Vitamin B6

Vitamin B-6 is a family of water-soluble compounds that includes pyridoxine, pyridoxal, and pyridoxamine. All three forms are found in foods. It is critical for a plethora of body functions and has been noted for its benefits in over a hundred health conditions. It is essential for hormonal balance, enzyme function, and a strong immune system.

Vitamin B-6, along with other B vitamins, is involved in the production of several body proteins and neurotransmitters. It is particularly indispensable to the action of amino acid neurotransmitters, like serotonin, dopamine, melatonin, and norepinephrine, which effect brain function. It is also involved in the metabolism of selenium, calcium, and magnesium. Severe deficiency of the nutrient is uncommon, though low levels are implicated in an increasing number of health problems. The incidence of these problems has risen in the past forty years, a likely result of an increased amount of Vitamin B-6 inhibitors in food and medicines.

This vitamin is strongly recommended for sufferers of premenstrual syndrome (PMS). A 1987 study showed than 150 milligrams reduced many PMS symptoms such as dizziness, nausea, poor mental performance and withdrawal from social activities or depression.1 Other studies have produced almost identical results. More is not necessarily better and it is important to limit the dosage of Vitamin B-6, probably to no more than 200 milligrams per day unless instructed by a physician.2

It is common for asthma patients to have impaired tryptophan metabolism and serotonin transport. This is possibly due to a decreased amount of Vitamin B-6. Research dating back to 1985 supports the use of Vitamin B-6 supplements to reduce the frequency and severity of asthmatic symptoms.3 Asthmatics being treated with the drug theophylline should note that this medication can inhibit Vitamin B-6.

The food additive monosodium glutamate (MSG), used often in Chinese cuisine, may be problematic to people deficient in Vitamin B-6. The vitamin is needed to metabolize MSG. A study conducted in 1981 indicated that Vitamin B-6 supplements can reduce the symptoms and side effects of so called ÒChinese Restaurant Syndrome.Ó4 One symptom is depression. Due to its function with brain neurotransmission of serotonin, it is not surprising that depressed persons are likely to have low levels of Vitamin B-6. Supplements of this nutrient have had a positive effect.

Vitamin B-6, in addition to folic acid and Vitamin B-12, is thought to lower the risk of heart disease. These nutrients can prevent an excess buildup of homocysteine, high levels of which can lead to atherosclerosis and eventually to cardiac arrest. Increased levels of homocysteine is also considered a risk factor for the development of osteoporosis in postmenopausal women. A 1995 study also found Vitamin B-6 to significantly lower systolic and diastolic blood pressure.5

Patients with carpal tunnel syndrome are often deficient in Vitamin B-6. This is a painful condition in which the median nerve between the bone and ligament in the wrist is compressed. Research in 1990 showed Vitamin B-6 may be a viable treatment for this condition, though benefits will occur slowly over time.6 Vitamin supplements may stand as a promising alternative to neurosurgery.

1 Lemoyne M, et.al., Amer J of Clin Nutr, 46:267-72, 1987.

2 Bartel P, Ubbink J, Delport R, et al: Vitamin B-6 supplementation and theophylline-related effects in humans. Am J Clin Nutrition 1994;60:93-99.

3 Reynolds RD and Natta CL, Depressed plasma pyridoxal-5-phosphate concentrations in adult asthmatics. Am J Clin Nutr 41, 684-688, 1985.

4 Folkers K, et al., Biochemical evidence for a deficiency of vitamin B-6 in subjects reacting to monosodium glutamate by the Chinese restaurant syndrome. Biochem Biophys Res Common 100, 972-977, 1981.

5 Ayback M, et al., Effect of oral pyridoxine hydrochloride supplementation on arterial blood pressure in patients with essential hypertension. Arzneim Forsch 45, 19-21, 1995.

6 Ellis JM, Folkers K, Clinical aspects of treatment of carpal tunnel syndrome with B-6. Annals NY Acad Sci 585, 302-320, 1990.

