Goitrogens – Myths Dispelled
Written by April-Tui Buckley
There seems to be an endless amount of food or nutrition myths out there and some more harmful than others. One that has been given a fair amount of attention and is a topic close to this hypothermic women’s heart, is goitrogens. Yes, I hear you sigh, what aren’t we allowed to eat now? But bear with me, I’m hear to tell you to ignore this misinformation! Anything that tells you to eat less healthy green foods has got to raise your suspicions. It did mine and I’m glad I looked into it further.
Soon after I was diagnosed hypothyroidism I came across a lot of other patients who were circulating various blogs or ‘articles’ about the dangers of goitrogenic food, particularly for those of us with ‘under active thyroid’ or hypothyroidism. I was desperate to get well at this point and didn’t want to do anything to make my condition worse, but equally I didn’t want to stop eating certain foods needlessly. I first had to understand what goitrogenic foods and a ‘goiter’ was. The theory is goitrogenic foods are foods which diminish iodine uptake, thereby causing a goiter to grow on your thyroid. A goiter is thick tissue growth on the thyroid that does not change in size. Contrary to popular belief, the most common cause of goiter is actually undiagnosed hashimoto’s thyroiditis which is not related to iodine deficiency. Common ‘goitrogenic foods’ are: broccoli, spinach, kale, cauliflower, cabbage, soy, sweet potatoes, strawberries, flaxseed and much more. These foods have been mistakenly labelled as foods to limit intake of, in order to avoid iodine deficiency. But this is based on studies conducted on rats using extremely high doses of the juice of certain foods. There are no *human* studies to support the theory that these foods in normal amounts are harmful to our thyroid. In fact these are all extremely healthy plant foods and should be part of a well varied diet.
Dr Kharrazian is a leading thyroid expert and in a November 2013 post he had this to say about goitrogens: “ The fear of goitrogenic foods is another example of how people have taken in vitro (test tube) studies using unbelievably excessive amounts of dietary goitrogens and concluded eating any small amount of these foods can cause a goiter. For those who don’t believe me, please go on a goitrogen diet loaded with strawberries, kale, peaches, broccoli, cauliflower, and spinach and see if you develop a goiter. I promise you will not. As a matter of fact, these phytochemical-rich foods are essential for health when you have an autoimmune disorder, except for soy, which is immune reactive for many Hashimoto’s patients.” ( 1 )
Soy is probably the most controversial of the listed so-called goitrogenic foods, and all this for a humble old bean! As Dr Kharrazian says, some with auto immune disorders, including Hashimoto’s, will have a problem with soy and particularly refined soy. Refined soy, like soy protein isolate, is a cheap food ingredient used in an enormous amount of highly processed food products. If you eat a lot of refined food, you are not going to help your thyroid problem. There is another theory that soy interrupts the endocrine system due to the phytoestrogens it contains, and there have even been reports that soy decreases sperm count and has a feminising effect on men. Neither is true (2 ). In fact many plant foods contain phytoestrogens and there is a wealth of evidence about their positive effects on the body, particularly for women. Most of the anti-soy position relies heavily on data that was derived from animal studies. Again this is not relevant for humans and the weight of sound scientific evidence refutes all of these claims. Indeed phytoestrogens are now thought to have a positive effect on serum cholesterol levels, bone formation and possibly even a protective effect against breast cancer. (3 ).
I personally include pretty much all these ‘goitrogenic foods’ in my diet and my hypothyroidism is well controlled now, in fact I continue to see improvements despite eating plenty of greens and soy! As always I encourage people to be careful about what they read online. This kind of reductionist approach to nutrition can result in causing far more confusion and concern than is necessary. When people isolate nutrients and then study the effects of high doses on animals, you are going to see results that have very little value in the human context. I hope I have shown that omitting healthful foods like kale and broccoli is both unnecessary and counter productive, whether you have a thyroid problem or not. These plant foods are wonderfully rich in nutrients and very beneficial to our hormones. Eat more plants! Your thyroid will thank you.
About Guest Contributor:
New Zealand-born April-Tui Buckley is an ethical vegan and the woman behind the popular blog thebalancedvegan
Passionate about all aspects of health and our entire food system, April-Tui is trained in nutrition and natural health. Her blog aims to encourage people to reconnect with their food, get back into the kitchen and rediscover food traditions. Recipes are designed to show people how easy, healthful and enjoyable being vegan is. She writes about other aspects of vegan life and wellness, with a particular interest in hormone health.
“I try to transfer my love of food and animals to my readers”. – April-Tui Buckley.