Biochemical Basis Of Nutrition (Bioc 7001)

Front 1

This chart shows the DRIs. What are they and what do they assess?

Back 1

EAR - Estimated average requirement (50% of measured requirements)
RDA - recommended dietary allowance (~2 SD > mean)
UL - upper limit before adverse effects are seen

Individuals: RDA and UL
Groups: EAR and variability

Front 2

Nutrients in bread, cereal, rice, pasta group? (8)

Back 2

Complex carbohydrates, dietary fiber, calories, niacin, thiamin, folate, B6, Mg

Front 3

Nutrients in vegetables and fruits? (9)

Back 3

Complex carbohydrates, dietary fiber, vitamins A and C, folate, thiamin, riboflavin, Mg, Mn

Front 4

Nutrients in milk and dairy? (10)

Back 4

Protein, Ca, P, vitamins A, D, and B6, thiamin, riboflavin, B12, Zn

Front 5

Nutrients in meat and beans group? (9)

("Chicks with dicks" = chicken nuggets + hot dogs)

Back 5

Protein, riboflavin, thiamin, niacin, vitamins B12 and B6, Fe, Zn, Cu (cholesterol and fat/complex CHO)

Front 6

Nutrients in fats, oils, and sweets group? (2)

Back 6

Essential fatty acids (EFAs), calories (satiety, flavor, texture, appetite appeal)

Front 7

Calorie level needed for many women and older adults?

Back 7

~1600 kcal

Front 8

Calorie level needed for children, teen girls, active women, and most men?

Back 8

~2200 kcal

Front 9

Calorie level needed for teen boys and active men?

Back 9

~2800 kcal

Front 10

% daily intake of calories from carbohydrates?

Back 10

60-65%

Front 11

% daily intake of calories from fat?

Back 11

20-25%

Front 12

% daily intake of calories from saturated fat?

Back 12

7-10%

Front 13

% daily intake of calories from protein?

Back 13

12-15%

Front 14

Recommended daily intake of sodium?

Back 14

2.4-3.0 g

(1 tbsp of soy sauce is 920 mg of sodium)

Front 15

Recommended daily intake of cholesterol?

(El Nino = Ground beef, sauteed onions, sour cream, lettuce, tomato and cheddar cheese wrapped in a large pepperoni pizza, totaling three pounds.)

Back 15

<300 mg

Front 16

Activity recommendations for adults wishing to:
1. Reduce risk of chronic disease?
2. Manage body weight and prevent gradual unhealthy body weight gain?
3. Sustain weight loss?

Back 16

1. 30 min moderate-intense physical activity on most days
2. 60 min moderate to vigorous activity on most days
3. 60-90 min moderate activity while not exceeding caloric intake requirements

Front 17

Physical activity recommendations for:
1. Children?
2. Pregnant women?
3. Breastfeeding women?
4. Older adults?

Back 17

1. at least 60 min most/all days
2. at least 30 min moderate activity most/all days
3. Acute or regular activity has no adverse effect
4. Regular activity reduces functional declines

Front 18

Food labels: Overall daily values based on daily intake of _______ kcal.

(Bacon wrapped pigs in a blanket wrapped in bacon)

Back 18

2000 kcal

There are 490 cal/ bacon wrapped pig in a blanket wrapped in bacon, so you can have 4 and still be safe :)

Front 19

Reference daily intake is?

Back 19

The highest RDA of all age and sex groups over 2 (not pregnant or lactating women).

Front 20

On nutrition facts, what four vitamins and minerals are included?

Back 20

Vitamin A and C, calcium, and iron

Front 21

What is the difference between primary and secondary nutrient deficiency/excess?

Back 21

Primary is due to diet, whereas secondary is due to a pathological problem.

Front 22

What is the energy store in adipose tissue (lipids)?

(Pictured is "The Sex Panther")

Back 22

9 kcal/gm

Front 23

What is the energy store in carbohydrates?

Back 23

4 kcal/gm

Front 24

What is the energy store in proteins?

Back 24

4 kcal/gm

Front 25

What is the difference between hyperplastic and hypertrophic obesity?

Back 25

Hypertrophic (increased cell size to max 0.7 micrograms) occurs in mild adult onset obesity. Hyperplastic obesity (increased number of adipocytes) starts in childhood or adolescence and is harder to manage.

Front 26

What is the difference between subcutaneous and visceral adipocytes?

-The fat removed in liposuction procedures is subcutaneous fat.

Back 26

Subcutaneous are smaller and pick-up/release FFA to general circulation. Visceral are larger, more sensitive to adrenergic stimulation, have higher metabolic activity, and release FFA to portal vein.

Front 27

Which type of adipose is more closely related to risk of HTN, CVD, hyperinsulinemia, and DM? Why?

Back 27

Visceral adipose tissue: more direct effect on liver metabolism.

Front 28

Body fat can be assessed by
1. Underwater weighing
2. Dual energy x-ray absorptiometry
3. Skinfold thickness
4. Bioelectric resistance
5. BMI
6. IBW
7. Regional fat distribution (Waist/Hip ratio; Waist circumference)

What are some advantages and disadvantages of the techniques?

Back 28

Underwater weighing and dual energy x-ray absorptiometry - most direct estimates; cannot be done in clinical offices/hospitals and are expensive.

Skinfold thickness and bioelectric resistance are indirect estimates that require special equipment and training and can be done in the office.

BMI or IBW are the most often used. The data uses mid 20s as the standard for all adults. People with decreased or increased lean body mass will have inaccurate measures.

Regional fat distribution - quick measure

Front 29

BMI:
1. How is it calculated?
2. What are the BMI values of:
a) average
b) overweight
c) obese
d) medically significant obesity
e) morbidly obese
d) super obese

Back 29

BMI = weight (in kg) / height (in m⁲)
<25 = average
25-29 = overweight
30-34 = obese
35-44 = med. significant O
45-49 = morbidly obese
>50 = super obese

Front 30

How is IBW calculated for men and women?

Back 30

Women: IBW = 100 lbs for 5' in height + 5 lbs for each additional inch

Men: IBW = 106 lbs for 5' in height + 6 lbs for each additional inch

Front 31

Regional fat distribution:
1. What ratios are "pear shaped" for men and women?
2. What ratios are "apple shaped" for men and women?
3. What are the healthy waist circumference values for men and women?

Back 31

1. Pear: lower body obesity (increased subcutaneous fat; common in women) - waist/hip ratio <0.8 for females; <1.0 for males
2. Apple: upper body obesity (greater increase in visceral fat) - waist/hip ratio >0.8 for females; >1.0 for males.
3. >40" in men; >35"

Front 32

Neuroendocrine disorder associated with obesity.

Early symptoms:
Body weakness, getting too tired easily, or having muscle or joint pains.
Dry, flaky skin or thin and brittle fingernails or hair.
Feeling depressed, irritable, or anxious.
Feeling too cold when the temperature is just right or normal for everyone else.
Heavy or irregular menstruation (monthly period).

Late symptoms:
Constipation (dry, hard bowel movements).
Enlarged thyroid gland.
Hoarseness or change in voice or speech.
Sleepiness or problems thinking clearly, such as being forgetful and easily confused.
Swelling around the eyes.
Too much and too sudden weight gain.
Very slow heartbeat and trouble breathing.

Back 32

Hypothyroidism

(Before and after treatment with TSH)

Front 33

Patient presented with a fatty hump between his shoulders, a rounded face, and pink/purple stretch marks on his skin, as well as high blood pressure, bone loss and diabetes. What neuroendocrine disorder caused his obesity?

