Thyroid Hormone Balance Crucial for Liver Fat Reduction

TOPLINE:

Greater availability of peripheral tri-iodothyronine (T3), indicated by higher concentrations of free T3, T3, and T3/thyroxine (T4) ratio, is associated with increased liver fat content at baseline and a greater liver fat reduction following a dietary intervention known to reduce liver fat.

METHODOLOGY:

• Systemic hypothyroidism and subclinical hypothyroidism are proposed as independent risk factors for steatotic liver disease, but there are conflicting results in euthyroid individuals with normal thyroid function.
• Researchers investigated the association between thyroid function and intrahepatic lipids in 332 euthyroid individuals aged 50-80 years who reported limited alcohol consumption and had at least one condition for unhealthy aging (eg, cardiovascular disease).
• The analysis drew on a sub-cohort from the NutriAct trial, in which participants were randomly assigned to either an intervention group (diet rich in unsaturated fatty acids, plant protein, and fiber) or a control group (following the German Nutrition Society recommendations).
• The relationship between changes in intrahepatic lipid content and thyroid hormone parameters was evaluated in 243 individuals with data available at 12 months.

TAKEAWAY:

• Higher levels of free T3 and T3/T4 ratio were associated with increased liver fat content at baseline (P = .03 and P = .01, respectively).
• After 12 months, both the intervention and control groups showed reductions in liver fat content, along with similar reductions in free T3, total T3, T3/T4 ratio, and free T3/free T4 ratio (all P < .01).
• Thyroid stimulating hormone, T4, and free T4 levels remained stable in either group during the intervention.
• Participants who maintained higher T3 levels during the dietary intervention experienced a greater reduction in liver fat content over 12 months (Rho = −0.133; P = .039).

IN PRACTICE:

“A higher peripheral concentration of active THs [thyroid hormones] might reflect a compensatory mechanism in subjects with mildly increased IHL [intrahepatic lipid] content and early stages of MASLD [metabolic dysfunction–associated steatotic liver disease],” the authors wrote.

SOURCE:

The study was led by Miriam Sommer-Ballarini, Charité–Universitätsmedizin Berlin, Berlin, Germany. It was published online in the European Society of Endocrinology.

LIMITATIONS:

Participants younger than 50 years of age and with severe hepatic disease, severe substance abuse, or active cancer were excluded, which may limit the generalizability of the findings. Because the study cohort had only mildly elevated median intrahepatic lipid content at baseline, it may not be suited to address the advanced stages of metabolic dysfunction–associated steatotic liver disease. The study’s findings are based on a specific dietary intervention, which may not be applicable to other dietary patterns or populations.

DISCLOSURES:

The Deutsche Forschungsgemeinschaft and German Federal Ministry for Education and Research funded this study. Some authors declared receiving funding, serving as consultants, or being employed by relevant private companies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.