Hypothyroidism and non-alcoholic fatty liver disease: A coincidence or a causal relationship?

Actions of thyroid hormones and thyromimetics on the liver

Thyroid hormones (triiodothyronine and thyroxine) are pivotal for metabolic balance in the liver and entire body. Dysregulation of the hypothalamus-pituitary-thyroid axis can contribute to hepatic metabolic disturbances, affecting lipid metabolism, glucose regulation and protein synthesis. In addition, reductions in circulating and intrahepatic thyroid hormone concentrations increase the risk of metabolic dysfunction-associated steatotic liver disease by inducing lipotoxicity, inflammation and fibrosis. Amelioration of hepatic metabolic disease by thyroid hormones in preclinical and clinical studies has spurred the development of thyromimetics that target THRB (the predominant thyroid hormone receptor isoform in the liver) and/or the liver itself to provide more selective activation of hepatic thyroid hormone-regulated metabolic pathways while reducing thyrotoxic side effects in tissues that predominantly express THRA such as the heart and bone. Resmetirom, a liver and THRB-selective thyromimetic, recently became the first FDA-approved drug for metabolic dysfunction-associated steatohepatitis (MASH). Thus, a better understanding of the metabolic actions of thyroid hormones and thyromimetics in the liver is timely and clinically relevant. Here, we describe the roles of thyroid hormones in normal liver function and pathogenesis of MASH, as well as some potential clinical issues that might arise when treating patients with MASH with thyroid hormone supplementation or thyromimetics.

Does Resveratrol Improve Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)?

Metabolic dysfunction-associated steatotic liver disease (MASLD) is influenced by a variety of factors, including environmental and genetic factors. The most significant outcome is the alteration of free fatty acid and triglyceride metabolism. Lipotoxicity, impaired autophagy, chronic inflammation, and oxidative stress, as well as coexisting insulin resistance, obesity, and changes in the composition of gut microbiota, are also considered crucial factors in the pathogenesis of MASLD. Resveratrol is a polyphenolic compound that belongs to the stilbene subgroup. This review summarises the available information on the therapeutic effects of resveratrol against MASLD. Resveratrol has demonstrated promising antisteatotic, antioxidant, and anti-inflammatory activities in liver cells in in vitro and animal studies. Resveratrol has been associated with inhibiting the NF-κB pathway, activating the SIRT-1 and AMPK pathways, normalizing the intestinal microbiome, and alleviating intestinal inflammation. However, clinical studies have yielded inconclusive results regarding the efficacy of resveratrol in alleviating hepatic steatosis or reducing any of the parameters found in MASLD in human patients. The lack of homogeneity between studies, low bioavailability of resveratrol, and population variability when compared to animal models could be the reasons for this.

Lifestyle and Quality of Life of Women Diagnosed with Hypothyroidism in the Context of Non-Alcoholic Fatty Liver

Interconnections between hypothyroidism and metabolic disturbances manifesting in the liver and body composition have not yet been comprehensively analyzed in the context of lifestyle. This study aimed to assess the selected lifestyle factors and quality of life in the context of the development of NAFL (non-alcoholic fatty liver) in women diagnosed with hypothyroidism. This study included 134 women categorized into three groups: with hypothyroidism and NAFL, with only hypothyroidism, and with only NAFL. We compared the groups concerning the KomPAN and WHOQOL-BREF questionnaires, anthropometric measurements, body composition parameters, and the stage of liver steatosis. The individuals with NAFL most frequently consumed lard, fried dishes, processed meats, red meat, sweets, and sweetened beverages. The individuals with hypothyroidism without coexisting NAFL exhibited the highest satisfaction with health. The NAFL group had the highest average body fat percentage. Selected lifestyle aspects influenced the development of NAFL in women diagnosed with hypothyroidism. Women's overall quality of life did not vary depending on the coexisting medical conditions. Preventive programs should promote the following: the regular consumption of meals, the appropriate energy supply, physical activity, mental health support, and striving for proper body composition parameters.

Lifestyle and Quality of Life of Women with Diagnosed Hypothyroidism in the Context of Metabolic Disorders

The lifestyle causes of metabolic disorders in patients with hypothyroidism should be investigated. We aimed to assess the lifestyle and quality of life of women diagnosed with hypothyroidism and search for the presence of differences between the lifestyle and quality of life of women with and without diagnosed lipid metabolism disorders. This study included 311 women. To assess the differences between the groups with and without metabolic disorders, a non-parametric Mann-Whitney U test was performed. Of the products that were potentially beneficial for health, statistically significant differences in the average frequency of consumption were observed for legume seeds (p = 0.014), and of the products potentially unbeneficial for health, the frequencies of consumption of fried dishes (p = 0.016) and fast-food products (p = 0.001) were significant. Only 11.9% rated their free-time physical activity as high. The quality of life was significantly different between the groups. The lifestyle was moderately appropriate. Compared with women with lipid metabolism disorders, women without them exhibited a higher frequency of correct dietary behaviors regarding the consumption of products with a potentially beneficial effect and sleeping duration. Women without lipid metabolism disorders had a better quality of life. Women with hypothyroidism should be educated about the beneficial aspects of the regular consumption of vegetables, fruits, legumes, and fish and sleeping for the optimal amount of time.