What is Soy?
Soy comes from a soybean, which is a legume and a great source of protein. It has been consumed for centuries by Asian populations and more recently by Western societies.
Soy contains less saturated fat than meat and doesn’t contain any cholesterol.
The soybean contains a source of an important class of (good) chemicals called isoflavones. Isoflavones are “active,” meaning they have many effects on our health. Let’s explore exactly what soy does to the human body and its positive health effects.
Let's review a few important topics
II Bone health
III Menopausal symptoms
IV Prostate cancer
V Breast Cancer
VI Feminization effects in men
This is the claim that brought soy into many American diets. In 1995, a study showed consuming soy significantly lowered cholesterol levels and LDL (bad cholesterol) levels. As a result of this evidence, in 1999, the Food Drug Association (FDA) approved a health claim. This meant food companies can claim a diet containing soy “may” or “might” reduce heart disease as a result of this cholesterol-lowering effect.
However, in 2006, the American Heart Association (AHA) became concerned. A growing body of new studies was not showing the same results as the 1995 study. The American Heart Association argued with FDA to reverse the soy’s health claim. The FDA revisited the research, and concluded there was enough solid research for the claim to stay.
There has been a lot of research about soy’s ability to promote bone health. The results of one study found soy intake improved bone health compared to women who did not eat soy.
MENOPAUSAL SYMPTOMS: HOT FLUSHES (aka “FLASHES”)
Women develop hot flushes (also known as “flashes”) because of reduced estrogen levels during menopause. Since isoflavones in soy have estrogen-stimulating properties, consuming soy foods or supplements containing isoflavones improve hot flush symptoms. One study showed a group taking an isoflavone tablet showed a significant improvement in hot flushes over 12 weeks.
A study showed a 26% reduction in risk of prostate cancer in those with high intake of soy food. This was compared to those with the lowest intake of soy food.
There is evidence soy can reduce prostate specific antigen (PSA) levels, which is a marker of prostate cancer. This was found to be in men already diagnosed with prostate cancer or at high risk of developing prostate cancer. However, there is no evidence that this occurs in middle-aged healthy men. What this means exactly, it’s still up in the air and we are awaiting further studies.
There have been many studies looking at the different rates of breast cancer in different societies, with lower rates in Asian populations. It is believed these differences are due to mostly diet and lifestyle, not genetics. The reason is because after several generations of Asian immigration to Western societies, rates of breast cancer of those who moved approach the rates of that country.
In another study, Asian women who consumed more soy had significantly lower rates of breast cancer. Another study showed women with breast cancer who had higher soy consumption had a decreased risk of death and cancer recurrence.
You may have heard in the news of soy actually promoting breast cancer. It is true that some animal studies have suggested that a chemical in soy actually enhances breast cancer cells in lab rats. However, these rats were under extreme artificial conditions and were being given large amounts of soy. The amount of soy given to rats was far beyond actual human consumption.
FEMINIZATION EFFECTS IN MEN
Unfortunately, there have been several news stories that suggested soy can enhance female characteristics in men. For example, one report described a man who developed enlarged breasts after drinking excessive amounts (nearly a gallon per day!) of soy milk for several months. However, there is no proof that his enlarged breasts necessarily resulted from the excessive soy intake or from other unrelated factors. There has been many other studies that show no connection between soy intake and male fertility.
Bottom Line: So men, you can rest assured that the overwhelming evidence DOES NOT implicate soy as a promoter of feminization or decreased fertility.
My OPINION ON SOY
Soy is a great source of alternative complete protein. Many people ask, “Is soy safe?” My response to that question is YES! Despite the negative press regarding soy, this bean has some positive health benefits. The benefits include lowering cholesterol, improving bone health, and potentially decreasing your risk of getting breast and prostate cancer. For you men out there concerned about the feminizing effects of soy, you can rest assure that these claims are not well supported. As with anything, if you consume in moderation, soy can be a great meat substitute and a valuable source of dietary protein.
Soy Foods I recommend
- Soy nuts