Combining many methods can reduce antinutrients substantially, sometimes even completely.
As an example, soaking, sprouting and lactic acid fermentation decreased the phytate in quinoa by 98%.
Similarly, sprouting and lactic acid fermentation of corn and sorghum degraded phytate almost completely.
In addition, soaking and boiling pigeon peas led to a 98-100% reduction in lectins, tannins and protease inhibitors.
The most effective way to reduce antinutrients in plant foods is to combine several different elimination strategies. Combining methods may even degrade some of the antinutrients completely
- Phytate (phytic acid): Soaking, sprouting, fermentation.
- Lectins: Soaking, boiling, heating, fermentation.
- Tannins: Soaking, boiling.
- Protease inhibitors: Soaking, sprouting, boiling.
- Calcium oxalate: Soaking, boiling.
Another consideration is that these anti-nutrients affect the absorption of nutrients eaten at the same meal. Therefore, to lower this risk, it is recommended to avoid eating large quantities of foods containing anti-nutrients at one meal, and to eat a balanced diet throughout the day with a variety of foods. For example, instead of eating two cups of bran cereal with milk for breakfast, choose one cup of cereal with milk and one cup of fresh berries.
People who are at high risk for diseases related to mineral deficiencies, such as osteoporosis with calcium deficiency or anemia with iron deficiency, may wish to monitor their food choices for anti-nutrient content. Another strategy could be to alter the timing of eating foods with anti-nutrients. Examples are to drink tea between meals instead of with a meal to reduce the chances of iron being poorly absorbed, or taking a calcium supplement a few hours after eating a high-fiber wheat bran cereal that contains phytates.
Studies on vegetarians who eat diets high in plant foods containing anti-nutrients do not generally show deficiencies in iron and zinc, so the body may be adapting to the presence of anti-nutrients by increasing the absorption of these minerals in the gut.
Keep in mind that anti-nutrients may also exert health benefits. Phytates, for example, have been found to lower cholesterol, slow digestion, and prevent sharp rises in blood sugar. Many anti-nutrients have antioxidant and anticancer actions, so avoiding them entirely is not recommended.
The takeaway: The pros and cons of anti-nutrients on long-term human health is an area of active research. Though certain foods may contain residual amounts of anti-nutrients after processing and cooking, the health benefits of eating these foods outweigh any potential negative nutritional effects. Eating a variety of nutritious foods daily and avoiding eating large amounts of a single food at one meal can help to offset minor losses in nutrient absorption caused by anti-nutrients.
Antinutrients can significantly reduce the nutritional value of many plant foods. Luckily, they can be degraded with a few simple methods such as heating, boiling, soaking, sprouting and fermenting.
By combining different methods, many antinutrients can be degraded almost completely.