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7 Foods That Harm the Thyroid

leaky gut

One of the most critical revolutions in health over the past decade is our growing understanding of the importance of personalization, when it comes to diet.

In the past, many doctors and health experts spoke in absolutes…

  • Broccoli is good for you…
  • Spinach is good for you…
  • Sweet potatoes are good for you…

Today, we understand there are no absolutes when it comes to health.

Foods that are exceptionally healthy for some people could make others very sick. And I’m not talking about allergies, like a “harmless” peanut butter sandwich that could cause a fatal reaction in some individuals.

I am talking about individual differences in our genetics, environment, previous health and dietary history, gut microbiomes (and dozens of other factors) that can play a profound role in how certain foods and compounds in foods affect your personal health.

Along these lines, we continue our discussion of thyroid disease, where we left off in our previous article.

Thyroid Disease Is A Growing Concern

You don’t hear as much about thyroid disease as you do about cancer, heart disease, diabetes and Alzheimer’s. But it has become a serious epidemic. It’s estimated that more than 50 million people worldwide suffer some form of thyroid disease.

It is also quite concerning that the prevalence of thyroid disease has skyrocketed in the last 20 years. This indicates that changes in our environment and exposure to radiation and toxins could play a large role.

But the foods you eat can also make a big difference to the health of your thyroid.

And our reactions to these foods vary widely from one individual to the next.

So if you know you have thyroid disease or symptoms of a thyroid disorder or if you simply don’t feel as well as you know you should, it is very important to consider what you are eating and how certain foods make YOU feel.

Because even the healthiest so-called “Superfoods” could be making you sick!

In my last article, we discussed specific harmful compounds in our foods and environment which can damage your thyroid, including:

  1. Lectins
  2. Goitrogens
  3. Oxalates and
  4. Heavy Metals.

Today, we discuss some common foods that contain these compounds (and what to watch out for if you or someone you love is not feeling your best)…

leaky gut

Thyroid-Harming Food #1: Wheat & Gluten Grains

By now most people understand that gluten can harm your health – even if you are not “sensitive” to gluten![i]

Wheat and other similar grains contain a lectin called wheat-germ agglutinin (WGA). These compounds can change the cellular structure of the small intestine. This not only causes leaky gut, but allows WGA to slip into the bloodstream where it creates an inflammatory immune response (which can damage the thyroid).[ii][iii]

These foods also trigger the release of zonulin, another compound that is associated with gut permeability and incidence of autoimmune disease.[iv]

These compounds trick the body into attacking itself – and the thyroid gland is often ground zero for “friendly fire” against our own tissues. The good news is that leaky gut can be arrested and reversed. And avoiding wheat and gluten-containing foods is vital in this process.

Thyroid-Harming Food #2: Nuts & Seeds

In moderation, nuts and seeds can be delicious and healthy for most people. But these foods also contain a variety of compounds that may impair thyroid function for others – including lectins, oxalates, goitrogens and phytic acid.

Here’s a quick rundown of potentially problematic compounds in common nuts and seeds:

  • Almonds: Oxalates (122 mg per ounce), Lectins
  • Brazil Nuts: Lectins
  • Cashews: Oxalates (49 mg per ounce), Lectins
  • Flax Seeds: Goitrogen, Lectins
  • Hazelnuts: Oxalates (28 mg per ounce)
  • Pecans: Oxalates (10 mg per ounce), Lectins
  • Pistachios: Oxalates(14 mg per ounce), Lectins
  • Pumpkin Seeds: Lectins
  • Sunflower Seeds: Lectins
  • Walnuts: Goitrogen, Oxalates (31 mg per cup), Lectins

Soaking and sprouting these foods (or using blanched nut flours) can help reduce the amount of these potentially-harmful compounds. But not all of these compounds are broken down with processing or cooking and you may wish to avoid these foods if you have a thyroid condition.

