Evidence that diet plays a role in the development of cancer is stronger for some cancers than others, in particular, breast and colon cancers. There is an inverse association between risk for these two cancers and foods high in fiber content. But studies show that the type of fibrous food makes a difference. The reduction in cancer risk may be due to another component besides fiber.
Phytic acid is one possibility. Some research suggests that the low incidence of breast cancer among Asian women may be due to soybeans that are high in phytic acid as well as fiber. Some scientists also believe that the lower cancer rates among people who eat a lot of unrefined cereal grains may be due to phytic acid, not the fiber content. Phytic acid (also known as inositol hexaphosphate or IP6) is a naturally occurring substance found in considerable quantities in unrefined grains, like wheat, corn and rice, as well as beans, nuts and seeds.
A Growing Consensus
Although phytic acid has shown an ability to halt abnormal cell proliferation and shrink tumors in laboratory studies within the last 15 years, its good reputation is still being established. For a long while, phytic acid was considered an anti-nutrient for its ability to bind with important minerals, like calcium, magnesium, iron and zinc, inhibiting the body from absorbing them. But according to molecular biologist, Ivana Vucenik, Ph.D., "In a normal western diet, this does not happen. Only in areas like India and South America where there is malnutrition and diets low in minerals can phytic acid act negatively if present in very large quantities."
Despite some nutritionists who still consider phytic acid an anti-nutrient, Dr. Vucenik says, "Through meetings and collaborations the field of nutrition is gradually coming to consensus that it is beneficial."
She thinks the many good effects will finally persuade others of phytic acid's nutritional importance. In addition to its cancer-fighting effects, phytic acid has also shown an ability to help prevent kidney stones and avert heart disease by lowering high blood cholesterol levels. These effects are mostly the result of its strong antioxidant properties and the ability to affect cell signaling and cell cycle regulation.
Discovering the Mechanisms
AICR awarded a grant to Dr. Vucenik to study one of the mechanisms by whichphytic acid might act to prevent cancer. These mechanisms are still largely unknown. Dr. Vucenik says, "Our preliminary data have shown that one way phytic acid fights cancer is reducing angiogenesis. Angiogenesis is the formation of new blood vessels. Without creating new blood vessels, a tumor can't grow greater than 1 centimeter."
This groundbreaking work will use both in vivo and in vitro (animal and test tube) models to show that phytic acid can affect the function of blood vessel and tumor cells. In her previous research with animals, Dr. Vucenik discovered an even more potent anti-cancer effect from a mixed supplement of phytic acid and its unmodified parent form, inositol. Although supplements for these substances are available, whole grains, beans, nuts and seeds are better sources because they provide other nutrients.
El-Sherbiny Y et al. G0/G1 arrest and S phase inhibition of human cancer cell lines by inositol hexaphosphate (IP6). Anticancer Res. 2001;21:2393-2404.
Vucenik I et al. Inositol hexaphosphate and inositol inhibit DMBA-induced rat mammary cancer. Carcinogenesis. 1995;16:1055-58.
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