No matter where you are in your menopausal journey — perimenopause, menopause or postmenopause — you’ve likely spent some time searching for reliable information about how diet and supplements might help to improve the many disruptive symptoms of menopause. Along the way, you’ve probably heard about phytoestrogens and, more specifically, soy isoflavones.
But what exactly are soy isoflavones? Do they help to address menopause symptoms? Who can they help if so, and do they ever do more harm than good? Read on to learn more.
What Are Phytoestrogens?
Phytoestrogens are compounds derived from plants that can mimic the effects of estrogen in the body. Phytoestrogens are present in many foods, including:1
- Soybeans/edamame and products made from soy, such as tofu tempeh and soymilk
- Prunes, dates and other dried fruits
- Sesame seeds and flaxseeds
- Cruciferous vegetables such as broccoli and brussels sprouts
Common Types of Phytoestrogens
Plants can contain many different types of phytoestrogens. Two of the most common are known as lignans and isoflavones:
Lignans are chemical compounds with antioxidant and anti-inflammatory properties that are structurally similar to the hormone estradiol (which is the primary form of estrogen present during the reproductive years and is the most potent form of estrogen).2,3 Nuts, seeds and whole grains are rich in lignans.4
Isoflavones belong to a category of phytonutrients called “flavonoids” that may protect cells from oxidation and reduce inflammation, among providing other benefits.5 Soybeans and foods made from soy are among the main dietary sources of isoflavones.6
Soy Isoflavones as Phytoestrogens
Soy isoflavones are considered phytoestrogens because they typically cause estrogenic activity within the body. They are able to mimic the effects of estrogen in some parts of the body, while blocking estrogen’s effects in others.7
In addition to specific dietary sources, soy isoflavones are also available as dietary supplements.
How Could Soy Isoflavones Help During Menopause?
When consumed as food or taken in supplement form, soy isoflavones may impact estrogen levels in the blood, potentially causing them to go up or down.8 Since menopause symptoms such as hot flashes are linked to decreased estrogen levels in the body, there is some evidence that soy isoflavones can mitigate some estrogen loss (and potentially reduce symptoms related to it),9 more research, however, is needed.
What Does the Science Say About Soy for Menopause Symptoms?
Research suggests soy isoflavones may be helpful for one menopause symptom in particular: hot flashes. An analysis of 19 studies conducted in 2002 found that soy isoflavones reduced hot flashes by about 26% compared to a placebo.10
However, the relationship between soy isoflavones and estrogen levels in the body is so complex that experts aren’t able to know for certain how — or how well — soy isoflavones work to reduce certain menopause symptoms.11
Other Benefits of Soy
Soy is considered to be a quality source of protein and other nutrients. In addition to possibly easing hot flashes, soybeans and products made from them may help to lower the risk of health problems such as heart disease, stroke and some types of cancer; it may also help to improve bone health.12
When Should Soy Be Avoided?
Experts say it’s generally safe to consume whole soy foods a few times a week.13 But supplements containing soy isoflavones have been linked to an increased risk of breast cancer in women with a personal or family history of breast cancer or those with thyroid problems,14 so thoughtful consideration, as to whether you should avoid soy supplements if you fall into one of these categories, is warranted.
Regardless of your medical history, it’s important to check-in with your healthcare provider before increasing your intake of soy or other phytoestrogen-containing products/foods, as they can help you determine any risks or concerns to consider.
Exploring Alternatives to Soy
If you are dealing with menopause symptoms but want to avoid isoflavones or other phytoestrogens, you do have some alternatives. Consider researching over-the-counter products that are both hormone- and phytoestrogen-free, meaning they don’t work through hormonal pathways and have no hormonal impact on the body. Alternatives are available, but as always, be sure to check in with your healthcare provider about your options.