Evidence for the use of soy in the diet dates back to 2838 BC China and has been a staple in the diet of Southeast Asians for several centuries. It is estimated that the protein in soy compromises 20-60% of the daily protein intake for this part of the world Tofu has been a revered food of many Emperors.
Americans mostly use soy for the production of soy bean oil. The oil is extracted with hexane and left over beans are defatted and exposed to very high temperatures. As you can imagine when processed in this fashion most or all nutritious value is lost and in fact the use of these highly processed soy components are in part responsible for a lot of the chronic health problems we see today. So you may be wondering how can I defend this bean?
When we look at whole food soy such as tofu, tempeh, miso and soy milk we see a different picture. So I am not talking about soy hot dogs, fake foods like soy ice cream, protein bars or powder.
While soybeans are noteworthy for their protein, vitamin and minerals, they are probably most known for containing phytoestrogens, particularly isoflavones. These isoflavones behave like weak estrogens and are able to bind estradiol receptors in many tissues in the body. In some cases they act like weak estrogens and in others they block effects of estrogens.
Unadulterated whole soy actually shows promise in the prevention and management of breast cancer not to mention its benefits on bone, heart and brain health.
- Epidemiological studies in which large populations of women have been followed have shown either no association between soy and breast cancer or a protective.
- Association – people who ate more soy had less breast cancer.
Also of note, early soy exposure and exposure during adolescence shows the most potential for risk reduction in girls. Young girls should aim for greater than one serving a day.
In women who have or have had breast cancer, especially ER positive, soy also confers a benefit regardless of whether taking tamoxifen or not.
Typical servings of soy:
- 1/2 cup edamame
- 1 cup soy milk
- 1/2 cup tofu
- 1/2 cup tempeh
- 2 tablespoons Miso
- Miso: paste made from fermented soy beans, Japanese culinary staple
- Tempeh: fermented soy, bound into firm cake like form, of Indonesian origin
- Tofu: made from bean curd which is pressed into a soft white block
- Edamame: immature soy beans in the pod, common in Japanese and Chinese cuisine
- Soy Milk: made from soaking dry soybeans and grinding with water
What to avoid:
- Soy supplements: soy isoflavones supplements
- GMO: unfortunately 80% of soy has been genetically modified, to avoid this choose organic
- Processed soy: soy protein isolate, soy bean oil
For many people digestibility of soy can be an issue. If you are new to soy foods you may want to try smaller portions or fermented soy (tempeh, miso, natto) which is easier to digest.
For those people with hypothyroid disorders soy can act like a goitrogen so best if modestly consumed.
Some of my favorite recipes for soy come from Heidi Swanson of 101.cookbooks.com;
Orange pan-glazed tempeh or Amaretto spiked Chocolate Mousse