OBJECTIVE: Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver morbidity. This condition often is accompanied by obesity, diabetes, and metabolic syndrome (MetS). The aim of this study was to evaluate the connection between lifestyle factors and NAFLD in individuals with MetS.
METHODS: A cross-sectional study with 328 participants (55-75 y of age) diagnosed with MetS participating in the PREDIMED-Plus trial was conducted. NAFLD status was evaluated using the non-invasive hepatic steatosis index (HSI). Sociodemographic, clinical, and dietary data were collected. Adherence to the Mediterranean diet (mainly assessed by the consumption of olive oil, nuts, legumes, whole grain foods, fish, vegetables, fruits, and red wine) and physical activity were assessed using validated questionnaires.
RESULTS: Linear regression analyses revealed that HSI values tended to be lower with increasing physical activity tertiles (T2, beta = -1.47; 95% confidence interval [CI], -2.73 to -0.20; T3, beta = -1.93; 95% CI, -3.22 to -0.65 versus T1, Ptrend = 0.001) and adherence to the Mediterranean diet was inversely associated with HSI values: (moderate adherence beta = -0.70; 95% CI, -1.92 to 0.53; high adherence beta = -1.57; 95% CI, -3.01 to -0.13 versus lower, Ptrend = 0.041). Higher tertiles of legume consumption were inversely associated with the highest tertile of HSI (T2, relative risk ratio [RRR], 0.45; 95% CI, 0.22-0.92; P = 0.028; T3, RRR, 0.48; 95% CI, 0.24-0.97; P = 0.041 versus T1).
CONCLUSION: Physical activity, adherence to the Mediterranean diet, and consumption of legumes were inversely associated with a non-invasive marker of NAFLD in individuals with MetS. This data can be useful in implementing precision strategies aimed at the prevention, monitoring, and management of NAFLD.
Nonalcoholic fatty liver disease (NAFLD) is defined by hepatic steatosis in the presence of alcohol intake within safe limits, defined by guidelines of scientific associations (usually 20 g or 2 units/day in women, 30 g or 3 units in men). The diagnosis is usually followed by medical counseling of total abstinence, in order to prevent disease progression.
This policy has been challenged by epidemiological studies, suggesting that the risk of liver disease and disease progression is lower in modest drinkers than in total abstainers. We revised the literature on the effects of modest alcohol intake on disease burden. Epidemiological data may suffer from several potential biases (recall bias for retrospective analyses, difficulties in the calculation of g/day), limiting their validity.
Prospective data suggest that NAFLD patients with regular alcohol intake, although within the safe thresholds, are at higher risk of liver disease progression, including hepatocellular carcinoma; a detrimental effect of modest alcohol drinking is similarly observed in liver disease of viral etiology. Alcohol intake is also a risk factor for extrahepatic cancers, particularly breast, oral, and pharyngeal cancers, with gender difference and no floor effect, which outweigh the possible beneficial effects on cardiovascular system, also derived from retrospective studies.
Finally, the negative effects of the calorie content of alcohol on dietary restriction and weight loss, the pivotal intervention to reduce NAFLD burden, should be considered. In summary, the policy of counseling NAFLD patients for alcohol abstinence should be maintained.
Non-alcoholic fatty liver disease (NAFLD) is the hepatic consequence of metabolic syndrome, which often also includes obesity, diabetes, and dyslipidemia. The connection between gut microbiota (GM) and NAFLD has attracted significant attention in recent years. Data has shown that GM affects hepatic lipid metabolism and influences the balance between pro/anti-inflammatory effectors in the liver. Although studies reveal the association between GM dysbiosis and NAFLD, decoding the mechanisms of gut dysbiosis resulting in NAFLD remains challenging. The potential pathophysiology that links GM dysbiosis to NAFLD can be summarized as: (1) disrupting the balance between energy harvest and expenditure, (2) promoting hepatic inflammation (impairing intestinal integrity, facilitating endotoxemia, and initiating inflammatory cascades with cytokines releasing), and (3) altered biochemistry metabolism and GM-related metabolites (i.e., bile acid, short-chain fatty acids, aromatic amino acid derivatives, branched-chain amino acids, choline, ethanol). Due to the hypothesis that probiotics/synbiotics could normalize GM and reverse dysbiosis, there have been efforts to investigate the therapeutic effect of probiotics/synbiotics in patients with NAFLD. Recent randomized clinical trials suggest that probiotics/synbiotics could improve transaminases, hepatic steatosis, and reduce hepatic inflammation. Despite these promising results, future studies are necessary to understand the full role GM plays in NAFLD development and progression. Additionally, further data is needed to unravel probiotics/synbiotics efficacy, safety, and sustainability as a novel pharmacologic approaches to NAFLD.
BACKGROUND: Adherence to a Mediterranean diet (MedDiet) is thought to reduce liver steatosis.
OBJECTIVES: To explore the associations with liver steatosis of 3 different diets: a MedDiet + extra-virgin olive oil (EVOO), MedDiet + nuts, or a control diet.
METHODS: This was a subgroup analysis nested within a multicenter, randomized, parallel-group clinical trial, PREvencion con DIeta MEDiterranea (PREDIMED trial: ISRCTN35739639), aimed at assessing the effect of a MedDiet on the primary prevention of cardiovascular disease. One hundred men and women (mean age: 64 +/- 6 y), at high cardiovascular risk (62% with type 2 diabetes) from the Bellvitge-PREDIMED center were randomly assigned to a MedDiet supplemented with EVOO, a MedDiet supplemented with mixed nuts, or a control diet (advice to reduce all dietary fat). No recommendations to lose weight or increase physical activity were given. Main measurements were the percentage of liver fat and the diagnosis of steatosis, which were determined by NMR imaging. The association of diet with liver fat content was analyzed by bivariate analysis after a median follow-up of 3 y.
RESULTS: Baseline adiposity and cardiometabolic risk factors were similar among the 3 treatment arms. At 3 y after the intervention hepatic steatosis was present in 3 (8.8%), 12 (33.3%), and 10 (33.3%) of the participants in the MedDiet + EVOO, MedDiet + nuts, and control diet groups, respectively (P = 0.027). Respective mean values of liver fat content were 1.2%, 2.7%, and 4.1% (P = 0.07). A tendency toward significance was observed for the MedDiet + EVOO group compared with the control group. Median values of urinary 12(S)-hydroxyeicosatetraenoic acid/creatinine concentrations were significantly (P = 0.001) lower in the MedDiet + EVOO (2.3 ng/mg) than in the MedDiet + nuts (5.0 ng/mg) and control (3.9 ng/mg) groups. No differences in adiposity or glycemic control changes were seen between groups.
CONCLUSIONS: An energy-unrestricted MedDiet supplemented with EVOO, a food with potent antioxidant and anti-inflammatory properties, is associated with a reduced prevalence of hepatic steatosis in older individuals at high cardiovascular risk.