Hashimoto's Hypothyroidism Induced by Artificial Sweeteners

Artificial sweeteners are found in many types of foods and beverages, and often is a turn-to product for many people as an alternative to sugar.  When can sugar-substitutes be detrimental to health? Animal studies associate the side effects of sugar-substitutes with a wide range of health problems—however, not much is known about similar implications in humans.

This is a unique case of a 52-year-old female whose diet included high consumption of artificially sweetened beverages.  She presented with Hashimoto's hypothyroidism.

• Thyroid Stimulating Hormone (TSH): 12.2 ml/U/L (Normal: 0.4 – 4.5)
• Free-T4: 0.5 ng/dl (Normal: 0.58 – 1.64)
• Anti-Thyroid Peroxidase Antibody (Anti-TPO Ab): 196 lU/ml (Normal: <35)

The patient was treated with levothyroxine 0.75 mg/day.  Her TSH remained between 1.23 mI/U/L and 2.16 mI/U/L.  Several years later, she stopped consuming sugar-substitutes.  Her TSH dropped to 0.005 mI/U/L and remained suppressed despite lowering levothyroxine to 0.5 mg and discontinuing it.

•  TSH: Normal
• Anti-TPO Ab: <20 IU/ml (Normal: <35)
• Thyroid Stimulating Immunoglobulin (TSI): 113% (Normal: <140%)
• Thyrotropin Binding Inhibiting Immunoglobulins (TBII): <6.0% (Normal: <16%)
• The patient remained euthyroid.

The authors urge physicians to consider artificial sweetener consumption in their patients diagnosed with Hashimoto's thyroiditis.  Eliminating sugar-substitutes and closely monitoring thyroid function is recommended.