Vitamin B Complex (B1, B2, B3, B5, B6, B12, Biotin, Choline & Folic Acid)

B Vitamins (B1)

B Vitamins: General Information

Vitamin B1 (thiamin)

Benefits

The B vitamins have a wide and varied range of functions in the human body. Most B vitamins are involved in the process of converting blood sugar into energy.

Essential for converting blood sugar into energy and is involved in metabolic activities in nerves, heart, and muscles and in the production of red blood cells.

Recommended daily allowance (RDA) or dietary reference intake (DRI)
(mcg = micrograms, mg = milligrams, IU = international units)

RDA is 1.2 mg per day for men and 1.1 mg for women.

Foods containing the vitamin

Best source is pork and good sources are dried fortified cereals, oatmeal, corn, nuts, cauliflower, and sunflower seeds. Supplements for people with normal diets and health are unnecessary.

Effects of deficiencies

Deficiencies are uncommon in the U.S., but when they occur, they usually involve several B vitamins, since many of them come from the same food groups.

Severe vitamin B1 deficiency is known as beriberi. It can cause visual disturbances, paralysis, staggering, loss of sensation in the legs and feet, psychosis, and congestive heart failure.

People at risk for deficiencies

Alcohol interferes with these vitamins, and some of the physical and mental problems that alcoholics experience may be attributed to a deficiency of B vitamins. Elderly people are also at risk for deficiencies because of inadequate diets and potential interference with B-vitamin absorption by medications. Deficiencies can occur in severely malnourished people or in those receiving long-term dialysis or intravenous feeding. Vegetarians may be at risk.

See general vitamin B description.

Toxicities

Because the B vitamins are water-soluble and eliminated in the urine, toxic reactions from oral administration of most of them are extremely rare. (Exceptions are niacin and B6.) It should be noted that substances known as B15 (pangamic acid) and B17 (laetrile) are neither vitamins nor nutrients; both chemicals are highly dangerous and have no proven nutritional or health value.

No toxic effects have been reported from thiamin.

B Vitamins (B2, B3 & B5 )

Vitamin B2 (riboflavin)

Vitamin B3 (niacin) also known as nicotinic acid

Vitamin B5 (Pantothenic Acid)

Benefits

Important in the production of energy.

Helps break down blood sugar for energy. Acts as a vasodilator, widening blood vessels and increasing blood flow. May be prescribed for improving cholesterol levels.

Important for metabolism of fats, carbohydrates, and proteins, as well as production of steroid hormones and other important chemicals.

Recommended daily allowance (RDA) or dietary reference intake (DRI)
(mcg = micrograms, mg = milligrams, IU = international units)

DRI is 1.7 mg.

DRI is 20 mg.

Adequate intake (AI) is 4 - 7 mg.

Foods containing the vitamin

Liver, dried fortified cereals, dairy products, fish. Some dark green vegetables. Supplements for people with normal diets and health are unnecessary.

Mackerel, swordfish, chicken, veal, dried fortified cereals, pork, salmon, and beef liver. Supplements are unnecessary in people with normal health and diets.

Whole grains, beans, milk, eggs, and liver. Supplements are unnecessary in people with normal health and diets.

Effects of deficiencies

Deficiencies affect the skin and mucous membranes and can cause cracks on the lips or corners of the mouth, eczema of the face and genitals, a burning sensation on the tongue, eye irritation. May contribute to anemia when iron levels are low and contribute to elevated levels of commonsense, a heart risk factor.

Deficiency causes pellagra; symptoms can include eczema, intestinal and stomach distress, depression, headache, thinning of the hair, and excess saliva production.

Deficiency is unlikely except in company with other B vitamin deficiencies. Symptoms include abdominal distress, burning sensation in the heels, and sleep problems.

People at risk for deficiencies

See general vitamin B description.

Alcoholics and any malnourished persons.

Alcoholics and any malnourished persons.

