There’s a lot of controversy over whether or not people should be eating soy, drinking soy milk, and consuming soy-based protein powders. Soy is considered a phytoestrogen and part of the controversy is that it can mimic the effects of estrogen in the body. We all have estrogen but too much can lead to premature aging and some cancers. Exposure to high levels of estrogen in young girls has been correlated with premature menarche and early-onset puberty too.
Phytoestrogens are sometimes called plant-based estrogens, which can be confusing when women are trying rebalance their estrogen levels. We know that estrogen dominance, an imbalance between estrogen and progesterone, can cause PMS, infertility, PCOS and a higher risk of developing breast, ovarian and uterine cancer. So, you’re right to think that eating phytoestrogens would add to this imbalance.
But what if your estrogen levels are too low? Well, this is what’s happens to women as they approach menopause so phytoestrogens can be very beneficial at this time! They inhibit estrogen-related cancers, decrease post-menopausal symptoms, lower blood cholesterol levels, protect against breast cancer, prostate cancer and osteoporosis, and decrease atherosclerosis. Phytoestrogens are also known as isoflavones, which destroy enzymes that transform normal cells into cancer cells and prevent tumours from forming in the blood supply.
A high intake of phytoestrogens is thought to explain why hot flashes and other menopausal symptoms rarely occur among women in Asian cultures. Be careful, though, if you’ve had breast, ovarian or uterine cancer, and speak to your doctor before increasing your intake.
Besides soy, isoflavones are also present in alfalfa, apples, beans, celery, corn, carrots, fennel, flaxseed, lentils, nuts, parsley, peanuts, peas, red clover, sesame seeds, sunflower seeds and whole grains.
One important type of isoflavone is lignan. Lignan acts as an antioxidant, blocks prostaglandins, and inhibits the production of estrogen by fatty tissues. Lignan helps lower cholesterol levels, protects against colon cancer, and helps to prevent the formation of gallstones. Food sources include barley, fatty fish, flaxseeds, millet, legumes, oats, plums, rice, soybeans, spelt, walnuts and wheat. Another type of phytoestrogen, genistein, may help prevent obesity; besides soy, genistein is found in chickpeas.
Soy does have the highest levels of phytoestrogens but it may not always be the best choice. Soy produced in North America is best avoided because the crops are most likely genetically modified and commercially grown with fertilizers and other nasty chemicals. Fermented soy, though, contains probiotics, so this type of soy is okay.
Phytoestrogens mimic the effects of estrogen in the body. People who already have adequate levels of estrogen, or who are estrogen dominant, should minimize their phytoestrogen consumption; too many phytoestrogen foods can create further hormonal imbalances and lead to some of the diseases associated with too much estrogen, like breast cancer. (Infants and young children should avoid soy-based foods as much as possible.)
However, women approaching perimenopause and menopause should start increasing their phytoestrogen intake. This will help to keep estrogen levels up and avoid symptoms like hot flashes and night sweats, as well as prevent diseases associated with too little estrogen.