Inositol (Vitamin B complex)

Inositol is a naturally occurring isomer of glucose, though it is generally considered to be a member of the B vitamin family. It is a key intermediate in the intracellular phosphatidyl inositol second messenger pathway activated by numerous serotonergic, cholinergic, and noradrenergic receptors. (1) In this capacity it serves as an important signal transduction molecule, but inositol is also a structural component of cellular membrane phospholipids. (2) Research indicates that inositol is an effective and safe option in the treatment of panic disorder, obsessive-compulsive disorder (OCD), bulimia nervosa, binge eating and/or depression. (3-9) Inositol's efficacy, in the absence of side effects, makes this nutrient an attractive addition to treatment plans for specific mood disorders. Following is a scientific review of inositol for the treatment of mood disorders, including a discussion of its anecdotal use for the treatment of insomnia and its cautioned use by pregnant women for the prevention of neural tube defects and embryopathies.

Inositol occurs naturally as phytic acid in the fiber component of numerous plant foods, especially whole grains, citrus fruit, nuts, and seeds, and as myoinositol in meat. In the intestinal tract, bacteria break down phytic acid into bioavailable inositol that is easily absorbed via the intestinal epithelium. Myoinositol is found to bioaccumulate most abundantly in the central nervous system, supporting a role for it in neurological function.

Inositol in Food
inositol in the form of phytic acid has been proposed as a possible agent in the cancer-fighting potential of whole grains. (10) The compound is heat- and acid-stable and is found in high concentration in many food items, including cereal grains, nuts, and seeds.

1. Belmaker, R. H. et al. 1995. Manipulation of inositol-linked second messenger systems as a therapeutic strategy in psychiatry. Adv Biochem Psychopharmacol 49: 67-84.
2. Hooper, N. 1997. Glycosyl-phosphatidylinositol anchored membrane enzymes. Clin Chim Acta 266(1): 3-12.
3. Levine, J. 1997. Controlled trials of inositol in psychiatry. Eur Neuropsychopharmacol 7(2): 147-155.
4. Levine, J. et al. 1995. Double-blind, controlled trial of inositol treatment of depression. Am J Psychiatry 152(5): 792-794.
5. Benjamin, J. et al. 1995a. Double-blind, placebo-controlled, crossover trial of inositol treatment for panic disorder. Am J Psychiatry 152(7): 1084-1086.
6. Benjamin, J. et al. 1995b. Inositol treatment in psychiatry. Psychopharmacol Bull 31(1): 167-175.
7. Gelber et al. 2001. Effect of inositol on bulimia nervosa and binge eating. Int J Eat Disord. 29(3):345-8.
8. Palatnik, A. et al., 2001. Double-blind, controlled, crossover trial of inositol versus fluvoxamine for the treatment of panic disorder. J Clin Psychopharmacol 21(3): 335-339.
9. Fux, M. et al. 1996. inositol treatment of obsessive-compulsive disorder. Am J Psychiatry 153(9): 1219-1221.
10. Graf, E. and J. W. Eaton. 1993. Suppression of colonic cancer by dietary phytic acid. Nutr Cancer 19(1): 11-19