Is it healthy to have soy or no soy in your diet?  This is a question that’s been out there awhile and one I continually hear asked. When I do my food shopping, one of the items I purchase is tempeh. Tempeh is a soy product.

What Is Soy?

Soy is a plant-based protein.  It’s a popular alternative to meats for vegetarian and vegan eaters. Soy is native to East Asia, and a lot of cuisine from that area contains soy.

Quite low in calories and fat and filled with great things like folate, iron, potassium, calcium, selenium, manganese and vitamin B6, you don’t have to be a vegetarian or vegan eater to enjoy it.

And it’s definitely a choice for protein, fiber, and vitamins without the associated cholesterol you would get from meat. Soy options are easy to find in the grocery store. Items such as tempeh or tofu are very versatile and mix easily into recipes to replace meat.

The soy I purchase is organic and non-GMO. Soy is one of those products where it is important to purchase organic. Soy is almost always genetically modified. However, the organic label does not mean that soy is GMO-free. As a result, I look for soy that contains both labels.

The average adult (sedentary) woman needs approximately 46 grams of protein per day (.36 grams per pound). Soy is a great protein choice, when eaten in moderation. Personally, I eat it approximately 2 times a week.

You can find lots of delicious recipes to choose from. What you don’t want to do is eat processed soy, such as “fake” soy products like the soy dogs in your supermarket.

Here are some of the big concerns regarding having soy or no soy in your diet:

Breast Cancer Risk

You’ve probably heard that high levels of estrogen and breast cancer risk are linked. The isoflavones found in soy are plant estrogens.

According to the Mayo Clinic, the isoflavone levels found in soy food are not high enough to cause an increased risk of breast cancer. However, higher levels of isoflavones can be found in soy (or isoflavone) supplements.

Some studies suggest a link between these supplements and increased risk of breast cancer in women with a family or personal history of breast cancer or thyroid problems.

The Traditional Asian Diet

Asian women are known to have a lower incidence of breast cancer.  They also digest a lot of soy in the traditional Asian diet. Perhaps this is because ingesting soy foods early in life may decrease the risk of developing breast cancer as an adult, due to a buildup of benefits over time.

So, if you’re thinking of taking soy isoflavone supplements now to decrease your risk of breast cancer, there is little clinical evidence that indicates that the risk for breast cancer and recurrent breast cancer will decrease.

The Harvard School of Public Health states that due to soy’s estrogenic properties, “its effects can vary depending on the existing level of hormones in the body. Premenopausal women have much higher circulating levels of estradiol—the major form of estrogen in the human body—than postmenopausal women. In this context soy may act like an anti-estrogen, but among postmenopausal women soy may act more like an estrogen.”

Read HSPH’s excellent report here.

Heart Health and Lower Cholesterol

The risk of heart disease increases with menopause. A diet rich in fruits, veggies, beans, nuts and perhaps some soy protein can help to keep your arteries clear and lower your cholesterol levels. It may also aid in weight loss. Even so, a higher soy intake does not seem to be linked with a lower risk of heart-related events in women from Western countries.

Bone Health

For postmenopausal women, consuming soy products may help preserve bone health. One study that measured women taking soy supplements, and who were not on HRT, showed that taking the supplements may be of benefit to bone health.

These findings need to be substantiated by longer-term studies that measure the effects of soy protein supplementation on bone mineral density, bone mineral content and fracture risk. So, the jury is out on this one.

Menopausal Symptoms

As for hot flashes and other symptoms of menopause, it’s possible that when isoflavones mimic estrogen, they may help to reduce these symptoms.

Sometimes, soy isoflavones bind to the same receptors as estrogen thus mimicking estrogen’s effect.  But they can also bind with receptors that block the effects of estrogen. Some women may benefit; others may not.

Cardiovascular Benefits

According to the Linus Pauling Institute, “two meta-analyses of randomized controlled trials indicated that isoflavones might exert cardiovascular benefits by improving vascular function in postmenopausal women.” (CLICK HERE for a lengthy summary from the institute for further information on ingesting soy.)

Putting It All Together

Any benefits that may be achieved from supplementing with soy or isoflavone supplements seem to be unclear. More research and better scientific evidence are needed.

My suggestion is to steer clear of the highly processed soy products such as energy bars, soy powders and so on. Obtain your soy in more natural forms like edamame, soy nuts, tempeh and tofu, in order to capture the benefits of soy without incurring any of the side effects it may produce.

When I eat soy (organic and non-GMO), I eat it in moderation – approximately 2 times per week, for dinner, in place of meat.

There are conflicting opinions regarding whether soy is healthy for you or not. What do you think? Do you feel soy is a good option for you — or not? Please comment below, we love to hear from you.

Please do your own research and remember to please consult with a qualified physician before engaging in any significant diet, fitness or lifestyle change or making any changes with regard to supplements, herbs, vitamins or prescription drugs.

According to an article on WebMD, soy interacts with medications for depression (MAOIs), some antibiotic drugs, estrogens, tamoxifen (Nolvadex) and/or Warfarin (Coumadin) and some medications changed by the liver.