Source: University of Mayland Medical Center
Also listed as: Pyridoxine
Vitamin B6, also called pyridoxine, is one of eight water-soluble B
vitamins. The B vitamins help the body to convert carbohydrates into
glucose (sugar), which is "burned" to produce energy. These vitamins,
often referred to as the B complex, are also essential in the
metabolism of fats and protein. B complex vitamins also play an
important role in maintaining muscle tone in the gastrointestinal tract
and promoting the health of the nervous system, skin, hair, eyes,
mouth, and liver.
Vitamins B12, B6, and B9 (folic acid) work closely together to control
blood levels of the amino acid homocysteine. Elevated levels of this
substance appear to be linked to heart disease. Plus, vitamin B6 is
essential for normal brain development and function, participating in
the process of making important brain chemicals called
neurotransmitters.
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. Pyridoxine has also been called the "woman's vitamin"
because it may help relieve symptoms of premenstrual syndrome (PMS).
In addition to other B complex vitamins, pyridoxine is considered an
"anti-stress" vitamin because it is believed to enhance the activity of
the immune system and improve the body's ability to withstand stressful
conditions.
Symptoms of pyridoxine deficiency include muscle weakness, nervousness,
irritability, depression, difficulty concentrating, and short-term
memory loss.
Heart Disease
Low dietary intake of vitamin B6 is associated with higher risk of
having heart disease. This may be related to the fact that vitamin B6,
together with vitamin B9 (folic acid) and vitamin B12, help to keep
homocysteine levels under control. Homocysteine is an amino acid.
Elevated levels of this amino acid are associated with increased risk
of heart disease and increased risk of stroke.
The American Heart Association recommends, for most people, that enough
of these important B vitamins be obtained from the diet, rather than
taking extra supplements. Under certain circumstances, however,
supplements may be necessary. Such circumstances include elevated
homocysteine levels with known heart disease or strong family history
of heart disease at a young age.
Nausea and Vomiting during pregnancy
A recent review of scientific studies concluded that vitamin B6 may help reduce the severity of nausea during early pregnancy.
Osteoporosis
Keeping bones healthy throughout life depends on getting sufficient
amounts of specific vitamins and minerals, including phosphorous,
magnesium, boron, manganese, copper, zinc, folate, and vitamins C, K,
B6, and B12.
Eating Disorders
Levels of important nutrients are often quite low in those with
anorexia or bulimia. At least 20% of people with anorexia admitted to a
hospital for treatment are deficient in vitamins B2 and B6
(pyridoxine). Some research information suggests that as many as 33% of
those with an eating disorder could be deficient in vitamins B2 and B6.
Dietary changes alone, without additional supplements, can often bring
vitamin B levels back to normal. However, extra B2 and B6 may be
required (which will be determined by your doctor or nutritionist).
Plus, B-complex vitamins may help alleviate stress and reduce symptoms
of depression, frequently associated with eating disorders.
Burns
It is especially important for people who have sustained serious
burns to obtain adequate amounts of nutrients in their daily diet. When
skin is burned, a substantial percentage of micronutrients may be lost.
This increases the risk for infection, slows the healing process,
prolongs the hospital stay, and even increases the risk of death.
Although it is unclear which micronutrients are most beneficial for
people with burns, many studies suggest that a multivitamin including
the B complex vitamins may aid in the recovery process. Vitamin B6,
along with other members of the B complex, may be of particular
importance, given their value in building protein. Protein is necessary
to recover from any kind of an injury. In addition, as stated earlier,
the amount of B complex needed may increase during times of stress.
Depression
Studies suggest that vitamin B9 (folate) may be associated with
depression more than any other nutrient. Between 15% and 38% of people
with depression have low folate levels in their bodies and those with
very low levels tend to be the most depressed. Many healthcare
providers start by recommending a multivitamin (MVI) that contains
folate, and then monitoring the homocysteine levels in the blood to
ensure the adequacy of therapy. Elevated homocysteine levels indicate a
deficiency of folate even if the levels of folate in the blood are
normal. If the MVI alone is not enough to lower homocysteine and
improve folate function, the provider may suggest additional folate
along with vitamins B6 and B12 to try to bring the homocysteine levels
down, thereby eliminating the functional folate deficiency and,
hopefully, helping to improve feelings of depression.
