A group of closely related chemical compounds with related names — pyridoxine, pyridoxal and pyridoxamine — that are transformed within the body to yet another form of vitamin B6, pyridoxal phosphate, that acts as a coenzyme. (A number of vitamins serve as coenzymes, substances that enhance the action of enzymes and thereby aid in catalyzing biochemical reactions.)
The vitamin B6 group is especially important to the function of the central nervous system, skin, and blood. Vitamin B6 is involved in the formation of red blood cells since pyridoxal phosphate is the rate-limiting substance in making heme, a component of hemoglobin, the key oxygen-carrying pigment in red blood cells.
The diet rarely lacks vitamin B6. Most foods contain it. However, deficiency of vitamin B6 within the body may occur due to poor absorption of it from the intestine or inactivation of it by some drugs (e.g., anticonvulsants, corticosteroids, estrogens, isoniazid, and penicillamine). Other causes of vitamin B6 include alcoholism and conditions such as hyperthyroidism and diabetes that increase the metabolic demand, creating a relative shortage of vitamin B6.
Vitamin B6 deficiency causes convulsions in infants and anemia in adults. An outbreak of convulsions in infants followed the inadvertent destruction of vitamin B6 in infant formulas. Several genetic syndromes also involve problems with vitamin B6.
- Vitamin C
An essential nutrient found mainly in fruits and vegetables. The body requires vitamin C to form and maintain bones, blood vessels, and skin. Vitamin C is also known as ascorbic acid. Vitamin C is a water-soluble vitamin, one that cannot be stored by the body except in insignificant amounts. It must be replenished daily. Vitamin […]
- Vitamin D
for those 1-70 years of age, 600 IU daily; for those 71 years and older, 800 IU daily; and for pregnant and lactating women, 600 IU daily. The IOM further recommended that serum 25(OH)D levels of 20ng/mL (= 50 nmol/L) is adequate, and levels > 50ng/mL (= 125 nmol/L) could have potential adverse effects As […]
- Vitamin D requirement
for those 1-70 years of age, 600 IU daily; for those 71 years and older, 800 IU daily; and for pregnant and lactating women, 600 IU daily. The IOM further recommended that serum 25(OH)D levels of 20ng/mL (= 50 nmol/L) is adequate, and levels > 50ng/mL (= 125 nmol/L) could have potential adverse effects
- Vitamin D3
A vitamin produced by the body when exposed to ultraviolet light or obtained from dietary sources. Vitamin D3 is a hormone that has an important role in calcium and phosphorus metabolism. Technically, vitamin D3 is not a vitamin because the body can produce it. Also known as cholecalciferol.
- Vitamin E
In the ATBC cancer prevention trial, men given alpha-tocopherol (vitamin E) had a lower incidence of prostate cancer than men given a placebo. The vitamin E-treated group also had significantly lower death rates from prostate cancer. However, newer studies from a trial called SELECT showed that taking vitamin E can actually be harmful. According to […]