Thyroid-Harming Food #3: Cruciferous Vegetables

Cruciferous vegetables include foods like broccoli, cauliflower, Brussels sprouts, cabbage, kale and many others. As I’m sure you learned from your Mother and Grandmother, who undoubtedly urged you to “eat your veggies” when you were a child… these foods have a wide variety of health benefits.

They promote detoxification by invoking Phase 2 Enzymes in the liver. They contain potent phytonutrients. And they have been found to reduce the risk of cancer.

But when it comes to thyroid, cruciferous vegetables have a dark side (for some people).

These foods contain thyroid-hampering compounds known as goitrogens (especially in their uncooked form). For most people, cooking cruciferous vegetables and reducing the amount you eat raw will be sufficient to ward off negative effects.

Thyroid-Harming Food #4: Potatoes & Sweet Potatoes

Potatoes, sweet potatoes and yams are a staple food worldwide.

And while you might already avoid these foods for their impact on blood sugar, you should also know that potatoes are rich in lectins. These compounds promote leaky gut and may increase bad bacteria (and bacterial toxins) in the gut. They also bind to tissues (including the thyroid).

Potatoes are also high in oxalates (with the amount in sweet potatoes more than three times higher than white potatoes). Avoiding the peel can reduce oxalates significantly.

It should also be noted that sweet potatoes are a known goitrogen.

So, if you have existing thyroid issues or similar symptoms, this may be a food to avoid.

Thyroid-Harming Food #5: Quinoa

Over the last decade, consumption of the “Incan Superfood” has exploded. But quinoa is NOT the superfood pseudo-grain it has been made out to be…

Research published in the American Journal of Clinical Nutrition found that quinoa can cross-react with gluten, due to lectin compounds called prolamins.

And while those pesky lectins promote leaky gut on their own, quinoa also contains saponins and phytic acid – two other gut-punching compounds – making it a potentially unsafe “gluten-free” option and potential promoter of autoimmune thyroid disorders.

Thyroid-Harming Food #6: Legumes

Legumes are typically considered healthy. But they contain a number of inflammatory anti-nutrients (including lectins) that can pose problems for those with thyroid disease.

In fact, the ability of lectins to damage the gut might account for the increased allergen potential of peanuts.[v] And while all legumes contain these compounds, peanuts and soy are “thyroid triple threats” because they also contain oxalates and goitrogens!

Soy is well known to promote leaky gut, the overgrowth of bad bacteria, autoimmune and allergic issues. Fermentation helps to enzymatically break down lectins (so foods like natto and soy sauce pose less of an issue).[vi][vii]

However, the high oxalates and goitrogens make this food a no-go. The same goes for virtually all beans… avoid if you are concerned about thyroid health.

Thyroid-Harming Food #7: Unsafe Seafood

Virtually all fish contain some mercury. But as you go up the food chain, this heavy metal concentrates in the flesh. Generally speaking, the larger the fish and the more predatory its nature, the more toxins it will contain.

Tuna, marlin, swordfish, orange roughy and shark are known to be high in methylmercury. While farm-raised fish – like tilapia, catfish, salmon and others – are often high in endocrine-disrupting PCBs.

These toxins suppress thyroid hormone receptors, reduce thyroid hormones, impair liver enzymes responsible for activating thyroid hormones, raise thyroid antibodies and enlarge the thyroid itself.[viii][ix][x][xi]

Regardless of the health of your thyroid, always seek the lowest-toxin wild fish and seafood.

Personalize Your Diet to Heal Your Thyroid

When it comes to the health of your thyroid, a “Paleo-template” is the ideal place to start. By removing grains, legumes and most forms of dairy, you’ll eliminate the biggest thyroid offenders.

From there, you can begin to unmask the sensitivities and reactions you have to common foods that can stand in the way of achieving optimum health.

Kelley HerringED NOTE: Kelley Herring is the co-founder of Wellness Bakeries, makers of grain-free, gluten-free, low-glycemic baking mixes for cakes, cookies, breads, pizza and much more. Kelley’s academic background is in biology and chemistry and for the last 15+ years, she has focused on the study of nutritional biochemistry…and the proven powers of compounds in foods to heal the body.