Vitamins

Thiamine B1

Part of coenzyme thiamine pyrophosphate- Carboxylase+Transferase Rxns

Deficiency- cooking/boiling destroys, ethanol inhibits absorption and TPP formation

Beriberi

Thiamine Deficiency

Dry- nervous system effects

Wet- cardiovascular system effects

Wernicke-Korsakoff Syndrome

Seen in alcoholics due to lack of thiamine to brain, stumbling around, look drunk

Riboflavin B2

Coenzyme in energy metabolism- flavin mononucleotide and flavin adenine dinucleotide

Deficiency- UV light and irradiation, angular cheilitis, photophobia, scrotal dermatitis

Niacin B3

Nicotinic acid and nicotinamide

NAD and NADP

Manufactured in the body from tryptophan

Niacin deficiency

Pellagra- diarrhea, dermatitis, dementia, then death

Hartnup’s disease- kidneys don’t reabsorb tryptophan

Niacin toxicity

Flush- itchy and tingly, can be painful

Due to supplementation

Pantothenic Acid B5

Part of chemical structure of coenzyme A

Deficiency + Toxicity are rare

Pyridoxine B6

Forms: Pyridoxal, pyridoxine, and pyridoxamine

Conversion to coenzyme PLP which is involved in AA metabolism, glycogen metabolism, tryptophan to niacin/serotonin conversion, heme synthesis, nucleic acid synthesis, and lipid synthesis

Pyridoxine deficiency

Rare in diet

High protein diet requires more pyridoxine- inhibits PLP

Alcohol and isoniazid (TB)

Pyridoxine Toxicity

Irreversible nerve degeneration of dorsal root ganglia

Biotin B7

Coenzyme that carries CO2 (Krebs, gluconeogenesis, FA synthesis, Isoleucine + valine synthesis)

Biotin Deficiency

Rare

Raw egg whites have a protein that binds biotin

GI Bacteria produce biotin

Folate B9

Folic Acid

Transfers single-carbon compounds in metabolism

Convert B12 to active form

DNA synthesis and repair, aids in cell division and growth

Folate deficiency

Spina bifida

Supplementation through 1st trimester= no spina bifida

Fortification, could mask B12 deficiency

Colbalamin B12

Depends on folate, folate does not depend on it

Regeneration of methionine, synthesis of FA, synthesis of DNA + RNA

Stomach HCl releases it from proteins

Intrinsic factor binds and helps absorb

B12 deficiency

Pernicious Anemia

Lack of HCl or intrinsic factor

Vegan, tape worms, excessive alcohol

Vitamin C

Cofactor in collagen formation- bone and tooth formation

Cofactor- tryptophan to serotonin

• tyrosine to norepinephrine

Defends against free radicals

Deactivates histamine to treat cold

Vitamin C deficiency

Gums bleed easily, capillaries under skin break easy

Scurvy

Vitamin C toxicity

Diarrhea, GI distress

Need high supplementation- kidney disease, gout, vit c breakdown

Vitamin A

Fat soluble

From Beta Carotene

In animal products- retinyl esters → retinol

In plant products- beta-carotene → Retinol

Can go from retinal → retinoic acid

Retinol

From retinyl esters in animals, supports reproduction

Important in sperm development, fetal development, and growth in children (promotes bone dismantling and remodelling)

Retinal

From Beta-carotene in plants, participates in vision

Maintains clear cornea

Photosensitive cells in retina as rhodopsin

Retinoic Acid

Derived from Retinal, supports growth

Helps protect skin from sunlight and helps maintain mucous integrity

Signals for DNA transcription

Vitamin A storage

Absorbed in lymphatic system

90% stored in liver

RBP binds and carries in blood

Vit A deficiency

Susceptible to infections, night blindness, corneal clouding and blindness

Vit A toxicity

Binding proteins are swapped, free vit A damages cells

Promotes bone dismantling, cell death in spinal cord before birth, acne

Actual risk due to fortified foods and supplements

Children most vulnerable

Vitamin D

Not essential

Body synthesis from sunlight and precursor from 7-DHC (hydroxylation in liver and kidneys creates)

5-10 mins of summer sun 2-3x a week is sufficient

Vit D roles

Active it acts as a hormone in intestines, kidneys, and bone, too much interferes with this

Deficiency can create calcium deficiency causing rickets in children and osteomalacia in adults

Most likely to be toxic and causes hardening of blood vessels and kidney stones

Vitamin E

Active in body as Alpha-tocopherol

Acts as an antioxidant to stop production of free radicals and protecting LDLs

Deficiency- fat mal-absorption causing erythrocyte hemolysis, thrombocytosis, and edema

Toxicity- very rare, may interfere with vitamin K activity

Vitamin K

Acts primarily in blood clotting, needed to activate clotting factors 2,7,9,10

Metabolism of bone protein osteocalcin (bone building protein)

Deficiency- rare, GI bacteria make half, failure to make bile, some drugs can disrupt absorption and synthesis