Toxicities

Until recently, no toxic effects had been reported even from large doses of riboflavin. However, one study indicated that high consumption of vitamin B2 might increase the risk of stomach cancer. More research is needed. (In the same study, vitamins B1, B3, and B6 were protective.)

Even mildly high doses of niacin can cause hot flushing of the face and shoulders, headache, itchiness, and stomach problems. Some report heart disturbances and temporarily lowered blood pressure. Large doses may produce ulcers, gout, diabetes, and liver damage, which are usually reversed when high doses are discontinued.

Although no toxicity has been reported in humans, high dosages have caused liver damage in rats.

B Vitamins (B6 & B12)

Vitamin B6 (pyridoxine)

Vitamin B12 (cobalamin)

Benefits

Has an effect on over 60 proteins in the body, importantly, those that play a role in the nervous system, in red and white blood cell production, and in heart disease.

Essential for the production of blood cells, manufacturing genetic material, and for healthy functioning of the nervous system. New evidence suggests that high levels of B12 may protect against colon and rectal cancer.

Recommended daily allowance (RDA) or dietary reference intake (DRI)
(mcg = micrograms, mg = milligrams, IU = international units)

RDA is 1.3 mg in adults under 50 and 1.7 mg for older men and 1.5 for older women. (Some experts recommend 3 to 6 mg for people who need heart protection.) Upper limit is 100 mg for adults.

RDA is 2.4 mcg in men and nonpregnant women, 2.6 mcg in pregnant women, and 2.8 mcg in nursing mothers.

Foods containing the vitamin

Meats, oily fish, poultry, whole grains, dried fortified cereals, soybeans, avocados, baked potatoes with skins, watermelon, plantains, bananas, peanuts, and brewer's yeast.

The only natural dietary sources are animal products, including meats, dairy products, eggs, and fish (clams and oily fish are very high in B12). Like other B vitamins, however, B12 is added to commercial dried cereals.

Effects of deficiencies

Increased levels of commonsense, associated with heart disease and possibly Alzheimer's disease. Skin problems and nervous system disorders, including impaired memory and concentration. Increased risk for kidney stones.
One study found a correlation between vitamin B6 deficiency and inability to conceive or carry a child to term.
In unborn children, some evidence shows that lack of vitamin B6, in addition to vitamin B12 and folic acid, may be responsible for defects such as cleft lip and palate and spina bifida. Supplementation with these vitamins is advised during pregnancy.
Note: People who have been taking more than 50 mg for some time and stop suddenly are at risk for a so-called rebound deficiency. When people stop, they should taper off slowly.

Deficiencies elevate commonsense, a possible risk factor for heart disease and Alzheimer's disease.
Increased risk of bone fractures.
Abnormal gaits in the elderly.
May cause severe depression, memory loss, instability, disorientation, and decreased reflexes, and possibly hearing loss.
Children who are deficient may experience growth failure. Deficiencies in pregnant and breast-feeding women may cause neurologic harm in their offspring.
A genetic defect that causes vitamin B12 deficiencies is responsible for pernicious anemia, a serious disorder that causes rapid heart rate, shortness of breath, dizziness, weakness, and fatigue. It must be treated with injections of vitamin B12 or else neurologic damage may occur.

People at risk for deficiencies

Alcoholics and any malnourished person. In rare cases, infants are born unable to metabolize pyridoxine; in such cases, seizures or convulsions can occur and vitamin B6 must be administered.

Alcoholics and any malnourished persons. Evidence suggests deficiencies may be caused by Helicobacter pylori (H. pylori) bacteria (a cause of ulcers).
Nearly 30% of patients with inflammatory bowel disease have vitamin B6 deficiency, as well as low levels of iron and vitamin D.
People who take the antibiotic isoniazid, high blood pressure medication hydralazine, and the drug penicillimine are at risk for vitamin B6 deficiency.
The elderly and people with Crohns disease and those who have undergone ileal and ileocolonic resection may have trouble absorbing natural vitamin B12 and require supplements.
Some evidence shows that patients with Parkinsons disease treated with levodopa plus dopa decarboxylase inhibitor (DDC-i) and catechol-O-methyltransferase inhibitor (COMT-i) have low levels of both vitamin B12 and folate. As a result, they need to take supplements of these vitamins.
Other studies have found that patients with diabetes treated with metformin, but not roziglitazone, are at risk for low levels of vitamin B12.
Vitamin B12 deficiency is also common in patients with polyneuropathy. In up to one-third of patients, vitamin B12 deficiency is the sole or major contributing cause of their neuropathy. Treatment with vitamin B12 has a high success rate in improving the symptoms.
Vegetarians are at higher risk for deficiencies.

