INOSITOL

General - water-soluble; muscle sugar;

• Exists in 9 different, natural, optically inactive or active forms; only one optically active form, myo-inositol (muscle sugar), possesses biological activity;
• In plant cells, inositol occurs in the hexaphosphate form, phytic acid, that binds calcium, iron & zinc, preventing their absorption from the digestive tract;
• Inositol is a lipotropic factor — promotes the metabolism of fats in the liver; along with choline, it occurs in high concentrations in lecithin preparations;
• History: recognized as growth-promoting factor for yeast in 1928; recognized as cure for hair loss in mice in 1941;

Nutrition

• Sources: heart, meats, fruit, milk, nuts, vegetables, whole grains; made in the body from glucose; present as phytate (hexa-phosphate inositol) in plants;
• Supplements: lipotropic, B-complex, multi-vitamin & multi-mineral-vitamin formulations;
• Absorption: from small intestine; can also be synthesized from glucose by the body; can be synthesized by intestinal bacteria;
• Antagonized by: coffee (which can deplete stored inositol), mineral oil & antibiotics;
• Storage: in heart, brain, nerves, liver & muscle;
• Excretion: through urine;
• Metabolism: part of membrane phospholipids (phosphatidyl inositol); diabetics excrete much higher quantities of inositol & their needs for it are higher;
• Interactions: sulphonamides increase need;

Functions of inositol

• Functions primarily at membrane level; as phosphatidyl inositol, has special response functions in various cells to external stimuli, e.g. hormones & neurotransmitters;
• Has close relationship with choline, biotin, B-6, folic acid, B-5 & PABA;
• May be involved in membrane permeability to Ca++;
• May have special functions in nerve & secretory cells;
• May be involved in mobilizing fats from liver;
• May help control blood & tissue levels of cholesterol;
• May prevent fatty deposits in the heart, liver & blood vessels
• May be involved in carbohydrate metabolism;
• Essential for growth of liver & bone marrow cells;
• May have beneficial effects on nerves, alleviating anxiety & insomnia;
• May have role in sperm production;
• Important in lecithin formation;

Quantities

• Measurement: in milligrams;
• Optimum: (SONA) averages not yet established;
• Individual optimum must be determined on an individual basis;
• Minimum: (DRI) has not been set; inositol is not an essential nutrient, because it can be made within the body;
• Deficiency of inositol may result from inadequate diet, inadequate absorption, inadequate endogenous production, abnormal bowel flora;
• At risk: people with diabetes mellitus; chronic renal failure; galactosemia; multiple sclerosis;
• Symptoms may include: atherosclerotic plaques; high blood cholesterol & fat deposition in intestinal mucousa cells (gerbils); fatty degeneration of liver; nerve damage; irregularities in fat metabolism; dermatitis, weight loss & death (in gerbils);
• Sub clinical deficiency symptoms may include alopecia (hair loss); constipation; eczema; saturated fats more detrimental than unsaturated in inositol deficiency; transport of lipoproteins from liver to blood may be impeded;
• Toxicity: none associated even with high intake of inositol;

Therapy with inositol

• 100 to 1,000 mg/day commonly used;
• Lowers serum cholesterol, stops hair loss & controls allergic reactions in the brain that result in abnormal behaviour;
• Part of lipotropic formula, for preventing fatty degeneration of liver & other inner organs;
• Improves peripheral neuropathy & sensory nerve function in diabetics;
• Stimulates contractions of intestinal tract, alleviating constipation;
• Has sedative-like effect that may be beneficial in insomnia;
• May help to lower high blood pressure;
• May be helpful in schizophrenia, hypoglycaemia, high copper & low zinc;