Supplements

Vitamin B6 (Pyridoxine)

Vitamin B6 is involved in more bodily functions than almost any other single nutrient. Vitamin B6 is a water-soluble vitamin that occurs naturally in three forms: pyridoxine (PN), pyridoxal (PL), and pyridoxamine (PM). This vitamin is non-toxic as long as you match high doses with similar amounts of the other B-complex vitamins and with a magnesium supplement. The vitamin is indispensable for manufacturing prostaglandins, the hormone-like compounds whose innumerable functions include dilating blood vessels and opening bronchial passages.

Treatment for epilepsy, attention deficit disorder and autism are among the neural disorders where at least partial success depends upon pyridoxine supplementation. In a review of eighteen different clinical studies on autistic children given high doses of B6, half of them benefited. It also plays a pivotal role in making norepinephrine and serotonin, brain chemicals responsible for feelings of well-being.

Asthma, acne, seborrheic dermatitis, and malignant melanoma respond well to B6 treatments.

Pyridoxine plays a major role in maintaining a balance of female hormones. It converts estradiol, (a form of estrogen) into estriol, its least harmful and least carcinogenic form, thereby counteracting one cause of cancer in women. It may be used to treat uterine fibroids, endometriosis, or fibrocystic breast disease for these same reasons. Because it is a natural diuretic it can relieve premenstrual syndrome and lower blood pressure.

Many women contend with an overgrowth of the Candida albicans yeast, and of those, two-thirds don't metabolize pyridoxine properly. The yeast prevents the body from converting B6 into its active form, pyridoxal-a5-phosphate.

A high blood sugar level, which is a blood test called glycosylated hemoglobin, indicates diabetes-related cellular harm. Taking B6 supplements can help to metabolize blood glucose and fight eye damage and vision loss from diabetic retinopathy. Diabetes drastically raises the risk of heart disease. B6, coupled with folic acid and vitamin B-12 help to reduce homocysteine levels (an amino acid whose elevated level in the blood corresponds to greater rates of strokes and heart attacks).

Deficiency: A deficiency in B6 can lead to tissue damage, inflammation, schizophrenia, and even cancer. In addition, low levels of B6 can cause blood thickening and clotting, which can block arteries. Other signs of deficiency include premenstrual syndrome, irritability, depression, impaired immune system, cataracts, eczema, high cholesterol, Parkinson's disease, and arthritis.

A vitamin B6 deficiency has been profoundly linked to a number of mental disorders, including clinical depression and schizophrenia.

Depleting Agents: Antidepressants, alcohol, oral contraceptives, estrogen, most drugs, stress. Diuretics and cortisone drugs block the absorption of this vitamin.

Precautions: Long term high doses, over 1,000 milligrams per day, and a little as 500 milligrams per day, of vitamin B6 can be toxic, and may result in nerve damage and loss of coordination. Vitamin B6 should be taken with its companion vitamin Bs in equal dosages and with a magnesium supplement to prevent sensory neuropathy.

Sources: The highest amounts of vitamin B6 are found in brewer's yeast, carrots, chicken, eggs, fish, meat, peas, spinach, sunflower seeds, walnuts, and wheat germ. Other sources include avocado, bananas, beans, blackstrap molasses, broccoli, brown rice and whole grains, cabbage, cantaloupe, corn, dulse, oatmeal, plantains, potatoes, rice bran, soybeans, and tempeh.

Herb Sources: Alfalfa, catnip and oat straw.

Dosage Ranges and Duration of Administration: As one's protein intake increases, so too does the requirement for vitamin B6. The RDA for vitamin B6 has been established as that needed for two times the RDA of protein intake.

RDA:

• Neonates to 6 mos.0.3 mg
• Infants 6 mos. to 1 year0.6 mg
• Children: 1 to 3 years1.0 mg
• 4 to 6 years1.1 mg
• 7 to 10 years1.4 mg
• Boys: age 11 to 14 years1.7 mg
• Men: age 15 years +2.0 mg
• Girls: age 11 to 14 years1.4 mg
• Women age 15 to 18 years1.5 mg
• Women age 19 years +1.6 mg
• Pregnant women2.2. mg
• Lactating women2.1 mg

A large number of people cannot convert B6 to pyridoxal-5-phosphate (P-5-P), the form that the body requires. For this reason at least 20 percent of our daily intake should be taken in the activated form. When repetitive stress injuries and carpal tunnel syndrome do not respond to standard B6 supplementation, the activated form is more potent, requiring approximately one-fifth the dosage, or between 25 and 100 mg daily. For general health protection, 50 mg a day is recommended, and for any specific conditions associated with a lack of B6, a better dosage range is 100-400 mg.