VITAMIN B-6: SOURCES

• Avocados
• Bananas
• Bran
• Brewer's yeast
• Carrots
• Flour, whole-wheat
• Hazelnuts (filberts)
• Lentils
• Rice
• Salmon
• Shrimp
• Soybeans
• Sunflower seeds
• Tuna
• Wheat germ

Available as:

• Tablets: Take with meals or 1 to 1-1/2 hours after meals unless otherwise directed by your doctor.
• Extended-release capsules or tablets: Swallow whole with full glass of liquid. Don't chew or crush. Take with or immediately after food to decrease stomach irritation.
• A constituent of many multivitamin/mineral preparations.
• Pyridoxine hydrochloride and pyridoxal-5-phosphate (most active form)1

1 From Griffith HW, Vitamins, Minerals, and Supplements.

VITAMIN B-6: PROVEN BENEFITS

• Participates actively in many chemical reactions of proteins and amino acids.
• Helps normal function of brain.
• Promotes normal red blood cell formation.
• Maintains chemical balance among body fluids.
• Regulates excretion of water.
• Helps in energy production and resistance to stress.
• Acts as co-enzyme in carbohydrate, protein and fat metabolism.
• Treats some forms of anemia.
• Treats cycloserine and isoniazid poisoning.
• Used in treatment of the following conditions: asthma, premenstrual syndrome, carpal tunnel syndrome, depression, morning sickness, and kidney stones.

What this vitamin does:

• Acts as co-enzyme for metabolic functions affecting protein, carbohydrates and fat utilization.
• Promotes conversion of tryptophan to niacin or serotonin.
• Involved in making proteins, chemical transmitters, and prostaglandins.
• Needed to maintain hormonal balance and immune function.1

1 From Griffith HW, Vitamins, Minerals, and Supplements.

VITAMIN B-6: UNPROVED SPECULATED BENEFITS

• Treats or prevents depression when used with oral contraceptives.
• Treats premenstrual syndrome.
• Reduces breast milk in nursing mothers with congested breasts.
• Relieves morning sickness.
• Helps arthritis.
• Cures migraines.
• Relieves nausea.
• Acts as a tranquilizer.
• Relieves nervous and muscle disorders.
• Lowers blood cholesterol.
• Retards aging.
• Treats diabetes.
• Treats mental retardation.
• Improves vision.
• Helps weight-reduction efforts.
• Helps infertility.
• Cures carpal-tunnel syndrome.1

1 From Griffith HW, Vitamins, Minerals, and Supplements.

VITAMIN B-6: SPECIAL CONSIDERATIONS

• Anyone with inadequate caloric or nutritional dietary intake or increased nutritional requirements.
• Older people (over 55 years).
• Pregnant or breast-feeding women.
• Those who abuse alcohol or other drugs.
• People with a chronic wasting illness, excess stress for long periods or who have recently undergone surgery.
• Those with a portion of the gastrointestinal tract surgically removed.
• People with recent severe burns or injuries.
• Women taking oral contraceptives or estrogen.

Miscellaneous information:

• Avoid cooking foods that contain Vitamin B-6 in large amounts of water.
• Freezing vegetables results in a 30 to 56% reduction of Vitamin B-6.
• Canning vegetables results in a 57 to 77% reduction of Vitamin B-6.1

1 From Griffith HW, Vitamins, Minerals, and Supplements.

VITAMIN B-6: DEFICIENCY SYMPTOMS

• Symptoms of Vitamin B-6 deficiency are non-specific and hard to reproduce experimentally.
• Weakness
• Mental confusion
• Irritability
• Nervousness
• Insomnia
• Poor coordination walking
• Hyperactivity
• Abnormal electroencephalogram
• Anemia
• Skin lesions
• Discoloration of tongue
• Muscle twitching
• Kidney stones
• Depression
• Convulsions
• Glucose intolerance
• Impaired nerve function
• Cracked lips
• Eczema1

1 From Griffith HW, Vitamins, Minerals, and Supplements.

VITAMIN B-6: UNPROVED SPECULATED SYMPTOMS

• Depression
• Diabetes1

1 From Griffith HW, Vitamins, Minerals, and Supplements.

VITAMIN B-6: LAB TESTS TO DETECT DEFICIENCY

• Pyridoxine level in blood
• Xanthurenic-acid level in urine
• Erythrocyte glutamic oxalo-acetic transaminase
• Lymphocytic growth response1

1 From Griffith HW, Vitamins, Minerals, and Supplements.

VITAMIN B-6: OPTIMAL LEVELS

5-200 mg.

