Many people are still confused about soy. 

The bottom line is: whole soyfoods are beneficial to health.

To ensure you’re getting the maximal health benefits, always recommend consuming primarily whole soy foods like edamame (green soybeans), tofu, tempeh, some soymilks and soy nuts. Processed soy ingredients (such as isolated soy protein found in bars, snacks, and other packaged foods) leave out many of whole soy’s nutritional components, including vitamins, minerals and fiber.

Read on to discover the facts behind the most common myths associated with soy.

Soy Myths and Facts:

Breast cancer

Myth: Breast cancer patients should avoid soy foods.

Fact: Not true! Recent human research shows that soy foods are safe and may possibly even be beneficial for some breast cancer survivors and for some at high risk for breast cancer.

More information: A recent study followed more than 9,500 women in the U.S. and China who had been diagnosed with breast cancer and found that those who consumed at least 10 milligrams of soy isoflavones per day (the amount in a half cup of soymilk) had a 25% lower chance of breast cancer recurrence than those who consumed less than 4 mg of isoflavones. Not unexpectedly, both the American Institute of Cancer Research (AICR) and the American Cancer Society (ACS) have concluded that soyfoods are safe for breast cancer patients.

Heart disease

Myth: Soy protein does not make much of a difference in lowering cholesterol.

Fact: Not true! Soy protein can help meet protein needs and the FDA authorized health claim for soy protein states that “25 grams of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease”. It may help reduce the risk of coronary heart disease (CHD) by lowering low-density lipoprotein cholesterol (LDLC) and perhaps also by lowering blood pressure. Isoflavones may also directly improve arterial health.

More information: Recent evidence provides support for the FDA soy and heart health claim showing around a 5% reduction in LDLC. Evidence suggests that every 1% reduction in LDLC leads to a 1% to 3% reduction in CHD risk, so this is great news for those looking to improve heart health. Other recent research suggests that isoflavones rich soy protein inhibits the progression of subclinical atherosclerosis in young postmenopausal women.

Male feminization

Myth: Soyfoods have feminizing effects on men.

Fact: Not true! The preponderance of evidence shows that soyfoods do not feminize men or impair male fertility.  Eating soyfoods will not make males less masculine, lead to man-boobs, cause early puberty or decrease fertility. A literature review 1 confirms that soyfoods do not have any feminizing effects on men or boys. In reality, a balanced diet that includes soyfoods can help support healthy growth and development for young boys, and soyfoods are a great option for men looking to maintain healthy weight and cholesterol levels.

More information: Extensive clinical research shows that even large amounts of soy do not lower testosterone levels or raise estrogen levels in men. Clinical research also shows that soy does not adversely affect sperm or semen parameters. In fact, Italian researchers suggested soy isoflavones could be a treatment for low sperm count.

Soybeans contain natural, bioactive components called isoflavones, or phytoestrogens. While the chemical structure of an isoflavone is similar to that of estrogen, the two function differently in the body. A significant review of more than 30 soy studies disproved any link between soy and an effect on testosterone levels in men. Consuming a well balanced diet that includes soyfoods does not increase estrogen levels in men or boys.


Myth: Many people have soy allergies.

Fact: Not true! Although some do have allergies to soy protein, in comparison, an allergy to milk protein is 40 times more common.

More information: A recent survey found that approximately only 1 out of 2,500 adults reported having a doctor-diagnosed allergy to soy protein. The rate is higher in children than adults, as children are more likely to have food allergies in general. However, by age 10 an estimated 70% of children will outgrow their soy allergies.


Myth: Soyfoods can lead to hypothyroidism.

Fact: Soy does not adversely affect thyroid function in healthy people and does not need to be avoided for those taking medication for hypothyroidism.