Vitamin B2 (Riboflavin) And Vitamin B6 (Pyridoxine, Pantothenic Acid And Biotin): Nutritive And Health Significance
Sborrheic Dermatitis In Riboflavin Deficiency
Riboflavin is essentiallt required in all oxidation reduction reactions involving the coenzymes flavin mononucleotide and flavin adenine dinucleotide which take part in tissue oxidation and respiration. It is moderately heat resistant, but boiling in alkaline media or exposure to sunlight destroys this vitamin.
Good dietary sources include liver, meat, eggs, kidney, milk, other dairy products, green leafy vegetables and sprouted cereals and pulses. Daily requirement is 0.60 mg/ 1000 Kcal (1.5 to 2 mg).
Signs of deficiency: Angulostomatitis, cheilosis, nasolabial, seborrhea, and possibly vascularisation of the cornea are the characteristic features. Angulostomatitis may also occur in deficiencies of niacin and folic acid. Mucosa of the lips appears red and denuded in cheilosis. On taking hot and spicy food, there may be soreness. Vascularisation of the cornea has been described in some surverys. Some cases show lesions in the oral mucosa, eyes and genitals (oculo-orogenial syndromes). In glossitis, the mucosa over the tongue is red, swollen and paingul. This responds to riboflavin therapy.
Treatment: Riboflavin in a dose of 2 to 5 mg thrice a day cures the condition in a few days.
Concussion Symptoms Dizziness In Pyridoxine Deficiency
The active form of this vitamin is pyridoxal. Pyridoxal phosphate acts as a coenzyme in several reactions, especially in the metabolism of amino acids and biological amines such as catecholamines and 5-hydroxytryptamine. It takes part in the biosynthesis of gamma-aminobutyric acid in the brain. Yeast, liver, meat, whole grain cereals, peanuts, bananas and legumes are good dietary sources. Normal daily requirement is 1.25 mg and it is present in the ordinary African diets and hence nutritional deficiency is rare in most parts of Africa and even India. Drugs like INH, oral contraceptives and hydrallazines may interfere with the metabolism of this vitamin and produce conditioned deficiencies. Clinical features include dermatitis, cheilosis, angulostomatitis, glossitis, dizziness, vomiting and peripheral neuropathy. Infantile conculsions have been attributed to nutritional pyridoxine deficiency. Pyridoxine deficiency is known to produce one form of sideroblastic anemia which responds to high doses of this vitamin. Concurrent administration of 6 mg of pyridoxine prevents the development of neuritis in subjects treated with INH.
Neuro-muscular Degeneration In Pantothenic Deficiency
Pantothenic acid is converted coenzyme A in the body. This vitamin is widely distributed in animal and vegetable foods and hence dietary deficiency is very rare. Though, the exact requirement is not clearly known, 10 mg may represent an adequate daily intake. Deficeincy in experiemental animals leads to dermal and hair changes, neurogmuscular degeneration, and fatal adrenal hemorrhage.
Calcium pantothenate has been used for other conditions like paralytic ileus, streptomycin toxicity and rheumatoid arthritis based on empirical findings. There is no conclusive proof to support these claims.
Ataxia In Biotin deficiency
This is an organic acid functioning as a coenzyme in several carboxylation reactions. It is present in several articles of food and is also synthesized by intestinal bacteria. Daily requirement is about 100 ug. Naturally, occurring deficiency is rare, but conditioned exclusively with egg white. This is due to the presence of avidin which antagonizes biotin. Infants who are on parenteral feeding with biotin deficient diets may develop symptoms such as lassitude, irritability, paresthesiae, anorexia, rashes and hair loss. All these improve with the administration of biotin.
Inherited disorders of biotin metabolism occur rarely. Two types are known. One type may present in the first few weeks of life with metabolic acidosis and a rash. The other type presents in the first few months of life with rash, keratoconjunctivitis, alopecia, ataxia, hypotonia, and metabolic and lactic acidosis. Both groups respond dramatically to large doses of biotin.
© 2014 Funom Theophilus Makama