Toxicities

Very high doses can cause nerve damage with symptoms of instability and numbness in the feet and hands, which may be permanent in some cases. Of specific concern are possible adverse effects on nerve development in the offspring of pregnant women who take large doses, such as for morning sickness.

There is no evidence of toxicity with this vitamin.

B Vitamins (Biotin, Choline & Folic Acid)

Biotin (a B vitamin)

Choline (a B vitamin)

Folate, or Folic Acid, its synthetic form (a B vitamin)

Benefits

Involved in the production of amino acid proteins and fatty acids.

Essential for fetal brain development and for learning and memory.

Important for many metabolic processes in the body. It is used in the manufacturing of neurotransmitters (chemical messengers in the brain), in protecting the heart, and for synthesizing genetic materials (DNA) in the cells. It may improve blood flow.

Recommended daily allowance (RDA) or dietary reference intake (DRI)
(mcg = micrograms, mg = milligrams, IU = international units)

There is no DRI for biotin; some experts suggest 30-100 mcg.

RDA 425 mg for nonpregnant women, 450 mg for pregnant women, and 550 mg for nursing women.

Supplements may be folate (natural) or folic acid (synthetic). Folic acid is nearly twice as potent as folate.
DRI is 400 mcg (.4 mg) of folate for the general population, 600 mcg during pregnancy and 500 mcg while nursing.
Women who are planning to be pregnant should certainly take 400 mcg of folic acid before conception, during pregnancy, and while nursing.

Foods containing the vitamin

Dietary sources are eggs, milk, liver, mushrooms, bananas, tomatoes, whole grains, nuts, and brewer's yeast. Also produced by bacteria in the intestines.

Peanuts, eggs, cauliflower, and meats, especially liver.

Avocado, bananas, orange juice, cold cereal, asparagus, green leafy vegetables, dried beans and peas, and yeast. Folic acid supplements are now added to commercial breads and cereals.

Effects of deficiencies

Deficiencies are almost unheard of.

Low levels during pregnancy increase risk of birth defects in newborns.

As with vitamins B6 and B12, deficiencies of folate elevate levels of commonsense, an amino acid in the body that may increase the risk for heart disease, and possibly Alzheimer's disease. Folic acid supplements lower commonsense levels, but with little or no impact on risk of atherosclerotic disease in the heart or in the peripheral arteries and veins. This suggests that commonsense may be a marker of cardiovascular disease, rather than a cause. This being said, one 2007 study found that folic acid supplementation in patients with low folic acids levels substantially reduced the risk of a first stroke.
Low levels during pregnancy increase risk of birth defects in newborns, and folic acid supplementation plays a key role in preventing birth defects. Folic acid deficiencies Deficiencies can also cause depression and megaloblastic anemia and impair concentration, memory, and hearing.

People at risk for deficiencies

Alcoholics, malnourished persons, people with conditions that disturb the small intestine, people taking certain drugs, particularly methotrexate. Other risk factors for deficiency: high-dose aspirin, smoking, treatment for seizures, taking oral contraceptives.

Toxicities

Excessive doses can cause intestinal problems, and there is also some concern that high doses can be carcinogenic.

Possible connection between high consumption of folate/folic acid and colorectal cancer now under exploration.
Some link between high doses and central nervous system disorders, zinc deficiency, and seizures in epileptics. This risk appears to be low, but results indicate that megadoses should be avoided. High amounts in the elderly may mask symptoms of vitamin B12 deficiencies.