Back 33

Cushing's syndrome: Due to excess cortisol (iatrogenic, paraneoplastic, pheochromocytoma)

Front 34

The fat, bearded lady at the circus presents with:
Oligomenorrhea or amenorrhea
Anovulation
Weight gain, obesity
Hirsutism
Insulin resistance
Acne
Male-pattern baldness
Multiple small ovarian cysts on sonogram
Acanthosis nigrican

What disease caused her obesity?

Back 34

Polycystic ovary syndrome

Front 35

Short-term regulators of hunger and satiety: neural mediators of the cephalic phase (7)

Back 35

CCK, pancreatic glucagon, insulin, bombesin, somatostatin, glucagon-like peptide, ghrelin

Front 36

Long-term regulators of weight maintenance and energy expenditure centered in the CNS:
1) Inhibitors of intake/stimulators of activity (4)
2) Stimulators of intake: (3)

Back 36

1) leptin, serotonin, bombesin, glucagons
2. neuropeptide Y, galanin, opioids

Front 37

Genes involved in obesity:

Back 37

ob gene
leptin gene
leptin receptor gene

Congenital leptin deficiency: before and after treatment

Front 38

Risk of obesity in offspring:
1. lean x lean
2. lean x obese
3. obese x obese

Back 38

1. 10%
2. 41-50%
3. 66-80%

Front 39

Neuroendocrine causes of obesity (<1% of obese population)

-8 causes listed

Back 39

Hypothyroidism, Cushing's syndrome, castration and ovarian failure (PCOS), insulinoma, hypothalamic lesions, and, much rarer Prader-Willi, Frohlich's and Laurence-Moon-Biedl Syndromes

-This baby has obesity and hypotonia, as are seen in Prader-Willi syndrome.

Front 40

T/F: Energy metabolism abnormalities have been supported as a cause of obesity.

Back 40

False: There is variability in basal metabolic rate and thermic expenditure, however the correlation with obesity is inconsistent.

Front 41

T/F: Average fat and energy intake has decreased since 1970, while rate of obesity has risen.

Back 41

True - reduction in physical activity may be the cause of increased obesity.

Front 42

Environmental factor influences on obesity include (list 3)

- This is the Guinness Book of World Records Largest Burger

Back 42

1. Variety of foods available
2. Easier access to foods
3. Increased package and portion size

Front 43

Three habits, beliefs, and attitudes that affect diet and nutrition are:

Back 43

1. Belief about the appropriateness of food (not biological need)
2. Habitual timing of meals (set by custom starting 6 mo of age)
3. Pleasure - sensory aspects of food

Front 44

T/F: Mortality (in the absence of co-morbid conditions) is due more to obesity than to sedentary lifestyle.

Back 44

False: Moderately overweight but otherwise healthy individuals who are fit have lower risk than unfit, lean persons.

Front 45

Obesity is a risk factor for surgery are due to retarded rate of healing. In excessive obesity this may be caused by... (2)

Back 45

Metabolic inertness of adipose tissue
Excess mass of tissue

Front 46

T/F: Effectiveness of caloric restriction in diet is independent of food source (i.e. protein, carbohydrate, fats)

Back 46

True

Front 47

Adipose tissue is approximately ______ kcal/lb.

Back 47

3500 kcal

Front 48

How will the body respond to a diet with inadequate amounts of glucose intake?

Back 48

Gluconeogenesis will be initiated and cause breakdown of lean mass.

Front 49

How is it possible that very-low-calorie diets (i.e. protein-sparing modified fasts) result in significant initial weight loss? What are the risks of such diets?

Back 49

There is a loss of lean mass in order to make adequate energy. Loss of lean mass, which is 73% water, and risk of cardiac arrhythmias are hazards of starvation and water fasting diets.

Front 50

T/F: Exercise, in conjunction with reduced caloric diets, has no effect on weight lost as fat-free mass (FFM).

Back 50

False: exercise decreases loss of lean tissue during diet

Front 51

T/F: In critical illness, decreased body weight is mostly due to loss in water and muscle (not fat).

Back 51

True

Front 52

Anorectics (fluoxetine, sertraline, phenteramine, diethylpropion, phenylpropanolamine, and sibutramine)

What are their effects on neurotransmitters? (3)
What side effects do they have? (6)

Back 52

Mechanism: Increase brain levels of serotonin, norepinephrine, and dopamine.

Side effects: tachycardia, hypertension, xerostomia, headache, insomnia, and constipation

Continued use is required to sustain weight loss

Front 53

Surgical procedures for obesity treatment:

Indications:
Procedures:

Back 53

Criteria for surgical procedures include:
1) severely obese (>100 lbs or 100% above IBW) for at least 3 years
2) serious medical conditions related to obesity
3) repeated failed attempts at weight loss

Procedures include:
1. Gastric reduction to 100cc
2. Esophageal banding

Front 54

How does Orlistat work?
Indications (BMI)?
Side effects on GI function and nutrient absorption?

Back 54

Orlistat (pentanoic acid ester) is a gastric and pancreatic lipase inhibitor that reduces fat absorption by about 30%.

It is indicated for patients with BMI of 30 or more or BMI >27 with other risk factors.

Side effects include oily spotting, flatulence, fecal urgency and increased defecation, decreased absorption of fat-soluble vitamins, beta-carotene, and carotenoids.

Front 55

Vitamin B12 (hydroxycobalamin, cyanocobalamin) is a _________ soluble vitamin that is synthesized by _________. It is detached from dietary proteins by _________ in the saliva and _________ in the stomach, and _________ in the intestine.

Back 55

Water
Bacteria
R protein
Gastric acid
Proteases

Front 56

Intrinsic factor is secreted by ________ cells in the _______, which promotes vitamin B12 absorption in the _________ by a specific receptor. It is transported to peripheral cells by __________ (B12-binding proteins).

Back 56

Parietal
Stomach
Ileum
Holotranscobalamins I, II, and III

Front 57

Cobalamin:
Sources?
Storage?

Back 57

Comes from intestinal bacteria, animal foods. Synthetic cyanocobalamin supplements.
Stored in liver (efficient resportion via enterohepatic circulation)

Front 58

Conversion of homocysteine to methionine requires: (two nutrients)

Back 58

Methyl-B12 (Cobalamin) and N-5-methyl THF

Front 59

What is the methylmalonyl-CoA mutase cofactor for conversion of methyl malonyl CoA to succinyl CoA in mitochondria in branched chain amino acid fatty acid catabolism (odd number of carbons).

Back 59

5-deoxyadenosyl derivative of B12

Front 60

Pteridine ring-based water soluble molecules with varying substitutions at positions 5 and 10 and different number of glutamate residues.

Back 60

Folates and folic acid - pteroylmonoglutamic acid and polyglutamate derivatives

Front 61

Folates:
Structure absorbed in intestine and enzyme needed?
Reduced by ______ to ______.
Food sources?
Functions?

Back 61

Absorbed at monoglutamate level by pteroylpolyglutamate hydrolase (brush border enzyme).

Reduced to THF by DHFR.

Widely distributed in foods: green leafy vegetables, liver, kidney, and meats. Cereals supplemented with folic acid. Synthetic folic acid supplements.

Required in biosynthesis of choline, serine, glycine, methionine, purines, and TMP. Participates in homocysteine metabolism.

Front 62

Folate trap hypothesis:

Back 62

Folate interconverts between many forms. The N5-methyl THF and cobalamin are cofactors in conversion of homocysteine to methionine, regenerating THF.

