Fatty liver – not a question of body weight?
Even slim people are affected by biscuits and Christmas goose
Berlin – Up to a quarter of people with a normal body mass index (BMI) can suffer from metabolic dysfunction-associated steatotic liver disease (MASLD), as recent studies show. Particularly explosive: In this subgroup, also known as ‘skinny fat’, the disease often progresses unnoticed and can lead to severe liver damage such as fibrosis, cirrhosis or liver cancer. The German Society for Gastroenterology, Digestive and Metabolic Diseases (DGVS) points out that even slim people should therefore make sure they eat a predominantly healthy diet around the festive season.
Fatty liver in slim people?
Fatty liver disease is often associated with being overweight or obese. However, studies show that up to a quarter of people with a BMI below 25 are also affected. This group often has one or more risk factors such as high blood pressure, elevated blood sugar or lipometabolic disorders, albeit less frequently than overweight people. ‘The disease often goes unrecognised in slim people as they are not considered a classic risk group,’ explains Professor Birgit Terjung, Medical Director of the GFO Clinics Bonn and media spokesperson for the DGVS.
Rapid disease progression and underestimated risk
The progression of the ‘lean fatty liver’ LEAN MASLD is worrying: studies suggest that severe liver damage such as fibrosis or cirrhosis and liver cancer (hepatocellular carcinoma, HCC) develop in this subgroup in the same way as in patients with higher body weight. ‘The lack of externally visible risk factors in particular also means that the disease is often discovered too late or underestimated,’ says Professor Andreas Geier, Head of Hepatology at the University Hospital of Würzburg.
Cardiovascular complications in particular are a serious threat. LEAN MASLD patients show an increased risk of cardiovascular disease, although according to current data it is lower than in people with obesity and fatty liver.
No customised therapies yet
Therapeutic options for LEAN MASLD are still in their infancy. While established approaches such as Resmetirom, a drug recently approved in the USA, target the entire complex of metabolic dysfunction-associated steatotic liver disease, studies specifically investigating the efficacy in lean patients are still lacking. The potential role of GLP-1 analogues, the active ingredient group of the so-called slimming injection, which show promising results in patients with a BMI over 30 kg/m², is also still unclear in LEAN MASLD.
‘What currently remains for those affected is a change in diet and sufficient exercise. The development of targeted therapies for this specific subgroup is an urgent research task,’ emphasises Geier. ‘The role of the so-called gut-liver axis, i.e. the interactions between the intestinal flora and the liver, could also open up important new therapeutic approaches. There is also still a considerable need for research here.’ However, it is already known that certain gene constellations favour the development of a fatty liver in slim people.
Prevention and education are crucial
The DGVS recommends that LEAN MASLD should also be more strongly focussed on diagnostics and prevention. ‘We need to sensitise doctors and the public to the fact that steatotic liver disease is not just a problem for overweight people,’ concludes Terjung. For the festive season, it is important to maintain a balance: ‘Four weeks of biscuits every day, sumptuous, fatty meals on all Christmas holidays and at the turn of the year – that’s too much for any liver. Enjoy yourself consciously, give your body breaks to process the sumptuous meals and always build in days on which you pay particular attention to a balanced, Mediterranean diet and exercise!’ says the DGVS media spokesperson.
Early identification of risk factors and close medical monitoring remain of central importance for patients and healthcare professionals in order to slow down the progression of this often silent disease.
Sources:
– Eslam, M., El-Serag, H.B., Francque, S. et al. Metabolic (dysfunction)-associated fatty liver disease in individuals of normal weight. Nat Rev Gastroenterol Hepatol 19, 638-651 (2022). https://doi.org/10.1038/s41575-022-00635-5Sato-Espinoza K, Chotiprasidhi P, Huaman MR, Díaz-Ferrer J. Update in lean metabolic dysfunction-associated steatotic liver disease. World J Hepatol. 2024 Mar 27;16(3):452-464. doi: 10.4254/wjh.v16.i3.452. PMID: 38577539; PMCID: PMC10989317.
– Tang A, Ng CH, Phang PH, Chan KE, Chin YH, Fu CE, Zeng RW, Xiao J, Tan DJH, Quek J, Lim WH, Mak LY, Wang JW, Chew NWS, Syn N, Huang DQ, Siddiqui MS, Sanyal A, Muthiah M, Noureddin M. Comparative Burden of Metabolic Dysfunction in Lean NAFLD vs Non-Lean NAFLD – A Systematic Review and Meta-analysis. Clin Gastroenterol Hepatol. 2023 Jul;21(7):1750-1760.e12. doi: 10.1016/j.cgh.2022.06.029. Epub 2022 Jul 19. PMID: 35863685.
– Krawczyk, M., Bantel, H., Rau, M. et al. Could inherited predisposition drive non-obese fatty liver disease? Ergebnisse aus deutschen tertiären Referenzzentren. J Hum Genet 63, 621-626 (2018). https://doi.org/10.1038/s10038-018-0420-4