Tofu: understand if the food is harmful to your health – 04/16/2023 – Equilibrium

I’ve heard conflicting stories about tofu. It’s either a great source of protein or loaded with estrogen and therefore unhealthy. What’s the truth?

If tofu and other soy foods were in the running for a spot on your weekly meal rotation, they would offer an impressive resume of nutritional credentials.

An 85g serving of tofu, for example, can provide between 4 and 14g of protein (depending on the style), including all nine essential amino acids.

It also provides B vitamins, healthy unsaturated fatty acids, and minerals like calcium, magnesium, zinc, and iron, says Amy Bragagnini, registered dietitian and spokesperson for the Academy of Nutrition and Dietetics.

However, soy-based foods also suffer from a nasty reputation. Bragagnini’s customers, for example, routinely ask whether soy foods are linked to cancer — a concern stemming from their relatively high levels of isoflavones, plant-based compounds that are structurally similar to the hormone estrogen.

The presence of isoflavones has also led to concern that soy could negatively affect fertility or give men more feminine characteristics.

But overall, studies have shown that including soy foods in your diet is not only safe, it can also benefit your heart and metabolic health, points out Qi Sun, associate professor of nutrition and epidemiology at the TH Chan School of Public Health. from Harvard.

And while it’s true that the isoflavones in soy can slightly mimic estrogen, he adds, they also appear to have anti-cancer, anti-inflammatory and antioxidant power.

See what we know here.

Cancer

A historical concern about soy has been that its estrogen-like isoflavones may promote breast cancer, but many studies have shown that women who eat larger amounts of soy foods are at no greater risk – or even have a lower risk – more likely to develop breast cancer than those who eat little or no soy, says Xiao-Ou Shu, professor of epidemiology at Vanderbilt University.

The protective association is strongest in studies conducted in Asian countries, she notes, where soy is commonly consumed from infancy to old age.

In a study published in 2012, Shu and her colleagues found that among women in China and the United States who were diagnosed with breast cancer, those who ate about half a serving or more of soy foods a day after diagnosis were less likely to have breast cancer. to have recurrence than those who ate smaller amounts.

Before this discovery, Shu points out, doctors sometimes warned breast cancer patients to avoid soy foods. Today, the American Institute for Cancer Research says “limited evidence” suggests that women who eat moderate amounts of soy may be more likely to survive breast cancer, and perhaps have fewer recurrences.

A moderate amount is defined as one to two servings of whole soy foods such as tofu, soy milk, edamame or soy nuts per day.

Some studies have also reported a protective effect of soy for prostate and lung cancers.

The American Cancer Society recommends soy foods and legumes as part of a healthy, balanced diet, but says the evidence that soy foods, in particular, can protect people from breast or prostate cancer are “too limited to draw firm conclusions”.

fertility and menopause

Concerns that soy may interfere with fertility — including affecting sperm count or quality, the ability to conceive, or testosterone or estrogen levels in men — have also not withstood the evidence, says Sun.

A few small studies have found that soy can modestly reduce menopause-related hot flashes, but those results have been mixed, says Bragagnini. Still, she adds, if you’re experiencing these symptoms, “it doesn’t hurt to add a serving or two a day” of whole soy foods to see if they help.

Research has also found that higher soy intake is associated with a lower risk of osteoporotic fractures in postmenopausal women.

heart health

There’s some evidence that including soy in your diet can benefit your heart, says Sun.

He led a study published in 2020 that found that consuming more soy isoflavones, particularly from tofu, was associated with a moderately lower risk of coronary heart disease.

And in another study of nearly 120,000 health professionals in the US, Sun and his colleagues found that over 30-plus years of follow-up, those who consumed at least one serving of tofu or soy milk a week were 15% more likely to 16% less likely to die than those who ate less than one serving a month.

“It’s almost obvious that people should choose tofu and other plant-based proteins over animal-based proteins,” especially those from processed and red meats, which are associated with a higher risk of heart disease, diabetes, colorectal cancer and early death. says Sun.

He adds that eating more plant-based foods can “not only improve human health, but also the health of the world” because protein sources like soy, beans, peas and nuts have smaller greenhouse gas footprints than meat. , cheese or eggs.

How to incorporate more soy foods into your diet

As a nutritionist, Bragagnini has found tofu to be sometimes a tough sell when she recommends it to clients.

“They just roll their eyes,” she says, “but they never really tried.”

Tofu and tempeh, which are made from fermented soybeans, take on just about any flavor profile and can be baked, sautéed or simmered in a sauce — or, Bragagnini’s favorite, crisped up in a deep fryer.

And if those soy protein blocks just aren’t your thing, she suggested eating soy nuts, cooking up some edamame, or making unsweetened soy milk shakes.

Bragagnini encourages people to include one or two servings of soy-based foods in their daily diet.

But she cautions against using isoflavone supplements, which can contain far greater amounts of the compounds than are found in food. And, as with all supplements, they are not well regulated in the country. “If a little is good, a lot is not necessarily better”, he concludes.

Translated by Luiz Roberto M. Gonçalves