Front 63

Pernicious anemia:
Histology?
Causes?
Symptoms?

Back 63

Macrocytic anemia with megaloblastic changes

Vitamin B12 deficiency: autoimmune reaction against parietal cells of stomach (ab against hydrogen pump) or IF.

Peripheral neuropathy via progressive demyelination (permanent)

Front 64

T/F: Folate deficiency is frequently noted in infants and pregnant women?

Back 64

True

Front 65

Folate deficiency:

Back 65

Inhibition of DNA synthesis (limited purine and TTP levels), macrocytic anemia, NTDs in fetus of deficient mothers.

Common in chronic alcoholics and individuals with intestinal disorders (i.e. celiac disease).

Front 66

Nutrient needs for 19-50 yrs:
Used for?
1. Protein
2. Calories, carbs, fats, proteins, and alcohol
3. Vitamin/mineral

Back 66

Maintenance + activity increment
1. maintain nitrogen balance, EAA = 20% intake
2. Maintain weight
3. Replace losses/maintain pools

Front 67

T/F: Bone density increases up to age 40.

Back 67

False - increases to about age 30.

Front 68

Pregnancy:
Nutrients used for:
1. Weight changes (fetus, maternal organ hypertrophy, other)
2. Energy cost is increased due to ________.
3. What is the effect of increased RBF (40%) and GFR (60%)?
4. What changes occur in the intestinal mucosa?
5. What changes occur in GI tract smooth muscle and what effect does it have?

Back 68

altered maintenance + altered activity + growth increment + storage

1. De novo synthesis of ~18 lbs fetal (9-11 lbs) and maternal (4-7 lbs), mostly in 2nd and 3rd trimesters. ~11 lbs "unaccounted weight gain".
2. Increased mass
3. Increased nutrient loss in urine
4. Hypertrophy of small intestinal mucosa - increased absorption of some nutrients
5. Reduced GI tract smooth muscle: slowed gastric emptying time, constipation, decreased LES competency (pyrosis)

Front 69

Lactation (4-6 mos of breast feeding, then weaning):
Nutrient needs used for:
1. Milk production in first 6 months = _____ ml/day. During weaning this decreases to _____ ml/day.
2. Lactation increases energy need by ______ cal/day and protein need by _____ g/day to support milk production.

Back 69

normal maintenance + activity + milk production increment

1. ~750 ml/day; ~600 ml/day
2. 500-700 kcal/day; 12-15 g protein/day

Front 70

1. Colostrum
2. Transitional milk
3. Mature milk

a. produced in first month during change of nutrient content
b. Contains Vit A, C, E and D, lipases, immunologic components. Beyond 6 mos, fat content can increase and protein decreases.
c. Yellowish, thin fluid of initial 3 days. 67 kcal/100 ml, high in viable cells, protein, carotene, and salts. Low in lactose and fat.

Back 70

1 - c
2 - a
3 - b

Front 71

Infancy (0-1 yr)
1. Nutrient needs - used for:
2. BMR is higher because...
3. Weight doubles by ___ and triples by ___. Brain size doubles by ___. Fat deposition required ____ kcal/g and protein requires ____ kcal/g. At birth ___% of energy intake is used for growth. At 12 months this has decreased to ___%.
4. Renal function at birth
5. GI
6. Hematopoiesis
7. Caloric recommendations (% from protein, CHO, fat, vitamins)

Back 71

1. maintenance + activity + growth increment
2. Surface area:mass ratio is large
3. Weight: 4 mos; 1 yr. Brain size: 1 yr. Fat: 10.9 kcal/g. Protein: 13.4 kcal/g. Birth = 27%; 12 mos = 5%.
4. Renal - reduced ability to excrete high acid load and concentrate urine at max of ~600 mOsm/L.
5. GI: at birth - no teeth, reduced coordination of swallowing and esophageal peristalsis, decreased LES pressure, gastric volume, bile acid formation/release, pancreatic exocrine function, delayed GET
6. Hematopoietic function: low at birth, then increases. Fe from fetal stores and milk are adequate for 4-6 mos.
7. 7-16% cal from protein, 35-65% cal from carbohydrates, 30-55% cal from fat, vitamin K injection at birth.

Front 72

Childhood (1-8 yrs) - reduced growth rate and change in body composition

1. Toddlers need ____ kcal/kg and ____ g/kg protein.

2. Early childhood: Compared to earlier, growth is _______.

Back 72

Increased maintenance + activity + small growth increment.

1. Toddlers (1-3 yrs) decline in weight/height gain rates and nutrient needs: 100 kcal/kg energy; 1.2 g/kg protein
2. Early childhood (4-8 yrs) - slow/sporadic growth; appetite parallels growth

Front 73

An 18 month old child needs 1180 kcal/day and 14.5 g high quality protein/day. A child receiving 350 g cassava (338 kcal and 1.6 g protein/100 g) is deficient in _____ and _____ of protein.

Back 73

Quality and quantity are deficient. Growth will slow or stop.

Front 74

Puberty/adolescence (9-13 yrs and 14-18 yrs)
1. Nutrient needs are used for...
2. Weight gain is about ____ kg/yr. Height gain is about ____ cm/yr.
3. Female puberty starts around _____ years old. Hormone changes caused increased rate of _____ deposition. Linear growth stops at age ___.
4. Male puberty starts at _____ years. Compared to females, growth period is ______ and the rate is ______. Testosterone and anabolic adrenal androgens lead to _______ in lean body mass, but smaller increase in fat, bone growth, and skeletal mass.
5. Other effects on:
Blood volume?
RBC count?
Neural tracts?

Back 74

1. increased maintenance + increased activity + growth increment
2. ~2-4 kg/yr; ~5-6 cm/yr
3. ~10-13: anabolic adrenal androgens, estrogen, and progesterone increase fat deposition; 17.
4. ~12-15 yrs; longer; more rapid (ends at 21); double lean body mass
5. Increased blood volume and RBC number, elongation of neural tracts (spastic activity)

There are also altered hormonal balance and metabolic pathways, menstruation (females), and acne

Front 75

Timing of puberty is related to _________.

Back 75

Sexual maturity, not age

Front 76

Older adults (51+ yrs)

1. Bone density changes for men and women?
2. Changes in energy use/body composition
3. Changes in renal activity?
4. Changes in B12?
5. Other changes in GI tract and GI smooth muscle?
6. Other health risks

Back 76

Frailer, chronic diseases, nutritional deficiency risk

1. Decreased bone density from 40 yrs; women increase more rapidly in first year after menopause
2. Decreased activity, lower BMR (about -2% per decade), increased total body fat, decreased lean body mass, decreased protein absorption/use
3. Decreased renal function: clearance of substances and hydroxylation of vitamin D
4. Reduced gastric IF and release of bound B12, increased bacterial use of B12 in intestine
5. Decreased smooth muscle motor (constipation), decreased taste/smell/salivation, risk of protein, B6, and B12 malabsorption
6. Decreased thirst, decreased sunlight (low provitamin D synthesis), decreased iron requirement in women after menopause, decreased mental acuity, vision, mobility, money, transportation, access to kitchen

Front 77

Macronutrients provide _______ for metabolic processes and _________ the body cannot synthesize.

Micronutrients

Back 77

Carbohydrates, proteins, and fats: body needs large amounts (grams). Provide energy and compounds.

Vitamins and minerals: body needs small amounts

Front 78

What is the energy store in alcohol?

Back 78

7 kcal/gram.

