VItamins Flashcards
1
Q
What enzymes require B1 (thiamin)?
A
Enzymes involved in carb metabolism - Pyruvate dehydrogenase
Transketolase
Dihydrolipoyl transacetylase
2
Q
The active from of thiamin
A
TPP - thiamin pyrophosphate
3
Q
Good sources of thiamin
A
Meat (pork), fish (trout), enriched whole grains (english muffin), fortified breakfast cereals
4
Q
What contains thiaminase and reduces B1 availability?
A
Raw seafood
5
Q
What does coffee and tea contain that can impair B1 absorption?
A
Tannins
6
Q
What is the upper tolerable limit of thiamin?
A
None
7
Q
B1 deficiency causes what conditions?
A
Beriberi
Wernicke-Koraskoff’s
Branched-chain keto acidosis
8
Q
Riboflavin is the precursor for the synthesis of ____
A
FAD - flavin adenin dinucleotide
9
Q
Main functions of riboflavin
A
Precursor for FAD and FMN in ATP production, role in metabolic pathways of carbs, FAs, and proteins, cell growth and function, metabolism of drugs and steroids
Antioxidant function - cofactor for glutathione reductase
Involved in conversion of b6 to active form P5P, helps work synthesis of B3 from tryptophan and folate to its coenzymes
10
Q
Deficiency of riboflavin and sx of deficiency
A
Ariboflavinosis (typically comes w/deficiency of other water soluble vitamins, seen more in low and middle income countries)
Think “flavors” when thinking “flavin” - affects the flavor tasting tongue/mouth
Cheilosis (cracks of lips), angular stomatitis (cracks/bleeding in corner of mouth), glossitis (inflamed tongue), itching or bloodshot eyes that are sensitive to light
11
Q
Good sources of B2
A
MOSTLY MILK & MEAT
Beef liver, milk/milk products (2% milk, yogurt), fortified cereals and oats, beef tenderloin, almonds
12
Q
60mg of Tryptophan yield how many milligrams of which B-vitamin?
60 mg B1
1 mg B1
1 mg B3
60 mg B3
A
1 mg B3
13
Q
B2 and folate have no known upper limit.
True or False
A
true
14
Q
What are the 4 D’s and what is the condition caused by niacin deficiency
A
Pellegra - dementia, diarrhea, dermatitis, and death.
15
Q
What is the upper limit for daily Niacin?
30mg
35mg
3mg
3g
When may flushing appear?
A
35 mg
Primer - safe at up to 2 g, some may experience facial flushing and mild discomfort at intakes greater than 500 mg
16
Q
Daily intakes that approximate 15-25x the 1998 adult RDA for what vitamin induce hepatic nicotine dehydrogenase and accelerate the clearance of nicotine from the circulation
A
B2
17
Q
Other forms/names of niacin
A
Nicotinic acid
Nicotinamide
Niacinamide
18
Q
What vitamin (in what forms) acts as a coenzyme for the synthesis of high-energy phosphate compounds, carb metabolism (glycolysis and the hexose monophosphate shunt), DNA metabolism (pyrimidine and purine biosynthesis) fatty acid oxidation, lipolysis, lipogenesis, cholesterol metabolism, vitamin metabolism, thyroxine synthesis, steroid synthesis, and NE/E synthesis?
A
Niacin; NADH, NADP+, NADPH
19
Q
What might lower the bioavailability of niacin?
A
Ingestion of large amounts of dietary niacin and amino acid imbalances
20
Q
Which nutrient at 1 gram a day or more affects total serum cholesterol and impacts VLDL formation?
Riboflavin
Thiamin
Folate
Niacin
A
Niacin
21
Q
Anticonvulsants, barbiturates, antimalarial drugs, oral contraceptives, estrogens, chemo agents, and EtOH reduce availability of which?
B1
Folate
Vitamin C
B3
A
folate
22
Q
Yeast, livers, pork, chicken liver, alfalfa, green leafy spinach are great sources of
Vitamin C
Folate
B3
Vitamin D
A
folate
23
Q
Good sources of niacin
A
Eggs, liver, fish, milk/cheese, potatoes, corn, broccoli, carrots, tomatoes are good sources of
24
Q
The biological activity of folate requires its activation to _____
A
Tetrahydrofolate
25
The content of folate in foods is reduced by….
Cooking, acidic environments, and exposure to sunlight
26
Chronic folate deficiency produces what in utero, and in children and adults?
Neural tube defects
Megaloblastic anemia
27
Large amounts of folate may prevent…..
Cervical dysplasia, colorectal cancer, and depression
28
What 3 b-vitamins can reduce plasma homocysteine concentrations?
