The B vitamin family is made up of eight B vitamins all of which are water-soluble, perform unique and important functions. They get easily destroyed during processes like cooking and unlike fat-soluble vitamins, do not get stored in the body. Hence, a continuous source of these vitamins is essential and any excess that the body does not need gets excreted in the urine.
Eight vitamins make up the B-group or B complex vitamins, which include:
- Vitamin B1 or thiamin
- Vitamin B2 or riboflavin
- Vitamin B3 or niacin
- Vitamin B5 or pantothenic acid
- Vitamin B6 or pyridoxine
- Vitamin B7 or biotin
- Vitamin B9 or folate (known as folic acid in supplements)
- Vitamin B12 or cyanocobalamin
Sources of B vitamins
Our daily diet is not sufficient to meet the dietary requirement of B vitamins. It is recommended that adults take vitamin supplements to avoid developing any deficiency. Pregnant and breast-feeding women require more folate and hence should take at least 400 micrograms of folic acid throughout the pregnancy.
Role of the B vitamins
1. Thiamin or Vitamin B1:This vitamin is responsible for numerous body functions such as nervous system, muscle
functioning and conversion of glucose to energy.
Dietary sources: Thiamin is found in a wide variety of foods with some of the best sources including beans, lentils, wholemeal cereal grains, red meats, yeast, nuts, seeds, peas, milk, cauliflower, spinach and legumes. Consumption of polished rice and flour, excessive alcohol and a very poor diet results in deficiency symptoms such as poor limb coordination, fatigue, muscle weakness, confusion and irritability. Many industrialized countries fortify white rice and flour with thiamin, as the vitamin is lost during the refining process. Severe thiamin deficiency results in the following conditions:
- ‘Wet’ and ‘Dry’ beriberi affect the cardiovascular, nervous, muscular and gastrointestinal systems. In ‘wet’ beriberi, heart abnormalities develop, leading to heart failure and in ‘dry’ beriberi there are nerve and muscle abnormalities resulting in a prickling sensation, leg cramps and weak muscles.
- Wernicke-Korsakoff syndrome results from a poor diet and excess alcohol intake, causing reduced thiamin absorption. Symptoms include involuntary eyeball movement, eye muscle paralysis, staggering and mental confusion.
Normally, thiamin supplements taken orally can correct the deficiency.
2. Riboflavin or Vitamin B2:This vitamin is essential for metabolism of carbohydrates (to produce energy), proteins and fats and keeps the eyes and skin (mucus membranes) healthy.
Dietary sources: Whole grain bread and cereals, milk and dairy products, fish, meat, green leafy vegetables, egg white and yeast
Deficiency of this vitamin results from excessive alcohol consumption, a diet lacking milk, and milk products. This deficiency is normally seen along with other B vitamin deficiencies, and includes symptoms such as inflamed tongue, cracks in the corners of the mouth, inflamed eye-lids along with sensitivity to light, burning and itching of eyes, hair loss, skin rash and peeling. The deficiency can be corrected by oral intake of supplements in high doses.
3. Niacin or vitamin B3:This vitamin also plays an important role in metabolizing carbohydrates and fat to produce energy, supporting the nervous and digestive systems and maintenance of skin. Unlike other B vitamins, niacin is very heat stable, and not much is lost during cooking.
Dietary sources: Milk and dairy products, meat, eggs, wholegrain breads and cereals, mushrooms and all protein-rich food
The body can also convert tryptophan (an amino acid found mainly in dairy products) to niacin, in cases where direct sources of niacin are not being consumed.
Deficiency of this vitamin results in a condition called Pellagra, which affects the skin, digestive tract and brain. Places where mainly maize is the staple diet, is a major cause for the people to develop pellagra as maize is low in niacin and tryptophan. Being an alcoholic and inadequate intake of nutrients like iron, riboflavin and pyridoxine (vitamin B6) increases the risk of developing the deficiency. The main symptoms that develop as a result are referred to as the three D’s – dementia, diarrhea and dermatitis. Other signs include swollen tongue, loss of appetite, anemia, irritability, mental confusion, weakness and dizziness. Taking oral doses of niacin can treat the deficiency. At times, high doses of niacin are prescribed for lowering blood cholesterol and lipids, which can result in flushing, itching and liver damage.