Front 79

Energy output: four forms

Back 79

1. Resting metabolic rate (RMR)
2. Thermic effect of food
3. Physical activity
4. Thermogenesis

Front 80

Energy equilibrium:
Causes of positive energy balance?
Causes of negative energy balance?

Back 80

Positive: growth, pregnancy, rebound from starvation, disease, or injury, unhealthy weight gain

Negative: Body uses energy stored in body-fat and muscle for shortfall in energy intake - leads to weight loss

Front 81

The _________ categorizes foods according to digestibility and absorbability of carbohydrates; low _________ foods have greater satiety and lower average insulin levels. A major shortcoming is...

Back 81

Glycemic index

Based on a serving of food that provides 50 g of carbohydrate.

Front 82

Glycemic load =

Back 82

(glycemic index x mass of carbohydrate/serving) / 100

Front 83

RDA for carbohydrates is _______ g/day. Inadequate intake is compensated by gluconeogenesis at the expense of ________ and leads to _________.

Back 83

130 grams/day
Expense of dietary and body proteins.
Leads to ketosis

Front 84

Fibers are nondigestible carbohydrates and lignins. They are NOT a source of carbohydrates - their role is in digestion, absorption, and elimination.

1. Soluble fiber is processed by ________ and releases _______.
2. Effects of insoluble fiber on a) water, b) fecal bulk, c) colonic transit
3. Effects of dietary fiber on: a) satiety, b) fat/cholesterol absorption, c) cholesterol excretion, d) glucose absorption
4. Adverse effects are due to _______ which bind to dietary constituents (i.e. zinc, EFAs) and prevent their absorption. Fiber may also cause ________ and ________.
5. Dietary recommendations for men and women:

Back 84

1. Gut bacteria; short chain fatty acids
2. attract water, increase fecal bulk, accelerate colonic transit
3. Decreases GET -> satiety, decrease fat/cholesterol absorption, increase cholesterol loss, decrease rate of glucose absorption
4. Phytates; bloating and flatus
5. 38 g/day for men and 25 g/day for women

Front 85

Name the essential amino acids for adults (9).

_________ is essential in infants and growing children.

Back 85

Histidine, methionine, threonine, valine, isoleucine, phenylalanine, tryptophan, leucine, lysine.

Arginine

Trivia/Mnemonic:
A man was recently arrested in California after police discovered a soda pop can with Valium and crystal meth in a hidden compartment.

Lou tried his three meths. Liz is fine w/ valium.

Front 86

T/F: Essential amino acids are called such because the body has increased need for them.

Back 86

False

Front 87

T/F: Proteins from animal sources have superior content of essential amino acids (compared to plant sources).

Back 87

True. This is scored by the Protein Digestibility Corrected Amino Acid Score (PDCAAS)

Front 88

Vegetarians may become deficient in essential amino acids. What is an excellent vegetable source of amino acids?

Back 88

Soybeans - PDCAAS of 1.0 (equal to milk and egg).

Front 89

T/F: Like carbohydrates (glycogen) and lipids (TAGs), amino acids can be stored in sufficient quantities.

Back 89

False - there is no specific storage depot for amino acids

Front 90

How can the amino acid pool be estimated? What is the meaning of positive or negative balance values?

Back 90

Nitrogen balance: Amount consumed in diet vs amount lost as urea, ammonia, and sloughed off cellular materials

Positive - net uptake exceeds nitrogen loss (as in growth and expansion of muscle in response to exercise)
Negative - net loss exceeds nitrogen uptake (as in fasting, starvation, protein malnutrition, and recovery from trauma/burns)

Front 91

What is the RDA for "high quality" protein for men and women in limited strenuous physical activity?

Back 91

56 grams/day for men
46 grams/day for women

Front 92

An 18 month old child presents with a swollen belly, thinning hair, and dermatitis. His mother tells you she is no longer breastfeeding and has been feeding him a diet consisting mostly of pureed vegetables and organic cereal puree. You suspect a chronic dietary protein insufficiency.

1. What is the disease?
2. Left untreated, what may occur?
3. T/F - Expedient intervention will undoubtedly allow the child to recover without sequelae and meat growth milestones?

Back 92

1. Kwashiorkor
2. Retarded growth and development, weak immune response.
3. False - permanent failure to meet growth milestones is possible, despite intervention

Front 93

A severely neglected child is rescued by social services and brought to the ER. He presents with wasting muscle and virtually no body fat. You suspect Marasmus.

1. What is deficient in the diet?
2. Why are muscle and fat mass lost in Marasmus?
3. T/F: Interruption of visceral organ function is less dramatic than in Kwashiorkor, resulting in a milder disease?

Back 93

1. Deficient for both calories and protein
2. Catabolic turnover of protein and TAGs for energy
3. True - organ and tissue function is calorie limited; moderates adverse effects of deficient diet

Trivia: This photograph, taken in Sudan, was first published in the New York Times in 1993. The photographer, Kevin Carter, was awarded a Pulitzer Prize in 1994. He stood by the "journalist as observer" stance and did not intervene and had no knowledge of what happened to this girl. Months after receiving the Pulitzer he commit suicide, unable to reconcile the horrors he had seen and his inaction. This has become a hallmark image in the debate of the journalist's role. A similar situation occurred for current NYTimes writer Nicholas Kristof, who's conscience troubled him after not intervening on behalf of a child prostitute in Cambodia who was sold in the sex trade and being held under debt bondage. On a subsequent trip to Cambodia he chose to break tradition and "purchase" the freedom of two young sex slaves and wrote a series of editorials documenting these experiences.

Front 94

Triacylglycerol constitutes more than ___% of total dietary lipid, including the Essential Fatty Acids ________ and _______, the precursor of _________. They are required for membrane fluidity and synthesis of _______.

Back 94

1. 90%
2. Linolenic [18:3 (9, 12, 15)]
3. Linoleic [18:2 (9, 12)]
4. Arachidonic acid [20:4 (5, 8, 11, 14)]
5. Eicosanoids

Front 95

Where does dietary cholesterol come from? What is the most important determinant of total plasma cholesterol?

Back 95

Cholesterol is from animal sources (not plants), but the effect is less important than the amount and types of fatty acids consumed, particularly saturated fat intake (mostly from dairy and meat products).

Front 96

Plants have TAGs with mostly ___________ fatty acids, except coconut and palm oil. Animal source TAGs contain a higher proportion of ____________ fatty acids, except fish which contain many omega-___-fatty acids.

Back 96

1. Unsaturated fatty acids
2. Saturated fatty acids
3. omega-3-fatty acids

Front 97

The dietary goal of ___% total calories due to fat is recommended, with cholesterol consumption reduction from 600 mg/day to _____ mg/day.

Back 97

1. 30% total calories
2. 300 mg/day (half of previous guideline)

Front 98

Cholesterol - T/F:
1. Individuals with higher blood cholesterol have higher incidence of atherosclerosis.
2. Levels of LDL are inversely correlated with heart disease.
3. 60% of fasting blood cholesterol is carried as LDL.
4. HDL levels are associated with decreased risk of heart disease.
5. Before menopause, women have lower levels of HDL than men.

Back 98

1. True
2. False - directly correlated
3. False - 80% of cholesterol is LDL
4. True
5. False - women have higher levels of HDL than men before cholesterol

Front 99

What is cholestyramine?

Back 99

A non-absorbable ionic resin that promotes excretion of bile acids and therefore decreases plasma cholesterol levels.

Front 100

T/F:
All saturated fatty acids cause hypercholesterolemia.