B6, b12, folate
29
Signs of biotin deficiency
dry scaly skin, nausea, anorexia, and seborrhea in adults (in infants < 6 months, seborrhea and alopecia)?
30
What is biotin necessary for?
metabolism of macronutrients
31
Which vitamin plays a critical role in fat and CHO utilization, oxidation/reduction rxns of energy metabolism, manufacturing of adrenal hormones, and RBC metabolism?
Biotin
B5
B6
B1
Pantothenic Acid (vitamin B5) plays a critical role in the utilization of fats and carbohydrates, in the oxidation/reduction reactions of energy production, in the manufacture of adrenal hormones and in the metabolism of red blood cells (following its conversion to coenzyme A)
32
What are good food sources of b5?
yeast, whole grains, egg yolks, organ meats (liver, heart, kidney), potatoes, peas, beans, and saltwater fish
33
What reduces the content of B5 in food?
The pantothenic acid content of foods is reduced by exposure to light, storage of milk in cartons or glass bottles, heat, evaporation, pasteurization, canning, cooking, and milling
34
Chronic pantothenic acid deficiency produces...
fatigue, nausea, and “burning feet syndrome” (numbness and shooting pains in the feet)
35
What is the upper safe limit of pantothenic acid intake?
There is no known upper safe limit of pantothenic acid intake (daily intakes of up to 10 g are safe). Large intakes may accelerate wound healing and reduce joint inflammation
36
Which nutrient is hindered by the presence of alcohol, antibiotics, and avidin (protein in egg whites)
B1
B3
Biotin
B6
Biotin
37
Chicken, lamb, pork, beef, veal liver, beans, yeast, milk/cheese, saltwater fish are sources of…
biotin
38
Upper limit for both biotin and b5?
10mg
100mg
1000mg
None known
none known
39
Which nutrient in large doses could accelerate wound healing and reduce joint inflammation?
B5
Biotin
B6
Vitamin A
B5
40
The biotin content of foods is reduced by...
cooking, acidic environments, and exposure to sunlight
41
Large amounts of biotin may promote...
strong nails and healthy hair and may aid in the treatment of seborrhea (skin condition characterized by excessive oil production and inflammation, resulting in greasy, flaky, and sometimes itchy skin) and diabetes
42
What is b12 needed for?
healthy blood formation and nervous system function because it is required for one-carbon methyl group transfers from methionine to methyl group acceptors, fatty acid oxidation, DNA synthesis, cell division and red blood cell differentiation
43
Dermatitis, anemia, irritability, fatigue, insomnia, nervousness, convulsions, brain wave abnormalities are signs of which deficiency?
B5
B6
B12
Biotin
B6
44
Inadequate production of _____ ____, a protein secreted by the stomach mucosa, limits vitamin ___ absorption in the intestine
intrinsic factor, b12
45
Good food sources of vitamin B12 include -
meat, fish, eggs, cheese, milk, liver, and kidney
46
The vitamin B12 content of foods is reduced by ...
heat, acid, light, and oxidizing substances
47
Chronic deficiency of what vitamin produces pernicious anemia, impaired nervous system function, confusion, depression, memory loss, impaired leg and finger coordination, psychosis, peripheral neuritis, moodiness, secondary folate deficiency and elevated urinary excretion of methylmalonic acid
vitamin B12
48
What is the upper safe limit of b12?
There is no known upper safe limit of vitamin B12 intake (up to daily intakes of 20 mg).
49
Large amounts of vitamin B12 may be useful in the treatment of...
anemia, anxiety and depression
50
Vitamin ____ is essential, after its conversion to ____, for protein and amino acid metabolism, neurotransmitter synthesis within the nervous system, immune system function, the synthesis of hormones, heme synthesis, the differentiation of red blood cells and the remethylation of tetrahydrofolate after conversion of (methyltetrahydrofolate + homocysteine) to (tetrahydrofolate + methionine)
b6 (pyridoxine)
PLP or P5P
51
In order to perform its coenzyme functions, pyridoxine must be phosphorylated to ....
pyridoxal-5’-phosphate (P5P
52
The bioavailability of what vitamin is reduced by food processing, large amounts of dietary fiber, oral contraceptives, hydrazine dyes, drugs (isoniazid, hydralazine, dopamine, penicillamine), and concurrent consumption of alcohol
b6
53
Good food sources of vitamin B6 include....
Brewer’s yeast, liver, eggs, fish, wheat germ, nuts, beans, avocados, bananas, carrots, and peas
54
The vitamin B6 content of foods is reduced by....
storage, heat, and milling
55
Safe upper limit of b6?
