hemoglobin function. Hemoglobin is the molecule in
red blood cells that carries oxygen throughout the body.
Vitamin B 6 appears to increase theefficiency of hemo-
globin, although the how this happens is not clear.
using stored glycogen. Glycogen is a special carbohy-
drate stored in the liver and in muscles. Physical
activity causes glycogen to be broken down into glu-
cose (sugar) that is used for energy. Vitamin B 6 is one
of several B vitamins that are essential to this process.
making new nucleic acids. DNA, the protein that
genes are made of, and RNA, a related protein, are
made of nucleic acids. Whenever cells divide to form
new cells, more DNA and RNA are needed. Because
vitamin B 6 is needed to create nucleic acids, it plays a
role in cell division and wound healing.
turning genes on and off. Vitamin B 6 joins with other
molecules to activate and inactivate different genes.
The exact mechanism by which this takes place is
unclear.
regulation of homocysteine. Increased levels of homo-
cysteine, an amino acid that is released when protein is
broken down, appears to be associated with increased
damage to blood vessels and increased risk of heart
disease. Vitamin B 6 , probably working with folic acid
and vitamin B 12 , lowers the level of homocysteine in
the blood. However, large doses of B 6 alone do not
appear to reduce heart disease.
Other health claims have also been proposed for
vitamin B 6. These include relieving premenstrual symp-
toms, boosting the immune system, improving mental
functioning in the elderly, decreasing the likelihood of
developing kidney stones, treating depression, treating
carpal tunnel syndrome, treating morning sickness in
pregnant women, treating drug-induced movement dis-
orders in people with schizophrenia, treating attention
deficit-hyperactivity disorder (ADHD) in children and
treating autism. None of the studies done using vitamin
B 6 to treat these disorders have produced conclusive
results that satisfy the practitioners of conventional
medicine. Clinical trials are currently underway to
determine safety and effectiveness ofvitamin Ein a
variety of situations. Individuals interested in partici-
pating in a clinical trial at no charge can find a list of
open trials at<http://www.clinicaltrials.gov>.Vitamin B 6 deficiency
Vitamin B 6 deficiency is uncommon in the United
States. It can result from a few rare genetic disorders.
People with alcoholism are at higher risk for develop-
ing vitamin B 6 deficiency, as are the elderly and people
taking certain prescription drugs (see Interactions
below). Internationally, malnutrition and lack of a var-ied diet are the greatest causes of vitamin B 6 deficiency.
Symptoms are slow to appear and include skin inflam-
mation, inflammation of the tongue, ulcers in the
mouth, irritability, depression, and confusion. These
symptoms have many other causes besides vitamin B 6
deficiency and should be evaluated by a physician.Precautions
Few precautions are necessary when taking vita-
min B 6 , although pregnant and breastfeeding women
should avoid taking large amounts as a dietary supple-
ment. Even at high doses, few side effects are reported,
but include nausea, vomiting, and breast soreness. Very
high doses (above 200 mg/day) taken over a long period
can result in loss of feeling in the arms and legs and
problems with balance. These symptoms usually go
away after several months when vitamin B 6 supplemen-
tation is stopped. The UL is 50 times higher than the
RDA, but no health benefits have been confirmed from
taking large daily supplements of vitamin B 6.Interactions
Vitamin B 6 reduces the effectiveness of tetracy-
cline antibiotics, the seizure drug phenytoin, and lev-
odopa used to treat Parkinson’s disease.
Tuberculosis drugs cycloserine and isoniazid
(INH), penicillamine (used to treat rheumatoid arthri-
tis) and theophylline (used to treat asthma) reduce the
level of vitamin B 6 in the blood. Vitamin B 6 supple-
mentation may be required on he advice of a physician
Interactions with herbal remedies are unknown.Complications
No complications are expected when vitamin B 6 is
used in the recommended amounts. The complications
resulting from insufficient or excess use are discussed
above.Parental concerns
Parents should be aware that the RDA and UL for
vitamins and minerals are much lower for children than
for adults. Accidental overdose may occur if children
are given adult vitamins ordietary supplements.Resources
BOOKS
Berkson, Burt and Arthur J. Berkson.Basic Health Publi-
cations User’s Guide to the B-complex Vitamins.Laguna
Beach, CA: Basic Health Publications, 2006.
Gaby, Alan R., ed.A-Z Guide to Drug-Herb-Vitamin Inter-
actions Revised and Expanded 2nd Edition: ImproveVitamin B
6