Back 100

False: Stearic acid (18:0) and short-chain saturated fatty acids (<10 carbons) don't raise blood cholesterol. Lauric (12:0), myristic (14:0), and palmitic (16:0) acids elevate blood cholesterol.

Front 101

For each statement below, is it true for mono-unsaturated fatty acids, poly-unsaturated fatty acids, or both?

1. Decrease LDL
2. Decrease total cholesterol
3. Slightly increase TAG levels
4. Decrease HDL
5. Favor oxidation of LDL (causing formation of foam cells and CAD)
6. Little or no change in HDL
7. Reduce total mortality by 70%
8. Examples include omega-6 fatty acids.
9. Examples include omega-3 fatty acids

Back 101

1. both
2. both
3. both
4. poly
5. poly
6. mono
7. mono
8. poly
9. mono

Front 102

N-6 fatty acids:
1. Which EFA is an n-6 FA?
2. What are their effects on LDL and HDL?
3. What are some sources of n-6 fatty acids?

Back 102

1. linoleic acid
2. lowers LDL and HDL
3. several plant oils (corn, safflower, sunflower)

Front 103

N-3 Fatty acids
1. Effect on TAG, heart disease, LDL, and HDL?
2. Sources?
3. Effect on eisocanoid formation?

Back 103

1. Lowers TAG, LDL, and risk of heart disease; raises HDL
2. Oily fish (SMASH = salmon, mackarel, anchovies, sardines, herring), soybean oil, canola oil, hazelnuts, almonds, pecans, cashews, walnuts, and macadamia (not peanuts and pines)
3. Inhibit conversion of AA to TXA2 by platelets; converted to TXA3, which is less thrombogenic

Front 104

Trans Fatty Acids:
1. How are they synthesized?
2. Relative to cis isomers, what is their effect on plasma cholesterol?
3. T/F: Trans fat content is listed on the nutrition facts labels.

Back 104

1. Hydrogenation of liquid vegetable oils (i.e. margarine)
2. Increased plasma cholesterol
3. False

Front 105

Dietary methods to reduce LDL: What is the effect on HDL?

1. Soy products?
2. Garlic?
3. Fiber?
4. Alcohol?

Back 105

1. lower HDL
2. small rise in HDL
3. may increase HDL
4. increase HDL (protective effect of alcohol against heart disease)

Front 106

Match diet with description:
a. High fat/low carbohydrate
b. Low fat/high carbohydrate
c. "Mediterranean" diet

1. abundant fish/poultry, olive oil and dairy, moderate alcohol consumption, fruit, vegetables, beans, legumes, nuts, and complex carbohydrates
2. ad libidum consumption of beans, fruits, grains and vegetables in smaller/more frequent meals. No meats, poultry, seafood, or alcohol. Avoid dairy, oily foods. Exercise daily.
3. Reduce refined sugar and complex carbs except those from fresh vegetables and fruits. High protein/fat diet - fatty acit oxidation and mild ketosis.

Back 106

1. c
2. b
3. a

Front 107

Vitamin D:
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 107

1. 200 IU
2. 2000 IU
3. Skin - UV light, milk, cod liver oil, salmon, shiitake mushrooms
4. Rickets - children; Osteomalacia - adults

Front 108

Vitamin K:
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 108

1. 90 micrograms
2. none
3. Intestinal bacteria, green leafy vegetables, egg yolk
4. Bleeding (coagulopathy)

Front 109

Vitamin A:
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 109

1. 800 micrograms
2. 10 mg
3. Retinyl ester from egg yolk, liver, fish oil, milk, butter; beta-carotene from fruits, vegetables
4. Night blindness, xerophthalmia

Front 110

Vitamin E (tocopherol)
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 110

1. 15 mg
2. 1000 mg
3. Vegetable oils, liver, eggs
4. Spinocerebellar degeneration

(An early sign of vitamin E deficiency is lipofuscin or age spots)

Front 111

Thiamine (Vitamin B1)
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 111

1. 1.1 mg
2. none
3. Whole wheat, peas, beans
4. Dry and wet beriberi; Wernicke Korsakoff syndrome

Front 112

Riboflavin (Vitamin B2)
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 112

1. 1.1 mg
2. none
3. Liver, yeast, wheatgerm, milk, eggs, green leafy vegetables
4. Cheilosis, glossitis, dermatitis

Front 113

Niacin (Vitamin B3)
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 113

1. 14 mg
2. 35 mg
3. Widely distributed: rich in meat; depends on Trp content
4. Pellagra - 4Ds (diarrhea, dermatitis, dementia, death)

Front 114

Pyridoxine (vitamin B6)
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 114

1. 1.3 mg
2. 100 mg
3. widely distributed: germs of grains, seeds, egg yolk, yeast, meat
4. Cheilosis, glossitis, dermatitis, peripheral neuropathy

Front 115

Biotin
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 115

1. 30 micrograms
2. none
3. Eggs, peanuts
4. none

Front 116

Cobalamin (vitamin B12)
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 116

1. 2.4 micrograms
2. none
3. liver, whole milk, eggs, shrimp, chicken, pork
4. pernicious anemia; neuropathy

Front 117

Folic acid
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 117

1. 400 micrograms
2. 1000 micrograms
3. widely distributed; supplemented
4. NTDs, megaloblastic anemia (without neuropathy)

Angelo was born with an encephelocele.

Front 118

Pantothenic acid
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 118

1. 5 mg
2. none
3. yeast, liver, eggs
4. none

Front 119

Ascorbic acid (vitamin C)
1. RDA
2. UL
3. Food sources
4. Deficiency syndrome

Back 119

1. 75 mg
2. 2 g
3. fresh fruits, vegetables
4. scurvy

Front 120

What is the most important cause of deficiency for water soluble vitamins?

Back 120

Decreased intake

Front 121

How does antibiotic treatment cause vitamin deficiency for vitamin K and biotin?

Back 121

Synthesis by enteric bacteria is interrupted.

Front 122

Kidney disease can lead to...

Back 122

Vitamin D deficiency - renal rickets.

Front 123

Liver damage (due to chronic alcoholism) can lead to...

Back 123

Deficiency in storage and modification of vitamins.

Front 124

What vitamins have enterohepatic circulation?

Back 124

Folate, vitamin B12, vitamin A, and vitamin D

Front 125

Cystic fibrosis and chronic cholestasis can cause...

Back 125

deficiency in vitamins D, A, K, and E due to fat malabsorption.

Front 126

Patients with bariatric surgery (roux-en-Y) may have vitamin malabsorption because...

Back 126

the upper part of the intestine is the main site of most vitamin absorption.

Front 127

During pregnancy and lactation there can be folic acid deficiency due to...

Back 127

increased physiological need.

Front 128

Newborns have particular vitamin needs:

1. Which two vitamins do not pass the placental membrane?
2. GI tract problems include...
3. How does the rate of cell growth affect nutrient requirement?
4. What is a common micronutrient supplement given at birth?
5. In cases of breast feeding, supplement with...
6. Infants in oxygen rich atmospheres are supplemented with...

