If you’re confused about soy you are not alone. The soy controversy remains one of the most prevalent in the food/nutrition industry. Even among health care professionals there seems to be a divide. Perhaps you’ve read about the cancerous link between consuming soy and a cancer diagnosis. The media has been quick to depict soy as an evil, cancer-causing food that can be dangerous to you children, thyroid, digestive tract, and mental health. However, nutritionists and soy proponents sing its praises relentlessly. So who should you believe?
Why the Confusion?
The verdict on soy has been up in the air for a long time. This is because the studies and findings have been conflicting. Soy was first used and studied as a method of fighting cancer – this is the first twist. Now, studies find both supportive results and results that link soy with an increased risk of cancer. It’s confusing, without a doubt. Let’s review some of the current claims and the most recent research behind them so you can have a better understanding of the real relationships between soy consumption and potential health threats.
Soy and Cancer
Soy was studied to reduce cancer in rats and mice because of the low rates of cancer in Asia compared to the United States. The difference in diet, whereas Asians consume more soy products than Americans (think just soy sauce alone), allowed scientists to study the isoflavones, which work like hormones, in soy. The fear was that increasing a hormone-like compound would increase cancer risk.
Facts about these studies:
- Rodent metabolism differs from human metabolism – this leads to higher levels genistein, a primary isoflavone in soy, in rodents. Lab tests on rodents can’t correctly evaluate the effects of soy’s isoflavones on humans.
- The Asian-American comparison is inaccurate because women who classify themselves as avid soy consumers in the US consume far less than Asian women who place themselves in the same category. It’s a difference in perception – “a lot” of something has different meanings in different cultures. This makes it nearly impossible to study cross cultures of women consuming the same amount of soy.
Another fear is that soy can interfere with hormone-related cancer treatments like tamoxifam. Here are the facts:
- The largest study to date, with nearly 10,000 breast cancer patients, showed us that consuming at least 10 mg/daily of isoflavones daily was linked to a 25% DECREASE in breast cancer recurrence.
- American Cancer Society’s 2012 Nutrition and Physical Activity Guidelines for Cancer Survivors concluded that current research finds no harmful effects from breast cancer survivors eating soy.
Whole vs. Processed Soy
This is where the second twist comes in: some studies suggest that soy is safe but the safety comes with conditions – it’s best in an unprocessed, whole form. This claim has WAY more leverage than the first. Like all foods, the least-processed option is the way to go. Tempeh, tofu and miso are great examples of whole soy foods.
Mark Messina, Ph.D. and author of The American Journal of Nutrition, recommends whole soy over processed soy the same way he’d recommend apples over apple juice. “It’s really important that we choose soy in its most unprocessed form,” he explains.
The bottom line: stay away from genetically modified soy (and genetically modified ANYTHING!)
Clearing Up Lingering Confusion
While recent research establishes soy’s safety, many previous studies still contribute to the remaining misconceptions. After all, the soy controversy has gone on for more than a decade. Messina explains that the studies released in the past few years have been strong enough to alleviate concerns regarding past findings.
Some people are still scared of soy, but soy foods can be used as healthy alternatives hundreds of products such as dairy products for lactose intolerant patients and red meat for vegetarians or those at risk for colon cancer.
If you’re interested in adding more soy to your diet but aren’t sure how, Karen Collins, MS, RD, CDN, a nutrition advisor for the American Institute for Cancer Research, offers the following suggestions for incorporating soy into the diet:
• Make tofu: Tofu can be stir-fried, grilled, added to stews and soups, and used in mixed dishes such as lasagna.
• Prepare tempeh: Tempeh is a great addition to chili and pasta sauce.
• Drink soymilk: Soymilk can be used in smoothies and on cereal.
• Eat edamame: Edamame can be used in soup, stir-fries, and salads or eaten as a snack.
• Munch on soybeans: Roasted soybeans (aka soynuts) can be eaten as a snack or added to salads.