Definitions

phytic-acid

Phytic acid

[fahy-tik, fit-ik]
IP6 redirects here. For the Internet Protocol, see IPv6

Phytic acid (known as inositol hexakisphosphate (IP6), or phytate when in salt form) is the principle storage form of phosphorus in many plant tissues, especially bran and seeds.

Inositol penta- (IP5), tetra- (IP4), and triphosphate (IP3) are also called phytates.

Significance in agriculture

Phosphorus in phytate form is, in general, not bioavailable to non-ruminant animals because they lack the digestive enzyme phytase, which is required to separate phosphorus from the phytate molecule. On the other hand, ruminants readily utilize phytate because of the phytase produced by rumen microorganisms.

In most commercial agriculture, non-ruminant livestock such as swine and fowl are fed mainly grains such as soybeans and maize. Because phytate from these grains is unavailable for absorption, the unabsorbed phytate passes through the gastrointestinal tract, elevating the amount of phosphorus in the manure. Excess phosphorus excretion can lead to environmental problems such as eutrophication.

The bioavailability of phytate phosphorus can be increased by supplementation of the diet with phytase enzyme. Also, viable low-phytic acid mutant lines have been developed in several crop species in which the seeds have drastically reduced levels of phytic acid and concomitant increases in inorganic phosphorus. However, reported germination problems have hindered the use of these cultivars thus far.

Phytates also have the potential to be used in soil remediation, to remove uranium, nickel and other inorganic contaminants.

Food science

Phytic acid is found within the hulls of nuts, seeds, and grains. In-home food preparation techniques can reduce the phytic acid in all of these foods. Simply cooking the food will reduce the phytic acid to some degree. More effective methods are soaking in an acid medium, lactic acid fermentation, and sprouting.

Phytic acid is a strong chelator of important minerals such as calcium, magnesium, iron, and zinc, and can therefore contribute to mineral deficiencies in people whose diets rely on these foods for their mineral intake, such as those in developing countries. It also acts as an acid, chelating the vitamin niacin, which is basic, causing the condition known as pellagra. In this way, it is an anti-nutrient. For people with a particularly low intake of essential minerals, especially young children and those in developing countries, this effect can be undesirable.

"Probiotic lactobacilli, and other species of the endogenous digestive microflora as well, are an important source of the enzyme phytase which catalyses the release of phosphate from phytate and hydrolyses the complexes formed by phytate and metal ions or other cations, rendering them more soluble ultimately improving and facilitating their intestinal absorption

Ascorbic Acid (vitamin C) can reduce phytic acid effects on iron

Food sources of Phytic Acid
Food [% minimum dry] [% maximum dry]
Tofu 1.46 2.90
Linseed 2.15 2.78
Oat Meal 0.89 2.40
Soy flour 1.24 2.25
Soybeans 1.00 2.22
Corn 0.75 2.22
Peanuts 1.05 1.76
Kidney beans 0.89 1.57
Rye 0.54 1.46
Oat bran 0.60 1.42
Wheat flour 0.25 1.37
Wheat 0.39 1.35
Oat 0.42 1.16
Barley 0.38 1.16
Whole wheat bread 0.43 1.05
Polished rice 0.14 0.60

Therapeutic uses

Phytic acid may be considered a phytonutrient, providing an antioxidant effect. Phytic acid's same mineral binding properties may also prevent colon cancer by reducing oxidative stress in the lumen of the intestinal tract. Researchers now believe that phytic acid, found in the fiber of legumes and grains, is the major ingredient responsible for preventing colon cancer and other cancers.

Phytic acid's chelating effect may serve to prevent, inhibit, or even cure some cancers by depriving those cells of the minerals (especially iron) they need to reproduce. The deprivation of essential minerals like iron would, much like other broad treatments for cancers, also have negative effects on non-cancerous cells. It is unknown whether this would affect other cells in the body that require iron (such as red blood cells) or whether the deprivation of minerals is more localized to the internal colon region.

Phytic acid has no known toxicity and is not known to cause mutagenic activity. It may have more therapeutic value when added to water rather than when naturally absorbed in foods, as it is difficult to free from fiber.

Phytic acid is one of few chelating therapies used for uranium removal.

As a food additive, phytic acid is used as a preservative with E number E391.

Food must be well cooked in order to free IP6 from the fiber and enable it to be absorbed in the gastrointestinal system. IP6 rarely appears in soluble fiber. It is usually attached to the bran, the hard (insoluble) fiber, which is difficult to digest. IP6 is found in legumes, peas, wheat, barley, and oats. Of any studied legumes, whole soybeans have the highest levels of phytic acid.

Those who argue for the beneficial effects of phytic acid and freeing it up for interaction with the system through cooking, do not argue that cooking destroys the phytic acid;this is a major difference between those arguing for the merits of processed grain products.

References

See also

External links

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