Hormones get blamed for a lot of things, from moodiness to weight gain, especially in women. While phytoestrogens -- plant-based hormones found in soy foods and flaxseeds -- have some estrogenlike behaviors, they're not known to cause weight gain. In fact, these plant chemicals may help you lose weight. If you're gaining weight and are unsure of the cause, consult your doctor for answers before making changes to what you eat.
Estrogen, Menopause and Weight
It seems that women equate supplemental estrogen, including the plant estrogen found in food, with weight gain. Hormone therapy is prescribed to help manage menopausal symptoms for women going through perimenopause. This also happens to be the period of time women experience the most weight gain. So, naturally, women taking hormone supplements who gain weight may blame the added therapy. However, estrogen hormones, whether from a supplement or from food, don't seem to be to blame for weight gain, according to an article published in 2000 in Maturitas. Instead, what most likely causes the additional pounds is the overall slowdown in metabolism that naturally occurs with aging.
Soy Foods and Weight
Whether you're trying to lose weight or gain a few pounds, total calories are the primary player. However, soy foods may help promote weight loss in people who are obese, according to a 2002 article published in the American Journal of Clinical Nutrition. It's not yet clear, however, whether the weight-loss benefits are from the phytoestrogens or another component in the soy food, such as the protein.
When they are part of your everyday diet over a lifetime, phytonutrients may also help prevent obesity, according to a 2015 animal study published in Molecular Nutrition and Food Research that found rats fed a diet rich in soy phytoestrogen were less likely to become obese. But it's important to note that animal studies don't always translate to humans. Before you make tofu scramble your everyday breakfast, keep in mind that the connection between phytoestrogen and weight loss is still under investigation, and more research is necessary to better understand if the plant hormones have benefits for weight control.
Pros and Cons of Phytoestrogens
The benefits of phytoestrogen go beyond weight. While the jury's still out on how beneficial the plant hormone is for your heart, it may be good for your bones. It seems phytoestrogens may help prevent bone loss and stimulate bone growth. This is especially good for women because of their increased risk of osteoporosis.
Because it can mimic estrogen, however, there is concern about how the plant nutrient might affect hormone-sensitive cancers in women, especially for breast cancer survivors. Researchers are still debating whether phytoestrogens are good or bad for those with a history of breast cancer due to conflicting evidence. Many health care professionals feel it's better to err on the side of caution and avoid the plant hormone. If you have a history of breast cancer, talk to your doctor about whether it's safe for you to include foods containing phytoestrogens in your diet.
Phytoestrogens in Foods
Although soy is considered one of the top sources of phytoestrogens, you may already be getting these plant hormones from other foods in your diet, including flaxseeds and other seeds, berries, nuts, grains and fruit.
If you want to up your phytoestrogen intake, try snacking on edamame or soy nuts, making a tofu stir fry or using soy milk in place of your usual cow's milk in your coffee or tea. You can also sprinkle flaxseeds into your morning yogurt or hot cereal, add a handful of nuts to your salad or eat berries for dessert.
- Maturitas: Weight Gain and Hormone Replacement Therapy: Are Women's Fears Justified?
- American Journal of Clinical Nutrition: Beneficial Role of Phytoestrogens in Obesity and Diabetes
- Linus Pauling Institute: Soy Isoflavones
- Molecular Nutrition and Food Research: Lifelong Exposure to Dietary Isoflavones Reduces Risk of Obesity in Ovariectomized Wistar Rats
- Front Neuroendocrinology: The Pros and Cons of Phytoestrogens