List of B vitamins:
- Vitamin B1 (thiamine)
- Vitamin B2 (riboflavin)
- Vitamin B3 (niacin or niacinamide)
- Vitamin B5 (pantothenic acid)
- Vitamin B6 (pyridoxine, pyridoxal, or pyridoxamine, or pyridoxine hydrochloride)
- Vitamin B7 (biotin)
- Vitamin B9 (folic acid)
- Vitamin B12 (various cobalamins; commonly cyanocobalamin in vitamin supplements)
Health benefits
The B vitamins are necessary in order to:- Support and increase the rate of metabolism
- Maintain healthy skin and muscle tone
- Enhance immune and nervous system function
- Promote cell growth and division—including that of the red blood cells that help prevent anemia.
- Reduce the risk of pancreatic cancer, one of the most lethal forms of cancer[1], when consumed in food, but not when ingested in vitamin tablet form.
B vitamin deficiency
Several named vitamin deficiency diseases may result from the lack of sufficient B-vitamins. Deficiencies of other B vitamins result in symptoms that are not part of a named deficiency disease.Vitamin B1 (thiamine)
Deficiency causes beriberi. Symptoms of this disease of the nervous system include weight loss, emotional disturbances, Wernicke's encephalopathy (impaired sensory perception), weakness and pain in the limbs, periods of irregular heartbeat, and edema (swelling of bodily tissues). Heart failure and death may occur in advanced cases. Chronic thiamine deficiency can also cause Korsakoff's syndrome, an irreversible psychosis characterized by amnesia and confabulation.
Vitamin B2 (riboflavin)
Deficiency causes ariboflavinosis. Symptoms may include cheilosis (cracks in the lips), high sensitivity to sunlight, angular cheilitis, glossitis (inflammation of the tongue), seborrheic dermatitis or pseudo-syphilis (particularly affecting the scrotum or labia majora and the mouth), pharyngitis, hyperemia, and edema of the pharyngeal and oral mucosa.
Vitamin B3 (niacin)
Deficiency, along with a deficiency of tryptophan causes pellagra. Symptoms include aggression, dermatitis, insomnia, weakness, mental confusion, and diarrhea. In advanced cases, pellagra may lead to dementia and death.
Vitamin B5 (pantothenic acid)
Deficiency can result in acne and paresthesia, although it is uncommon.
Vitamin B6 (pyridoxine)
Deficiency may lead to anemia, depression, dermatitis, high blood pressure (hypertension), water retention, and elevated levels of homocysteine.
Vitamin B7 (biotin)
Deficiency does not typically cause symptoms in adults but may lead to impaired growth and neurological disorders in infants.
Vitamin B9 (folic acid)
Deficiency results in a macrocytic anemia, and elevated levels of homocysteine. Deficiency in pregnant women can lead to birth defects. Supplementation is often recommended during pregnancy. Researchers have shown that folic acid might also slow the insidious effects of age on the brain.
Vitamin B12 (cobalamin)
Deficiency results in a macrocytic anemia, elevated homocysteine, peripheral neuropathy, memory loss and other cognitive deficits. It is most likely to occur among elderly people as absorption through the gut declines with age; the autoimmune disease pernicious anemia is another common cause. It can also cause symptoms of mania and psychosis. In rare extreme cases, paralysis can result.
B vitamin toxicity
Although most B vitamins are eliminated regularly in the urine, taking large doses of certain B vitamins may produce harmful effects.Vitamin B1 (thiamine)
No known toxicity from oral intake. There are some reports of anaphylaxis caused by high dose thiamin injections into the vein or muscle. However, the doses were greater than the quantity humans can physically absorb from oral intake.
Vitamin B2 (riboflavin)
No known toxicity
Vitamin B3 (niacin)
Tolerable Upper Intake Level: 35 mg/day from supplements, drugs or fortified food
Flushing (redness of the skin, often accompanied by itching or a mild burning sensation). Intake of 3000 mg/day of nicotinamide and 1500 mg/day of nicotinic acid are associated with nausea, vomiting, and signs and symptoms of liver toxicity.
Vitamin B5 (pantothenic acid)
No known toxicity
Vitamin B6 (pyridoxine)
Tolerable Upper Intake Level: 100 mg/day from supplements, drugs or fortified food
Sensory neuropathy and dermatological lesions.
Vitamin B7 (biotin)
No known toxicity
Vitamin B9 (folic acid)
Tolerable Upper Intake Level: 1 mg/day
Masks B12 deficiency, which can lead to permanent neurological damage
Vitamin B12 (cobalamin)
No known toxicity
B vitamin sources
B vitamins are found in all whole, unprocessed foods. Processing, as with sugar and white flour, tends to significantly reduce B vitamin content. B vitamins are particularly concentrated in meat and meat products such as liver oil, liver, turkey, and tuna. Other good sources for B vitamins are potatoes, bananas, lentils, chile peppers, tempeh, beans, nutritional yeast, brewer's yeast, and molasses. Marmite and Vegemite bill themselves as "one of the world's richest known sources of vitamin B". As might be expected, due to its high content of brewer's yeast, beer is a source of B vitamins, although this may be less true for filtered beers and the alcohol in beer may impair the body's ability to absorb certain vitamins.The B-12 vitamin is of note because it is not available from plant products, making B-12 deficiency a concern for vegans. Manufacturers of plant-based foods will sometimes report B-12 content, leading to confusion about what sources yield B-12. The confusion arises because the standard US Pharmacopeia (USP) method for measuring the B-12 content does not measure the B-12 directly. Instead, it measures a bacterial response to the food. Chemical variants of the B-12 vitamin found in plant sources are active for bacteria, but cannot be used by the human body. This same phenomenon can cause significant over-reporting of B-12 content in other types of foods as well.
Vitamin B may also be delivered by injection to reverse deficiencies.
Another popular means of increasing one's vitamin B intake is through the use of dietary supplements purchased at supermarkets, health centers, or natural food stores. B vitamins are also commonly added to energy drinks. Many energy drinks have been marketed with large amounts of B vitamins (5-Hour Energy contains an astounding 8,333% of the recommended dietary allowance of vitamin B-12 and 2,000% of the RDA for vitamin B-6. Red Bull offers 360% of the RDA for vitamin B-6, 120% of B12, 140% of niacin (vitamin B3)") with claims that this will cause the consumer to "sail through your day without feeling jittery or tense." Nutritionists, such as Professor Hope Barkoukis, dismiss these claims: "It's brilliant marketing, but it doesn't have any basis [in fact]."
While B vitamins do "help unlock the energy in foods... Just about everyone in America already gets all of the B vitamins they could possibly need in their diets… Extra B vitamins are generally just flushed out of the system—although everyone's limit of absorption is different in regards to B complex vitamins and no-one knows how much is needed on an individual basis of these vitamins…" The elderly and athletes may need to supplement their intake of B-12 and other B vitamins due to problems in absorption and increased needs for energy production. Also, Vitamin B9 (folic acid) deficiency in early embryo development has been linked to neural tube defects. Thus, women planning to become pregnant are usually encouraged to increase daily dietary folic acid intake and/or take a supplement. However, for "most typical consumers of energy supplements or drinks, B vitamins are nothing more than a 'gimmick' when they are making these false claims."
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