Vitamin B6 is relatively nontoxic. A few nervous system reactions have been reported with daily intakes of 2 to 6 grams.
56
Large intakes of what vitamin have been used to... enhance immune system function and may be useful for amelioration of the symptoms of premenstrual syndrome, carpal tunnel syndrome and asthma and for the prevention of kidney stones
B6 (Pyridoxine)
57
What is vitamin C required for?
Collagen synthesis, formation of NE, iron metabolism, synthesis of proline, tryptophan, dopamine and tyrosine, reduction of free radicals
58
Good food sources of vitamin C
Citrus fruits, berries, vegetables (bell peppers)
59
How is the vitamin C content in food reduced?
Heat, cooking, and exposure to air (vegetables lose vitamin c when they’re cut)
60
Chronic deficiency of what vitamin causes scurvy, bleeding gums, extreme weakness and fatigue, poor wound healing, bruises, and weight loss?
Vitamin C
61
Large ingestions of vitamin c interfere with diagnostic tests that are used to determine the presence of ____
Oxalate in urine
62
Large ingestions of vitamin C can interfere with the effectiveness of what drugs?
Anticoagulants (heparin, coumarin)
63
Consuming vitamin C with what other nutrient helps with the absorption of that nutrient. Are there any downsides to this?
Iron - can result in excess iron accumulation (“iron overload”; hemochromatosis)
64
What is vitamin A required for?
Vision (especially in low light situation), normal growth in children, resistance to infections, epithelial integrity/mucus membranes in respiratory, GI, sex organs, and the prevention of cancer (by promoting cell differentiation), spermatogenesis and hormone synthesis (corticosteroids, estrogens, androgens), mobilizes iron stores to build new RBCs (can help prevent iron-associated anemia)
65
Good sources of vitamin A
Squash, yams, cantaloupe, dark green leafy vegetables, fish liver oil, and liver meats
66
Vitamin A deficient produces….
Xeropthalmia (abnormal dryness of eyes), bitots spots, hyperkeratosis (skin condition causing excess keratin like eczema), anemia, ridged/brittle nails, dry skin, acne, nightblindness, loss of appetite or sense of taste/smell
67
Is there a toxic limit to vitamin A?
Yes, both fat and soluble active forms can be toxic when ingested in large amounts (over 25,000 IU/day) - toxicity usually not observed in adults in levels under 15000 RE even when taken long term
Daily intakes greater than 10,000 IU may be teratogenic in humans (can cause structural or functional abnormalities in developing fetus or embryo during pregnancy)
68
What are the reversible sx of vitamin A overdose?
Hypercalcemia, scaly skin, dry skin/lips, bone loss, headache, blurred vision, reduced thyroid activity
69
25 mg of B-carotene is equivalent to roughly ___ IU of vitamin A?
7000
70
Is there a known upper safe limit of intake of beta carotene?
No, but daily intakes of 25 mg or more of beta carotene may promote tumorigenesis in lung epithelial cells in the presence of large amounts of nicotine
71
Which vitamin has a form that can, when given alone, increase lung cancer risk in smokers, but when given with Vitamin C, can reduce that risk?
Vitamin A
72
Vitamin D is required for?
Maintains serum calcium and phosphorus (to help w/bone mineralization and to prevent hypocalcemic tenant = muscle spasms and cramps)
formation of bone (growth and remodeling)
Promotes calcium absorption in gut
Immune system, enhances activity and response of WBCs in infection
73
Vitamin D levels increase via two ways -
Ingested or produced from cholesterol in the skin (D3, cholecalciferol) OR made by certain fungi (D2, ergocalciferol)
74
Describe the process of activating vitamin D?
Cholecalciferol is converted to 25-hydroxycholecalciferol in the liver, and then undergoes hydroxylation in the kidney (stimulated by PTH, phosphorus, and calcium) producing 1, 25-dihydroxycholecalciferol)
25-OH is what’s found most in circulating, most physiological effects are from 1,25-OH
75
Good food sources of vitamin D
Cod liver oils, fatty fish (salmon, mackerel), meats, and milk and other dairy & DF products that are fortified, mushrooms (shitake)
76
Chronic vitamin D deficiency produces what in children and what in adults?
Rickets, osteomalacia (softening of bones d/t inadequate mineralization of newly formed bone vs. osteoporosis = loss of bone mass d/t imbalance between bone formation and resorption)
77
Vit D toxicity sx
Nausea, fatigue, hypercalcemia, and calcification of kidneys & heart, bone loss, kidney stones
78
What is the role of vitamin E?
