Vitamins and micronutrients

Question 1

Vitamins based on solubility

Answer 1

• Water soluble: Vit C and all B vitamins
• Fat soluble: A, D, E, K
• Water soluble are more readily excreted, fat soluble more easily stored (B12 can be stored well too)
• Fat vitamins are packaged w/ chylomicrons and thus anything that interferes w/ absorption of fat will lead to fat soluble vitamin decrease
• Other malabsorption state can lead to vit def

Question 2

Vitamin sources

Answer 2

• Vitamins that are not required in diet: vit D (sun + cholesterol derivative), vit K (made by bacteria), niacin (synthesized from trp)
• Must eat variety of foods to get all necessary vitamins
• Overcooking veggies or leaving them exposed to air will result in loss of vitamins
• Up to 2x DV is considered safe, fat-soluble vits more likely to be toxic than water-soluble ones
• Groups that are most at risk for toxicity or deficiency: babies/young, pregnant women, elderly, alcoholics, dialysis pts, malabsorptive pts

Question 3

Vitamin deficiency syndromes 1

Answer 3

• Vit C def leads to scurvy: bleeding gums, easy bruising, petechiae near hair
• Vit D def leads to rickets (in children) and osteomalacia (in adults)
• Thiamin def leads to beri beri, either wet or dry
• Wet beri beri: HF and edema
• Dry beri beri: CNS Sxs
• Pellagra from niacin def: dermatitis, diarrhea, dementia, death (4 Ds)
• Def of vit B6: rare but can occur when a pt is on isoniazid (TB Rx)
• B6 def Sx: glossitis, stomatitis (inflammation of mouth and lips), seizures, peripheral neuritis, sideroblastic anemia

Question 4

Vitamin deficiency syndromes 2

Answer 4

• B12 def and/or folic acid: macrocytic anemia
• Folic acid def during pregnancy can lead to neural tube defects (spina bifida)
• B7 (biotin def): can get from eating raw eggs, leads to nausea, rash, muscle pain
• Vit A def: most preventable source of blindness
• Starts w/ loss of green light-> impairment to adapt to dim light-> night blindness-> blindness
• People at risk for vit D def: elderly, renal/liver failure, fat malabsorption
• Vit D def leads to malabsorption of Ca
• Vit K def: newborns, ppl on antibios, fat malabsorption
• Pts on coumadin need consistent vit K intake
• If one vitamin is def likely others are too

Question 5

Vitamin toxicity syndromes

Answer 5

• Nicotinic acid (niacin’s derivative): flushing of skin, itching, nausea, liver damage (niacin flush)
• Vit B6: can be irreversible nerve damage, difficulty walking, numbness of hand and feet
• Individual sensory nerve damage is reversible, ganglia damage is irreversible
• Vit A: is teratogenic, acute (GI upset, HA, blurred vision, incoordination), and chronic (redness of skin, dermatitis, hair loss, bone fractures/malformations, hemorrhage, liver tox)
• Vit E: can inhibit vit K metabolism-> hemorrhage
• Other Sx: muscle weakness, fatigue, HA, nausea

Question 6

Minerals

Answer 6

• Macrominerals (≥100mg/day): Ca, Mg, Na, K
• Microminerals ( goiter, Fe def-> anemia/cold/chews ice
• Raw egg white contains avidin, which will bind up all the biotin (B7) leading to nausea, muscular pain, and rash