Vitamin B6

Vitamin B6 is a water-soluble vitamin that exists in three major chemical forms: pyridoxine, pyridoxal, and pyridoxamine. It performs a wide variety of functions in your body and is essential for your good health. For example, vitamin B6 is needed for more than 100 enzymes involved in protein metabolism. It is also essential for red blood cell metabolism. The nervous and immune systems need vitamin B6 to function efficiently, and it is also needed for the conversion of tryptophan (an amino acid) to niacin (a vitamin).

Haemoglobin within red blood cells carries oxygen to tissues. Your body needs vitamin B6 to make haemoglobin. Vitamin B6 also helps increase the amount of oxygen carried by haemoglobin. A vitamin B6 deficiency can result in a form of anemia that is similar to iron deficiency anemia.

An immune response is a broad term that describes a variety of biochemical changes that occur in an effort to fight off infections. Calories, protein, vitamins, and minerals are important to your immune defenses because they promote the growth of white blood cells that directly fight infections. Vitamin B6, through its involvement in protein metabolism and cellular growth, is important to the immune system. It helps maintain the health of lymphoid organs (thymus, spleen, and lymph nodes) that make your white blood cells. Animal studies show that a vitamin B6 deficiency can decrease your antibody production and suppress your immune response.

Vitamin B6 also helps maintain your blood glucose (sugar) within a normal range. When caloric intake is low your body needs vitamin B6 to help convert stored carbohydrate or other nutrients to glucose to maintain normal blood sugar levels. While a shortage of vitamin B6 will limit these functions, supplements of this vitamin do not enhance them in well-nourished individuals.

When can a vitamin B6 deficiency occur?

Vitamin B6 deficiency can occur in individuals with poor quality diets that are deficient in many nutrients. Symptoms occur during later stages of deficiency, when intake has been very low for an extended time. Signs of vitamin B6 deficiency include dermatitis (skin inflammation), glossitis (a sore tongue), depression, confusion, and convulsions. Vitamin B6 deficiency also can cause anemia. Some of these symptoms can also result from a variety of medical conditions other than vitamin B6 deficiency. It is important to have a physician evaluate these symptoms so that appropriate medical care can be given.

Who may need extra vitamin B6 to prevent a deficiency?

Individuals with a poor quality diet or an inadequate B6 intake for an extended period may benefit from taking a vitamin B6 supplement if they are unable to increase their dietary intake of vitamin B6. Alcoholics and older adults are more likely to have inadequate vitamin B6 intakes than other segments of the population because they may have limited variety in their diet. Alcohol also promotes the destruction and loss of vitamin B6 from the body.

Asthmatic children treated with the medicine theophylline may need to take a vitamin B6 supplement. Theophylline decreases body stores of vitamin B6, and theophylline-induced seizures have been linked to low body stores of the vitamin. A physician should be consulted about the need for a vitamin B6 supplement when theophylline is prescribed.

Vitamin B6 and premenstrual syndrome

Vitamin B6 has become a popular remedy for treating the discomforts associated with premenstrual syndrome (PMS). Unfortunately, clinical trials have failed to support any significant benefit and there is no convincing scientific evidence to support recommending vitamin B6 supplements for PMS.