Back 128

1. E and K
2. GI tract not fully functional - malabsorption; sterile (biotin and vitamin K)
3. Increased rate of cell growth and division increases need for vitamins
4. Vitamin K injection at birth
5. Vitamin D supplement for breast fed newborns
6. Vitamin E supplement in Oxygen rich environment

Front 129

Anticonvulsant drug effects:
1. Vitamin K
2. Vitamin D
3. Folate
4. Biotin
5. Vitamin B6

Isoniazid effects:
6. Pyridoxine

Back 129

1. negatively interact with vitamin K
2. influence bioactivity of vitamin D
3. increased need for folate
4. increased need for biotin
5. increased need for vitamin B6
6. Isoniazid binds pyridoxine

Front 130

1. Name the four fat-soluble vitamins.
2. Where are they absorbed in the GI tract?
3. Where are they stored? (2)
4. In order to pass into the epithelial cells, they need normal function of _________. Once in the cells, they must be absorbed twice in ____________ circulation. In the liver they can be conjugated to _________ for transport in the bloodstream and delivery to tissues.

Back 130

1. D - calcium homeostasis
A - rhodopsin production; antioxidant
K - carboxylation of glutamic residues in prothrombin and clotting factors
E - antioxidant

2. Absorbed in the Ileum
3. Liver and adipose; bile salts; enterohepatic circulation; lipoproteins (delivery)

Front 131

Cholecalciferol:
Ergocalciferol:
25-(OH)D:
1-alpha-25-(OH)2D:
24,25 (OH)2D:

Back 131

Vitamin D3 - formed by UV light conversion in skin from a cholesterol synthesis intermediate; can be supplement - milk, OJ, yogurt, and cheese are fortified
Vitamin D2 - supplement in yeast, plants (less effective than D3)
25-(OH)D is hydroxylated form from liver
1-alpha,25-(OH)2D - further hydroxylation in proximal convoluted tubule of kidney to active form - transcription moderator
24,25(OH)2D - inactive form of metabolized vitamin

Front 132

Requirement of Vitamin D is ____ minutes on area size of the hand. Deficiency may be due to increased melanin, sunscreen, and lack of sun.

Signs of vitamin D toxicity (100,000IU for weeks or months):

Back 132

20 minutes

Toxicity - loss of appetite, nausea, thirst, stupor

Front 133

Role of vitamin D:
1. Steroid hormone that binds receptors in...
2. Regulates _______ directly and _______ indirectly.
3. Active form effects:

Back 133

1. intestine, bones, kidneys
2. calcium, phosphorus
3. stimulate intestinal absorption of calcium and phosphorus, mobilize bone calcium (with PTH), stimulate PTH dependent reabsorption of Ca in distal renal tubules

Front 134

A child presents with improper mineralization of cartilage and osteoid matrix, leading to soft bones. There is lordosis of the spine and bowing of the legs. You suspect _______ due to inadequate synthesis, absorption, or intake of ______.

Following treatment, what is the prognosis?

Back 134

Rickets
Vitamin D
Complex clinical picture - may be permanent.

Front 135

A 54 year old man with poor diet has had frequent bone fractures without gross changes in bone contour. You suspect ______ due to deficiency of ________, causing _________ of existing bone.

Back 135

Osteomalacia
Vitamin D
Demineralization

Front 136

Osteoporosis:
1. Skeletal growth modeling ends in the ______ decade of life.
2. Steady loss of bone mass begins in ______ decade in both men and women with average of ____% loss per year.
3. Menopause accelerates loss of bone mass in women, so the ratio in frequency for fracture is _____.
4. The most common fracture sites are___.
5. Treatments and their mechanism of action include
6. Primary risk factors include:

Back 136

1. Third decade
2. Fourth decade
3. 1:40 ratio of men:women
4. vertebrae, femoral neck, pelvis
5. bisphosphonates and subcutaneous injections of PTH increase osteoblast activity
6. Diet, race, short stature, small bones, smoking, alcohol abuse, physical activity, leanness, genetics (alleles of vitamin D receptor)

Front 137

Roles of vitamin D other than calcium homeostasis include:

Back 137

low vitamin D increases mortality from CVD, type II diabetes, colon, breast, pancreatic, and prostate cancers, multiple sclerosis, autoimmune disease, cognitive loss in elderly, skeletal muscle and sports performance, immunity

Front 138

Source and function of -

Retinol (pictured):
Retinyl esters:
Retinal:
Retinoic acid:
B-carotene:

Word bank:
Dietary
Epithelial differentiation
Storage
Transport
Vision

Back 138

Retinol - transport form; hormone involved in differentiation of mucus-secreting epithelium

Retinyl esters - storage form; retinyl phosphate involved in glycoprotein and mucopolysaccharide synthesis

Retinal - vision; delta-11-cis retinal chromophore bound to opsin; bleaching releases opsin and all trans retinal with nerve impulse. Important for night vision.

Retinoic acid - epithelial differentiation and growth regulating hormone

B-carotene (dietary in vegetables) - cleaved and converted to retinol in intestinal mucosa; anti-oxidant

Also involved in immune function and bone remodeling

Front 139

Vision problems and blindness, night blindness, xerophthalmia, acne, psoriasis, and susceptibility to infection are caused by deficiency of ___________.

Back 139

Vitamin A

Front 140

Vitamin A:
Stored in ______ as ______.
High doses over months or year result in toxicity, leading to _________.
Which form shows no toxicity?
What is the clinical utility of synthetic retinoids?

Back 140

Stored in liver as retinyl-palmitate

Toxicity: bone pain, dermatitis, hepatosplenomegaly, nausea, diarrhea, birth defects

B-carotenes show no toxicity

Synthetic retinoids treat acne - reduced toxicity. Depress sebum production and inflammatory response.

Front 141

Source:
K1 (phylloquinone, phytylmenaquinone)
K2 (menaquinone, multiprenylmenaquinone)
K3 (menadione)

What is the principal action of Vitamin K?

What is warfarin?

What is the effect on bone?

Back 141

K1 - vegetables
K2 - intestinal bacteria
K3 - synthesized from synthetic precursor

Acts as coenzyme for gamma-glutamyl carboxylation of prothrombin and factors VII, IX, and X - carboxylated residues can bind calcium. Calcium-prothrombin complex can bind phospholipids on platelet surface.

Warfarin is a vitamin K antagonist - inhibits clotting

Favors calcification

Front 142

Hypoprothrombinemia and increased coagulation times are due to deficiency of ________. This is uncommon except in __________.

Back 142

Vitamin K deficiency
Newborns
Broad spectrum antibiotic treatment
Problems with fat absorption (i.e. CF)

Front 143

Vitamin K toxicity:
T/F
1. Natural forms are not toxic.
2. Large amounts interfere with heparin action.
3. Infants receiving vitamin K3 can develop hemolytic anemia and jaundice due to toxic effects on bone marrow.

Back 143

1. true
2. false - interfere with coumadin
3. false - toxic effects on RBCs

Front 144

Vitamin E is a family of _________ compounds. It is absorbed into the __________ system by the small intestine and the biologically active form, ___________, is incorporated into ______ in the _______. It is the most effective lipid soluble antioxidant. ___________ are rich sources. _________ and _______ contain moderate amounts. As intake of polyunsaturated fatty acids increases, requirement _________. It is the least toxic fat soluble vitamin.

Back 144

Tocopherol
Lymphatic system
Alpha-tocopherol
VLDL
Liver
Vegetable oils
Liver and eggs
Increases

Front 145

Deficiency is rare except in infants. In children and adults it is associated with defective lipid absorption, abetalipoproteinaemia, chronic cholestasis, or transport defect. Deficiency causes spinocerebellar degeneration and axonal sensory neuropathy with ataxia, areflexia, and other symptoms after 10-20 years of deficiency.

Back 145

Vitamin E

Front 146

Free radical damage is implicated in aging, heart disease, alzheimer's disease, and diabetes.

