Aspartame, Sucralose, and Thyroid Function

Aspartame, Sucralose, and Thyroid Function

Video | Artificial Sweeteners | Affect on Thyroid Function | Hashimoto’s | Your Gut & Thyroid 

If you have thinning hair, dry skin, fatigue, and trouble losing weight despite what you eat, you might have a thyroid problem. If you regularly use artificial sweeteners, you might be making your situation worse. This blog post will explain how aspartame, sucralose, and thyroid function are related. 

Aspartame, Sucralose, and Thyroid Function Summary

  • Aspartame is found in Equal packets, diet sodas, and sugar-free kid’s drinks.
  • Sucralose is found in Splenda packets, diet sodas, and low-sugar foods.
  • Scientific evidence linking artificial sweeteners to thyroid issues is strong enough for the AACE to warn patients with Hashimoto’s thyroiditis to stop using artificial sweeteners.
  • Artificial sweeteners might ramp up the immune system to attack the thyroid, as in the case of autoimmune Hashimoto’s Disease
  • Sugar substitutes may alter the gut microbiome, leading to an indirect assault on healthy thyroid cells.

Aspartame, Sucralose, and Thyroid Function [Video]

In this video, you’ll learn…

  • Where you can find aspartame and sucralose.
  • How artificial sweeteners affect your thyroid!
  • How Aspartame and Sucralose affect your gut health.

Aspartame and Sucralose

Sucralose and aspartame are common sugar substitutes. 

Aspartame is the sweetener found in the little blue packets of Equal that you get when you go to a restaurant. Aspartame is also a part of NutraSweet products and is a common ingredient in Diet Coke and sugar-free kid’s drinks, like Kool-Aid. 


Sucralose is found in the little yellow packets of Splenda. It is also commonly found in Diet Pepsi products as well as a range of baked goods, chewing gums, jellies, and frozen dairy desserts. 


How Sucralose and Aspartame Affect Thyroid Function

Studies have shown that regular use of artificial sweeteners may lead to elevated TSH levels (1) (2)

If you have had your thyroid gland tested, you might be familiar with TSH, which stands for thyroid-stimulating hormone. Its job is to stimulate or tell the thyroid when to make hormones.

If your TSH level is too high, it can indicate that your thyroid is not getting the TSH message. If the message does not get there, the thyroid doesn’t make enough of its hormones, and you end up with an underactive thyroid and a sluggish metabolism. 

The evidence linking artificial sweeteners, like aspartame and sucralose, to thyroid function was convincing enough to warrant a recommendation by the American Association of Clinical Endocrinologists (AACE) to urge clinicians to discourage Hashimoto’s Thyroiditis patients from using artificial sweeteners.

Hashimoto’s Disease

Hashimoto’s is an autoimmune disease. When you have an autoimmune disease, your body’s immune system mistakenly attacks your healthy tissues. With Hashimoto’s, the attack is aimed at the thyroid.

While the mechanism of how sugar substitutes impact the thyroid is not clear, the studies speculate that the sweeteners might be ramping up the immune system to attack the thyroid.

This reaction of the immune system might have to do with the way your body metabolizes aspartame or how sucralose affects immune system organs like the thymus gland and spleen. 

Hashimoto's Disease and Artificial Sweeteners

Artificial Sweeteners, Gut Health & Your Thyroid

There is also growing evidence that artificial sweeteners alter the gut microbiome or the good bacteria in your gut (3).

But what does your gut have to do with the thyroid gland located in your neck? As it turns out, quite a bit. Sugar substitutes, like Equal and Splenda, are inflammatory foods, just like the sugar they are trying to replace.

Inflammation in the digestive tract can lead to a condition called leaky gut, which sounds like a silly and obscure condition. However, it is a common disorder, especially in people who eat the Standard American Diet. 

Leaky Gut is what it sounds like. Your intestinal lining develops leaks that allow small food particles to pass into your bloodstream, where your immune system identifies them as foreign invaders that must be attacked.

Some of these food particles, like gluten and dairy proteins, look a lot like thyroid cells to your immune system. Healthy thyroid cells become victims of mistaken identity and get attacked. After the attack, your damaged thyroid can no longer produce sufficient amounts of thyroid hormones, and you become hypothyroid.

Also, as I mentioned in my blog post on foods that boost thyroid function, Splenda can inhibit the absorption of zinc and iodine, which are two nutrients needed to make thyroid hormones. 

Gut health

Bottom Line

There is evidence that artificial sweeteners and sugar substitutes can interfere with the function of the thyroid. But are they causing you problems? That is likely best tested by giving them up for a month. If your energy returns, you lose weight, and you feel better, sweeteners should be dropped from your diet. 

Thanks for reading and have a wonderful week!


(1) Wojtas, Natalia, Lidia Wadolowska, and Elżbieta Bandurska-Stankiewicz. “Evaluation of Qualitative Dietary Protocol (Diet4Hashi) Application in Dietary Counseling in Hashimoto Thyroiditis: Study Protocol of a Randomized Controlled Trial.” International journal of environmental research and public health 16.23 (2019): 4841.

(2) Sachmechi, Issac, et al. “Autoimmune thyroiditis with hypothyroidism induced by sugar substitutes.” Cureus 10.9 (2018).

(3) Suez, Jotham, et al. “Artificial sweeteners induce glucose intolerance by altering the gut microbiota.” Nature 514.7521 (2014): 181-186.

About the Author

Becky Gillaspy, DC graduated Summa Cum Laude with research honors from Palmer College of Chiropractic in 1991.

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