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The amount of phytate in grains, nuts, legumes and into severe problems. With a phytate-rich diet, their seeds is highly variable. The levels that researchers find bodies suffer from lack of calcium and phosphorus, with when they analyse a specific food probably depend on poor bone growth, short stature, rickets, narrow jaws and growing conditions, harvesting techniques, processing tooth decay, and from lack of zinc and iron with anaemia methods, testing methods and even the age of the food —_ and mental retardation. being tested. Phytic acid is much higher in foods grown using modern high-phosphate fertilisers than in those | The Experiments of Edward Mellanby grown in natural compost.‘ As early as 1949, the researcher Edward Mellanby Seeds and bran are the highest sources of phytates, | demonstrated the demineralising effects of phytic acid. containing as much as two to five times more phytate By studying how grains with and without phytic acid han even some varieties of soybeans, which are highly affect dogs, Mellanby discovered that consumption of indigestible unless fermented for long periods. high-phytate cereal grain interferes with bone growth Remember the oat bran fad? The advice to eat bran, or and interrupts vitamin D metabolism. A high level of igh-fibre foods containing different types of bran, isa phytic acid in the context of a diet low in calcium and recipe for severe bone loss and intestinal problems due vitamin D results in rickets and a severe lack of bone o the high phytic acid content. formation. His studies show that excessive phytate Raw unfermented cacao (cocoa) beans and normal consumption uses up vitamin D, a vitamin that can cocoa powder are extremely high in phytates. Processed _ mitigate the harmful effects of phytates. According to chocolates may also contain Mellanby: "When the diet is rich phytares, but more research is in phytate, perlec bone needed. White chocolate and ormation can only be procure cc bates ocoaty twee |The advice to eat bran... J sfiventctiun s ated made from the fat of the beans. isa recipe for severe bone Mellanby's studies show that Coffee beans also contain phytic cor loss and intestinal problems he rickets-producing effect of oatmeal is limited by calcium.” due to the high phytic Calcium salts such as calcium carbonate or calcium phosphate prevent oatmeal from exerting he rickets-producing effect. phytates result in mineral According to this view, the deficiencies. In populations degree of active interference where cereal grains provide a major source of calories, _ with calcification produced by a given cereal depends on rickets and osteoporosis are common.” Interestingly, | how much phytic acid and how little calcium it contains, the body has some ability to adapt to the effects of — or how little calcium the diet contains. Phosphorus in phytates in the diet. Several studies show that subjects the diet (at least from grains) needs some type of given high levels of whole wheat at first excrete more calcium to bind to. This explains the synergistic calcium than they take in, but after several weeks on this combination of sourdough bread with cheese. diet they reach a balance and do not excrete excess _— Historically, the cultivation of grains was usually calcium.'' However, no long-term studies of this | accompanied by the raising of dairy animals. A high phenomenon have been carried out; nor have level of calcium in the diet mitigates the mineral- researchers looked at whether we can adjust to the _—_ depleting effects of phytic acid. phytate-reducing effects of other important minerals In Mellanby's experiments with dogs, increasing the such as iron, magnesium and zinc. vitamin D intake made stronger bones regardless of the The zinc- and iron-blocking effects of phytic acid can _ diet, but this increase did not have a significant impact be just as serious as the calcium-blocking effect. Inone on the amount of calcium excreted. Those on high- study, a wheat roll containing 2 mg phytic acid inhibited phytate diets excreted lots of calcium; those on diets zinc absorption by 18 per cent; 25 mg inhibited it by 64. high in phosphorus from meat or released from phytic per cent; and 250 mg inhibited it by 82 per cent.’ Nuts acid through proper preparation excreted small amounts have a marked inhibitory action on the absorption of — of calcium. iron due to their phytic acid content.” Based on Mellanby's thorough experiments, one can Over the long term, when the diet lacks minerals or — conclude that the growth of healthy bones requires a contains high levels of phytates or both, the metabolism diet high in vitamin D, absorbable calcium and goes down and the body goes into mineral-starvation absorbable phosphorus, and low in unabsorbable mode. The body then sets itself up to use as little of | calcium (supplements, pasteurised dairy) and these minerals as possible. Adults may get by for — unabsorbable phosphorus (phytates). decades on a high-phytate diet, but growing children run Interestingly, Mellanby's experiments show that Demineralising Effects of High- 9 Phytate Diets acid content. Diets high in phytic acid or into severe problems. With a phytate-rich diet, their bodies suffer from lack of calcium and phosphorus, with poor bone growth, short stature, rickets, narrow jaws and tooth decay, and from lack of zinc and iron with anaemia and mental retardation. is a recipe for severe bone loss and intestinal problems due to the high phytic acid content. 34 * NEXUS The advice to eat bran... AUGUST - SEPTEMBER 2010 www.nexusmagazine.com