MAINTAINS CELL MEMBRANE INTEGRITY THROUGH Antioxidant activity - works with glutathione peroxidase and vit. C in limiting free radical damage
Protects cellular proteins from oxidative damage during CV evens
Antithrombotic - slows down action of thrombin (clotting protein)
79
What affects the bioavailability of vitamin E?
Exposure to oxidizing conditions (strong oxidizing agents are oxygen, hydrogen peroxide, or halogens leading to rxn like burning or rusting) i.e. vegetables or fruits browning = oxidized (enzymes react with oxygen)
or fat malabsorption conditions
80
Good food sources of vitamin E?
cold pressed vegetable oils, nuts (almonds, pine nuts), seeds (sunflower seeds) wheat germ oil
81
The vitamin E content in food is reduced by…
Reduced by food processing, oxidizing conditions
82
Symptoms of chronic vitamin E deficiency?
Hemolysis and anemia (decreased membrane integrity of RBCs causes this), atrophy and skeletal muscle weakness, degeneration of nerve cells
83
Known toxicity of vitamin E?
None, probably least toxic of all fat soluble vitamins
Doses up to 1600-3200 mg have been used for prolonged periods of time w/o significant side effects
Those taking anti-coagulant drugs and potentially diabetics should be caution with high doses d/t bleeding or hypoglycemia risks
84
What is vitamin K required for?
Required cofactor in the formation of prothrombin and clotting factors VII, IX, and X (facilitates blood clotting, so coagulation!!) also coenzyme for carboxylase (vit K dependent enzyme required for synthesis of proteins involved in hemostasis (clotting)
maintain bone health (cofactor for osteocalcin, a protein that regulates calcium metabolism and vit D activity at sites of bone turnover
85
What reduces the bioavailability of vitamin K?
Certain antibiotics, Dilantin (anti-epileptic drug), aspirin, anticoagulant drugs (Coumadin, warfarin), and large amounts of vitamin E.
86
Most healthy individuals absorb adequate amounts of vitamin K from that synthesized and secreted by the intestinal micro flora.
True or False
True
87
Chronic vitamin K deficiency can be produced by…
Malabsorption d/t bowel obstruction, spruce, chronic liver disease, UC, regional ilieitis, or bowel shunts that may produce a reduced ability to coagulate blood and disturbances in bone architecture, alcoholism
88
Excessive amounts of vitamin K (usually obtained through injection) and cause….
Excessive amounts of vitamin K (usually obtained through injection) and cause hemolytic anemia and jaundice, although no adverse effects are caused at daily intakes up to 4 g
89
What are carotenoids? What’s the most common one in food?
Family of compounds found in plants that can converted to vitamin A. Beta-carotene is the most common and can be absorbed intact or can be split into two molecules of vitamin A by intestinal cells and absorbed as vitamin A
90
where is vitamin A stored? Is beta carotene stored in the same place?
Liver, beta-c is fat cells
91
What nutrients help with absorption/assimilation of vitamin A?
Vit E (absorption and tissue uptake)
Zn (role in transport, deficiency associated with decrease circulating A and hepatic levels)
Protein, fat, bile, thyroid (thyroxine enhances conversion of beta-c to vit A )
92
What are inhibitors of vitamin A?
Alcohol, low fat and protein, mineral oil (a lubricant laxative that coats intestinal walls and prevents fat soluble vitamins from getting absorbed)
93
What can cause vitamin A deficiency?
Stress, infection, surgery, fat malabsorption d/t disease, heavy alcohol consumption, cig smoke, meds (cholesterol lowering, laxatives, barbituates)
94
Any drug/nutrient interactions w/vit A?
laxatives (decrease absorption)
Cholestyramine (cholesterol lowering) Through interfering with fat absorption, cholestyramine might decrease the absorption of vitamin A. Separate by 4 hrs
Barbiturates (sedative meds for seizures, insomnia, migraines) decrease liver stores
Alcohol - Chronic alcohol abuse depletes the liver of retinol and increases retinol mobilization to extra-hepatic tissues, although the mechanisms are not understood. Avoid high doses of vitamin A and β-carotene in alcoholics because chronic alcohol abuse increases the risk of retinol-induced hepatotoxicity.
Colestipol (bile acid sequestrant) - studies limited so effects unsure. Monitor pts on long term
Orlistat may decrease the intestinal absorption of carotenoids and fat-soluble vitamins (vitamins A, D, E, and K). Separate by 2 hrs
95
What can vitamin A be used for in prevention and therapy?
Anemia, gastric ulcers (d/t maintain mucus production), skin/scalp disorders (dandruff, premature aging, eczema, psoriasis), acne, bronchitis, pneumonia, infectious diarrheal disease
96
Vitamin A and pregnancy?
