The Soy Stigma (What the Science Says)

The on-going soy controversy, including statements linking the soy plant to cancer, has created a widespread stigma about the protein-rich meat alternative. While there is some element of truth to the assertions made by certain studies and food industries (such as the meat and dairy industry), their statements are profoundly misleading. The bottom line: not one scientific study refutes the fact that soy, in its pure forms, such as tempeh, tofu, or whole soybeans is a perfect food, and can actually aid in preventing cancer and other diseases when eaten in the proper amounts and forms.

If you dig a little deeper into the research you will find that the controversy actually lies with soy isolate, a processed commercial bi-product of the soy bean. Scientific studies connecting soy to negative health effects are always conducted on this isolate. Think of soy isolate like the high fructose corn syrup of soy. It’s been extracted, and processed and manipulated to create fake meat tectures, and creamy soy protein powders, the composition of soy isolate looks nothing like the whole soy bean.

So what about the whole soy bean? Dr. Dean Ornish (President of the Preventive Medicine Research Institute) promotes whole soy products as one of his main recommended food groups and states that “A moderate intake of minimally processed soy foods such as edamame, tofu, and soymilk, along with fermented soy foods such as tempeh, natto, and miso are health-promoting ways to enjoy soy. They offer potential protection against coronary heart disease, certain cancers, and menopausal symptom relief.”

So, what is soy isolate and why is it bad?

Soy isolate is a dietary protein “isolated” from soybeans that contains isoflavone phytoestrogens. Food manufacturers add fillers, flavoring, and preservatives to the majority of soy isolate products. Why, you ask? Additives make the product cheaper and tastier, and they give it a longer shelf life. It’s about business, not health. No different than any other processed food.

In select studies conducted on monkeys and rats, this soy protein isolate has been linked to allergic reactions, brain damage, and thyroid problems.

The truth about the cancer scare

Population studies have failed to show a relationship between soy consumption and increased risk of breast cancer.  The biggest concern related to soy revolves around women with hormone receptor positive forms of breast cancer. Isoflavones are a type of phytoestrogen, which is a dietary form of estrogen. The isoflavones in soy have a mild estrogenic effect (this means they are able to bind to estrogen receptor sites in human tissue) blocking excess estrogen, and therefore actually benefiting cancer patients

Concerned about the estrogen-like effect of soy on breast cancer survivors, researchers at Vanderbilt University Medical Center examined soy consumption among 5,000 Chinese women treated successfully for breast cancer. The study, published in the Journal of the American Medical Association and supported by grants from the Breast Cancer Research Program in the U.S. Department of Defense and the National Cancer Institute, found that women who ate the most soy protein — and therefore consumed the greatest amount of isoflavones — were about one third less likely to suffer a recurrence of breast cancer or die during the four years of follow-up.

The scientists noted that soy consumption benefited everyone, including women with either estrogen-positive (cancer cells that need estrogen to grow) or estrogen-negative (cancer cells that don’t need estrogen to grow) illnesses.

The National Cancer Institute also found that soy consumption early in life conferred protection against breast cancer later. The women studied were of Chinese, Japanese and Filipino ancestry, and were living in California or Hawaii. Their findings stated that those who had consumed the largest amounts of soy foods as children (between ages five and 11) lowered their risk for breast cancer as adults by 60%.

So why soy? And how often?

Soy is an amazing source of plant protein. Some plants contain protein, which is made from building blocks called amino acids linked together in a chain. Of the 20 amino acids found in the body, nine are considered essential because the body can’t make them, so they must be consumed. Soy protein is one of the few plant proteins that is considered “complete” due to the fact that it contains all 9 essential amino acids in the right balance. The soybean is also the only vegetable that has more protein than carbohydrates. The amount of soy recommended for women specifically to help protect against breast cancer is 25 to 35 grams per day or one to two standard servings a day. So eat your edamame with confidence, knowing that you are supplying your body with hormone balancing, quality plant protein, and maybe skip the faux deli meat packed with processed isolates and preservatives.