Vitamins, Minerals and Dietary Supplements

What is inositol? Why do we need it?

Inositol is a simple carbohydrate required for the proper formation of cell membranes. In the body, it plays an important role in the transmission of nerve impulses; it also helps in the transporting of fats within the body.

Preliminary studies have shown that inositol supplements may improve the transmission of neural signals in patients with diabetes, nerve damage and numbness. Some double-blind studies have found that it also may help patients who suffer from depression, anxiety, and obsessive-compulsive disorder.

How much inositol should I take?

Most people do not need to take inositol supplements. However, many double-trials have used a dose of 12-18 grams of inositol per day. Some practitioners recommend 500mg of inositol supplements daily.

What are some good sources of inositol? What forms are available?

Nuts, beans, citrus fruit (especially cantaloupes and oranges), nuts, rice, veal, pork and wheat germ are excellent sources of inositol. Most dietary inositol is in the form of phytate, a naturally occurring plant fiber that is believed to possess antioxidant properties.

What can happen if I don't get enough inositol? What can happen if I take too much? Are there any side-effects I should be aware of?

No clear deficiency levels for inositol have been established, although diabetic patients do have increased inositol excretion. Similarly, no toxicity levels have been established; however, people with chronic renal failure often show increased inositol levels.

Large amounts of phytate can reduced the absorption of certain minerals, particularly iron, calcium and zinc. However, inositol supplementation does not have this effect.

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References

• Benjamin J, Levine J, Fux M, et al. Double-blind, placebo-controlled, crossover trial of inositol treatment for panic disorder. Am J Psychiatry 1995;152:1084—6.
• Colodny L, Hoffman RL. Inositol – clinical applications for exogenous use. Altern Med Rev 1998;3:432—47.
• Fux M, Levine J, Aviv A, Belmaker RH. Inositol treatment of obsessive-compulsive disorder. Am J Psychiatry 1996;153:1219—21.
• Levine J, Barak Y, Kofman O, Belmaker RH. Follow-up and relapse analysis of an inositol study of depression. Isr J Psychiatry Relat Sci 1995;32:14—21.
• Sandberg A-S, Brune M, Carlsson N-G, et al. Inositol phosphates with different numbers of phosphate groups influence iron absorption in humans. Am J Clin Nutr 1999;70:240—6.