Toxic levels can cause birth defects so total intake shouldn’t exceed 2500 RAE
1 mcg RAE = 1 mcg retinol, 2 mcg supplemental beta-carotene, 12 mcg dietary beta-c
97
Vitamin A RDA to UL in adults
Adults:
700 mcg females
900 mcg males
UL - 10,000 IU
98
Pregnancy and lactation vitamin A needs
770 mcg pregnancy
1300 mcg lactation
99
What are new borns fed exclusively breast milk at risk for abnormal bleeding? How is this prevented?
Breast milk has very little vit K and newborns colons are sterile for first few days so bacteria can’t synthesize K, putting them at risk for deficiency
most are given intramuscular vit K at birth d/t this
100
Describe the absorption of fat soluble vitamins?
Same as fats - taken up into micelles in lumen of SI and enter enterocytes via passive diffusion, then in enterocytes incorporated into chylomicrons where they leave enterocyte and enter lymph
In circulation, carried mainly in lipoproteins
101
Is vitamin K stored in the body?
Mainly in liver, but only small amounts since its metabolized quickly so there are relatively low levels in blood and tissue stores compared to other fat soluble vitamins
102
RDA for vit K for adult males and females
Males 120 mcg
Females 90 mcg
103
Do vitamin K levels change in pregnancy and/or during lactation?
No - 90 mcg for both
(For 14-18 years old, 75 mcg for both)
104
Top food sources for vit K
Mustard greens, Swiss chard, kale, broccoli, collard greens, Brussels sprouts
105
Supplemental form of vit K and dose
K1 (phyllouqiunone)
30-100 mcg
106
Drug/nutrient interactions for vit K
Anticoagulants antagonize, so dietary vit K needs to be consistent (warfarin, coumarin)
Broad spectrum ABs
Drugs that impair fat absorption (some antacids, orlistat [wt loss], cholestryamine (lowers cholesterol)
Bile acid sequestrants (colestipol)
Dilantin (epilepsy drug)
Aspirin
107
What protein and what enzyme in the body are vitamin K dependent? What do they do?
Osteocalcin - protein involved in calcium metabolism and vit D activity at sites of bone turnover
Carboxylase - enzyme required for synthesis of proteins in hemostasis (blood clotting) and bone metabolism
108
Nutrients that increase absorption or inhibit/compete for absorption of vit K?
Vit D may have synergistic effects, fat increases absorption
Vit E may have anti-vit K effects and increase bleeding risk, high doses of vit A can decrease k2 production from intestinal bacteria
109
Nutrients that help with absorption/assimilation/antioxidant effects of vit E? Does it enhance other nutrients?
Vit E helps with vit A absorption and tissue uptake
CoQ10 may increase its anti-inflammatory effects
110
Nutrient inhibitors of vit E or those that increase its needs? Or nutrients IT inhibits?
Increased PUFA consumption increases need for vit E since vit E helps protect PUFAs from oxidation
Vit K may be inhibited with E
Vit C functions with E, so supplementation with one may increase need of other
Iron may interfer with absorption
111
Vit E RDA for adults
15 mg
112
Do vit E requirements increase with pregnancy and lactation?
Pregnancy no, still 15 mg
Lactation yes - 19 mg
113
Most bioavailable form of vit E ?
Alpha-tocopherol - only form capable of meeting human requirements (d-alpha-tocopherol) - MUCH more bioavailable than synthetic form dl-alpha-tocopherol)
114
Drug-nutrient interactions with vit E
Anticoagulant and anti platelet meds (Wafarin (Coumadin) - supplement vit E @ or above 400 IU thought to increase risk of bleeding when on these meds
Simvastain and niacin - when E taken with other antioxidants (V, selenium, beta-c) there has been a blunted response in rise of HDL in those on these meds/vitamin
Aspirin - High doses of supplemental vitamin E may potentiate the antiplatelet effects of aspirin (avoid high dose E)
Cholestyramine - may decrease fat absorption so separate from E supplement by 4 hrs
Colestipol (bile acid sequestrant) - may interfere with absorption but research isn’t clear - monitor those on drug long term
115
What can vit E be used to prevent/treat?
Anemia, cataracts, rheumatic disorders, skin conditions/wound healing, PMS, fibrocystic breasts, immunity
116
NFPE for vit E
Purpura- colored spots and patches on skin and in mucous membranes, including lining of the mouth - see with excessive vit E
117
Nutrition partners that help with assimilation/absorption of vit D (or vice versa)
Vit D increases absorption of calcium and phosphorus
Fat enhances, but some vit D is absorbed even w/o dietary fat
118
Adult men and women RDA for vit D and UL
600 IU (15 mcg)
70+ = 800 IU (20 mcg)
UL = 4000 IU (100 mcg)
119
Pregnancy/lactation requirements for vit D? UL?