Premenstrual Syndrome (PMS)
A comprehensive review of studies concluded that vitamin B6 may be more
effective than placebo in improving symptoms of PMS, particularly
depression. Most studies were poorly designed, however. Still, even
though the science is not definitive, many healthcare providers and
their female patients report improvement in PMS from using vitamin B6.
Therefore, how well you respond to vitamin B6 may be very individual.
Until more research is completed, talk with your doctor about whether
using B6 is appropriate and safe for you. Then, if taking the vitamin,
follow your symptoms closely. It can take up to 3 months until any
change is noticeable.
Diabetes
Preliminary evidence suggests that vitamin B6 may help control blood
sugar in people with diabetes. In a study of people with diabetes,
those who received pyridoxine alpha-ketoglutarate (a form of vitamin
B6) for one month experienced significant reductions in fasting blood
sugar levels compared to those who did not receive the supplement. More
research in this area is needed before conclusions can be drawn about
the relationship between vitamin B6 and diabetes.
Human Immunodeficiency Virus (HIV)
Vitamin B6, particularly together with a complete B complex, may help alleviate the stress associated with having HIV or AIDS.
Attention Deficit/Hyperactive Disorder (ADHD)
Adequate levels of vitamin B6 are required for normal brain
development and are essential for the synthesis of essential brain
chemicals including serotonin, dopamine and norepinephrine. A
preliminary study found that pyridoxine was slightly more effective
than methylphenidate (a medication used to treat ADHD) in improving
behavior among hyperactive children. Although intriguing, the results
of this study were not significant and no other studies have been able
to confirm these findings. Therefore, supplementation with vitamin B6
is not considered standard treatment for ADHD.
Rheumatoid Arthritis
Low levels of vitamin B6 have been associated with rheumatoid
arthritis. This may be due to low dietary intake of vitamin B6 and
other important nutrients by people with this joint disorder. Eating a
balanced diet, including a complete vitamin B complex, is a good idea
for anyone with a chronic illness, such as rheumatoid arthritis. It is
not known if taking extra vitamin B6 is of any use if you have
arthritis.
Good dietary sources of vitamin B6 include chicken, turkey, tuna,
salmon, shrimp, beef liver, lentils, soybeans, nuts, avocados, bananas,
carrots, brown rice, bran, sunflower seeds, wheat germ, and whole-grain
flour.
Vitamin B6 can be found in multivitamins (including children's chewable
and liquid drops), B complex vitamins, or can be sold individually. It
is available in a variety of forms including tablets, softgels, and
lozenges. Vitamin B6 is also sold under the names pyridoxal,
pyridoxamine, pyridoxine hydrochloride, and pyridoxal-5-phosphate.
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 healthcare provider before giving vitamin B6 supplements to a
child.
Daily recommendations for dietary vitamin B6 are listed below.
Pediatric
- Newborns to 6 months: 0.1 mg (adequate intake)
- Infants 7 months to 1 year: 0.3 mg (adequate intake)
- Children 1 to 3 years: 0.5 mg (RDA)
- Children 4 to 8 years: 0.6 mg (RDA)
- Children 9 to 13 years: 1 mg (RDA)
- Males 14 to 18 years: 1.3 mg (RDA)
- Females 14 to 18 years: 1.2 mg (RDA)
Adult
- 19 to 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.
Nausea and vomiting during early pregnancy: studies on this topic have
used 10 mg per day. The amount to use, however, should be determined
together with your obstetrician.
Therapeutic doses for some of the conditions discussed in the Uses
section have ranged from 100 to as high as 1,800 milligrams per day.
Using doses higher than 200 mg per day for long periods of time,
however, may cause neurologic disorders (see Precautions).
Because of the potential for side effects and interactions with
medications, dietary supplements should be taken only under the
supervision of a knowledgeable healthcare provider.
