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Vitamin B6, also called pyridoxine, is one of 8 B vitamins. All B vitamins help the body convert food (carbohydrates) into fuel (glucose), which is "burned" to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body metabolize fats and protein. B complex vitamins are necessary for healthy skin, hair, eyes, and liver. They also help the nervous system function properly.
All B vitamins are water-soluble, meaning that the body does not store them. Vitamin B6 helps the body make several neurotransmitters, chemicals that carry signals from one nerve cell to another. It is essential for normal brain development and function, and helps the body make the hormones serotonin and norepinephrine (which influence mood) and melatonin (which helps regulate the body clock).
Along with vitamins B12 and B9 (folic acid), B6 helps control levels of homocysteine in the blood. Homocysteine is an amino acid that may be associated with heart disease. B6 is also necessary for proper absorption of vitamin B12 and for the production of red blood cells and cells of the immune system.
It is rare to have a significant deficiency of B6, although studies indicate many people may be mildly deficient, especially children and the elderly. Certain medications can also cause low levels of B6 in the body. Symptoms of serious deficiency include muscle weakness, nervousness, irritability, depression, difficulty concentrating, and short-term memory loss.
What is Pyridoxine ?
Vitamin B6, also called pyridoxine, is one of eight water-soluble B vitamins. Vitamin B6 (pyridoxine) serves as coenzyme and is involved in the metabolism of protein and carbohydrates, the production of insulin and red and white blood cells, and the synthesis of neurotransmitters, enzymes, and prostaglandins. Vitamin B6 is essential in numerous biochemical pathways
involving red blood cells, the immune system, central nervous system function, protein metabolism, homocysteine metabolism, and also the production of energy. Pyridoxine is an especially important vitamin for maintaining healthy nerve and muscle cells and it aids in the production of DNA and RNA, the body's genetic material. It is necessary for proper absorption of vitamin B12 and for the production of red blood cells and cells of the immune system.
More specifically, vitamin B6 consists of six specific compounds, namely pyridoxine, pyridoxal, pyridoxamine, and their respective phosphates, the latter group of which are the most active components in numerous reactions involving amino acid and protein metabolism. There are six forms of vitamin B6: pyridoxal (PL), pyridoxine (PN), pyridoxamine (PM), and their phosphate derivatives: pyridoxal 5'-phosphate (PLP), pyridoxine 5'-phosphate (PNP), and pridoxamine 5'-phospate (PNP). PLP is the active coenzyme form, and has the most importance in human metabolism. In the body, pyridoxine is found primarily in the liver and muscles. Pyridoxine is utilized by the liver to synthesize pyridoxal phosphate (PLP), the active coenzyme form. PLP functions as transamination and decarboxylation coenzymes, which are involved in amino acid and protein metabolism. PLP is also involved as a coenzyme in the synthesis of heme, niacin and serotonin. Alcohol impairs vitamin B6 metabolism in the body.
The major forms of vitamin B6 from animal products are pryridoxal 5'-phosphate and pyridoxamine 5'-phosphate. The major forms of vitamin B6 from plant-derived foods are pyridoxine, pyridoxine 5'-phosphate and pyridoxine glucosides. Pyridoxine hydrochloride is the principal form of vitamin B6 used for food fortification and in nutritional supplements. Pyridoxal 5'-phosphate is also available as a nutritional supplement. Pyridoxal 5'-phosphate, is involved in a wide range of biochemical reactions, including the metabolism of amino acids and glycogen, the synthesis of nucleic acids, hemogloblin, sphingomyelin and other sphingolipids, and the synthesis of the neurotransmitters serotonin, dopamine, norepinephrine and gamma-aminobutyric acid (GABA).
Where it is found
Sources of pyridoxine are whole (but not enriched) grains, bread, liver, cereals, spinach, green beans, and bananas. Vitamin B6 (pyridoxine) is contained in some amounts in all foods. Foods that contain the highest amounts are brewer's yeast, carrots, chicken, eggs, fish, meat, peas, spinach, sunflower seeds, walnuts, and wheat germ. Pyridoxine is needed in proportion to the amount of protein consumed. Foods rich in vitamin B6 include white meat (poultry and fish), bananas, liver, whole-grain breads and cereals, soyabeans and vegetables. Vitamin B6 is sensitive to ultraviolet light and heat, so large amounts of this nutrient are lost during the cooking process.
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Benefits / uses
Heart Disease
People who don't get enough B6 in their diet have a higher risk of heart disease. Low dietary intake of vitamin B6 is associated with higher risk of having heart disease. And as mentioned, B6 plays a role in lowering levels of homocysteine in the blood. High levels of homocysteine appear to be associated with heart disease.
Nausea and Vomiting during pregnancy
A daily dose of 30 mg of B6 may help reduce morning sickness. However, other studies have found no benefit. If you are pregnant, be sure to ask your doctor before taking any supplements, including vitamin B6.
Depression
Vitamin B 6 plays a role in the production of serotonin. Because low levels of serotonin are associated with depression, and some antidepressant medications work by raising levels of serotonin, some researchers think that vitamin B6 might help reduce symptoms of depression. More research is needed to determine whether there is any true benefit.
Premenstrual Syndrome (PMS)
Vitamin B6 help improve PMS symptoms.Some health care providers and their female patients report that vitamin B6 improves their PMS symptoms. It is possible that response to vitamin B6 may be based on the individual.
Carpal Tunnel Syndrome
Some early studies suggested that B6 might help reduce inflammation and symptoms of carpal tunnel syndrome.
Rheumatoid Arthritis
Low levels of vitamin B6 have been associated with rheumatoid arthritis, and some studies indicate that people with RA may need more vitamin B6 than healthy people because chronic inflammation may lower B6 levels. Eating a balanced diet, including a complete vitamin B complex, is a good idea for anyone who has a chronic illness, such as rheumatoid arthritis.
Doses
People who eat a balanced diet containing good sources of vitamin B6 should be able to meet the daily requirement without taking a supplement. Vitamin supplements should always be taken with water, preferably after a meal. As with all medications and supplements, check with a health care provider before giving vitamin B6 supplements to a child.
Daily recommendations for dietary vitamin B6 are listed below.
Pediatric
Newborns - 6 months: 0.1 mg (adequate intake)
Infants 7 months - 1 year: 0.3 mg (adequate intake)
Children 1 - 3 years: 0.5 mg (RDA)
Children 4 - 8 years: 0.6 mg (RDA)
Children 9 - 13 years: 1 mg (RDA)
Males 14 - 18 years: 1.3 mg (RDA)
Females 14 - 18 years: 1.2 mg (RDA)
Adult
19 - 50 years: 1.3 mg (RDA)
Males 51 years and older: 1.7 mg (RDA)
Females 51 years and older: 1.5 mg (RDA)
Pregnant females: 1.9 mg (RDA)
Breastfeeding females: 2.0 mg (RDA)
Prevention of heart disease and lowering of homocysteine levels: 3.0 mg per day.
Larger doses have been used to treat some of the conditions discussed above, but you should not take doses above 100 mg per day without a doctor's supervision.
Possible Side effects / Precautions / Possible Interactions:
Vitamin B6 is usually safe, at intakes up to 200 mg per day in adults. However, vitamin B6 can cause neurological disorders, such as loss of sensation in legs and imbalance, when taken in high doses (200 mg or more per day) over a long period of time. Vitamin B6 toxicity can damage sensory nerves, leading to numbness in the hands and feet as well as difficulty walking. Symptoms of a pyridoxine overdose may include poor coordination, staggering, numbness, decreased sensation to touch, temperature, and vibration,; and tiredness for up to six months.
Research studies / References
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