Biochemistry · Short notes

Vitamins and Minerals: Short Notes & Cheat Sheet

Fat- and water-soluble vitamins with their functions, deficiency diseases and toxicity, plus the key minerals and trace elements.

Short notes

Read these before you attempt the topic's MCQs.

Pair each vitamin with its deficiency disease; this single link answers many MCQs.

They are absorbed with fat, stored in the body and can build up to toxic levels. Deficiency occurs with fat malabsorption, orlistat or cholestyramine.
Vitamin A (retinol) is needed for vision (rhodopsin) and epithelia. Deficiency causes night blindness, Bitot's spots and xerophthalmia. Excess is teratogenic.
Vitamin D is made in skin (D3), 25-hydroxylated in the liver and 1α-hydroxylated in the kidney to active calcitriol. Deficiency causes rickets in children and osteomalacia in adults; deficiency is very common in Pakistan.
Vitamin E is an antioxidant; deficiency causes haemolytic anaemia in premature babies and neuropathy.
Vitamin K is needed to γ-carboxylate clotting factors II, VII, IX and X and proteins C and S. All newborns receive vitamin K at birth to prevent haemorrhagic disease.

B1 (thiamine): deficiency causes beriberi and Wernicke–Korsakoff syndrome in alcoholics. Give thiamine before glucose.
B2 (riboflavin): deficiency causes angular cheilitis and glossitis.
B3 (niacin): deficiency causes pellagra (dermatitis, diarrhoea, dementia). It can be made from tryptophan.
B6 (pyridoxine): needed for transamination. Isoniazid causes B6 deficiency and neuropathy, so pyridoxine is given with it.
B9 (folic acid): deficiency causes megaloblastic anaemia and neural tube defects. Take 400 µg daily before conception (5 mg if high risk). Methotrexate, trimethoprim and phenytoin interfere with it.
B12 (cobalamin) needs intrinsic factor and is absorbed in the terminal ileum. Deficiency causes megaloblastic anaemia plus nerve damage (subacute combined degeneration). Risk: pernicious anaemia, vegans, metformin.
Vitamin C is needed for collagen hydroxylation. Deficiency causes scurvy (bleeding gums, poor wound healing). It enhances iron absorption.

Iron deficiency is the most common nutritional deficiency and causes microcytic, hypochromic anaemia. Iron poisoning in children is treated with desferrioxamine.
Iodine deficiency causes goitre and cretinism; salt iodisation prevents it.
Zinc supports wound healing and immunity and is given to children with diarrhoea.
Copper builds up in Wilson's disease (treated with penicillamine); Menkes disease is copper deficiency.
Selenium is part of glutathione peroxidase. Fluoride prevents caries but excess causes fluorosis. Cobalt is part of vitamin B12.

High-yield facts in one place. Cover the right-hand column and test yourself.

Vitamin	Deficiency disease
A	Night blindness, xerophthalmia
D	Rickets, osteomalacia
E	Haemolysis in premature babies, neuropathy
K	Bleeding; haemorrhagic disease of newborn
B1	Beriberi, Wernicke–Korsakoff
B2	Angular cheilitis, glossitis
B3	Pellagra
B6	Neuropathy, sideroblastic anaemia
B9	Megaloblastic anaemia, neural tube defects
B12	Megaloblastic anaemia + neuropathy
C	Scurvy

Mineral	Excess or deficiency
Iron	Microcytic anaemia; toxicity in children
Iodine	Goitre, cretinism
Zinc	Poor growth and healing
Copper	Wilson's (excess), Menkes (deficiency)
Fluoride	Caries (low), fluorosis (high)
Selenium	Keshan cardiomyopathy (low)

Fat-soluble = ADEK: Vitamins A, D, E and K are fat-soluble; all the others are water-soluble.
Pellagra's 3 Ds: Dermatitis, diarrhoea, dementia (and death if untreated).

Folate deficiency causes megaloblastic anaemia without nerve damage; B12 deficiency causes both.
Giving folic acid alone to a B12-deficient patient can correct the anaemia while nerve damage continues.
Vitamin D becomes active only after hydroxylation in the liver and then the kidney.
Isoniazid-induced neuropathy is prevented with pyridoxine (B6), not thiamine.

Attempt the Vitamins and Minerals MCQs while the notes are fresh. Anything you get wrong is saved to your incorrect list for the next revision round.