The term “Vitamin” is derived from Latin (Vitalis, vital), which means “life” or “essential to life”. Vitamins are micronutrient food factors containing natural amines, chemical group of compound having basic reaction properties with functional group represented by the formula R-NH2. These are included in diet of humans and some animals because they are unable to synthesize these compounds through natural metabolism but important for regular metabolic functions of the body like respiration, digestion, absorption, catabolism and anabolism. Vitamins are group of natural organic substances that help transform other food substances (like carbohydrates, sugars, starch, proteins) inside body into necessary parts of bones (osteocytes), skin tissues (dermatocytes), glands (adenoids), nerve cells (neurocytes), brain cells and blood cells (erythrocytes).
Vitamins generally assume a physiological role in metabolism to assist enzymes (biocatalysts) in carrying out biological function (activity) rather participate in built-up of structural units. Vitamins improve availability of other functional groups (hydroxyl, carboxyl, amides, ketones, amino acids or fatty acids), and simple proteins that make structural units of body cells and tissues. Vitamins assist to regulate the energy mechanism of the body and provide precursors such as ATP, GTP, CTP, NADP, NAD, FAD that create energy reserves inside the body and regulate cellular transport. These are required in small amounts in diet and deficiency of any one of essential vitamin(s) in human diet leads to deficiency disorder like anemia or impotency (see figure 1).
Deficiency of vitamins may be cause by improper diet management or abnormality of the body cells/glands to absorb vitamins. Vitamins are broadly classified into two major categories as fat-soluble vitamins like Vitamins in group A, D, E and K and water-soluble vitamins like Vitamins in group B (B-1, B-2, B-6, B-12) and C. Additionally, vitamins utilize at least twenty mineral compounds in human body that make-up for body salts and help in metabolism. Some essential minerals include: Sodium, Potassium, Calcium, Zinc, Phosphorus, Sulfur, Iron, Chloride, Fluoride, and Iodide. Many biological sources of food supplement (milk, vegetables, cereals, sea food, oils, fruits) contain both groups of fat-soluble and water-soluble vitamins, minerals in various amounts but they are also supplemented to diet in the form of medicated oral formulations (tablets, capsules, caplets, exilir and tonics) in case of deficiency, metabolic disorder, or illness.
Vitamin and multivitamin preparations are available alone or in combination with other mineral salts like iron, zinc, magnesium, hydrochloride that help to absorb vitamins in blood stream. Therapeutic activity of vitamin B-1 as HCl compound is antineuritic activity caused by 0.003 mg or 3 µg of crystalline thiamine hydrochloride. Thiamine HCl (Aneurine) can be supplemented to ill patients as injection IM, IV (100 mg/ml), tablet (50 mg – 500 mg) or syrup (10 mg/ml). Vitamin B complex (B-1 – B-6 and B-12) are available as tablets, capsules or syrups either alone or combination with vitamin C and folic acid (B-9). Vitamin B-3, B-5 and B-12 are usually formulated with folic acid, ferrous sulfate salts, zinc salts for fever, liver disease, kidney disease and post-treatment recovery.
Vitamin B belongs to a group of water-soluble organic substances naturally found in foods like legumes, cereals, pulses, lentils, bran, whole meal bread, brown rice, nuts, meat, eggs, vegetables, milk, yeast and seaweeds. Processed, polished or refined foods may sometimes contain less of B vitamins than unprocessed or unpolished cereals. Typical composition of Vitamin B along their deficiency disorder is show in tabular format in figure 2. Vitamin B-1 (Thiamine and its derivatives) is heat-liable compound artificially synthesized by breakdown of food components containing thiamine and contribute in many metabolic reactions. TPP participates as co-enzyme for electron transfer action that assist other enzymes like carboxylases and decarboxylases, transketolases or oxoacid dehydrogenases. Thiamin pyridinylase enzyme is capable of transferring other bases into position of pyrimidine (T, C) in thiamin thus serving as a building block for DNA and RNA chains. Beri Beri (associated with deficiency of vitamin B-1) is a type of nutritional polyneuropathy that mostly affecting sensory nerves to cause severe medical conditions like bell’s palsy, trigeminal neuralgia, insomnia (restlessness), sciatica (back ache), alzheimer’s disease, megaloblastic anemia, and congestive heart failure (CGF).
An excess intake of thiamin may result in ability of the body to absorb other vitamins. It is needed in excess in case of over-active thyroid. Vitamin B-2 (Riboflavin) is an obsolete term used for complex of folic acid (B-9), nicotinic acid (B-3) and its derivative nicotinamide and pantothenic acid (B-5). Riboflavin is a heat stable factor of vitamin B complex whose isoalloxazine nucleotides are co-enzymes of the flavodehydrogenases – FAD, FMN, FADH2, principle co-enzymes present in cytosol that help in electron transfer reactions during biosynthesis.
Dietary requirement for Vitamin B-2 is about 1.3 mg – 1.7 mg per day and higher amounts in women during pregnancy or lactation. Deficiency of vitamin B-2 may lead to metabolic disorders like migraine, hyperlipidemia, impaired glucose tolerance, osteoarthritis, diabetes, cyanosis of feet and hands. Ariboflavinosis is a condition characterized by dry & scaly lips and skin (cheiolsis). Biotin (vitamin B-7), is a factor associated with vitamin B-2 complex (co-enzyme R) that acts as a carrier protein for many carboxylation reactions (acetyl-CoA carboxylase) and also responsible for nonspecific ß-oxidation of side chain of fatty acids. Deficiency of biotin may lead to seboherric dermatitis, brittle nails and diabetic neuropathy.
