Health Centers
 loading...
if not loaded., try Site map to view all
 
 
 
 
bookmark | print this page | mail to friend | site map | help

General Nutrition and Diet Facts

FONT SIZE

T T T

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.
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).
Hemoglobin within red blood cells carries oxygen to tissues. Your body needs vitamin B6 to make hemoglobin. Vitamin B6 also helps increase the amount of oxygen carried by hemoglobin. 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.

Foods that provide vitamin B6

Vitamin B6 is found in a wide variety of foods including fortified cereals, beans, meat, poultry, fish, and some fruits and vegetables.

Table of Food Sources of Vitamin B6

Food Milligrams (mg) per serving %DV*
  Ready-to-eat cereal, 100% fortified, c   2.00   100
  Potato, Baked, flesh and skin, 1 medium   0.70   35
  Banana, raw, 1 medium   0.68   34
  Garbanzo beans, canned, c   0.57   30
  Chicken breast, meat only, cooked, breast   0.52   25
  Ready-to-eat cereal, 25% fortified, c   0.50   25
  Oatmeal, instant, fortified, 1 packet   0.42   20
  Pork loin, lean only, cooked, 3 oz   0.42   20
  Roast beef, eye of round, lean only, cooked, 3 oz   0.32   15
  Trout, rainbow, cooked, 3 oz   0.29   15
  Sunflower seeds, kernels, dry roasted, 1 oz   0.23   10
  Spinach, frozen, cooked, c   0.14   8
  Tomato juice, canned, 6 oz   0.20   10
  Avocado, raw, sliced, cup   0.20   10
  Salmon, Sockeye, cooked, 3 oz   0.19   10
  Tuna, canned in water, drained solids, 3 oz   0.18   10
  Wheat bran, crude or unprocessed, c   0.18   10
  Peanut butter, smooth, 2 Tbs.   0.15   8
  Walnuts, English/Persian, 1 oz   0.15   8
  Soybeans, green, boiled, drained, c   0.05   2
  Lima beans, frozen, cooked, drained, c   0.10   6


DV = Daily Value.

Recommended Dietary Allowance for vitamin B6 for adults

The Recommended Dietary Allowance (RDA) is the average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97 to 98 percent) healthy individuals in each life-stage and gender group.

Vitamin B6 for adults, in milligrams, are:

Life-Stage Men Women Pregnancy Lactation
  Ages 19-50    1.3 mg   1.3 mg      
  Ages 51+   1.7 mg   1.5 mg      
  All Ages            1.9 mg   2.0 mg


Vitamin B6 deficiency

Clinical signs of vitamin B6 deficiency are rarely seen. Many older people, however, have low blood levels of vitamin B6, which may suggest a marginal or sub-optimal vitamin B6 nutritional status. 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.
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.

Some issues and controversies about vitamin B6

Vitamin B6 and the nervous system

Vitamin B6 is needed for the synthesis of neurotransmitters such as serotonin and dopamine. These neurotransmitters are required for normal nerve cell communication. Researchers have been investigating the relationship between vitamin B6 status and a wide variety of neurologic conditions such as seizures, chronic pain, depression, headache, and Parkinson's disease.
Lower levels of serotonin have been found in individuals suffering from depression and migraine headaches. So far, however, vitamin B6 supplements have not proved effective for relieving these symptoms. One study found that a sugar pill was just as likely as vitamin B6 to relieve headaches and depression associated with low dose oral contraceptives.
Alcohol abuse can result in neuropathy, abnormal nerve sensations in the arms and legs. A poor dietary intake contributes to this neuropathy and dietary supplements that include vitamin B6 may prevent or decrease its incidence.

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. In addition, vitamin B6 toxicity has been seen in increasing numbers of women taking vitamin B6 supplements for PMS. There is no convincing scientific evidence to support recommending vitamin B6 supplements for PMS.

Vitamin B6 and interactions with medications

There are many drugs that interfere with the metabolism of vitamin B6. Isoniazid, which is used to treat tuberculosis, and L-DOPA, which is used to treat a variety of neurologic problems such as Parkinson's disease, alter the activity of vitamin B6. There is disagreement about the need for routine vitamin B6 supplementation when taking isoniazid. Acute isoniazid toxicity can result in coma and seizures that are reversed by vitamin B6, but in a group of children receiving isoniazid, no cases of neurological or neuropsychiatric problems were observed regardless of whether or not they took a vitamin B6 supplement. Some doctors recommend taking a supplement that provides 100% of the RDA for B6 when isoniazid is prescribed, which is usually enough to prevent symptoms of vitamin B6 deficiency. It is important to consult with a physician about the need for a vitamin B6 supplement when taking isoniazid.

What is the relationship between vitamin B6, homocysteine, and heart disease?

A deficiency of vitamin B6, folic acid, or vitamin B12 may increase your level of homocysteine, an amino acid normally found in your blood. There is evidence that an elevated homocysteine level is an independent risk factor for heart disease and stroke. The evidence suggests that high levels of homocysteine may damage coronary arteries or make it easier for blood clotting cells called platelets to clump together and form a clot. However, there is currently no evidence available to suggest that lowering homocysteine level with vitamins will reduce your risk of heart disease.

Health risk of too much vitamin B6

Too much vitamin B6 can result in nerve damage to the arms and legs. This neuropathy is usually related to high intake of vitamin B6 from supplements, and is reversible when supplementation is stopped. Several reports show sensory neuropathy at doses lower than 500 mg per day. And also it has been established an upper tolerable intake level (UL) for vitamin B6 of 100 mg per day for all adults. As intake increases above the UL, the risk of adverse effects increases.

Vitamin B6 intakes and healthful diets

Vitamin B6 is found in a wide variety of foods. Foods such as fortified breakfast cereals, fish including salmon and tuna fish, meats such as pork and chicken, bananas, beans and peanut butter, and many vegetables will contribute to your vitamin B6 intake.
Nutrient needs should be met primarily through consuming foods. Foods provide an array of nutrients and other compounds that may have beneficial effects on health. In certain cases, fortified foods and dietary supplements may be useful sources of one or more nutrients that otherwise might be consumed in less than recommended amounts. However, dietary supplements, while recommended in some cases, cannot replace a healthful diet.

A healthy diet is described as one that:
  • emphasizes a variety of fruits, vegetables, whole grains, and fat-free or low-fat milk and milk products;
  • includes lean meats, poultry, fish, beans, eggs, and nuts;
  • is low in saturated fats, trans fats, cholesterol, salt (sodium), and added sugars; and
  • stays within your daily calorie needs.

 


 
Your feedback?




 
Other navigational links under General Nutrition and Diet Facts
 
 

Rate this page?
Good Average Poor



Rating accepted

Thanks for your note! Suggestion if any, will be taken up by the editor squad on a prority. We appreciate your gesture.
Hecapedia squad
Improve hecapedia - Join the squad


 
 
Nothing on this web site, in any way to be viewed as medical advice. All contents should be viewed as general information only.
All health care decisions should only be made with consultation from your physician.

About us | Link to us | Contact us | Associates | Media Center | Business services | Feedback | Report Bugs | Sitemap | Help
privacy policy | disclaimer | terms and conditions | accessibility | anti-spam policy
© 2006 hecapedia