Soy foods are popular with vegetarians. And for a good reason. Soybeans are a great vegetarian protein source. It has all the essential amino acids, and lots of fiber, potassium, folic acids, vitamins, and minerals.
There's even a Food and Drug Administration (FDA) approved health claim that appears on hundreds of products:
But is soy as healthy as you've been lead to believe? Yes and no. Animal studies now show that eating soy can cause some serious health problems.
In 2005, the Journal of the American Dietetic Association said studies on soy and cancer are inconsistent, and high soy consumption might increase breast cancer risk, instead of decreasing it. The U.S. Agency for Healthcare Research and Quality said that most of the research on soy and menopause is "inconclusive," of "poor quality" and "too short duration."
Yet, in Asian countries, there's a high consumption of soy foods and a history of positive results. Take Okinawa, Japan, for example. Soy consumption there is the highest in the world. But, coronary heart disease, stroke, and cancer are the lowest. In fact, they're known as the healthiest and longestlived people in the world.
Sales of soy foods increased from $300 million in 1992 to $4 billion in 2008.
Why the conflicting information? Most likely, the key is the type of soy products that are consumed.
In Asia, they do not eat soy byproducts or raw soybeans. Raw soybeans contain unhealthy toxins, and phytic acid is one of them.
Phytic acid interferes with zinc, calcium, magnesium, and copper absorption. Soy contains the largest amount of phytic acid, which is why zinc deficiency is a concern for vegetarians.
Raw soybeans are also hard to digest. They have inhibitors that block digestive enzymes, including trypsin that your small intestine needs to break down protein.
Soy byproducts are purely a Western phenomenon and are not healthy. For one thing, the process used to make them changes the characteristics of the soy protein in a negative way. What's more, some processes also include boiling the soy in petroleumbased solvents, bleaching, deodorizing, and adding artificial flavors.
Check product labels and be sure to avoid all the following soy byproducts:
The fermentation process eliminates the harmful toxins and eliminates most of the phytic acid. And, while tofu and bean curd are not fermented foods, the processes used to make them removes most of their toxins.
There's no reason to avoid soy altogether. Simply stay away from soy byproducts, and choose fermented foods and other, healthy, whole soy foods.
Sally Fallon and Mary G. Enig, Ph.D., "Cinderella's Dark Side," http://www.mercola.com/article/soy/avoid_soy.htm
James Nestor, "Too Much of a Good Thing? Controversy rages over the world's most regaled legume," August 13, 2006, San Francisco Chronicle, http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/08/13/CMGJKK1BP31.DTL&type=printable
Al Sears, MD, "This Modern Health Food May Be Poisoning Prisoners," http://www.alsearsmd.com/this-modern-health-food-may-be-poisoning-prisoners/
Joene Hendry, "Soy's Healthy, but Cholesterol Benefits May Be Minimal," American Diabetes Association http://docnews.diabetesjournals.org/content/3/7/7.full
Frank M. Sacks, MD; Alice Lichtenstein, Dsc; Linda Van Horn, Ph.D., RD; William Harris, Ph.D.; Penny Kris-Etherton, Ph.D.; Mary Winston, EdD, " Soy Protein Isoflavones, and Cardiovascular Health," AHA Science Advisory, http://circ.ahajournals.org/cgi/content/abstract/113/7/1034
John Robbins, "Response To Misleading Article About Soy In Mothering Magazine," The Food Revolution, http://www.foodrevolution.org/mothering.htm