Both stay same….600 IU 15 mcg)
UL = 4000 IU (100 mcg
120
Most bioavailable form of vit D?
D3 (cholecalciferol) - 2x more bioavailable than D2 (ergocalciferol)
121
What do some researchers say is the recommendation for sun exposure to get sufficient vit D synthesis? What factors are considered?
Some researchers says that ~5-30 mins of sun exposure between 10 AM and 4 PM either daily or at least 2x/week to face, arms, hands, and legs w/o sunscreen usually leads to sufficient vit D synthesis
Most people meet at least some of their needs through exposure to sunlight. Factors that affect UV radiation exposure = season, time of day, length of day, cloud cover, smog, skin melanin content, sunscreen
122
Who’s at risk for vit D deficiency.
Strict vegans/vegetarians, elderly (d/t poor diet and sun exposure), those living up north, chronic kidney disease, fat malabsorption disorders
123
Can vit D be toxic? Describe why, levels, and UL
No specific condition, but EXCESS AMOUNTS OF VITAMIN D ARE TOXIC - b/c vit D increases calcium absorption in the GI tract, toxicity results in marked hypercalcemia.
In extreme cases, toxicity can cause renal failure, calcification of soft tissues through body (including coronary vessels and heart valves)
UL stated above, but also notes by NIH that s/s of toxicity are unlikely at daily intakes below 250 mcg (10,000 IU), hypercalcemia seen @ 50,000 IU
124
NFPE for vit D
Gums - Gingivitis, swollen, spongy, bleeds easily, redness, retracted gums
Bones - tenderness or pain or rickets (kids) or osteomalacia (adults), epiphyseal enlargement of wrists, legs, and knees
125
Drug/nutrient interactions for vit D
Orlistat - together with a reduced fat diet can decrease absorption
Statins - they reduce cholesterol synthesis, b/c vit D synthesis requires cholesterol, statins may also reduce vit D synthesis - high intakes of vit D may also reduce potency of some statins b/c they compete for same metabolizing enzyme
Steroids - corticosteroid meds (prednisone) can reduce calcium absorption and impair vit D metabolism
Thiazide diuretics (hygroton, Lozol, microzide) decrease urinary calcium excretion - these drugs combined with vit D supps (which increase calcium intestinal absorption) might lead to hypercalcemia
126
Main functions of thiamin?
Cofactor for 5 enzymes involves in glucose, lipid, and amino acid metabolism, located in nerve cell membrane and important for transmission of nerve impulses in brain and peripheral nerves, role in NT metabolism (serotonin, acetylcholine), role in collagen synthesis
127
Nutrient that helps with absorption/assimilation of B1?
Mag - needed for absorption and activation to active form w/in cell
128
Is thiamin stored in the body?
Very small amounts in liver, body reserves very small
129
inhibitors that decrease/compete for thiamin absorption?
Alcohol, raw seafood (contains thiaminase that reduces B1 availability, black tea/coffee (tannins) radiation, refining of grains destroys most B1, high temps and prolonged cooking, significant amounts lost in cooking water since its water soluble (boiling veg can destroy up to 2/3 of thiamin content)
130
Supplemental form of thiamin and typical dose
Thiamin HCl - 1.5 mg +
131
Sx of thiamin deficiency
Sensory loss, loss of reflux, foot drop, motor loss, insomnia, headache, irritability, depression, staggered gait
132
Method of lab testing for thiamin?
Blood not reliable indicator of status.
Transketolase enzyme is indirect measure (enzyme that depends on TPP) or urinary thiamin excretion (shows dietary intakes not tissue stores)
133
NFPE for thiamin
Body edema, round swollen face, foot drop, calf tenderness, tingling (pins/needles), inability to concentration, peripheral neuropathy
134
Causes of thiamin deficiency
Alcohol, black tea/coffee (tannins), folate deficiency can impair absorption, stress, physical exertion, burns, preg/lactation, oral BC, diabetes (levels seen much lower in T1D and T2D) - most of these require more thiamin, so deficiency comes from not meeting increased needs
135
What can thiamin be used for in prevention and therapy?
