Throughout our reviews on different meal replacement shakes out there, you may have noticed that we do not endorse the use of soy protein in the formulas. In fact, this lowers our overall rating in general. You might be asking why do we advise avoiding it so strongly?
In the past few decades, soy has gained popularity for being a healthy food option and a great meat substitute for vegetarians. Popularity rose as observation showed that Asian cultures that consumed high levels of soy had fewer health issues than the Western populations including breast cancer, prostrate cancer, cardiovascular disease, and others. Studies also backed up these observations, claiming that soy protected against cancers and helped support overall health. The U.S. Food and Drug Administration approved a claim in 1999 that stated “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.” During this time, the sale of soy foods in the US rose from $300 million to $4 billion. Something seem fishy to you? Another thing is that soy is also very inexpensive, and is in more than 60% of processed foods. It is the second largest crop in cash sales in the United States.
However, there are many issues associated with soy, including thyroid disorders, digestive disorders, and reproductive disorders. Additionally, most soybean crops are genetically modified (GMO) to tolerate herbicide. The long-term effects of ingesting GMO foods are undetermined as of now. Soy contains plant compounds that have structures very similar to estrogen and can trick the body, causing early puberty in girls, promoting breast cancer, and reducing male fertility. In fact, experts such as The American Cancer Society and The American Academy of Pediatrics who used to endorse the usage of soy in food products have began retracting their statements, now recommending it only in small doses and circumstantially.
In 2009, the Journal of the American Medical Association observed 5,000 breast cancer survivors in China and found women who consumed soy regularly had an improved prognosis. Also, those who ate over 15grams of soy protein per day were 30% less likely to suffer a recurrence compared to those who ate less than 5grams of soy protein a day. However, the Chinese women in this study were eating traditional, whole soy foods, not GMO, processed soy protein, which is found most often in food products in the U.S. Traditional, whole soy foods are fermented, which destroy the “antinutrients” in soybeans and enable you to enjoy soy’s nutritional benefits. Unfortunately, 90% of westerners consume unfermented or GMO soy. So unless the label actually states “non GMO Soy” you may be at risk.
Also, soy in Asian cultures is typically eaten as a condiment (and in small doses) rather than a meat replacement (in large doses). Studies show that the Japanese typically consume 7-8grams of soy protein per day, with isoflavone consumption at 25 milligrams. However, mainly because of the way it’s packaged and sold in the US, Americans consumed much more than this. Some shakes have as much as 20 grams of soy protein and 160 milligrams of isoflavones in just one serving!
In conclusion, if you have to incorporate soy into your diet, make sure it is in the traditional fermented form and limit consumption to just 3-5 servings a week. Avoid processed forms of soy, including soy bars, soy based protein shakes, and soy meat substitutes.