Soy is a controversial food. Some consider it a superfood whereas others consider it to be a hormone disruptor. Should you include soy in your diet? That depends on how much you eat and whether you have certain health conditions.
The Pros and Cons of Soy
Whole raw soybeans are high in nutrients, mostly minerals including calcium and iron, as well as some B vitamins and Vitamin K. However, soybeans are poisonous when eaten raw.
They are a good source of protein, although not as good as meat and eggs. They are also one of the best sources of plant protein. However, cooking soy at high temperatures denatures soy proteins.
Soy is also high in phytates, which are compounds that bind minerals and decrease their absorption.
More than 90% of soy grown in the US is genetically modified and sprayed with Roundup. Once the soy is harvested, most of it is used to make soybean oil, which is used in processed food. Some is used to make livestock feed because of its high protein content (50%). The remainder is isolated soy protein, which is used to make processed food and infant formulas. By this time, the soy has been processed so much that very little of its original nutritional content remains.
Nevertheless, even in its highly processed state, soy has been shown to have health benefits. According to some studies, it can lower total and LDL (bad) cholesterol and also reduce the risk of prostate cancer.
Is soy a hormone disruptor?
Soy contains isoflavones, which are phytoestrogens (plant sources of estrogen) that can increase or decrease estrogen activity in the body depending on the receptors they bind to. This is why soy may be effective for reducing menopausal symptoms. It can also reduce bone loss in menopausal women.
However, the consumption of soy isoflavones has been linked with breast cancer. It is therefore best to avoid soy if you have breast cancer or a family history of breast cancer.
Excess soy consumption has also been linked to hypothyroidism.
Is fermented soy better than unfermented soy?
Natto, miso, and tempeh are fermented soy products consumed in Asia. Fermentation reduces the phytic acid content of soy but not the isoflavone content. This means that fermented soy has more bioavailable minerals and is easier to digest than unfermented soy, but it should still be avoided by women with or at risk of breast cancer. In addition, natto contains Vitamin K2, which is good for heart and bone health.
How to Eat Soy: Summary
It is safe to eat soy in moderation. Here are some guidelines:
- Choose fermented soy products because they are easier to digest.
- Avoid soy-based processed foods because they have very little nutritional value.
- Avoid eating soy if you are pregnant, planning on being pregnant, breastfeeding, or if you have breast cancer.
- Safe amounts of soy are 1 to 1 ½ servings per day.
If you follow these guidelines, you can enjoy the health benefits of soy and minimize the health risks.