Inositol Hexaphosphate DESCRIPTION
Inositol hexaphosphate, also known as phytate, is a component of most cereal grains and seeds, occurring in conjunction with plant fiber, and is a source of myo
-inositol in the diet. Inositol hexaphosphate is responsible for storing more than 80 percent of the total phosphate in cereals and legumes. Phytate has strong chelating power for doubly charged metal ions, such as magnesium, calcium and zinc. Some studies suggest that phytate may slow tumor growth rates.
Inositol hexaphosphate, in addition to being known as phytate, is known as myo
-inositol hexaphosphate, and myo
-inositol 1,2,3,4,5,6-hexakisphosphate. Inositol hexaphosphate is abbreviated as InsP6 and sometimes as IP-6. The structural formula is:
Inositol hexaphosphateACTIONS AND PHARMACOLOGY ACTIONS
Inositol hexaphosphate is a putative antiproliferative agent and may have antioxidant activity. MECHANISM OF ACTIONS
Some speculate that inositol hexaphosphate's possible antiproliferative activity is due to its chelating divalent cations which may be important for tumor growth. Others speculate that inositol hexaphosphate, along with inositol, are metabolized to inositol triphosphates, which are believed to be involved in cell signaling and regulating cell growth, and that this may underlie its possible effects. Chelation by inositol hexaphosphate of ferrous cations could inhibit the Fenton reaction, a reaction which generates reactive oxygen species. Enhancement of natural killer cell activity is offered as still another speculative mechanism. PHARMACOKINETICS
It is unclear how much inositol hexaphosphate is absorbed in humans following ingestion. Inositol hexaphosphate may, in part, be hydrolyzed to myo
-inositol. (See myo
-inositol.) INDICATIONS AND USAGE
There is preliminary evidence that inositol hexaphosphate may eventually find some use in the treatment of some cancers. RESEARCH SUMMARY
A few studies performed in vitro
and in animal models suggest that inositol hexaphosphate inhibits some cancers, specifically epithelial cancers, including breast and colon cancers. It has also significantly inhibited human rhabdomyosarcoma in an animal model. More research is needed to see whether this substance can play a role in the clinical treatment of some cancers. There is some epidemiologic data suggesting that dietary phytate may have chemopreventive activity. CONTRAINDICATIONS, PRECAUTIONS, ADVERSE REACTIONS CONTRAINDICATIONS
None known. PRECAUTIONS
Supplemental inositol hexaphosphate should be avoided by pregnant women and nursing mothers, due to lack of long-term safety studies. ADVERSE REACTIONS
No significant adverse effects were noted in one report on the use of a daily dose of 8.8 grams of inositol hexaphosphate taken for several months. INTERACTIONS
Inositol hexaphosphate may form chelates with divalent cations such as calcium, magnesium, manganese, zinc, copper and iron found in foods, if taken with foods or nutritional supplements containing these elements. It may also interact with food proteins. OVERDOSAGE
No reports of overdosage. DOSAGE AND ADMINISTRATION
None recommended. LITERATURE
Graf E, Eaton JW. Antioxidant function of phytic acid. Free Rad Biol Med
. 1990; 8:61-69.
Jariwalla RJ, Sabin R, Lawson S, Herman ZS. Lowering of serum cholesterol and triglycerides and modulation by dietary phytates. J Appl Nutr
. 1990; 42:18-28.
Jariwalla RJ, Sabin R, Lawson S, et al. Effect of dietary phytic acid (phytate) on the incidence and growth rate of tumors promoted in Fisher rats by magnesium supplement. Nutr Res
. 1988; 8:813-827.
Porres JM, Stahl CH, Cheng W-H, et al. Dietary intrinsic phytate protects colon from lipid peroxidation in pigs with a moderately high dietary iron intake. Proc Soc Exp Biol Med
. 1999; 221:80-86.
Shamsuddin AM. Inositol phosphates have novel anticancer function. J Nutr
. 1995; 125:725S-732S.
Shamsuddin AM. Reduction of cell proliferation and enhancement of NK-cell activity. 1992. United States Patent Number 5,082,833.
Vucenik I, Kalebic T, Tantivejkulk, Shamsuddin A. Novel anticancer function of inositol hexaphosphate. Inhibition of human rhabdomyosarcoma in vitro
and in vivo
. Anticanc Res
. 1998; 18:1377-1384.