encyclopedia

Vitamin B6

Natural Sources:
Brewer’s yeast, potatoes; bananas; garbanzo beans, soybeans; poultry, meat, fish, sunflower seeds; spinach; some fruits and vegetables; whole grains; and fortified cereals.

Forms:
Standardized Vitamin B6 supplements including liquid multi-vitamin and mineral products, capsules and tablets; ‘greens’ supplements; and fortified foods.

Therapeutic Uses:
– Aging Disorders

– Arthritic Pain Relief

– Asthma

– Attention Deficit Hyperactivity Disorder (ADD/ADHD)

– Bone and Joint Problems

– Carpal Tunnel Syndrome

– Cellular Regeneration

– Cleansing/Detoxifying

– Depression

– Digestive Disorders

– General Debility

– Gravel

– Heart Health Maintenance

– High Homocysteine

– Immune System Health

– Infections

– Infertility

– Kidney Health Maintenance

– Low Energy

– Melancholy

– Nervous Disorders

– Pellagra

– Skin Disorders

– Sugar Control

– Urinary System Health Maintenance

– Vascular Disorders

– Vitamin B6 Deficiency (RDA = 2.0 – 3.0 mg/day)

Overview:

Vitamin B6 (Pyridoxine), is considered to be a fragile, water-soluble compound, particularly important as a catalyst or coenzyme in the metabolism of carbohydrates, fats, and, especially, proteins. It performs a wide variety of functions in the body and is essential for good health. Vitamin B6 is needed for more than 100 enzymes involved in protein metabolism. According to researchers at Tufts University, vitamin B6 deficiency results in more rapid aging, particularly seen as a failing immune system, declining mental status, compromised health, various infectious diseases and possibly abnormal growths. Without adequate levels within the body, reduced production of specific immune cells including T-cells, T-helper cells and antibodies results. Being low in B6 decimates the percentage of lymphocytes significantly, along with the production of interleukin-2 for helping T-cells. Thankfully, just three weeks of daily supplements (2mg for women and 3mg for men) completely restores normal functioning. Additionally, vitamin B6 helps to convert stored carbohydrate or other nutrients to glucose to maintain normal blood sugar levels when caloric intake is low. It is also essential for the proper functioning of red blood cells, as vitamin B6 is needed to make hemoglobin and increase the amount of oxygen carried by hemoglobin (a deficiency can result in a form of anemia). Vitamin B6 is also required by the nervous and immune systems and for the formation of vitamin B3 (niacin) from the amino acid, tryptophan. Vitamin B6 also helps maintain the health of lymphoid organs (thymus, spleen, and lymph nodes) that make white blood cells and a deficiency can decrease antibody production and suppress your immune response. Gladys Anderson Emerson (1903-1984), an American biochemist and nutritionist, isolated the B complex vitamins in 1942. In research on rhesus monkeys, she discovered that a deficiency of vitamin B6 causes hardening of the arteries.

Chemistry:
Vitamin B6, also known as pyridoxine, was first isolated in 1938 and has the structure of 3-hydroxy-4,5-bis(hydroxymethyl)-2-methylpyridine. The name “pyridoxine” was given to this compound by P. Gyφrgy and came into general use as a synonym for “vitamin B-6”. Two other natural compounds possessing vitamin B6 activity detected in 1944 and recognized as the aldehyde, or 4-formyl analogue of pyridoxine, and the corresponding amine, or 4-aminomethyl analogue, were designated “pyridoxal” and “pyridoxamine” respectively. Supplements often use vitamin B6 hydrochloride or B6 phosphate.

Suggested Amount:
The U.S. Recommended Dietary Allowance (RDA) of vitamin B6, depending upon age and weight, is between 2 to 3 mg/day for an adult and 0.2-1.0 mg/day for a child. Clinical trials involving positive results for treating leg cramps used B vitamin complex including 30mg of pyridoxal phosphate daily. The typical dosage in supplements is 3mg, and for therapeutic purposes it can range between 2-100 mg. The Institute of Medicine recently established an upper tolerable limit of 100 mg per day of vitamin B6 for adults.

Note: Water-soluble vitamins, including B vitamins, cannot be stored and rapidly leave the body in urine if taken in greater quantities than the body can use. Foods and/or supplements that contain water-soluble vitamins need to be eaten daily to replenish the body’s needs. Food Sources of Vitamin B6 include: Potatoes (1 medium) 0.7mg; bananas (1 medium) 0.7mg; garbanzo beans (1/2cup) 0.6mg; poultry (1/2 chicken breast) 0.52mg, meat (3oz beef round steak) 0.32mg; fish (3oz trout) 0.29; sunflower seeds (1oz) 0.23mg; spinach (1/2cup) 0.14mg; Tomato juice (6oz canned) 0.2mg; avocado (sliced, 1/2cup) 0.2; wheat bran (1/4 cup) 0.18mg; peanut butter (2tbs. Smooth) 0.15mg; and fortified cereals (3/4 cup) 2.0mg. [Reference: Clinical Nutrition Service, Warren Grant Magnuson Clinical Center, National Institutes of Health (NIH), Bethesda, MD, in conjunction with the Office of Dietary Supplements (ODS) in the Office of the Director of NIH].

Drug Interactions:
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 neurological problems such as Parkinson’s disease, alter the activity of vitamin B6. It is important to consult with a physician about the need for a vitamin B6 supplement when taking any of these drugs.

Contraindications:
None known.

