Vitamin | Main function | Main deficiency symptoms |
Retinol (Vitamin A) | Maintain healthy surface linings of the eyes, the respiratory, urinary, and intestinal tracts, the skin and mucous membranes; night vision; bone development; antioxidant. | Bitot’s spots, xerophthalmia, corneal ulcers, scarring of the cornea and blindness; impaired dark adaptation. High incidence of respiratory illnesses and diarrhoea; increased mortality |
Thiamin (Vitamin B-1) | Carbohydrate metabolism, coenzyme for synthesis of nucleic acids | Polyneuropathy (PN), diminished sensation and weakness in the extremities. Muscle pain and tenderness, seizures (severe deficiency). Signs of congestive heart failure |
Niacin (Vitamin B-3) | Metabolism of carbohydrates, fats and proteins and synthesis of fatty acids and cholesterol | Dermatitis, diarrhoea, bright red tongue, vomiting, and diarrhoea, apathy and fatigue |
Pyridoxine (Vitamin B-6) | Coenzymes that catalyse gluconeogenesis, synthesis of neurotransmitters, heme, nucleic acids, conversion of homocysteine to cysteine, production of lymphocytes and IL-2 | PN, irritability, confusion, seizures in severe deficiency. Inflammation of the tongue, sores or ulcers of the mouth, angular stomatitis and anaemia. |
Folic acid (Vitamin B-9) | Metabolism of nucleic acids and amino acids, synthesis of DNA, RNA, conversion of homocysteine to methionine. | Megaloblastic anaemia and symptoms of anaemia (fatigue, weakness, and shortness of breath) |
Cobalamin (Vitamin B-12) | Amino acid metabolism, methylation of a number of sites in DNA and RNA, production of energy from fats and proteins, haemoglobin synthesis. | Megaloblastic anaemia, PN, difficulty walking, mood changes, tongue soreness, appetite loss, and constipation |
Ascorbic acid (Vitamin C) | Synthesis of collagen, synthesis of carnitine which is essential for thetransport of fat into mitochondria for theproduction of energy, metabolism of cholesterol to bile acids. Antioxidant, enhance chemotaxis and phagocytosis | Bleeding and bruising easily hair and tooth loss, and joint pain and swelling, fatigue |
Cholecalciferol Vitamin D) | Absorption of calcium and hardening of bones. DNA synthesis and transcription of genes, cellular differentiation, modulates immune cells e.g. dendritic cells and macrophages | Rickets, muscle weakness and pain, frequent bacterial infections |
Alphatocopherol (Vitamin E) | Antioxidant, maintain integrity of cell membranes, affect the expression and activities of enzymes in immune and inflammatory cells | PN and muscle weakness |