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Phytic acid is an antinutrient that interferes with the absorption of minerals from the diet.

Antinutrients are natural or synthetic compounds that interfere with the absorption of nutrients.^[1] Nutrition studies focus on those antinutrients commonly found in food sources and beverages.

One common example is phytic acid, which forms insoluble complexes with calcium, zinc, iron and copper.^[2] Proteins can also be antinutrients, such as the trypsin inhibitors and lectins found in legumes.^[3] These enzyme inhibitors interfere with digestion. Another particularly widespread form of antinutrients are the flavonoids, which are a group of polyphenolic compounds that include tannins.^[4] These compounds chelate metals such as iron and zinc and reduce the absorption of these nutrients, but they also inhibit digestive enzymes and may also precipitate proteins. However, polyphenols such as tannins have anticancer properties, so foods such as green tea that contain large amounts of these compounds might be good for the health of some people despite their antinutrient properties.^[5]

Antinutrients are found at some level in almost all foods for a variety of reasons. However, their levels are reduced in modern crops, probably as an outcome of the process of domestication.^[6] Nevertheless, the large fraction of modern diets that come from a few crops, particularly cereals, has raised concerns about the effects of the antinutrients in these crops on human health.^[7] The possibility now exists to eliminate antinutrients entirely using genetic engineering; but, since these compounds may also have beneficial effects (such polyphenols reduce the risk of cancer, heart disease or diabetes), such genetic modifications could make the foods more nutritious but not improve people's health.^[8]

Many traditional methods of food preparation such as fermentation, cooking, and malting increase the nutritive quality of plant foods through reducing certain antinutrients such as phytic acid, polyphenols, and oxalic acid.^[9] Such processing methods are widely-used in societies where cereals and legumes form a major part of the diet.^[10][11] An important example of such processing is the fermentation of cassava to produce cassava flour: this fermentation reduces the levels of both toxins and antinutrients in the tuber.^[12]

See also

• Antimetabolite

References

Further reading

• Shahidi, Fereidoon (1997). Antinutrients and phytochemicals in food. Columbus, OH: American Chemical Society. ISBN 0-8412-3498-1.