Phytoestrogens

Phytoestrogens, also known as plant-derived xenoestrogens or "dietary estrogens," constitute a diverse group of nonsteroidal compounds found in various plant-based foods. Structurally resembling estradiol, these compounds can elicit estrogenic or antiestrogenic effects. While not essential nutrients, they are present in foods like nuts, oilseeds, soy products, cereals, legumes, and more. The phytoestrogen content varies among foods, with flax seeds and soybeans having the highest concentrations. Studies on their impact on cancer prevention, particularly breast cancer, yield conflicting results, with some suggesting protective effects and others asserting safety for patients with breast cancer. Their role in mitigating the effects of low estrogen levels remains uncertain. Phytoestrogens are also researched in relation to male sexuality, with isoflavones potentially influencing sperm characteristics. However, conflicting evidence on male fertility prompts further investigation. Structurally similar to mammalian estrogens, phytoestrogens, including isoflavonoids, flavonoids, stilbenes, and lignans, interact with estrogen receptors and affect sex hormone-binding globulin concentrations. Foods like soy-based products contain notable amounts of phytoestrogens, contributing to their presence in various processed foods. Despite their structural affinity with estradiol, phytoestrogens exhibit low potency in comparison.

A list of foods that contain phytoestrogens from highest concentration to lowest concentration includes

1. Flax Seeds: Known for their high lignan content, particularly secoisolariciresinol diglucoside (SDG).
2. Soy Products: Soybeans, tofu, tempeh, and soy-based foods contain significant amounts of isoflavones, such as genistein and daidzein.
3. Soy-based Processed Foods: Including textured soy protein, soy protein isolate, and various processed foods with soy additives.
4. Legumes: Particularly soybeans, which are rich in isoflavones.
5. Berries: Some berries, like strawberries, raspberries, and blackberries, contain varying levels of phytoestrogens, especially flavonoids.
6. Nuts and Oilseeds: Such as walnuts, almonds, and sunflower seeds, containing lignans.
7. Whole Grains: Including grains like oats, barley, and wheat, which may contain lignans.
8. Cereals and Bread: Certain cereals and whole-grain breads can contribute to phytoestrogen intake.
9. Wine: Red wine, in particular, may contain some phytoestrogens e.g. Resveratrol.
10. Fruits and Vegetables: While generally lower in phytoestrogens compared to other food groups, some fruits (e.g., apples) and vegetables contribute to overall intake.
11. Alcoholic and Non-alcoholic Beverages: Certain beverages, such as beer and tea, may contain trace amounts of phytoestrogens. Notably, one potent phytoestrogen is 8-prenylnaringenin contained in hops.