell function and an inflammatory response. One positive role of free radicals in the body is that they play a part in the immune system (are released from immune cells in response to pathogens)
do carotenoids function as antioxidants? does vitamin A?
they both function as antioxidants
why are elderly at risk for marginal vitamin D deficiency?
they have a decreased synthesis of vitamin D, milk consumption and exposure to sunlight
how are fat-soluble vitamins absorbed into the body?
they require bile for digestion and absorption while water-soluble vitamins can diffuses across the epithelial membrane
will someone that has lost 30lbs require more, less, or the same amount of calories as someone who has been that (30lb lighter) their whole life?
they will require less energy because of their BMR. someone that has always been that weight will be able to have a higher intake than someone that is losing weight because their body is more comfortable at that state. someone that is losing weight is challenging their body to make changes that it doesn't necessarily want to make.
B1-thiamin
thiamin pyrophosphate
what is a free radical? are they normally produced in the body?
used to destroy pathogens in a process termed the respiratory burst, they are normally produced in the body
what does a bomb calorie measure?
uses direct calorimetry to povide a measure of heat released when a food is burned.
major food sources of vitamin E:
vegetable oils, seeds, nuts, and green leafy vegetables
compare plant and animal sources of vitamin A?
vegetables and fruits contain the precursors- carotenoids. animal sources contain retinoids
fat stored within the abdomen cavity in associated with the internal abdomen organs
visceral fat
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?
vitamin A is a fat-soluble vitamin so it is stored in adipose tissue and can be used as needed from there
describe vitamin A's involvement in this form of irreversible blindness by explaining vitamin A's role in epithelial cell differentiation
vitamin A is used to maintain the epithelial cells surrounding the skin and mucous membranes of the eye. when there is not enough vitamin A, to maintain these cells, the eye will begin to produce keratin, a protein that the epithelial cells will produce when they are under damage or stress.
vitamin D has been described as both a vitamin and a hormone, why?
vitamin D assists in bone growth (vitamin) while also protecting against cognitive decline and regulating cells of adipose tissue that influence the development of obesity (hormone)
___________ helps iron serve as a cofactor in the hydroxylation of proline to hydroxyproline which cements the protein matrix collagen
vitamin c
a person suffering from scurvy has pinpoint hemorrhaging in the skin and at point 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
vitamin c is responsive for making collagen in the body which is the issue in scurvy. vitamin c to make collagen so our body can stay intact in those areas
carried in blood, excreted in urine, needed in frequent small doses, unlikely to reach toxic levels in body, watery parts of body
water-soluble vitamin
why is niacin an essential nutrient for human?
we can make it from tryptophan only after protein synthesis needs have been met.
what must occur prior to folate absorption?
we have to remove a glutamate
what is BMI equation?
weight (kg) / (height in cm)^2
BMI=
weight in kg / (height in m) ^2
is milk a good source of vitamin A?
when milk is skimmed, vitamin A is lost, so reduced-fat or low-fat milks are usually fortified.
what is Xeropthalmis?
when the cells in the eye begin to produce keratin-which will lead to permeant eye blindness.
"the less dietary fat i consume, the less body fat i will have"
when you eat fat it doesn't just automatically become stored in the body as fat until you eat it in excess. but any of the macronutrients consumed in excess will be stored as fat in the body. fat is an essential nutrient so it is necessary to consume it everyday.
raising BMR =
when you're growing, high levels of activity, more lean body mass, gender, genetics, good nutritional state
biotin is found in what 2 sources
widespread in food sources including egg yolks. it also synthesized by bacteria in the GI tract
what is vitamin A's role in bone health?
with vitamin A, bone dismantling cells destroy selected sites in the bone, removing the parts that arent needs and allowing bone making cells to come in and build the bone
why must women during their childbearing years be aware of their folate intake? since fortifying the food supply in the US, has the incidence of neural tube defect been reduced to zero? list foods rich in folate.
women should be aware of their folate intake to prevent neural tube defects. rates dropped 25-50%. good sources are legumes, leafy green veggies, fortified grains
what are the cut-off in terms of adult waist circumferences and risks for increased chronic diseases?
women: >35 inches men: >40 inches waist circumference should be less than 1/2 person's height. as waist circumference goes up, risk of disease for up as well
what areas are highest in LPL activity for women and men?
women: breast, hips, and thighs have highest LPL men: abdomen produces highest LPL