Vitamin B-3 (Niacin – nicotinic acid or nicotinamide derivatives – NAD, NMN, NADH, NADP) is a vasodilator due to its stimulating action on acetylcholine and other nicotine-like agents that acts on autonomic ganglia, adrenal medulla, respiratory metabolism, striated muscles and motor nerves. These catalyze many oxidation-reduction reactions and electron-transfer mechanism in mitochondria for synthesis of energy yielding compound ATP. Deficiency of Vitamin B-3 or Niacin is chief cause of Pellagra, which leads to gastrointestinal disturbances, erythema, desquamation of mucous layers, chronic fatigue, parkinson’s disease and neurologic problems.
Vitamin B-4 is an obsolete term used for Adenine, which is one of the two purine base(s) forming principal component of DNA and RNA. Adenine is the major constituent of ATP (Adenoside tri-phosphate) that is the principle element involved in energy function of cells. Vitamin B-5 (Pantothenic Acid) is ß-alanine amide of pantoic acid and a precursor of co-enzyme A (Co A), which is involved in transacetylation reactions i.e. transfer of acyl (-R-COO-) groups (1-C units). Pantothenic acid is an essential growth factor in cells and tissues that controls number of allergic manifestations and support adrenal medulla. It lowers lipid content by lowering cholesterol and triglycerides. It is sometimes also called as anti-dermatitis factor.
Vitamin B-6 (Pyridoxine and its derivatives –Pyridoxamine and pyridoxal 5-phosphate (PLP)) are involved in utilization of unsaturated fatty acids (C=C), decarboxylation and transamination reactions. Transamination or process of conversion of amino-acids to keto-acids and vice versa is of great importance in tissue metabolism. Deficiency of pyridoxine is responsible for many cardiovascular diseases, convulsions, epilepsy and diabetic neuropathy. Vitamin B-12 (Cobalamin or Cyanocobalamin) is a complex of cyanide and cobalamin with cyanide occupying 6th position of coordinate bond of cobalt. Biological activity of vitamin B-12 is from liver extracts for compounds containing cobalt that serves as an essential antianemic factor. Physiologically active vitamin B-12 coenzymes are methylcobalamin and deoxyadenosinecobalamin. Deficiency of vitamin B-12 is often associated with certain anemia and methylmalonic acidurias. Other disorders of vitamin B-12 deficiency include: crohn’s disease, male infertility, memory loss, multiple sclerosis (thickening of arteries, veins, capillaries and blood vessels). Folic Acid (vitamin B-9) is a hemopoietic vitamin member of vitamin complex that is necessary for normal production of RBCs. Folic acid serves as a growth factor for bacteria Lactobacillus casei because it contains olingoglutamic acid conjugates with peptide linkages in liver, vegetables and yeast. Folic acid and cobalamin (vitamin b-12) are essential in controlling homocystein levels as homocystein level in blood plasma is an important indicator of cardiovascular diseases like thrombosis, arthrosclerosis and stroke. Tetrahydrofolic acid (Co-enzyme F) participates in methylation of C-1 of homocystein. Deficiency of folic acid or folate results in folic acid deficiency anemia, a form of macrocytic and megaloblastic anemia. Deficiency of folic acid in pregnant woman may lead to neural tube defects. Other effects of folic acid deficiency includes gingivitis, osteoporosis, lactation and cervical dysplasia. Recommended daily allowance of folic acid is 400 µg/day for normal adult and about 1 mg/day for pregnant women. Para amino benzoic acid is a factor in vitamin b complex required for formation of folic acid. It helps to neutralize bacteriostatic effects of sulfonamides (antibiotic medicines containing sulphur group). Carnitine (trimethylamminoium derivative of ?-amino ß-hydroxy butyric acid) is another factor of vitamin b complex that regulates fatty-acid metabolism. Carnitine is an acyl carrier with respect to inner mitochondrial membrane and a thyroid inhibitor found in muscle and meat extracts. Deficiency of carnitine may cause hyperlipidemia, hypoglycemia and energy depletion leading to weakness of skeletal muscles, cardiomyopathy and metabolic acidosis.
Vitamins are essential for the normal growth and development of a multicellular organism. It helps to inherit genetic blueprint from its parents in a developing fetus from the nutrients it absorbs. These nutrients facilitate the chemical reactions that produce body parts and organs among other things like skin, bones, and muscles. If there is serious deficiency in one or more of these nutrients, a child may develop a deficiency disease. Even minor deficiencies in parental intake may cause permanent damages in newborn. Once growth and development is complete, vitamins still remain essential nutrients for the healthy maintenance of the cells, tissues, and organs in multicellular organisms. Vitamin B enables us to efficiently use the chemical energy provided by food we eat and help process the proteins, carbohydrates, and fats required for normal physiology like respiration. Alcohol consumption has negative effect on absorption of vitamin B as it inhibits absorption of thiamine (B1), riboflavin (B2), niacin (B3), biotin (B7), and folic acid (B9). Many international studies emphasizes that elevated consumption of beer and other alcoholic beverages results in net deficit of B vitamins and the health risks associated with such deficiencies.
(The author is MD of VMG Biotech Consultants, New Delhi, a premier biotechnology consultancy and Contract Research Organization)