Phytic acid (or phytate when in salt form) is a substance found in many foods, but especially soybeans and soy products, oatmeal, corn, peanuts, kidney beans, whole wheat, and rye. In the human gut, it acts as a chelator and an anti-nutrient. It reduces the absorption of valuable vitamins and minerals such as niacin, calcium, iron, magnesium, and zinc.
Relatively high concentrations of phytates occur in the following foods. Soaking, fermenting or sprouting beans and grains will neutralize much of the phytic acid, except in soybeans, which must be cooked for more than 10 hours at very high temperatures to remove the anti-nutrients. Cooking helps reduce it in the vegetables:
- Most whole-grain cereal foods (wheat, rye, rice, oats)
- Nuts and seeds (pumpkin, sunflower)
- Soybeans, other types of beans
Phytic Acid Health Effects
High consumption of improperly prepared phytate heavy foods can result in mineral and niacin deficiencies. This is particularly true for those with low mineral intakes, including children and people in developing countries where grain-based foods make up the majority of the diet.
Loren Cordain, an anthropologist at Colorado State University writes this about cereal grains, which are high in phytic acid:
“For the vast majority of mankind’s presence on this planet, he rarely if ever consumed cereal grains. With the exception of the last 10,000 years following the agricultural ‘revolution’, humans have existed as non-cereal-eating hunter-gatherers since the emergence of Homo erectus 1.7 million years ago… the inability of humans to physiologically overcome cereal grain anti-nutrients such as phytates, alkylresorcinols, protease inhibitors, and lectins is indicative of the evolutionary novelty of this food for our species.”
Laura Johnson Kelley, an anthropologist at Cornell University in New York has pointed out that skeletal abnormalities increased in human populations as they began to cultivate and consume grains, and that celiac disease (an inability to digest grain foods) in Europe is linked to the spread of grain-based agriculture.
This, I think, is due to the smaller amounts of digestible, available nutrients in grain seeds and bran, the niacin and mineral binding abilities of phytic acid, and the poisonous effects of lectin proteins present in improperly prepared whole-grain foods. As grain consumption went up, mineral loss increased, which resulted in skeletal abnormalities.
Phosphorus, which is bound in grain phytates as an insoluble salt, cannot be absorbed by humans and other non-ruminant animals (like pigs and chickens) because of the lack of the digestive enzyme, phytase, required to separate phosphorus from the phytate molecule.
In most commercial factory farms, non-ruminant livestock such as pigs and poultry are fed a diet rich in soybeans and corn. Because the phytate from these foods cannot be broken down, it passes through the gastrointestinal tract of these animals and elevates the amount of phosphorus in the manure excreted.
Excess phosphorus excretion can lead to environmental problems such as eutrophication, a process in which the concentrations of phosphorus and nitrogen increase in nearby lakes and ponds. This causes an overgrowth of algae which covers the surface of the lake. It blocks off the light, and reduces the dissolved oxygen, resulting in the death of fish and other wildlife-dependent upon these factors.
Some Health Benefits?
Excess iron is known to have disease-causing effects, so the fact that phytate prevents some of the iron absorptions may actually be a good thing. Phytic acid is also an antioxidant (like vitamin C).
Some research suggests that phytate has the potential ability to lower blood glucose, reduce cholesterol and triacylglycerols, and reduce the risks of cancer and heart disease, and it may play a part in reducing colon cancer through its absorption of iron and other minerals that cancer cells need for growth.
However, it also deprives non-cancerous cells of the minerals needed for health.
Resources for Further Reading
- Cereal Grains: Humanity’s Double-Edged Sword by Loren Cordain, PhD
- Going Against the Grain by Melissa Diane Smith
- Life Without Bread by Christian Allan, Ph.D. and Wolfgang Lutz, M.D.