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. Discontinuing high doses usually leads
to a complete recovery within 6 months.
There have been extremely rare reports of allergic skin reactions to high doses of vitamin B6 supplements.
If you are currently being treated with any of the following
medications, you should not use vitamin B6 supplements without first
talking to your healthcare provider.
Antibiotics, Tetracycline
Vitamin B6 should not be taken at the same time as the antibiotic
tetracycline because it interferes with the absorption and
effectiveness of this medication. Vitamin B6 either alone or in
combination with other B vitamins should be taken at different times
from tetracycline. (All vitamin B complex supplements act in this way
and should therefore be taken at different times from tetracycline.)
Antidepressant Medications, Tricyclic
Taking vitamin B6 supplements may improve the effectiveness of
certain tricyclic antidepressants such as nortriptyline, especially in
elderly individuals. Other tricyclic antidepressants include
desipramine and imipramine.
On the other hand, another class of antidepressants called monoamine
oxidase inhibitors (MAOIs) may reduce blood levels of vitamin B6.
Examples of MAOIs include phenelzine and tranylcypromine.
Antipsychotic Medications
Preliminary evidence suggest that pyridoxine may prove useful in
treating tardive dyskinesia, a common but frustrating side effect from
medications used to treat schizophrenia. Tardive dyskinesia is marked
by involuntary movements of the mouth and tongue. More research is
needed to know if vitamin B6 can help prevent or treat this side
effect.
Tuberculosis Medications
Anti-tuberculosis medications such as isoniazid (INH) and cycloserine
(used for resistant forms of tuberculosis) reduce the levels of vitamin
B6 in the blood.
Birth control medications
Birth control medications may reduce blood levels of vitamin B6.
Chemotherapy
Vitamin B6 may reduce certain side effects of 5-fluorouracil and
doxorubicin, two agents used to treat cancer without reducing the
effectiveness of the chemotherapy.
Erythropoietin
Erythropoietin therapy used for severe anemia may decrease vitamin
B6 levels in red blood cells. Therefore, vitamin B6 supplementation may
be necessary during erythropoietin therapy.
Hydralazine
Vitamin B6 decreases the effectiveness of hydralazine, a medication used to treat high blood pressure.
Levodopa
Vitamin B6 reduces the effectiveness of levodopa, a medication used to treat Parkinson's disease.
Methotrexate
People with rheumatoid arthritis taking this medication often have low levels of vitamin B6.
Penicillamine
Penicillamine, a medication used in the treatment of rheumatoid
arthritis and Wilson's disease (excessive amounts of copper in the body
that can lead to liver damage) may decrease levels of vitamin B6 in the
body.
Phenytoin
Vitamin B6 reduces the effectiveness of phenytoin, a medication used to treat seizures.
Theophylline
Long-term treatment with theophylline for asthma may reduce blood levels of vitamin B6.
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- Review Date:
4/1/2002
- Reviewed By: Participants in the review process include: Ruth
DeBusk, RD, PhD, Editor, Nutrition in Complementary Care, Tallahassee,
FL; Jacqueline A. Hart, MD, Department of Internal Medicine,
Newton-Wellesley Hospital, Harvard University and Senior Medical Editor
Integrative Medicine, Boston, MA; Gary Kracoff, RPh (Pediatric Dosing
section February 2001), Johnson Drugs, Natick, Ma; Steven Ottariono,
RPh (Pediatric Dosing section February 2001), Veteran's Administrative
Hospital, Londonderry, NH. All interaction sections have also been
reviewed by a team of experts including Joseph Lamb, MD (July 2000),
The Integrative Medicine Works, Alexandria, VA;Enrico Liva, ND, RPh
(August 2000), Vital Nutrients, Middletown, CT; Brian T Sanderoff, PD,
BS in Pharmacy (March 2000), Clinical Assistant Professor, University of Mayland School of Pharmacy; President, Your Prescription for
Health, Owings Mills, MD; Ira Zunin, MD, MPH, MBA (July 2000),
President and Chairman, Hawaii State Consortium for Integrative
Medicine, Honolulu, HI.
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