Soy has become a source of controversy in recent years. Its proponents claim that is a perfect superfood that should be consumed at every meal, while its detractors claim it is toxic and should not be eaten. As with most health claims related to food, the truth lies somewhere in the between these two claims.
Soy can be found as an ingredient in many foods, from breakfast cereals to energy bars. There are also several soy products that health food junkies will recognize, such as tofu, soy milk, and tempeh. Japanese food aficionados will be familiar with edamame, which are whole, immature soybeans, and miso, a type of fermented soy. Since soy is everywhere, it is crucial to know just how safe it is to eat.
Some of the health claims made about soy are true. They are an excellent source of protein and fiber, and they are rich in nutrients like iron, calcium, magnesium, and some of the B vitamins. Consuming soy protein can help reduce levels of dangerous LDL cholesterol. High levels of this type of cholesterol is associated with an increased risk of heart disease and stroke. Soy can also help raise your levels of healthy HDL cholesterol.
In addition to these cardiovascular benefits, soy may help protect us against some forms of cancer. The high levels of isoflavones present in soy can help prevent the growth of estrogen-dependent breast cancer, since they make the body break down estrogen before it can stimulate cancer cells. These isoflavones may also slow the growth of prostate cancer cells.
There are some potential drawbacks to soy, however. The main fatty acid in soybeans is Omega-6 polyunsaturated fats. This type of fat is good for you, but in very large amounts it can lead to inflammation and other health issues. You are not likely to get too much Omega-6 from eating tofu or edamame on occasion, but the amounts found in soybean oil may be high enough to be dangerous. Therefore, you should avoid using soybean oil or consuming foods made with it.
The estrogen-like substances that make soy so effective in slowing cancer cell growth may also negatively affect thyroid function. Regularly eating soy and soy products may lead to the development of hypothyroidism, which can cause weight gain and fatigue, among other problems. Menopausal women have a higher risk when they eat soy products because of they are already prone to hyperthyroidism. Unfortunately, women of this age can also benefit most from the cancer protections that soy can give them.
Some studies have also shown that eating soy can cause brain cells to age more quickly. One study showed that elderly people who ate soy regularly for 30 years or more had brains that functioned as though they were four years older than their true age. This may put elderly soy eaters at greater risk for dementia.
So, what is the soy lover to do? While there is no reason to give up on soy products completely, you probably should not have it at every meal. As with all foods, the best advice is to eat soy in moderation, as part of a diet that is rich in whole grains and plant-based foods.