Discuss reactivity, transportation, and synthesis of these compounds:
Superoxide-
Hydrogen peroxide-
Hydroxyl radical-

Back 146

Superoxide - moderately reactive; penetrates membranes through anion channels

Hydrogen peroxide - moderately reactive oxygen intermediate (not free radical); formed by SOD; diffuses across cell membranes

Hydroxyl radical - very reactive; formed in Fenton reaction (iron and hydrogen peroxide); diffusion controlled rates

Front 147

Effects of free radicals on:
1. Protein
2. Lipid
3. DNA

Antioxidant defenses:
4. enzymes
5. endogenous chemicals
6. exogenous chemicals

Back 147

1. Protein oxidation - decreased activity; thermo-labile
2. Lipid peroxidation - loss of membrane integrity
3. Modification of DNA - strand breaks
4. Antioxidant enzymes: SOD, glutathione peroxidase, catalase
5. Endogenous antioxidant chemicals: glutathione, ubiquinol
6. Exogenous antioxidant chemicals: vitamin E, vitamin C, beta carotenes, lycopenes (from tomatoes - highest single oxygen quenching capacity)

Front 148

Thiamine (vitamin B1):
1. coenzyme form and synthesis
2. Major reactions
3. Deficiency

Back 148

1. Thiamine pyrophosphate (TPP) - transfer of pyrophosphate from ATP to thiamine (obtained from plants or microorganisms)
2. Oxidative decarboxylation of alpha-keto acids (pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase); pentose-phosphate pathway (transketolase); synthesis of acetylcholine
3. Leads to buildup of pyruvate levels, reduced ATP, ribose, and NADPH

Front 149

A patient who eats a large amount of polished rice presents with cardiovascular problems, causing edema in the legs, fluid in the lungs, and tachycardia.

Back 149

Wet beriberi from thiamine deficiency

Front 150

Patient has memory loss, mental confusion, pain in hands and feet, involuntary eye movements, and trouble standing and moving.

Back 150

Dry beriberi due to thiamine deficiency

Front 151

A chronic alcoholic presents with mental confusion, loss of eye coordination, and ataxia.

Back 151

Wernicke-Korsakoff syndrome due to thiamine deficiency

Front 152

Riboflavin (Vitamin B2)
1. Synthesis of coenzymes
2. Major reactions
3. Deficiency

Back 152

1. Obtained from green plants, bacteria, and fungi to synthesize flavin mononucleotide (FMN) by riboflavin kinase (with ATP) and is adenylated by FAD synthetase to flavin dinucleotide (FAD)
2. Used by 150 enzymes, including NADH dehydrogenase and succinate dehydrogenase (complex I and II of ETC), and methylenetetrahydrofolate reductase
3. Deficiency accompanies other vitamin deficiencies; leads to dermatitis, cheilosis, glossitis

Front 153

Niacin (Vitamin B3)
1. Synthesis of coenzymes
2. Major reactions
3. Deficiency
4. Other uses - effect on VLDL and LDL

Back 153

1. Synthesized in all organisms (conversion from tryptophan). Amidated to nicotinamide and converted to NAD or NADP.
2. Used by many enzymes for redox reactions (synthesis of fatty acids, cholesterol, steroid hormones)
3. Deficiency leads to pellagra
4. Combined with statin, decreases VLDL and LDL at high doses by inhibiting lipolysis in adipose tissue.

Front 154

A patient presents with erythematous, desquamative dermatitis, chelitis, glossitis, loose stools, and mental confusion three months after Roux-en-Y bariatric surgery.

Back 154

Pellagra due to Niacin deficiency. 4D's: dermatitis, diarrhea, dementia, death

Front 155

Pyridoxine (Vitamin B6)
1. synthesis of coenzyme forms (3)
2. Major reactions
3. Deficiency

Back 155

1. synthesized in green plants and microorganisms - 3 forms (derivatives of pyridine): pyridoxal, pyridoxine-P, pyridoxal-phosphate (PLP). PLP is the active cofactor form
2. Used by 112 enzymes: synthesis, interconversion, and catabolism of amino acids and heme; required for all known transaminases; used in deamination, decarboxylation, and condensation reactions; energy production from amino acids; synthesis of serotonin, norepinephrine, sphingolipids; glycogen phosphorylase; NAD synthesis; homocysteine metabolism. Cofactor forms covalent linkage (Schiff base) with lysyl residue in enzyme - converted to a substrate-PLP when attacked by substrate amino group.
3. Behavioral changes (neurotransmitters and myelination) and anemia. Deficiency can be induced by isoniazid.

Front 156

A patient presents with a cough productive of sputum. CXR is shown. A PPD is positive and you begin treatment. Several weeks later, the patient presents with confusion and peripheral blood smear shows sideroblastic anemia.

Back 156

Vitamin B6 deficiency due to inactive pyridoxine-isoniazid complex formation

Front 157

Biotin (Vitamin B7)
1. Synthesis of coenzyme
2. Major reactions

3. Your patient is a boxer who had a serious bacterial infection which was treated with a prolonged course of broad spectrum antibiotics. He has been working to recover his strength, and after several weeks of vigorous training, he presents with xeroderma, seborrheic dermatitis, fungal infections, rashes including red, patchy ones near the mouth (erythematous periorofacial macular rash), fine and brittle hair and signs of alopecia. He informs you that he has been eating large amounts of raw eggs for protein. Explain the risk factors causing his biotin deficiency (a very rare micronutrient deficiency).

Back 157

1. Made by enteric flora
2. coenzyme in carboxylation reactions; carrier of activated carbon dioxide. Binds epsilon-amino groups of lysine residues on enzymes. Pyruvate carboxylase (formation of oxaloacetate in gluconeogenesis); cytosolic acetyl-CoA carbosylase, mitochondrial propionyl CoA carboxylase
3. Deficiency is rare except in long antibiotic therapy or excessive consumption of raw eggs (avidin binds biotin -> decreased absorption)

Front 158

Cobalamin (Vitamin B12)
1. Synthesis of coenzyme
2. Major reactions
3. Deficiency

Back 158

1. Synthesized by microorganisms in intestine. Animal products are good source. Has corrin ring structure with a cobalt on 4 nitrogens of pyrrole groups and dimethylbenzimidazole on 5th position. 6th position has 5-deoxyadenosine in the 5-deoxyadenoxylcobalamine form and a methyl in methylcobalamin.
2. Homocysteine methyltransferase (homocysteine + 5-methyl-THF form methionine and THF); methylmalonyl CoA mutase (mitochondrial enzyme - isomerization of methylmalonyl CoA from amino acid and fatty acid degradation).
3. Low requirement - not obtained from plant diet. Deficiency results in N5-methyl-THF buildup in rapidly dividing cells and decreased THF needed for purine and thymine synthesis. Causes pernicious anemia. Demyelination of nerve cells due to decreased methylmalonyl CoA mutase (fatty acids accumulate in cell membranes and disrupt). Liver stores up to 6 years worth, so most deficiency is due to inadequate absorption (not diet). Can be caused by self-reactive Ab against IF or parietal cells.