INTERACTIONS

Cycloserine, Isoniazid
Antituberculosis medications such as cycloserine and isoniazid (INH) reduce the pyridoxine blood levels and may lead to peripheral neuritis. Supplementation with vitamin B6 during therapy with either of these medications prevents the development of both deficiency and peripheral neuropathy.

Erythropoietin
In one study, 13 stable patients on chronic hemodialysis received pyridoxine (5 mg/day) in combination with erythropoietin (EPO). EPO therapy increased hemoglobin synthesis, which decreased erythrocyte pyridoxine status.The pyridoxine concentration in erythrocytes was restored by increasing the dose to 20 mg/day. Supplementation with pyridoxine may be warranted in EPO-treated patients.

Fluorouracil
Administration of vitamin B6 (50 to 150 mg/day) during treatment with 5-FU has been reported to reverse 5-FU-induced palmar-plantar erythrodysesthesia without any adverse effects or interruption of chemotherapy. Palmar-plantar erythrodysesthesia, a skin condition that can make holding objects, driving, or walking painful, may occur in cancer patients undergoing continuous infusions of 5-FU.

Hydralazine
In the presence of pyridoxine, the hypotensive effects of hydralazine are diminished.

Levodopa
Vitamin B6 reduces the therapeutic effects of levodopa by increasing the intestinal metabolism of levodopa to dopamine. The anti-Parkinson effect of levodopa is decreased as a result of the inability of dopamine to cross the blood brain barrier. This antagonistic interaction between pyridoxine and levodopa is more likely to occur at higher pyridoxine doses. It is suggested that pyridoxine supplements not be taken with levodopa.

Monoamine Oxidase Inhibitors (MAOIs)
There have been case reports of MAOIs such as tranylcypromine and phenelzine interfering with vitamin B6 and reducing blood levels of this nutrient. MAOI-induced decreases in pyridoxine status have been associated with peripheral neuropathy and carpal tunnel syndrome, both of which respond well to pyridoxine supplementation.

Nortriptyline
Supplementation with vitamins B1, B2, and B6 (10 mg each) at the start of tricyclic antidepressant therapy improved cognitive functioning and depression ratings in 14 geriatric patients undergoing treatment with nortriptyline. B vitamins may augment the treatment of depression in elderly patients.

Oral Contraceptives
Oral contraceptives deplete vitamin B6 levels, possibly through induction of tryptophan oxidase. Side effects such as depression may be due to altered metabolism of vitamin B6 and other B vitamins. Please refer to the depletions monograph on oral contraceptives for additional information.
Penicillamine
In a study involving 144 rheumatoid arthritis patients treated with penicillamine (125 to 1000 mg/day), 17% developed vitamin B6 deficiency; however, there were no clinical signs of deficiency. Chronic penicillamine therapy may warrant monitoring of pyridoxine status.

Phenobarbital, Phenytoin
A study with 27 epileptic patients aged 15 to 54 who received phenobarbitone (90 mg/day phenobarbital) and diphenylhydantion (300 mg/day phenytoin) regularly for 3 to 32 years noted that serum levels of vitamin B6 and B12 were increased significantly relative to controls. Increased serum vitamin levels may be indicative of hepatic damage from anticonvulsant therapy. However, supplementation with vitamin B6 may decrease the pharmacologic effects of phenytoin.

Tetracycline
In one study, the bioavailability of tetracycline hydrochloride was reduced significantly by concomitant administration of vitamin B complex to healthy subjects. Patients should be cautioned to take vitamin B complex supplements at different times from tetracycline.

Theophylline
Slow-release theophylline lowered serum vitamin B6 levels by 40% in 16 asthmatic children treated this medication for over a year.