Nutrition

How Safe is Soya? Debunking the Two Biggest Soya Myths

by Rudy Hadisentosa, Veggie123

As the popularity of soya milk, tofu and other soya products grows, so does the inevitable backlash of claims that it's somehow unhealthy. Some of it is dairy industry propaganda, but there are also avid anti-soya activists out there saying that soya is dangerous, and can lead to osteoporosis, thyroid problems or worse. I don't know what these individuals have to gain from spreading misinformation about soya, but I'd like to offer some facts to counter these ridiculous claims.

First of all, soyabeans have been around for a very, very long time. They've been a staple food in Asia for over 5,000 years, and they've been grown in the U.S. since 1829 – in fact, Civil War soldiers brewed up soyabean coffee when they couldn't get coffee beans!

Today, people in Western nations enjoy soya milk, tofu, and fermented foods like tempeh, miso and soya sauce. Even people who don't embrace a full vegetarian lifestyle eat soya nuts and use soya protein in their morning breakfast shakes. And with soya meat-substitutes, ice cream, yoghurt and other foods, the need to understand the safety of soya has never been more important. So let's take a look at the two biggest fibs told about soya.

Soya Myth Number 1: Soya contains plant hormones that will interfere with healthy thyroid function. 

Obviously, this isn't true. If it were, then China and Japan would be populated by giants! The chemicals in soya that concern some people are called "goitrogens" and, yes, they do occur naturally in soya. But they can also be found in vegetables like broccoli, sweet potatoes and lima beans. Goitrogens interfere with the thyroid gland's ability to utilise iodine, and only cause a problem when iodine intake is extremely low – not a problem in anyone with an even moderately healthy diet.

The urban legend that soya consumption can cause hyperthyroidism comes from a period between 1951 and 1962 when several cases of goiter were diagnosed in babies who had been fed infant formula that was made from soya flour. But the formulation for soya-based baby food was changed in the 1960s, from soya flour to soya protein isolates, and manufacturers began supplementing the formula with additional iodine. Since the change, not a single case of goiter in infants has been caused by soya formula. So rest assured that soya isn't going to harm your thyroid, or your baby's.

Soya Myth Number 2: Soya increases the risk of breast cancer.

This one's also related to the belief that plant oestrogen (isoflavones) present in soya can alter oestrogen levels in the human body. To judge whether that's a danger, all you have to do is look at the breast cancer rates in countries where the residents eat a lot of soya. The fact is, they have less cases of breast cancer than in Western countries. Studies have shown that the relationship between human hormones and soya consumption is actually quite complicated – studies have shown that small amounts of soya can, indeed, increase the growth of cancer cells, but that large amounts inhibit cell growth. And the benefits appear to be greater for women who start eating soya during puberty.  The truth of the matter is that soya not only doesn't increase the risk of breast cancer, it may actually decrease that risk in some women!