Nerve disorders - deficiency can decrease pain tolerance so may ease chronic pain; peripheral neuropathy
CNS disorders - Alz, depression, anxiety
Anemia - deficiency can cause anemia that looks like folate or b12 deficiency (macrocytosis = elevated mean corpuscular volume [MCV])
136
Drug/nutrient interactions with thiamin
Fluorouracil (flaw -ruh-yur-uh-sil) (chemo) - inhibits phosphorylation of B1 —> TPP
and loop diuretics (taking a MV w/B1 may help prevent defiance) - increases urinary flow so may prevent renal reabsorption of B1
137
Notable functions of B2 in specific stages of lifecycle?
Low levels may be associated with preeclampsia in women, may be beneficial for lowering cataract risk
138
Does the RDA for riboflavin change for pregnancy and lactation?
Yes, from 1.1 mg —>
1.4 mg (pregnancy)
1.6 mg (lactation)
139
What other nutrients is riboflavin required for? Does anything help absorption on B2?
Synthesis of niacin from tryptophan, activation of b6, folate (FAD is cofactor for MTHFR)
Thyroid hormone increases absorption, so hypothyroidism can look like B2 deficiency (synthetic thyroid hormone decreases absorption)
140
How bioavailable is riboflavin in food? What form?
FAD and FMN, 95% is bioavailable
141
Causes of riboflavin deficiency and groups at risk?
Thyroid hormone insufficiency, vegan/vegetarians that don’t consume a lot of milk products, pregnancy/lactation increases needs, malabsorption conditions like celiac, chronic diarrhea, IBS
142
What can riboflavin be used to prevent or for therapy?
Migraines, since it has antioxidant properties it can decrease cataract risk, helps with skin/mucus membrane so may help cheilosis, stomatitis, skin rashes, and supplements may help in those with increased needs that feel fatigued and/or depressed
143
Main functions of Mg
Cofactor in more than 300 enzyme systems including protein synthesis, energy production, glycolysis, oxidative phosphorylation, muscle and nerve function, blood glucose control, and BP regulation
Plays role in active transport of calcium and potassium ions across cell membrane, a process that’s important to nerve impulse conduction, muscle contractions, and normal heart rhythm
Important for structure of teeth and bone (with calcium and phosphorus)
“Natures calcium channel blocker” - works in opposition of calcium, more parasympathetic
144
Where is magnesium stored in the body?
50-60% in bone, most of the rest in soft tissue, less than 1% of total in blood serum
145
Nutrient partners that help with absorption/assimilation of Mg (or vice versa?)
Mg helps transport Ca++ across cell membranes
Involved in vit D metabolism in liver and kidneys and needed for its absorption
Helps absorption of B1 and activation to TPP
146
Does Mg requirements change for preg/lactation?
Pregnancy yes, 350-360 vs 310-320
Lactation stays the same
147
Top food sources of Mg?
Green leafy veg (spinach), legumes (black beans, edamame), nuts (almonds, cashews, peanuts), seeds (pumpkin, chia), soy milk
**foods that contain fiber generally contain Mg
148
Best forms of Mg in supplements
Organically bound forms (gluconate, asparatate, citrate, chloride, chelated forms) vs. inorganic forms like sulfate and oxide
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Who’s at risk for Mg deficiency? What populations have an increased need?
Low dietary intake, certain meds, diabetes, hyperparathyroidism, intestinal malabsorption conditions (IBD, chronic diarrhea, pancreatitis), regular alcohol intake
Athletes in strenuous training have increase requirements
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Mg deficiency sx - how common?
Symptomatic deficiency d/t low dietary intake in otherwise healthy people is uncommon d/t kidneys limiting urinary excretion
Nausea, vomit, loss of appetite, depression, irritability, muscle cramps/spasms
Severe deficiency = increased Ca++ and K+ losses leading to hypocalcemia and hypokalemia
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Mg toxicity?
No condition name
In healthy adults, its nontoxic at doses up to 1 g/d; kidneys eliminate excess amount from dietary sources so not a problem. In chronic kidney failure Mg cannot be excreted efficiently & can cause high blood levels with sx of nause, vomiting, low BP, arrhythmias
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Mg can be used in prevention and therapy for….
Diabetes (deficiency common and may lower insulin sensitivity), kidney stones (can reduce calcium-oxalate stones), CVD, hypertension/preeclampsia, muscle cramps, irritability/anxiety/insomnia, PMS (cramps, irritability, water retention), osteoporosis
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How much Mg from food is actually absorbed?
30-40%
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Where is b2 stored in body?
Highest amounts in retina
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Do any nutrients get in the way of riboflavin absorption?
Calcium - chelates with B2 and decreases absorption
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Main functions of potassium?
Most abundant INTRACELLULAR cation - has strong relationship with sodium (Na+/K+ pump); one of main functions is membrane polarization in muscle and neurons ….
