Benefits and Risks of Consuming Soy

7 Dec

You may have heard about soy foods in the news, including claims that soy prevents diseases such as cancer and heart disease. On the other hand, people have complained that they have had bad reactions to eating soy and that is toxic to their thyroid. So should you continue to eat soy or not?  Today’s blog will focus on the benefits of eating soy.  Later this week, I’ll list the risks of eating soy and whether soy should be included or avoided in your diet. 

 What is soy?

 According to, soy (or soybeans) are a type of legume that have been used for 5,000 years in China for food — i.e., tofu, tempeh, and edamame beans – and for medicinal purposes. Soybeans are considered a source of protein, and are processed into many meat and dairy substitutes. Soy contains isoflavones, which are plant hormones that have been linked to the following health benefits.  

What are the benefits of eating soy?

1. Good source of protein: Soybeans are considered by many agencies to be a source of complete protein.  A complete protein is one that contains significant amounts of all the essential amino acids that must be provided to the human body because of the body’s inability to synthesize them. For this reason, soy is a good source of protein, amongst many others, for vegetarians and vegans or for people who want to reduce the amount of meat they eat.

2. Reduces cancer risk: states that several large population studies have shown that consumption of soy foods is associated with a reduction in prostate cancer risk in men, is significantly associated with decreased risk of death and recurrence of breast cancer among women, and may reduce the risk of colorectal cancer in postmenopausal women

3. Reduces heart disease: The Food and Drug Administration (FDA) concluded that foods containing soy protein, which are included in a low fat saturated diet may reduce the risk of heart disease by lowering blood cholesterol levels.  (

 4. Contains many healthy nutrients: Soy foods are a great source of protein and contain other important nutrients, such as fiber, B vitamins, and omega-3 fatty acids.

5. Reduces osteoporosis: Isoflavones, contained in soy, may help prevent bone loss, therefore lowering the risk of osteoporosis.

 Risks of Soy Consumption

 1. Taste: A common complaint by first-time users is that soy tastes too “beany.” Still, manufacturers believe a soy revolution is coming. Soy-based yogurt, pudding, and hot dogs may soon compete with soy burgers for space on grocery shelves.

 2. Allergies: Soy is one of eight foods responsible for the majority of food allergies, and one of five foods most commonly associated with food allergies in children. People with a soy allergy can suffer everything from hives and diarrhea to breathing difficulties upon eating this food. (

 3. Slows thyroid function: Some people believe that soy is particularly toxic to thyroid patients. Soy falls into a category of foods known as goitrogens — vegetables, grains and foods that promote formation of goiter — an enlarged thyroid. Some goitrogens appear to slow thyroid function, and in some cases, trigger thyroid disease.  (

 To eat or not to eat soy

Some experts suggest that soy itself is not inherently a problem, but it’s primarily overconsumption — and secondarily, the issue of genetic modification — that are the concerns.

There are estimates suggesting that Asians consume some 10 to 30 milligrams of isoflavones from soy a day — and it’s soy in traditional food form that is not processed or genetically modified. In theU.S., however, some people are getting as much as 80 to 100 milligrams of soy isoflavones a day, by consuming soy milk, soy nuts, soy protein shakes, soy candy bars, soy cereal, and foods enriched with soy, as well as soy supplements. Some soy and isoflavone supplements have as much as 300 milligrams of isoflavones. Isoflavones are also increasingly being added as a so-called “healthy” component of foods and other supplements.

They argue that soy that is not genetically modified (aka unprocessed), and consumed in food forms — like tofu, tempeh, and miso — can be safely incorporated into the diet when used in moderation. Avoid processed soy products — including soy powders, textured vegetable protein, soy protein isolates, soy protein, protein shakes, and other processed forms of soy. Additionally, do a pantry, fridge, and freezer check (Boca Burger or Luna bar anyone?) and toss foods with these ingredients. These ingredients are also common in fast food and school lunch programs.

The bottom line

Eat soy in moderation. Soybeans, tofu, and other soy-based foods are an excellent alternative to red meat. On the other hand, there’s no reason to go overboard on eating soy. Approximately two to four servings a week is a good target; eating more than that likely won’t offer any health benefits and it is unknown whether or not it will do harm.


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