Natural estrogens (phytoestrogens) are found in plant products, and therefore are in many of the foods we eat. According to researchers at Cornell University, there are three main classes of phytoestrogens: isoflavonoids, coumestans and lignans. In the body, phytoestrogens act as our naturally produced estrogen. If you are experiencing estrogen dominance, then you will want to cut back on foods high in phytoestrogens; conversely, if you have low estrogen levels, you will want to increase your intake of phytoestrogens.
Food Sources of Isoflavonoids
Beans and legumes are especially high in isoflavonoids, with soy beans and soy products being the richest source. Other foods high in isoflavonoid phytoestrogens, as listed by the USDA, are kidney, navy, pinto, red, small white and mung beans. Chickpeas, split peas, peanuts and clover sprouts also make the list. Processed foods that are made with soy--such as veggie burgers and infant formula--are also high in isoflavonoids.
Lignans
Lignans tend to be found in foods that are also high in fiber. Researchers at Cornell University report that the highest amount of lignans are found in flaxseeds. Other seed sources of lignans are sesame seeds, poppy seeds and sunflower seeds. Products made with wheat and rye flours, whole grain and white rice are also lignan sources. Fruits such as strawberries, peaches, pears, raisins, cherries, grapefruit, mandarin, kiwi, plums, oranges and apricots have lignans, with apricots having the highest amount. Vegetable sources of lignans include broccoli, cauliflower, brussel sprouts, cabbage, onions, garlic, leeks, French beans, red and green peppers, carrots, spinach, cucumbers, tomatoes and kale, with kale being the richest source of lignans. Other food products include tomato paste, tofu and chocolate.
Coumestan
Like isoflavonoids, coumestan phytoestrogens are found in high concentrations in some beans, such as split peas and lima beans. According to Cornell University, the foods with the highest concentration of coumestans are clover and alfalfa sprouts. A study in a 2002 issue of the "Journal of Nutrition" points out that coumestans form--and are in highest concentration--during the germination phase, which is why sprouts are such a rich source.
