Influence of lifestyle factors and staple foods from the Mediterranean diet on non-alcoholic fatty liver disease among older individuals with metabolic syndrome features

Highlights

• Sedentary lifestyle and lower adherence to the Mediterranean diet is associated with risk for non-alcoholic fatty liver disease in older individuals diagnosed with metabolic syndrome.

• Higher legume intake is related to an improvement in liver status.

• Recommendations of healthy lifestyles for the prevention and management of non-alcoholic fatty liver disease in patients at high cardiovascular risk are warranted.

Abstract

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, β = –1.47; 95% confidence interval [CI], –2.73 to –0.20; T3, β = –1.93; 95% CI, –3.22 to –0.65 versus T1, P_trend = 0.001) and adherence to the Mediterranean diet was inversely associated with HSI values: (moderate adherence β = –0.70; 95% CI, –1.92 to 0.53; high adherence β = –1.57; 95% CI, –3.01 to –0.13 versus lower, P_trend = 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.

Introduction

Non-alcoholic fatty liver disease (NAFLD) has become a prevalent chronic liver disease, as it is the primary cause of liver-related morbidity and mortality [1]. The increasing rates of NAFLD most likely accompany the increase in incidence of obesity, type 2 diabetes, metabolic syndrome (MetS), and cardiovascular disease (CVD) [2,3], especially in Western countries [1]. Indeed, NAFLD is a multifactorial chronic condition whose pathogenesis results from a complex interaction among genes, gut microbiota, and lifestyle factors [4]. Furthermore, the aging process is associated with an increased risk for developing cardiometabolic abnormalities and NAFLD progression [5]. NAFLD encompasses a spectrum of liver damage features being characterized at the initial stage by an excessive accumulation of intrahepatic triacylglycerols, which can progress to non-alcoholic steatohepatitis (NASH) and eventually lead to cirrhosis, hepatocellular carcinoma (HCC), or both if not detected early and treated [4]. Liver biopsy is the gold standard for NAFLD diagnoses [4]. However, it is an expensive and invasive procedure that may result in clinical complications [4]. Thus, several alternative non-invasive liver scores have been devised and developed [2], [3], [4]. The hepatic steatosis index (HSI) has demonstrated good performance in several population studies and has been used for large-scale NAFLD primary screening [6], [7], [8]. The management of all stages of NAFLD has been focused on improving the metabolic profile by encouraging a healthy lifestyle, such as adherence to certain dietary patterns and increased physical activity [2], [3], [4]. The Mediterranean diet (MedDiet) is a healthy dietary pattern that includes high consumption of plant-derived foods (fruits, vegetables, and legumes), whole grain foods, fish, olive oil, nuts, and low to moderate intake of red wine, meat, and dairy products [9]. Additionally, the MedDiet has demonstrated beneficial effects on the lipid profile, glycemic control, and blood pressure [10]. The presence of these clinical conditions are associated with higher risk for NAFLD and more advanced disease stages [2]. Epidemiologic and clinical studies have suggested that staple components of the MedDiet provide specific health bioactive compounds with healthy antioxidant and anti-inflammatory properties [10], [11], [12], [13]. In fact, the effects of the MedDiet on liver status could be attributed to specific compounds such as polyphenols, fiber, carotenoids, ω-3 polyunsaturated fatty acid (PUFA), and oleic acid [12,14] Physical activity has been shown to potentially reduce hepatic steatosis and improve insulin resistance, some MetS features, and cardiovascular events [15]. Current available recommendations suggest weight loss for NAFLD treatment (–5% or –10% of initial body weight) as the key intervention based on energy restriction. However, not only is the loss of body weight important but the characteristics of nutrient composition as well as adherence to a healthy lifestyle should be strongly considered in treatment of this disease [4]. To our knowledge, there is little available data regarding lifestyle factors of older patients with MetS. Against this background, we hypothesized that lifestyle factors, especially adherence to the MedDiet and nutritional/food characteristics and physical activity, would be associated with a decreased risk for NAFLD in a population of aduklts 55 to 75 y of age diagnosed with MetS at high cardiovascular risk.