Inositol is a water soluble nutrient that is often associated with B vitamins. While its role in human nutrition is a source of ongoing debate, it was finally recognized as a vitamin in 1940. Chemically inositol is a sugar which is metabolized slowly and without the involvement of insulin. Inositol is found in cell membranes throughout the brain and central nervous system, the muscles, heart tissues, reproductive organs, and bones. It is also involved in the transportation and metabolism of fatty acids and cholesterol, and is a component of lecithin and several enzymes. This nutrient is also a hydroxyl free-radical scavenger that may aid in treating arthritis.

Animals fed a diet deficient in inositol evidence symptoms such as fatty liver deposits, intestinal disorders, and nerve damage similar to diabetes. Though such symptoms have never been observed in humans, researchers are studying this nutrient as a possible treatment for diabetes related nerve disorders.

There is no recommended daily intake, nor are there any recognized toxicity symptoms for inositol. Found in a wide range of foods, those highest in inositol include fruits, whole grains, vegetables, meats, and dairy products.