Smooth, skeletal, and cardiac muscle contraction, nerve transmission, maintains electrolytes balance (kidneys control K+), pH balance
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After absorption, where does K+ go? Where it is stored? How is it excreted?
Crosses blood via K+ channel
95-98% is found INSIDE cells, present in all body tissues
Excreted via urine by kidneys, some from sweat and feces
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Nutrients that help with absorption of K+
Nutrients inhibitors that decrease/compete with absorption?
+ ….. Mg needed for K+ uptake (reduced Mg levels can contribute to decrease in K+ absorption), K+ decreases Ca++ excretion (opp of Na+!!), excessive intake of licorice root can lead to excess K+ in blood
K+ intake can contribute to increase loss of Na+
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Top food sources K+
How well absorbed and what can decrease?
Fruits, veg, legumes, potatoes
Beet greens, Swiss chard, Lima beans, acorn squash, yam, baked potato, spinach, water chestnuts, cooked plantains
85-90% absorbed, boiling veg can lead to up to 50% loss of K+
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Populations where K+ deficiency may be prevalent?
ED, Mg depletion, high intakes of dietary licorice (contains aldosterone which increases K+ excretion), laxative abuse, meds, CHF, bloating/constipation/ab pain (K+ is needed for muscle contractions, including smooth muscle in GI tract - low K+ can reduce gut motility and worsen constipation. K+ also needed for nerve signal transmission, so the enteric NS is influenced by electrolyte balance)
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Symptoms of K+ deficiency?
Toxicity?
Deficiency - postural hypotension, palpitations, elevated BP, arrhythmias, muscle cramps and weakness, irregular bone turnover, anxiety/irritability (hyperexcitability of NS can be caused by low K+ b/x there’s too much Na+ inside the cell vs
Tox - hyperkalemia (usually caused by impaired renal function), arrhythmias, muscle weakness, diarrhea, ulcers, tingling in extremities
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Methods of lab testing for K+
Plasma K+ - shows how well its functioning in body but not dietary intake since levels are so tightly regulated by kidneys
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Drug/nutrient interactions for K+
Diuretics, corticosteroids (prednisone), high dose ABs, insulin - all decrease
ACE inhibitors, ARBs, K+ sparring. Diuretics, NSAIDs - all increase
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Main functions of copper
Collagen formation (lyse oxidase is Cu dependent)
Oxidation - cofactor for cytochrome c oxidase (final step of ETC)
Pigmentation - melanin is Cu dependent
Protein & iron metabolism (needed for mobilization)
Enzyme cofactor (Epi, NE synthesis, breakdown of serotonin, histamine, dopamine)
RBC formation
“Copper keeps collagen & color”
Also plays role in antioxidant defense (Zu/Cu/SOD works w/glutathione peroxidase
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Where is Cu located in the body, is it stored, and how is it excreted?
Located in skeleton and muscle, small amount stored, excreted via bile (liver) & small amount in urine
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Nutrient-nutrient interactions copper
Needed for iron mobilization
High supplemental molybdenum, zn, and iron can decrease copper
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Top food sources of copper
Beef liver, oysters, baking chocolate, potatoes, sunflowers, cashews, whole grains & wheat bran cereals
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Supplemental forms of copper (best)
Organically bound (copper ortate or chelate) more bioavailable, copper sulfate is the most common form (inorganic)
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Causes of copper deficiency
High supplemental iron, molybdenum, zinc, GI disorders, increased oxidative stress (chronic illness like RA, environmental chemicals, cig smoke
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Copper deficiency sxs
Increase cholesterol and triglycerides, glucose intolerance, anemia resembling IDA but not completely responding to Fe, vitiligo, changes/loss of hair and skin pigmentation, osteoporosis/abnormal skeletal growth, weakness, fatigue, increased vulnerability to oxidative damage
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Copper toxicity & sxs
Generally well tolerated & safe at doses up to 5 mg/day in healthy, doses higher than 7 mg/d can cause….
Ab pain, vomit, diarrhea, liver damage
Toxicity can happen with Wilsons disease (affects Cu storage), biliary excretion is impaired which increases Cu in liver & brain leading to cirrhosis, liver failure, and neuro damage
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Method of testing for Cu
RBC preferred for functional and nutritional status
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Drug-nutrient interactions with copper
Chronic antacid use and decrease absorption
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What can copper be used for in prevention and therapy?
Anemic - microcytic, or used if on iron supplemental to prevent decreasing cu levels
RA
CVD - chronic low Cu may increase risk d/t increase in cholesterol and TGs while weakening vascular wall
Immune function - even mild Cu def may decrease by decreasing T-cell activation
Zinc therapy
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