Something I have seen and read a lot while I’ve been searching for information on my thyroid disorder, is this theory that we should avoid goitrogenic food or at least cook them. A notion I found so troubling due to the health benefits of these foods that I had to look into it more and find out where this theory comes from and if it had any validity.
Before I share what I have found, let me briefly go over and list foods that are referred to as goitrogenic, what the term means and why people believe them to be bad for the thyroid.
A goitrogen is a substance that interferes with thyroid function by affecting iodine uptake. Common foods considered ‘goitrogenic’ include: broccoli, spinach, kale, cauliflower, cabbage, soy, sweet potatoes, strawberries, pine nuts, flaxseed, peaches, pear and many many more. You might look at this list and be alarmed as this is likely a list of foods that plant based and vegan people eat regularly. Theses are foods we have always been told are healthy, right? Well, they are. The myth that these foods eaten in normal amounts will cause a goiter is completely unfounded. Goitrogens will not cause goiter- thick tissue growth of the thyroid. The most common causes of goiter is chronic undiagnosed Hashimoto’s Thyroiditis, an auto immune thyroid disorder and iodine deficiency- but we only need a small amount of iodine for optimal thyroid function. The theory that they cause a goiter is based on in vitro studies using excessive amounts of goitrogenic foods. Unfortunately many have made the incredibly giant leap and declared we must avoid or cook all goitrogenic foods. If someone tells you this, ask them to prove it. Not with a link to an article they found, but to multiple sources which include references to studies on HUMANS, rat studies are not relevant to humans. Whenever I have asked someone this they are only able to send links to Weston A Price who reference rat studies.
Soy is probably the most controversial of all goitrogens and not just because of its ‘goitrogenic’ status. Like many plants, soy contains phytoestrogens and it is this that causes much of the hysteria surrounding soy- very clever and effective campaigning by the dairy industry I must say. I am going to dedicate a post just to soy next week, so for now I will stick to the goitrogen and thyroid issue. According to leading expert Dr Kharrazian, soy can cause an inflammatory response in some people with auto immune conditions: ‘ I have seen several patients develop thyroiditis swelling with soy and conclude the soy caused a goiter. In those cases the thyroid swelling reduced when they removed the soy from their diet, confirming that the swelling was due to an inflammatory response and not goiter.’ Soy does not irritate me personally, but if you are ever in doubt about a food, you can always eliminate it temporarily and see if you feel better. I do not advise anyone eats refined soy such as soy protein isolate, in large quantities. I don’t agree with heavily processed foods fullstop but refined soy in particular is pretty nasty stuff and you’ll find it in a lot of processed foods, especially sports or energy bars. It is a cheap way to increase the protein content of a product. I had one really irrational lady in a support group tell me that soy ‘almost killed her’. She was consuming a high amount of refined foods with soy in it, amongst other things. I personally stick to organic tofu, tempeh, miso and occasionally the bean itself. It has not hindered my recovery at all by still consuming soy and my thyroid labs continue to improve.
There are medications and environmental toxins that promote goiter, I include a link to Dr Kharrazian’s article below (1)
I am perplexed and concerned that thyroid patients avoid goitrogenic foods because they all have tremendous benefits to our health. Cruciferous vegetables are known for their anti cancer benefits and are beneficial for balanced sex hormones. These fruits and vegetables are complex carbohydrates which offer us wonderfully high amounts of fibre, so crucial for good digestive health. It is simply a myth that has circulated for so long in the ‘natural health’ community and we must highlight how dangerous it can be to take advice online without checking the source of the information. I don’t expect you to take my advice at face value either! I will add some links below and here are my tips for helping you when reading about nutrition online:
– what is the source of this information? Are there references to scientific studies?
– are the references used animal studies? Rodents are commonly used and they process nutrients very differently to humans. Rat TSH levels rise much greater in response to goitrogens than humans do as they lack a thyroid-binding protein.
– who has funded the research? Do they have a conflict of interest?
– who are the lead authors of a study and what are their links to the food industry?
I hope you seek the truth for yourself so you don’t exclude any healthful plant foods unnecessarily. As always, if you know something irritates you, you will obviously want to avoid it. But don’t believe this goitrogen myth, you will be far healthier and far more likely to balance your hormones by including these wonderful healthy plants.
1. More from Dr Kharraziac on Goiter, goitrogens and thyroid enlargement here, including medications that promote goiter:
2. Stop The Thyroid Madness on Goitrogens and Soy
3. A Review of the scientific literature on the effects of soy and thyroid function
4. Soy and the Thyroid