While the term “heart-healthy” has become an almost obligate prefix when talking about whole-grains, many people do not know that whole-grains possess a variety of antinutrients that might not make them the essential component to optimal health that they appear to be on the surface. Today, we are going to discuss phytic acid, also known as phytate in the salt form, which is a chemical present at high levels in grains and legumes. Phytates are essential to plants, as they are their primary method of storing phosphorous; however, they also have a high chelating, or binding, affinity to various micronutrients and macronutrients when consumed by animals. This binding affinity has a negative effect on vitamin and mineral absorption and can contribute to micronutrient deficiency when consumed regularly. Micronutrient deficiency can lead to a host of disorders, as is covered in depth in Naked Calories.
According to a 2010 literature review by Kumar et al., in the Journal of Food Chemistry, the primary minerals affected by this chelation effect are calcium, copper, iron, magnesium, manganese, and zinc. Other studies have found it also negatively affects chromium, vitamin D, and niacin (vitamin B3). Deficiencies in these micronutrients can lead to a number of health conditions, including but not limited to, osteoporosis, nervous system disorders, anemia, high blood pressure, reproductive issues and dwarfism, respectively. Niacin deficiency leads to a condition known as pellagra. The phytates form an insoluble phytate-mineral complex that cannot be broken down in the body, as we do not posses the phytase enzyme essential to their breakdown.
So what does this all mean? Consuming lots of grains, nuts, seeds, and legumes (this includes soy, and peanuts) can lead to micronutrient deficiencies, which will lead to poor health. As such, they generally are not the best choice for an optimal diet. However, in the case of plant-based diets or those who refuse to remove these foods, there is still hope. Traditional preparation methods such as soaking, sprouting and fermenting can help mitigate the deleterious effects. This happens because these processes increase the naturally present phytases in the plant themselves.
In spite of these issues, the story of phytic acid is not all gloom and doom. Kumar et al. found several potential therapeutic uses for phytic acid. These include as an anti-oxidant and in combating cancer, coronary heart disease, diabetes mellitus, and even HIV. So depending on the population, it may actually have some beneficial applications.