SWH Executive Director Holly Thacker, MD Discusses If Soy Foods Help With Menopause

Posted on October 30, 2023

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Source: Everyday Health

Menopause symptoms can be particularly frustrating. They’re different for every person, and it’s unclear why some of the most common symptoms, such as hot flashes, happen in some women but not others.

The consumption of soy, such as tofu or soybeans, or in the form of supplements, in place of hormone therapy is one option — but research shows the approach may not be as helpful as the hype proclaims.

Scientists have been exploring soy for menopause symptoms for decades, and most of the research on whether soy can relieve things like hot flashes and vaginal dryness has turned up mixed results. In its latest statement on nonhormone therapies for menopause, published in June 2023 in the organization’s journal Menopause, the North American Menopause Society does not recommend soy foods, soy extracts, or the soy metabolite equol — a soy-based compound made in the lab — stating there is “limited or inconsistent scientific evidence” for the intervention.

So, why do researchers keep studying it?

“We’ve been in search of something that does all the good things estrogen does but without the stimulation of the uterus and breast,” says Holly Thacker, MD, a physician at Cleveland Clinic’s Center for Specialized Women's Health and a menopause expert.

Though the risks are relatively low, certain hormone therapies can increase a person’s risk of endometrial and breast cancer if used long-term. It can also increase the risk of blood clots, stroke, and gallstone problems, the Cleveland Clinic says.

Still, hormone therapy is the right choice for many people, and risk depends on the age of the person using it, the dose, and any preexisting conditions, according to the American College of Obstetricians and Gynecologists (ACOG).

In fact, some research has suggested that combined hormone therapy that contains progesterone and estrogen may actually protect against heart attacks in women younger than 60 years who start hormone therapy within 10 years of menopause, ACOG says.

A study published in June 2023 in the journal Hypertension found that localized estrogen delivered through a patch carries fewer heart risks than estrogen taken in pill form. The study found that women taking estrogen-only pills during menopause were nearly 15 percent more likely to be diagnosed with high blood pressure than those who used estrogen-only patches.

What the Research Says

During menopause, the ovaries make very little estrogen and progesterone, causing both hormones to drop drastically. This disruption in hormone levels is believed to be the reason why we experience a variety of menopause symptoms. In response, doctors have been treating menopause symptoms with hormone therapy for decades, and researchers have been exploring alternatives — most notably soy.

Soy isoflavones have the ability to bind to estrogen receptors in some people and weakly mimic the effects of estrogen in the body, the Harvard T.H. Chan School of Public Health says.

But the effect is weak, and the process may not occur often in humans.

According to Dr. Thacker, early studies on soy and menopause symptoms were conducted on nonhuman primates that are able to convert soy isoflavones into a very weak form of estrogen. “But most humans don’t do that,” she says.

A lot of the studies on menopause and soy have been small and have not included a placebo arm — which is important, adds Thacker.

“In testing any agent used to treat hot flashes, you need a placebo arm in a study because the placebo effect is so strong,” she says.

A randomized controlled trial published in January 2023 in the journal Menopause included 84 women going through menopause who reported having at least two moderate to severe hot flashes per day. Each was part of the Women’s Study for the Alleviation of Vasomotor Symptoms (WAVS) trial and were randomly assigned to either a control group who ate their normal diet, or an intervention group who ate a low-fat vegan diet that included a half cup of cooked soybeans every day. Because one group changed their diet and the other did not, there was no placebo group.

After 12 weeks, those in the group who switched to the vegan diet reported an 88 percent decline in hot flashes compared with 34 percent for the control group. Half of the people in the control group also reported having no hot flashes at all.

The research team concluded that a plant-based diet, minimal oils, and daily soy consumption reduced the frequency and severity of post-menopausal hot flashes — but it’s unclear what role, if any, the diet change played, and whether soy was the main driver of those benefits.

Whether soy can help quell menopause symptoms may also depend on dose and form — that is, whether it’s consumed through food or supplements.

A double-blind randomized control trial published in 2021 in the Journal of Alternative and Complementary Medicine, included 78 women in Korea who had mild to moderate menopause symptoms. Half took a combination of soy and hop extracts while the other group took a placebo intervention. At the end of 12 weeks, the women who took the soy and hop extract reported a 70 percent greater improvement of symptoms that included vaginal dryness, fatigue, and myalgia. But it’s unclear whether it was the soy or the hops that had the effect.

In a review of 33 randomized clinical trials published in 2021 in the European Journal of Obstetrics and Gynecology and Reproductive Biology, researchers concluded that phytoestrogens — estrogen-like compounds that come from plants, in particular, soy — may be able to improve the thinning and drying of the vaginal walls and urinary disorders as well as issues with sexual function associated with menopause. The studies in the review did not include a single method of consuming phytoestrogens, which can come in supplement or food form. The studies also did not have standardized doses.

The authors did note that phytoestrogens are safe, accessible, and low-risk, compared with hormone therapy. For some, soy may be worth trying. But for others, it may not be a strong enough alternative to hormone therapy, says Thacker.

“People think they will just have some disruptive symptoms and then come out the other side, but you don’t come out the other side once you lose your hormones,” she says.

Once a person goes through menopause, their estrogen and progesterone levels never go back to what they used to be. They stay low, but just how low a woman’s hormone levels drop varies depending on many factors, including age and genetics.

Soy Can Be Part of a Healthy Diet — but Isn’t a Miracle Cure

The use of diet to treat menopause isn’t the right solution for everyone, cautions Thacker.

“One size does not fit all,” she says, which goes for both hormones and diet interventions. “If you’re a rapid loser [of hormones], food replacement is not going to be effective.”

A drop in estrogen during menopause can also cause other serious side effects, such as bone loss, according to Mayo Clinic.

“If you’re a woman who just wants to lose some weight and you have hot flashes, but do not have bone loss or other issues, diet changes can be good for you,” Thacker says. “But many women going through menopause have a hormonal deficiency, so using food as an intervention doesn’t change that.”

Spicy foods, caffeine, and alcohol are common hot flash triggers, so avoiding them can help, according to Cleveland Clinic. Other diet changes, such as following a Mediterranean style of eating, which includes minimal processed foods, can help prevent other diseases associated with aging, such as dementia and osteoporosis.

The Data Is Limited, but Soy Can’t Hurt

Although the research supporting soy as a menopause treatment is quite weak, soy-based foods in an overall healthy diet and a lifestyle that also includes regular exercise has been shown to have health benefits for menopausal women.

Rapid hormonal drops during menopause trigger dramatic changes in fat, bone, and muscle composition. These changes can increase the risk for chronic diseases including heart disease, osteoporosis, and obesity.

According to a scientific statement from the American Heart Association (AHA), published in 2020 in the journal Circulation, lower estrogen levels post-menopause commonly cause weight gain as well as thickening and stiffening the arteries, raising a person’s risk of heart disease.

Diet can help offset this risk. “Soy is effective in some people as a protein substitute,” says Thacker.

A diet high in saturated fats, processed meats, and red meat has also strongly been linked to increased risk of heart disease. On the flip side, people who ate vegetarian or pescatarian diets had a 13 percent lower risk of heart disease in a study of nearly 100,000 people published in February 2023 in the International Journal of Environmental Research and Public Health.

Although it's a common misconception, research has not shown soy to raise the risk of cancer, including breast and thyroid cancers, Thacker notes. Meanwhile, other factors associated with menopause are known cancer risk factors.

“One of the most unappreciated causes of uterine and breast cancer is weight gain, and weight gain happens in most women as they age,” she says. “Age is the biggest risk factor in developing cancer.”