Pyridoxine is a natural diuretic and is often helpful not only for the previously mentioned premenstrual problems but also in overweight and fluid-retaining people and as an adjunct to blood pressure control. Vitamin B6 (along with magnesium) has received some note in regard to preventing the formation of kidney stones or the recurrence of stones in those who have had them. In his book Nutrition and Vitamin Therapy (Grove Press, 1980), Michael Lesser, M.D., states that in a study reported in 1974 by the Journal of Urology, 10 mg. of vitamin B6 and 300 mg. of magnesium oxide prevented recurrence in about 80 percent of patients with a long history of kidney and urinary tract stone formation. Dr. Lesser also noted that the B6-magnesium combination helps in some hyperactive kids and those with fits or problems of autism. He states that pyridoxine in fairly large doses will stimulate dream activity as well as reduce the potential toxicity of barbiturate drugs, carbon monoxide and some other chemical exposures, and irradiation. Vitamin B6 works best when taken with magnesium, zinc, riboflavin, and brewer's yeast or the other B vitamins.

Pyridoxine, probably more than the other B vitamins except folic acid, is supportive of healthy immune function. B6 deficiency can produce immune weakness, and B6 treatment may be helpful against infections and cancer. Recent studies have shown that pyridoxine can inhibit the growth of some cancer cells, specifically mice and human melanoma cells. Further research with B6 will likely find an even wider range of uses.

Deficiency and toxicity: There is basically no toxicity with pyridoxine at reasonable daily dosages, though there has been some recent concern about this. Regular oral intake of 200 mg. and intravenous doses of 200 mg. have shown no side effects. Usually, the toxic doses are much higher, between 2Ð5 grams. Some recent reports in the medical literature show that regular usage of over 2,000 mg. per day, which some women especially have been taking, are correlated with episodes of peripheral neuritis. Although the experience of weakness or tingling of arms or legs has been transient and mostly correctable by decreasing the B6 dosage, this does warrant some concern about excessive use of B6, especially long-term use. Since part of the neuropathy problem comes from the liver's inability to convert all of the pyridoxine to active P5P, this concern can be lessened by supplementing some of the B6 as pyridoxal-5-phosphate (as I have done in many of my programs), especially when the dose of vitamin B6 exceeds 200 mg. per day. In addition, using increased amounts of magnesium with the higher levels of vitamin B6 will reduce the occurrence of the peripheral neuritis.

Deficiency, as usual, is a bigger concern with vitamin B6, as it is with all the B vitamins. So many functions are performed by pyridoxine that its deficiency affects the whole body. Most of these deficiency symptoms are fairly vague. Muscle weakness, nervousness, irritability, and depression are not uncommon. Many of the symptoms are similar to those of both niacin and riboflavin deficiencies; depression is common in all of them.

Metabolically, pyridoxine deficiency has a dramatic effect on amino acid metabolism, with a decreased synthesis of niacin from tryptophan, a decrease in neurotransmitter chemicals, and a decrease in hemoglobin production. Fatigue, nervous system symptoms, and anemia are all influenced by deficiency. Further nerve-related problems include paraesthesia, incoordination, confusion, insomnia, hyperactivity, and, more severely, neuritis, electroencephalogram (EEG) changes, and convulsions. Other problems include dermatitis or cracks and sores at the corners of the mouth and eyes and visual disturbances.