Inositol
 

Inositol Introduction

Inositol is often confused with other similar sounding nutrients, namely inositol hexaphosphate (IP-6) or inositol nicotinate, but is not the same. Inositol may be referred to as vitamin B-8, or as myo-inositol as well. Although inositol is often referred to as a B-vitamin compound, it is not a true vitamin in that small amounts are manufactured in the human body. Inositol works within cells; assisting in the processes of cellular communication, regulation of metabolism, and growth. It is known to exist in several different forms called stereoisomers, or chemicals with similar structural makeup yet different biologic function. [1] Myo-inositol is the most widely available stereoisomer of the brain.

Inositol Food Sources

Humans can manufacture some inositol in the body. This amount is biosynthesized primarily from glucose. Inositol is found widely in foods derived from both plants and animals; a standard American diet will provide roughly one gram of the nutrient per day. More specifically, inositol is found in the largest amounts in cereals, legumes, and other rich sources of dietary fiber.

Inositol Uses

Inositol in the body exists as part of the cell membrane, phospholipid arrangement. It can work as a weak lipotropic agent, meaning it has the ability to move fat from the liver and intestinal cells. [2] Because of its roles in cellular communication, inositol is used in several different neurological related conditions. Inositol plays a key role in cellular signals, which involve serotonin, norepinephrine, and cholinergic receptors in the brain. [3]

In fact, some research points to the ability of inositol to act similarly to the selective serotonin reuptake inhibitor drugs (SSRIs) in certain neurological conditions. For persons with obsessive-compulsive disorder (OCD), inositol supplementation may improve their symptoms after a minimal duration; usually several weeks of treatment. [4]

Similarly, in people with panic disorder, inositol supplementation can decrease the number and intensity of panic attacks after only 4 weeks of treatment. [5] Studies have also compared inositol to a commonly used drug for panic attacks (fluvoxamine), deeming it equally effective. [6]

Inositol occupies an interesting niche as well; in that it appears to alleviate psoriasis that is made worse by lithium therapy. [7] While its pathology is not entirely known, it has been theorized that lithium-induced psoriasis may be caused by lithium’s ability to reduce inositol in the brain and other areas of the body. Taking inositol and lithium together will not affect lithium’s efficacy. [8]

One of inositol’s isomers, D-chiro-inositol may assist women with polycystic ovarian syndrome (PCOS) in ovulation. Researchers speculate that the over production of insulin and genetic factors are to blame for the onset of this condition. Although there is no treatment for genetic predisposition, D-chiro-inositol may improve insulin sensitivity. [9] By decreasing insulin sensitivity, other symptoms related to PCOS (i.e. high blood pressure, hyperlipidemia, obesity, diabetes, and elevated testosterone levels) are improved as well. [10]

Inositol Dosages

Dosage of inositol varies and no particular recommended dosages exist. However, for treatment of obsessive-compulsive disorder, 18 grams per day has been used with varying success. [11]

In panic disorder, 12 to 18 grams per day is a common dosage. [12, 5] In depression, 12 grams per day has been used.[13]

Treatment of lithium-induced psoriasis utilized 6 grams per day. In PCOS, 1200 milligrams per day of the inositol isomer, D-chiro-inositol was used for treatment in numerous clinical applications. [14, 15]

Inositol Deficiencies and Toxicities

Inositol Deficiency

Because inositol is manufactured in the body, no established conditions of deficiency are known to exist. However, inadequate production may lead to subtle deficiencies in healthy function at the cellular level, with negative health ramifications that may not be immediately attributable to this compound.

Inositol Toxicity

Supplemental dosing of inositol is generally without side effects. However, when side effects do occur they have been reported to include fatigue, headaches, nausea and dizziness. [6, 14]

References

1. Colodny L, Hoffman RL. Inositol–clinical applications for exogenous use. Altern Med Rev 1998;3:432-47.

2. Levine J. Controlled trials of inositol in psychiatry. Eur Neuropsychopharmacol 1997;7:147-55.

3. Benjamin J, Agam G, Levine J, et al. Inositol treatment in psychiatry. Psychopharmacol Bull 1995;31:167-75.

4. Fux M, Levine J, Aviv A, Belmaker RH. Inositol treatment of obsessive-compulsive disorder. Am J Psychiatry 1996;153:1219-21.

5. 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.

6. Palatnik A, Frolov K, Fux M, Benjamin J. Double-blind, controlled, crossover trial of inositol versus fluvoxamine for the treatment of panic disorder. J Clin Psychopharmacol 2001;21:335-9.

7. Allan SJ, Kavanagh GM, Herd RM, Savin JA. The effect of inositol supplements on the psoriasis of patients taking lithium: a randomized, placebo-controlled trial. Br J Dermatol 2004;150:966-9.

8. Allan SJ, Kavanagh GM, Herd RM, Savin JA. The effect of inositol supplements on the psoriasis of patients taking lithium: a randomized, placebo-controlled trial. Br J Dermatol 2004;150:966-9.

9. Nestler JE, Jakubowicz DJ, Reamer P, et al. Ovulatory and metabolic effects of D-chiro-inositol in the polycystic ovary syndrome. N Engl J Med 1999;340:1314-20.

10. Nestler JE, Jakubowicz DJ, Reamer P, et al. Ovulatory and metabolic effects of D-chiro-inositol in the polycystic ovary syndrome. N Engl J Med 1999;340:1314-20.

11. Fux M, Levine J, Aviv A, Belmaker RH. Inositol treatment of obsessive-compulsive disorder. Am J Psychiatry 1996;153:1219-21.

12. Palatnik A, Frolov K, Fux M, Benjamin J. Double-blind, controlled, crossover trial of inositol versus fluvoxamine for the treatment of panic disorder. J Clin Psychopharmacol 2001;21:335-9. 5 Ibid

13. Levine J, Barak Y, Gonzalves M, et al. Double-blind, controlled trial of inositol treatment of depression. Am J Psychiatry 1995;152:792-4.

14. Allan SJ, Kavanagh GM, Herd RM, Savin JA. The effect of inositol supplements on the psoriasis of patients taking lithium: a randomized, placebo-controlled trial. Br J Dermatol 2004;150:966-9.

15. Nestler JE, Jakubowicz DJ, Reamer P, et al. Ovulatory and metabolic effects of D-chiro-inositol in the polycystic ovary syndrome. N Engl J Med 1999;340:1314-20. 6 Ibid 14 Ibid