Front 159

Folic acid
1. Synthesis of coenzyme
2. major reactions
3. deficiency

Back 159

1. From yeasts and leafy vegetables or animal liver. Polyglutamate form - ingestion and storage. Glutamate removed in intestinal mucosa by conjugase to make more soluble. Reduced within cells (liver) to THF by DHFR (requires NADPH). Pteridine ring linked to PABA forms pteroic acid. Glutamic acid residues conjugated to pteroic acid.
2. Involved in one-carbon metabolism; transfer of carbon for synthesis of amino acids purine and thymine.
3. Deficiency causes decreased purine and thymidine synthesis and leads to megaloblastic anemia. Need is increased in pregnancy and lactation -> deficiency causes NTD in fetus. Ala222Val polymorphism affects folate responsiveness

Front 160

Pantothenic Acid (vitamin B5)
1. Synthesis of coenzyme
2. major reactions
3. deficiency

Back 160

1. From green plants, eggs, liver, yeast, and microorganisms. Component of coenzyme A and phosphopantetheine in fatty acid synthase.
2. CoA used in over 70 enzymes. CoA - transfer of acyl groups (metabolism of fats, carbohydrates, proteins).
Phosphopantetheine - fatty acid synthesis
3. Deficiency rare

Front 161

Ascorbic acid (vitamin C)
1. synthesis of coenzyme
2. major reactions
3. deficiency

Back 161

1. Synthesized by all organisms except humans, primates, and guinea pig.
2. Prolyl hydrosylase (collagen stability); lysine hydroxylase (collagen cross-linking); catabolism of tyrosine; synthesis of epinephrine; synthesis of bile acids; reducing agent in many reactions (ferric -> ferrous iron in intestine); biosynthesis of corticosteroids, aldosterone, reducing agent for mixed-function oxidases; antioxidant (free radical scavenger)
3. Deficiency causes scurvy. Most unstable of vitamins (destroyed by long term storage and exposure to alkali)

Front 162

A patient presents with easy bruising, muscle fatigue, soft swollen gums, decreased wound healing, and hemorrhaging, osteoporosis, and anemia.

Back 162

Scurvy due to vitamin C deficiency

Front 163

677C->A (A222->Val) in ______ leads to a ___________ enzyme with ___________ activity, lower binding of _______, and accumulation of _____________. It is associated with ______________ disease in adults and ____________ in infants.

Back 163

Methylenetetrahydrofolate reductase (MTHFR)
Thermolabile
Reduced
FAD
Homocysteine
Cardiovascular
Neurtal tube defects

Front 164

As many as 1/3 of mutations in enzymes result in increased ________________ (Km) (measure of how tightly the enzyme is bound to the coenzyme).

Thiamine for enzyme defect:
The ____ subunit (pyruvate decarboxylase) of the pyruvate dehydrogenase complex binds ____. Defects lead to lethal _____________, psychomotor retardation, CNS damage, Muscle fiber atrophy, and developmental delay due to ___________ buildup and decreased _____. Treatment with ________ leads to decreased serum __________ and amelioration of symptoms.

Back 164

Michaelis constant (Km)
E1
TPP
Lactic acidosis
Lactate buildup
Decreased ATP
Thiamine
Lactate

Front 165

A cross-country runner presents with anemia. What may be deficient in his diet? (3)

Back 165

Iron, folate, B12

Front 166

A gymnast sustains a stress fracture. You are concerned that her diet may be deficient in... (3)

In female gymnasts, amenorrhea is a common occurrence and suggests ___________. Disordered eating patterns are not uncommon in athletes; be alert for signs of distorted body image, unrealistic weight goals, and compulsive eating behaviors. Assess supplement use; many carry mild to severe health risks.

Back 166

Energy intake, calcium, vitamin D

Inadequate energy intake or excessive energy expenditure.

Front 167

1. T/F: Fat oxidation increases at higher levels of exertion.
2. Glycogen stores kick in when energy demands exceed ______ kcal/hour.
3. __________ are often the limiting macronutrient because large amounts are needed to quickly replenish glycogen stores after training sessions and exhausting competitions.
4. During the first seconds of muscle contraction, _____ provide the initial burst of energy.
5. T/F: When ATP stores run out after 2-3 minutes, creatine phosphate can recharge ATP supplies by transferring high-energy phosphates to ADP.
6. Fuel metabolism begins after approximately ______ seconds.

Back 167

1. False: stays the same at most levels of exertion
2. 300-400 kcal/hr
3. Carbohydrates
4. Local ATP stores
5. False - ATP runs out after 2-3 seconds
6. 10-15 seconds

Front 168

1. T/F: Glycogen stores are only depleted in vigorous exercise.
2. T/F: Glycogen stores are rapidly replenished following cessation of exercise.
3. Without glucose, anaerobic metabolism predominates but is extremely inefficient: it can utilize only about ____% of the energy content of glucose.
4. Critical micronutrients for the utilization of fat and glucose-derived intermediary metabolites through the Krebs cycle are... (7)

Back 168

1. False: Maximal muscle exertion can deplete within minutes as much muscle glycogen as hours of a more moderate effort level.
2. False: Takes hours
3. 6%
4. thiamin, riboflavin, niacin, biotin, pantothenate, magnesium, and iron: Most athletes are likely to get enough of each, but young women, particularly vegetarians, may need extra iron

Front 169

1. Carbohydrate loading requires intakes near ____ g/kg body weight and a carefully controlled pattern of exercise to boost muscle glycogen concentrations well beyond normal levels.
2. Repletion of glycogen stores requires ___ g of carbohydrate for every ___ kcal expended. Intake of about ____ g carbohydrate every two hours is optimal.
3. Top achievers in strength-based sports like weight-lifting require increased protein intake (_____ g/kg/d).

Back 169

1. 10 g/kg: Most women can achieve this goal only by eating in excess of energy requirements. Repeated doses of carbohydrate during exercise spare some glycogen, but cannot provide the full amount that is expended by moderate- to high-intensity exercise.
2. 100 g; 400 kcal; 50 g (Athletes in endurance disciplines often benefit from a carbohydrate-rich diet (6-10 g/kg/d))
3. 1.6-1.7 g/kg/d

Front 170

1. During exercise, heat is dissipated by... (3)
2. In a severely dehydrated athlete, what are the effects on:
a) sweat production
b) temperature regulation
c) sports performance
d) serum osmolality
e) blood volume
3. What is the most powerful stimulus for thirst and ADH release?
4. T/F: When blood volume drops 20% or more, baroreceptors stimulate thirst and water conservation.

Back 170

1. Evaporation of sweat from the skin and water vaporization from the respiratory system (primary defense against overheating); conduction, convection, and radiations
2. a) decreased; b) impaired; c) declines; d) raised; e) decreased
3. Serum osmolarity (above 290 mOsm)
4. False: triggered at 10% drop in blood volume

Front 171

A wrestler reports to you that he has been deliberately dehydrating by excessive sweating, spitting, limiting fluid and food intake, and using laxatives and OTC diuretics in order to make weight class.

You inform him that...

1. Even as little as ____% loss of body water harms performance.
2. Dehydration distresses regulatory systems can result in decreased blood flow to... (3)

Rank in order of increasing severity:
a) heat exhaustion
b) heat stroke
c) heat cramps

Reduced work capacity of muscles occurs around ______% loss of body water, often accompanied by spasms and cramping.

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1. 1-2%
2. Muscle, skin, and kidney
3. c, a, b (Heat cramps < Heat exhaustion < Heat stroke)
4. 5 to 10%

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Summary of guidelines for athletes:

Drink ___ ml of fluid ___ hours before activity, _____ ml every ____ minutes during the activity, and _____ ml for every _____ kg of weight loss after the activity. For events under 1 hour, both water and sports drinks work equally well. For longer duration, sports drinks with ____% carbohydrate and ____ g sodium/L are more effective.

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~500 mL
2 hours
150-250 mL
15-20 minutes
450-675 mL
0.5 kg
4-8%
0.5 g