Concerns about the effects of soy on men may have arisen because soy and other legumes contain isoflavones. These are phytoestrogens, or estrogenic compounds that are structurally similar to human estrogens. However, “they have different biological properties than human estrogen and do not promote harmful estrogen effects on the body,” Hensrud says. “In fact, they can be protective.”
Research generally does not support the idea that drinking soy milk causes men to grow breasts or experience other feminizing effects. Research also refutes the idea that soy increases a woman’s risk of breast cancer.
“I have not seen any data showing that drinking soy milk or eating soy products promotes feminization in men, which in turn promotes breast growth and similar negative health effects such as breast cancer in women. No,” says David Jenkins. University Professor in the Department of Nutritional Sciences and Medicine, Temerty Faculty of Medicine, University of Toronto. “I encourage my patients, both men and women, to consume soy. I don’t see any adverse effects,” he said, adding that no major health organization has warned of the dangers associated with soy consumption.
At least two early studies each linked a single instance of soy intake to feminizing effects in men, including breast enlargement, erectile dysfunction, and decreased sex drive. has been done. But experts say the two subjects each consumed unusually high amounts of soy, in one case three quarts of soy milk a day, many times the average dietary intake. It was pointed out that this is also the case.
“That’s a very high amount of soy milk on an ongoing basis. Most people don’t drink that much water every day,” Hensrud says. “These are two rare cases and are not representative of the overall evidence regarding soy phytoestrogens.”
“Breast growth, or gynecomastia, occasionally occurs in men and adolescent males,” he says, also mentioning other causes of gynecomastia in young men. “Most importantly, there is strong evidence that soy consumption provides many health benefits with few risks.”
Numerous studies have also found that soy milk and other soy products may reduce the risk of breast cancer, perhaps contributing to the lower breast cancer incidence among Japanese women who traditionally follow a diet high in soy. This may be the cause of the low. Research shows that soy consumption may also reduce a woman’s risk of breast cancer recurrence.
Although women with estrogen-positive breast cancer may be concerned about soy, Hensrud says the data doesn’t indicate a greater risk. Other studies have shown increased incidence of breast cancer among Japanese women who reduce their soy intake and adopt a Western diet.
Additionally, research shows that soy milk may have cardiovascular benefits by lowering blood pressure, inflammation, and low-density lipoprotein (bad) cholesterol. Further research shows that soy may reduce the risk of prostate cancer and prevent memory loss associated with aging and cognitive impairment.
What else you need to know
Soy milk is a processed food and may have added sugar, flavorings, and other ingredients. Also, people with soy allergies should avoid it.
In addition to isoflavones, soy foods are rich in B vitamins, dietary fiber, potassium, and magnesium. Also, unlike some plant proteins, soy protein contains all nine essential amino acids and is a complete protein. Soy foods can be unfermented or fermented, the latter meaning they have been cultured with beneficial bacteria, yeast, or mold.
“Fermented soy milk, like other fermented foods, may have even more health benefits,” Hensrud says.
