Nonalcoholic Fatty Acid Liver Disease, Exercise & Vitamin D
A healthy liver should be relatively fat-free because it sends lipids elsewhere in the body to be a fuel source, used to make cell membranes, or stored in fat tissues. The accumulation of fat in the liver is an early sign of dysfunction. As more people are overweight or obese, the prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing. Unfortunately, there are no outward signs of NAFLD which can progress to cirrhosis.
New research finds NAFLD is an independent risk factor for all-cause, cardiovascular (CVD) and non-cardiovascular mortality (Tao et al, 2014). Serum 25(OH)D levels are lower in healthy men with NAFLD than their age-matched controls even after adjusting for body mass index (BMI) and metabolic syndrome (Rhee et al, 2013). Jablonski et al (2012) reported that serum vitamin D levels were significantly lower in NAFLD patients. The patients had better vitamin D status than the average American (CDC table 18.104.22.168)
The vitamin D receptor (VDR) and serum 25(OH)D levels have been linked with NAFLD (Barchetta et al, 2012). Since the liver also metabolizes vitamin D, it isn’t known if vitamin D status affects NAFLD or vice versa but lower serum 25(OH)D levels were found in people with signs of inflammation. To date, scientists have only scratched the surface on the association between vitamin D and NAFLD. We still don’t have a causal mechanism of action.
Nevertheless, these studies do make me want to get outside (in the sunshine) and exercise to keep those extra pounds off.
Tao K, Shi K-H, Wu J-X, Zhan H-Y. Nonalcoholic fatty liver disease is a potential risk factor for cardiovascular diseases. 2014 Nutr Metab Cardiovas Dis doi: 10.10.1016/j.numecd.2013.04.012
Rhee EJ, Kim MK, Park SE, Park CY, Baek KH, Lee WY, Kang MI, Park SW, Kim SW, Oh KW. High serum vitamin D levels reduce the risk of nonalcoholic fatty acid disease in healthy men independent of metabolic syndrome. 2013 Endocrin J doi: 10.1507/endocrj.EJ12-02387
Jablonski KL, Jovanovich A, Holmen J, Tagher G, McFann K, Kendrick J, Chonchol M. Low 25-hydroxyvitamin D level is independently associated with non-alcoholic fatty liver disease. 2012 Nutr Metab Cardiov Dis doi: 10.1016/j.numecd.2012.12.006