Parul Kharod
Soy has been the topic of many controversies and debates. There are several sources that will tell you never to eat soy as it can increase your risk of cancer and many other diseases. So what is the truth? Is soy really safe?
The first thing you have to realize is that soy is not a new food that has just been discovered or invented. Soy foods have been around for centuries. Japan, China and other Asian countries have used soy products in their cuisine without causing any increased health risks. In fact, one of the healthiest, long-lived populations in the world – the Okinawan Japanese are frequent soy consumers. The traditional Okinawan diet has about two servings of soy a day. If soy foods were dangerous, its effects would be reflected in the health and longevity of these populations. Soy has been extensively researched. About 2,000 new studies on soy are released every year.
Soy is a good source of nutrients that has many health benefits. Soybeans are high in protein and healthy fat. Soybeans have unsaturated fat and are also a good source of omega-3 fatty acids. Whole soybeans are a rich source of fiber. Soybeans are high in B-vitamins and are also good sources of minerals such as calcium, iron, magnesium and copper.
There are two types of soy foods, fermented and unfermented. Fermented foods include tempeh, miso, natto, and soy sauce; unfermented foods are tofu, soymilk, edamame, soybeans, and soy nuts. These traditional natural soy foods are the healthiest and safe.
It is important to avoid highly processed forms of soy. Processed soy products such as soy burgers, soy energy bars, fake meats, and products made with soy protein isolate powders are not recommended.
Soy and Breast Cancer – Most of the health concerns about soy are because of phytoestrogens, a group of natural compounds that chemically resemble the hormone estrogen. Soy contains a group of natural plant chemicals called isoflavones. They are found in small amounts in a number of legumes, grains and vegetables; however, soybeans are the most concentrated source of isoflavones in our diet. Since isoflavones bind to estrogen receptors, they can have similar effects as estrogen. But various studies have shown that the isoflavones in soy do not have the same negative effect as animal-based estrogen hormone. Studies show that eating soy foods early in life decreases risk of breast cancer in adults. Studies suggest that children and/or teens who consume as little as one serving of soy daily decrease their risk of breast cancer later in life by 25 to 50 percent. The American Cancer Society has stated that eating traditional soy foods — like tofu, miso, tempeh and soy milk — may help lower the risk of breast, prostate and other cancers.
Soy consumption has also been suggested to reduce hot flashes in menopausal women. Girls who have been eating soy since a young age may also prevent early onset of puberty.
Soy has been shown to have no effect on men’s health and testosterone levels.
Soy and Thyroid – The health concerns rise from the claim that soy contains natural chemicals known as goitrogens that interfere with thyroid function. These can cause an enlargement of the thyroid gland (a “goiter”) and symptoms of hypothyroidism, such as lethargy, dullness, coldness, and depression. The fact is that soy is not the only food that contains goitrogens. Many other foods such as cruciferous vegetables (cabbage, cauliflower, broccoli, and Brussel sprouts), sweet potatoes, lima beans, and millet also have these chemicals. However, these foods have been found only to cause problems when iodine intake is low. Soy does not cause thyroid problems in healthy, well-nourished people who are not deficient in iodine. People who do not get adequate amount of iodine in their diet could increase their risk of thyroid problems if they eat a lot of soy and/or other foods rich in goitrogens. So the answer is not to avoid soy or cruciferous vegetables, but to get enough iodine from sources such as iodized salt or supplements.
Soy and Brain Health Most recent studies show that soy has no effect on cognitive function, which means that while eating soy may not lower your risk of dementia or Alzheimer’s, it does not increase any risk either. Soy consumption has also been associated with lower risk of depression.
Soy and Heart Health – Soy may be helpful in reducing heart disease risk. The isoflavones found in soy foods help with the production of nitric oxide, which helps to dilate blood vessels, thus keeping the arteries healthy and lower blood pressure. The fiber and protein present in whole soy foods also has been known to help lower cholesterol.
Soy and Bone Health – Studies indicate that women approaching menopause who eat isoflavone-rich soy protein are more likely to boost their bone mineral density and thus help prevent osteoporosis. Studies have also shown that soy isoflavones may reduce the risk of fractures.
How much soy? One to two servings a day of whole soy foods can provide the benefits of the isoflavones. A serving is a cup of soymilk or one half-cup of tofu, tempeh, edamame or soy nuts. GMO soy foods may contain pesticides therefore choose non-GMO and organic products.
For all Indian dishes, it may be a healthier option to use tofu instead of paneer. Paneer is milk-based and is high is saturated fat. So using tofu would make the heavy paneer based dishes more heart healthy. Soy milk can be used as a good protein source to make smoothies. As a reminder, avoid processed soy or isoflavone supplements and eat moderate amounts of healthy natural soy foods for maximum benefits.
— Parul Kharod, MS, RD, LDN is a registered dietitian and licensed nutritionist and works as a Clinical Dietitian with Outpatient Nutrition Services at WakeMed Hospital in Cary and Raleigh. She can be reached at [email protected]
Posted: Monday, April 4, 2016
