(NaturalNews) In the last installment of this whole grain article series, we looked at phytic acid and its potentially negative health effects. Phytic acid is an indigestible form of the mineral phosphorous, which we need. High-phytate diets result in mineral deficiencies. In populations where cereal grains provide a major source of calories, rickets and osteoporosis are common. (Footnote 1)
Interestingly, the body has some ability to adapt to the effects of phytates in the diet. Several studies show that subjects given high levels of whole wheat at first excrete more calcium than they take in, but after several weeks on this diet, they reach a balance and do not excrete excess calcium.(F 2) However, no studies of this phenomenon have been carried out over a long period; nor have researchers looked at whether human beings can adjust to the phytate-reducing effects of other important minerals, such as iron, magnesium and zinc.
The zinc- and iron-blocking effects of phytic acid can be just as serious as the calcium-blocking effects. For example, one study showed that a wheat roll containing 2 mg phytic acid inhibited zinc absorption by 18 percent; 25 mg phytic acid in the roll inhibited zinc absorption by 64 percent; and 250 mg inhibited zinc absorption by 82 percent.(F 3) Nuts have a marked inhibitory action on the absorption of iron due to their phytic acid content.(F 4) Not all foods high in phytic acid block iron absorption, like coconut. This is a sign that there are other factors at play when looking at the toxicity of grains.
Over the long term, when the diet lacks minerals or contains high levels of phytates or both, the metabolism goes down, and the body goes into mineral-starvation mode. The body then sets itself up to use as little of these minerals as possible. Adults may get by for decades on a high-phytate diet, but growing children run into severe problems. In a phytate-rich diet, their bodies will suffer from the lack of calcium and phosphorus with poor bone growth, short stature, rickets, narrow jaws and tooth decay, and for the lack of zinc and iron anemia and mental retardation may result.
The figures for the amounts of phytic acid can vary somewhat because of different levels of moisture in the test food, as well as because different varieties of the same plant can yield different results.
More Phytic Acid Figures. Milligrams per 100 grams / 3.5 ounces of food. (F 5) Sesame seeds dehulled 5,360 Pinto beans 600 - 2,380 Navy beans 740 - 1,780 Parboiled brown rice 1,600 Barley 1,190 Coconut meal (similar to coconut flour) 1,170 Whole corn 1,050 Rye 1,010 Wheat flour 960
In the next installment of Whole Grain Toxicity, we'll look at the surprising connection between vitamin D and grain consumption. You will also begin to learn how to block the negative effects of phytic acid in your diet.
References / Footnotes 1. Wills MR and others. Phytic Acid and Nutritional Rickets in Immigrants. The Lancet, April 8, 1972, 771-773. 2. Walker ARP and others. The Effect of Bread Rich in Phytate Phosphorus on the metabolism of Certain Mineral Salts with Special Reference to Calcium. The Biochemical Journal 1948 42(1):452-461. 3. Iron absorption in man: ascorbic acid and dose-depended inhibition. American Journal of Clinical Nutrition. Jan 1989 49(1):140-144 4. Inhibitory effect of nuts on iron absorption. American Journal of Clinical Nutrition 1988 47:270-4. 5. Reddy NR and others. Food Phytates, CRC Press, 2001.