Vitamin D – supplement vid NAFLD / NASH : Effekt på leverenzym: en systematisk litteraturöversikt

Sammanfattning

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide and is strongly associated with obesity, insulin resistance, and type 2 diabetes. The disease ranges from simple fat accumulation in the liver to more severe stages such as non-alcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. Despite the increasing prevalence of NAFLD, there is currently no established pharmacological treatment, and management mainly focuses on lifestyle changes. Vitamin D has gained increasing attention because of its possible role in inflammation, metabolism, and insulin sensitivity. Several studies have shown that vitamin D deficiency is common among patients with NAFLD and may be associated with disease severity. The aim of this literature review was to investigate whether vitamin D supplementation could improve liver enzyme activity and liver-related indices in patients with NAFLD and NASH, and whether vitamin D may be useful as a complementary treatment. A systematic literature review was conducted based on a PubMed search of randomized controlled trials published during the last ten years. Five studies met the inclusion criteria and were included in the analysis. The studies were compared regarding treatment type, dosage, duration, and outcomes related to liver enzymes, metabolic parameters, inflammatory biomarkers, and liver-related measurements. The results showed that vitamin D supplementation consistently increased serum 25(OH)D levels in all studies. Some studies also reported improvements in liver enzymes, inflammatory markers, and metabolic parameters, particularly alanine aminotransferase (ALAT). However, the results were inconsistent, and most studies did not show clear improvements in structural liver outcomes such as steatosis or fibrosis. Differences in study design, treatment duration, dosage, and patient populations may partly explain the varying results. In conclusion, vitamin D supplementation may have positive effects on certain metabolic and inflammatory processes in patients with NAFLD and NASH. However, current evidence is still limited, and there is insufficient support for clear effects on liver structure or disease progression. Vitamin D should therefore be considered a possible complementary treatment rather than primary therapy.