4. Pantothenic acid or vitamin B5: This vitamin is required for metabolizing carbohydrates, proteins, fats and essential for growth. In addition to playing a role in the breakdown of fats and carbohydrates for energy, vitamin B5 is critical to the manufacture of red blood cells, as well as sex and stress-related hormones produced in the adrenal glands (small glands that sit atop the kidneys). Vitamin B5 is also important in maintaining a healthy digestive tract, and it helps the body use other vitamins, particularly B2. It is sometimes called the “anti-stress” vitamin, but there is no concrete evidence whether it helps the body withstand stress. Pantothenic acid is widely available in plant and animal food sources including organ meats such as liver and kidney, milk, eggs, yeast, cashew and peanuts, legumes, soybeans and brown rice. Pantothenic acid deficiency is extremely rare but may include symptoms such as fatigue, insomnia, depression, irritability, vomiting, stomach pains, burning feet, and upper respiratory infections.
Dietary sources: Legumes, broccoli, cabbage, peanuts, whole grain cereals, milk, eggs, meat, yeast, poultry and fish. Not much of this vitamin is lost during cooking. As pantothenic acid is found in a broad range of foods, deficiency is rarely seen. If present, symptoms include fatigue, loss of appetite, and intestinal problems.
5. Pyridoxine or Vitamin B6: This vitamin is involved in metabolization of carbohydrates, proteins, fats, helps in normal nerve functioning as well as formation of red blood cells.
Dietary sources: Cereal grains, legumes, green leafy vegetables, potatoes, milk, cheese, eggs, fish, meat, nuts and fruit.
A deficiency can result due to excessive alcohol consumption, in women (especially those on the contraceptive pill), the elderly and people with thyroid disease. Symptoms as a result include insomnia, depression, anemia, cracked corners of the mouth, muscle twitching, confusion and dermatitis. In infants, deficiency can result in seizures. This vitamin is at times recommended to treat premenstrual syndrome in women and carpal tunnel syndrome, but caution must be taken as over dosage of the same can result in irreversible nerve damage.
6. Biotin or vitamin B7: This vitamin is essential for forming fatty acids and glucose to provide the body energy, and is also involved in amino acid metabolism.
Dietary sources: cauliflower, peanuts, poultry, egg yolks, mushroom, carrots, bananas, soy flour and yeast. Biotin is found in various food sources and is also produced by the intestinal bacteria, so deficiency is rare. Otherwise, symptoms include pale skin, sore tongue, dermatitis, hair loss, muscle pain and fatigue.
7. Folate or vitamin B9: This vitamin is essential for the formation of red blood cells, development of fetal nervous system and deoxyribonucleic acid (DNA) synthesis as well as cell growth. Women who are pregnant or of child-bearing age must have a diet rich in folate. While folate occurs naturally in food, folic acid is the synthetic form of folate.
Dietary sources: Green leafy vegetables, legumes, seeds, eggs, cereals, citrus fruits, mushroom, yeast and poultry. Often, breads and cereals have folic acid added to them, which are labeled as ‘enriched.’ A diet deficient in this vitamin can result in fatigue, weight loss, folate-deficiency anemia and in pregnant women, increases the risk of neural tube defects like spina bifida or cleft palate in the baby.
8. Cyanocobalamin or vitamin B12: This vitamin plays an important role in protecting nerve cells, red blood cell formation, mental ability and metabolizing fatty acids and amino acids.
Dietary sources: Meat, fish, shellfish, dairy products and food of animal origin.
Since the human body can store vast amounts of this vitamin, a nutritional deficiency is very rare. Aged people and those unable to absorb vitamin B12 may face the risk of deficiency. Others prone to deficiency are vegans and strict vegetarians who may not be getting correct amounts of the vitamin, and breastfed babies of vegan mothers, who develop pernicious anemia (due to lack of intestinal absorption of vitamin B12). Symptoms that develop include fatigue, lack of appetite, weight loss, anemia, depression, smooth tongue and nerve degeneration. Both folate and vitamin B12 depend on each other to work properly.
Supplementing Vitamins is Crucial to Health!
All the B vitamins are available as a vitamin B complex supplement, as this collection of eight vitamins is essential for various body metabolic processes. It is important to remember that these vitamins need to be regularly consumed as supplements, since they cannot be stored in the body and extended cooking reduces their availability.
Supplements are extra sources of dietary components taken in addition to food. A dietary supplement has certain nutritive elements that complement the basic diet and enhances nutrient intake by body. Dietary supplements may include: vitamins, minerals, herbs, amino acids, and substances such as enzymes, metabolites. Dietary supplements can be taken in many forms such as tablets, capsules, softgels, gelcaps, liquids, or powders.
1. Manzetti S, Zhang J, van der Spoel D. Thiamine function, metabolism, uptake, and transport. Biochemistry (2014) 53(5):821–35.