Side Effects:
There are no known side effects to taking vitamin B6 at normal levels. However, too much vitamin B6 can result in nerve damage (neuropathy) to the arms and legs, and is reversible when supplementation is stopped. Vitamin B6 toxicity has been seen in increasing numbers of people taking high doses of vitamin B6 for treating carpal tunnel syndrome and also in women for treating PMS. One review indicated that neuropathy was present in 23 of 58 women taking daily vitamin B6 supplements for PMS whose blood levels of B6 were above normal. There are also documented cases in the literature of neuropathy caused by excessive vitamin B6 taken for treatment of carpal tunnel syndrome. According to the Institute of Medicine, “Several reports show sensory neuropathy at doses lower than 500 mg per day”. The Institute of Medicine recently established an upper tolerable limit of 100 mg per day of vitamin B6 for adults.

References:

Byar D, Blackard C. 1977. Comparisons of placebo, pyridoxine, and topical thiotepa in preventing recurrence of stage I bladder cancer. Urology. 1977 Dec; 10(6): 556-61.

Chan P, Huang TY, Chen YJ, Huang WP, Liu YC. 1998. Randomized, double-blind, placebo-controlled study of the safety and efficacy of vitamin B complex in the treatment of nocturnal leg cramps in elderly patients with hypertension. J Clin Pharmacol. 1998 Dec; 38(12): 1151-4.

Duke JA. 1992. Handbook of Biologically Active Phytochemicals and their Activities. CRC Press, Boca Raton, FL, p. 144.

van Dijk RA, Rauwerda JA, Steyn M, Twisk JW, Stehouwer CD. 2001. Long-term homocysteine-lowering treatment with folic acid plus pyridoxine is associated with decreased blood pressure but not with improved brachial artery endothelium-dependent vasodilation or carotid artery stiffness: a 2-year, randomized, placebo-controlled trial. Arterioscler Thromb Vasc Biol. 2001 Dec; 21(12): 2072-9.

Wilson ML, Murphy PA. 2001. Herbal and dietary therapies for primary and secondary dysmenorrhoea. Cochrane Database Syst Rev. 2001; (3): CD002124. Review.

Additional Information:

Positive Clinical Trial For Treating Recurrent Epileptic Seizures:

To determine the efficacy of pyridoxine in treating seizures, 90 infants and children with recurrent convulsions primarily due to acute infectious diseases were enrolled in a study. Forty patients were treated with high-dose pyridoxine (30 or 50 mg/kg/day) by intravenous infusion, and 50 subjects served as controls. Antiepileptic drugs and other therapies were similar in the two groups except for pyridoxine. Clinical efficacy criteria were based on the frequency of convulsions per day and on the duration of individual seizures after therapy was initiated. The results indicated that total response rates in the pyridoxine group and control group were 92.5% and 64%, respectively (significant results; P < .001). After initiation of therapy, seizures resolved after 2.4 +/-1.4 days in the pyridoxine group and after 3.7 +/- 2.0 days in the control group (significant results; P < .001). No adverse effects of pyridoxine were apparent during the observation period. We conclude that pyridoxine is an effective, safe, well-tolerated, and relatively inexpensive adjunct to routine antiepileptic drugs for treatment of recurrent seizures in children. Positive Clinical Trial Results On Treating Nocturnal Leg Cramps: Nocturnal leg cramps are a common and troublesome problem in elderly individuals, and their etiology is unknown. Treatment with quinine is a common practice, but the effectiveness of the drug is doubtful and adverse drug effects are common. This randomized, double-blind, placebo-controlled study was conducted to evaluate the safety and efficacy of vitamin B complex capsules (fursulthiamine 50 mg, hydroxocobalamin 250 micrograms, pyridoxal phosphate 30 mg, and riboflavin 5 mg) in 28 elderly patients with hypertension who had severe nocturnal leg cramps that disturbed their sleep. Self-reported ratings of leg cramp frequency, duration, and intensity were used to evaluate severity of nocturnal leg cramps. Both the patients taking vitamin B capsules (n = 14) and those taking placebo (n = 14) received medications three times daily, and were examined regularly at 2-week intervals for 3 months. After 3 months, 86% of the patients taking vitamin B had prominent remission of leg cramps, whereas those taking placebo had no significant difference from baseline. Treatment with vitamin B complex significantly reduced the frequency, intensity, and duration of nocturnal leg cramps. Because quinine is not without potential for side effects, and vitamin B complex is a relatively safe and effective alternative, clinicians should reconsider the treatment of choice for nocturnal leg cramps. Vitamin B6 Deficiency: The U.S. Department of Agriculture cites that 80% of Americans are deficient in vitamin B6, primarily due to significant losses of this nutrient with cooking. A serious 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, and confusion. Pellagra can also result from a vitamin B6 deficiency resulting from inadequate intake or absorption of niacin, one of the components of the vitamin B complex (B6 is required for niacin formation within the body). Pellagra begins with weakness, low energy, insomnia, and weight loss. Exposed skin on the neck, hands, arms, feet, and legs, particularly after exposure to sunlight, becomes rough, reddened, and scaly, and painful mouth lesions develop. The gastrointestinal disturbances consist of loss of appetite, indigestion, and diarrhea; nervous system involvement appears later in the course of the disease and includes such symptoms as headache, vertigo, generalized aches, muscular tremors, and mental disturbances. Alcoholics and older adults are more likely to have low vitamin B6 intakes due to poor diet and/or decreased absorption with age. Alcohol also promotes the destruction and loss of vitamin B6 from the body. Asthmatic children treated with the medicine theophylline may also 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. 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.