VITAMIN B-6: MINIMUM DOSAGE

Recommended Dietary Allowance (RDA):

Estimate of adequate daily intake by the Food and Nutrition Board of the National Research Council, 1989. The therapeutic dose is between 50-100mg.

Age RDA

0-6 months 0.3mg

6-12 months 0.6mg

1-3 years 1.0mg

4-6 years 1.3mg

7-10 years 1.4mg

MALES

11+ 14 1.7mg

15+ 2.0mg

FEMALES

11-14 1.4mg

15-18 1.5mg

19+ 1.6mg

Pregnant +2.2mg

Lactating +2.1mg

VITAMIN B-6: WARNINGS AND PRECAUTIONS

Don't take if you:

• You are allergic to Vitamin B-6.
• Consult your doctor if you have:
• Intestinal problems.
• Liver disease.
• Overactive thyroid.
• Parkinson's disease.

Over age 55:

• More likely to have marginal deficiency.

Pregnancy:

• Don't take megadoses.

Breast-feeding:

• Megadoses can cause dangerous side effects in the infant.

Effect on lab tests:

• May produce false-positive results in urobilinogen determinations using Ehrlich's reagent.

Storage:

• Store in cool, dry place away from direct light, but don't freeze.
• Store safely out of reach of children.
• Don't store in bathroom medicine cabinet. Heat and moisture may change action of vitamin.

Others:

• Regular B-6 supplements are recommended if you take chloramphenicol, cycloserine, ethionamide, hydralazine, immunosuppressants, isoniazid or penicillamine. These decrease
• pyridoxine absorption and can cause anemia or tingling and numbness in hands and feet.
• Don't crush, break or chew tablets before swallowing.1

1 From Griffith HW, Vitamins, Minerals, and Supplements.

VITAMIN B-6: OVERDOSE/TOXICITY

Signs and symptoms:

• Clumsiness, numbness in hands and feet.
• Vitamin B-6 may lead to toxicity over time. Doses over 2000 mg may lead to nerve damage.

What to do:

• For symptoms of overdosage: Discontinue vitamin, and consult doctor. Also see ADVERSE REACTIONS OR SIDE EFFECTS.
• For accidental overdosage (such as child taking entire bottle): Call your local poison control center.1

1 From Griffith HW, Vitamins, Minerals, and Supplements.

VITAMIN B-6: ADVERSE REACTIONS OR SIDE EFFECTS

Reaction or effect What to do

Doses of 200 mg/day can produce dependency, Discontinue megadoses gradually.

requiring need to continue to take high doses

(undesirable).

Large doses (2 to 6 grams of pyridoxine/day) Discontinue megadoses. Call

taken for several months are reported to doctor immediately.

cause severe sensory neuropathy with

unsteady gait, numb feet and hands, clumsiness.

Causes depression when taken Discontinue pyridoxine. Call doctor with oral contraceptive pills.1 when convenient.

1 From Griffith HW, Vitamins, Minerals, and Supplements.

VITAMIN B-6: INTERACTION WITH OTHER SUBSTANCES

• Chloramphenicol, cycloserine, ethionamide, hydralazine, isoniazid, penicillamine, immunosuppressants, such as adrenocorticoids, azathioprine, chlorambucil, ACTH, cylcophosphamide, cylcosporine, and mercaptopurine: May increase excretion of pyridoxine and cause anemia or peripheral neuritis, which includes pain, numbness, and coldness in feet and fingertips. If you take these medications, you may need increased pyridoxine. Consult your doctor.
• Estrogen or oral contraceptives increase requirements of pyridoxine. Also causes depression.
• Levodopa prevents levodopa from controlling symptoms of Parkinson's disease. This problem does not occur with carbidopa-levodopa combination.
• Phenytoin: Large doses of B-6 hasten break-down of phenytoin.
• Magnesium: B-6 relies on magnesium for its conversion.
• Tobacco decreases absorption. Smokers may require supplemental Vitamin B-6.
• Hydrazine dyes inhibit Vitamin B-6 action (e.g. FD&C yellow #5).
• Alcohol inhibits B-6.
• Excess protein inhibits B-6.1

1 From Griffith HW, Vitamins, Minerals, and Supplements.

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