2. Singleton CK, Martin PR.. Molecular mechanisms of thiamine utilization. Curr Mol Med (2001) 1(2):197–207.
3. Bettendorff L. Thiamine in excitable tissues: reflections on a non-cofactor role. Metab Brain Dis (1994) 9(3):183–209.
4. Bettendorff L, Wins P. Biological functions of thiamine derivatives: focus on non-coenzyme roles. OA Biochem (2013) 1(1):10.
5. Thakur K, Tomar SK, Singh AK, Mandal S, Arora S. Riboflavin and health: A review of recent human research. Crit Rev Food Sci Nutr. 2016 Mar 30:0. [Epub ahead of print]
6. Jacobson EL, Kim H, Kim M, Jacobson MK. Niacin: vitamin and antidyslipidemic drug. Subcell Biochem. 2012;56:37-47.
7. Rucker R.B., Bauerly K. Pantothenic acid. In: Zempleni J., Suttie J.W., Gregory J.F. III, Stover P.J., editors. Handbook of Vitamins. 5th ed. CRC Press; Boca Raton, FL, USA: 2013.
8. Uchida Y., Ito K., Ohtsuki S., Kubo Y., Suzuki T., Terasaki T. Major involvement of na+-dependent multivitamin transporter (SLC5A6/SMVT) in uptake of biotin and pantothenic acid by human brain capillary endothelial cells. J. Neurochem. 2015;134:97–112
9. Sturman J.A., Rivlin R.S. Biology of Brain Dysfunction. Springer; Berlin, Germany: 1975. Pathogenesis of brain dysfunction in deficiency of thiamine, riboflavin, pantothenic acid, or vitamin B6; pp. 425–475.
10. Food and Nutrition Board, Institute of Medicine . Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin and Choline. National Academies Press; Washington, DC, USA: 2000.
11. Smith A.D., Kim Y.-I., Refsum H. Is folic acid good for everyone? Am. J. Clin. Nutr. 2008;87:517–533.
12. Dullemeijer C., Souverein O.W., Doets E.L., van der Voet H., van Wijngaarden J.P., de Boer W.J., Plada M., Dhonukshe-Rutten R.A., In’t Veld P.H., Cavelaars A.E. Systematic review with dose-response meta-analyses between vitamin B-12 intake and european micronutrient recommendations aligned’s prioritized biomarkers of vitamin B-12 including randomized controlled trials and observational studies in adults and elderly persons. Am. J. Clin. Nutr. 2013;97:390–402.
13. Eussen S.J., de Groot L.C., Clarke R., Schneede J., Ueland P.M., Hoefnagels W.H., van Staveren W.A. Oral cyanocobalamin supplementation in older people with vitamin B12 deficiency: A dose-finding trial. Arch. Intern. Med. 2005;165:1167–1172.
14. Bradbury K.E., Williams S.M., Green T.J., McMahon J.A., Mann J.I., Knight R.G., Skeaff C.M. Differences in erythrocyte folate concentrations in older adults reached steady-state within one year in a two-year, controlled, 1 mg/d folate supplementation trial. J. Nutr. 2012;142:1633–1637.
15. Homocysteine Lowering Trialists’Collaboration Dose-dependent effects of folic acid on blood concentrations of homocysteine: A meta-analysis of the randomized trials. Am. J. Clin. Nutr. 2005;82:806–812.
16. Miner S.E.S., Cole D.E.C., Evrovski J., Forrest Q., Hutchison S., Holmes K., Ross H.J. Pyridoxine improves endothelial function in cardiac transplant recipients. J. Heart Lung Transplant. 2001;20:964–969.
17. Moat S.J., Lang D., McDowell I.F., Clarke Z.L., Madhavan A.K., Lewis M.J., Goodfellow J. Folate, homocysteine, endothelial function and cardiovascular disease. J. Nutr. Biochem. 2004;15:64–79.
18. Nie T., Lu T., Xie L., Huang P., Lu Y., Jiang M. Hyperhomocysteinemia and risk of cognitive decline: A meta-analysis of prospective cohort studies. Eur. Neurol. 2014;72:241–248.
19. Nilsson T.K., Yngve A., Böttiger A.K., Hurtig-Wennlöf A., Sjöström M. High folate intake is related to better academic achievement in swedish adolescents. Pediatrics. 2011;128:e358–e365.
20. Petridou E.T., Kousoulis A.A., Michelakos T., Papathoma P., Dessypris N., Papadopoulos F.C., Stefanadis C. Folate and B12 serum levels in association with depression in the aged: A systematic review and meta-analysis. Aging Ment. Health. 2015:1–9.