Nonalcoholic Fatty Liver Disease (aka NAFLD) is a somewhat common liver condition that affects about 25% of Americans. A healthy liver naturally contains some fat, but NAFLD is a condition where there is an excessive build- up of fat. Alcohol consumption can be one reason for increased fat in the liver, but not in the case of NAFLD. Instead, it’s caused mainly by obesity, diabetes, elevated cholesterol or poor dietary choices.

NAFLD can be mild and symptomless, but it can also cause problems such as fatigue, swelling in legs, nausea and other non-fatal conditions. There is even the possibility that it can progress to liver cancer or liver failure over time. So it’s important to know if you have it in order to stop the progression.

Beyond the known causes previously mentioned, NAFLD may also be linked to low thyroid function. A large study was published recently that looked at over 9000 people who were monitored to see if they developed NAFLD over the course of 10 years. Researchers measured everyone’s thyroid levels (free T4 hormone and TSH) at the start of the study and at the end.
The researchers found that the higher the thyroid hormone levels were to start, the lower the risk of developing NAFLD. Patients who were diagnosed with hypothyroidism had the highest risk. Researchers noticed that people who were considered to have “normal thyroid” tests, but were on the lower end of normal, also had increased risk of developing NAFLD.

Patients who had elevated TSH levels, the standard test used to diagnose hypothyroidism, (high TSH = low thyroid hormone) had a higher risk for NAFLD. The overall trend was that the more “normal” the thyroid and TSH tests were, the lower the person’s risk of developing NAFLD.

This study is interesting because it links liver health to thyroid levels fairly convincingly. Anyone with low- normal thyroid levels, hypothyroidism or Wilson’s Temperature Syndrome, should be aware of this connection and have their liver checked out (liver enzyme tests) by their physician. The reverse is also true- if you have liver problems, you should check to see if your thyroid is sluggish. By taking your temperature, you will see whether or not you have a slow metabolism. If so, standard thyroid tests will help you see whether you have hypothyroidism or Wilson’s Temperature Syndrome. Instructions for taking your temperature are HERE.

J Clin Endocrinol Metab. 2016 Aug;101(8):3204-11. Thyroid Function and the Risk of Nonalcoholic Fatty Liver Disease: The Rotterdam Study. Bano A1, Chaker L1, Plompen EP1, Hofman A1, Dehghan A1, Franco OH1, Janssen HL1, Darwish Murad S1, Peeters RP1.