Mediterranean diet may reduce type-2 diabetes risk in fatty liver patients

By Hugo Francisco de SouzaReviewed by Benedette Cuffari, M.Sc.Nov 8 2024

High adherence to the Mediterranean diet may lower T2DM risk in MAFLD patients, especially men without weight gain, supporting dietary recommendations.

Study: Protective Effect of High Adherence to Mediterranean Diet on the Risk of Incident Type-2 Diabetes in Subjects with MAFLD: The [email protected] Study. Image Credit: Shutterstock AI / Shutterstock.com

In a recent study published in Nutrients, researchers investigate the relationship between Mediterranean diet (MD) adherence and subsequent risk of type-2 diabetes mellitus (T2DM) in Spanish adults with confirmed metabolic dysfunction-associated fatty liver disease (MAFLD).

Mitigating the risk of diabetes in liver disease patients

Previously termed as 'non-alcoholic fatty liver disease (NAFLD),' MAFLD is a chronic liver disease characterized by excess liver fat alongside evidence of metabolic dysfunction and at least one metabolic risk factor such as overweight, obesity, and T2DM. MAFLD significantly increases the risk of liver-centric mortality and morbidity, as well as the risk of its comorbidities, particularly T2DM.

Previous studies have revealed that modifiable behaviors can alter MAFLD outcomes. For example, dietary interventions like the MD have been shown to improve disease outcomes and extend patient lifespans.

MD is a dietary pattern characterized by high fruit, vegetable, cereal, olive oils, and fish intake, moderate intake of dairy, red wine, and eggs, and limited red meat consumption. This dietary pattern has been clinically validated to reduce the risk and progression of several metabolic conditions, including T2DM and MAFLD.

MD has been independently demonstrated to benefit MAFLD and T2DM patients, with these benefits attributed to the high anti-oxidant and anti-inflammatory properties of this diet. However, the impact of MD adherence of both MAFLD and T2DM simultaneously has not been investigated.

About the study

The present study addresses existing knowledge gaps by elucidating the hypothesized health benefits of MD against T2DM development in MAFLD patients. The study design adopted a secondary analyses approach, leveraging a long-term follow-up period of 7.5 years.

Data were obtained from the population-based diabetes study, which comprised 5,072 adults recruited from the National Health System in Spain. Based on intra-participant comparisons at follow-up, participants were divided into 'no weight increment' and 'weight increment' subcohorts, which reflected individuals whose weight stayed the same or decreased or gained weight, respectively.

Prospective participants with severe chronic disease, pregnancy, lactation, or recent surgery were excluded from analyses. MAFLD was diagnosed in cases where fatty liver index (FLI)-confirmed hepatic steatosis co-occurred with metabolic dysfunction or excessive body weight. FLI values exceeding 60 were considered confirmatory for MAFLD.

Data collection included demographic factors like age, sex, and region of residence, anthropometric measurements for body weight, height, and waist circumference, clinical measurements like blood pressure, fasting glucose serum levels, and insulin, levels, as well as patients' medical health records.

MD adherence was estimated using a daily 14-point MedDiet adherence screener (MEDAS) questionnaire. Chi-squared tests and analysis of variance (ANOVA) analyses were used to identify differences in participants' baseline variables, whereas regression models adjusted for covariates in combination with Hosmer-Lemeshow tests were used for outcomes evaluation.

Study findings

Of the 5,072 participants, 714 with a mean age of 52 met the study inclusion criteria. About 56% of the study cohort were male, with a high prevalence of metabolic disorders including hypertension, insulin resistance, and metabolic syndrome reported at study initiation.

Comparisons between 2008 and 2017 metrics revealed that 52.8% of study participants reduced or maintained their weight throughout the 7.5-year-long follow-up period, with the cohort-wide weight change estimated at a reduction of 0.81 kg.

When adjusted by sex, age, and abdominal obesity, MD adherence was inversely associated with age, weight, BMI, waist circumference, the presence of insulin resistance, and physical activity. These associations were observed in both the overall study populations, as well as individuals who did not experience any weight loss at the follow-up visit.

Study participants whose weight remained the same or declined and adhered to MD exhibited significantly higher hepatic enzyme levels than those with low adherence. The prevalence of prediabetes was directly associated with MD adherence in these individuals.

Over the 7.5-year follow-up period, 98 participants developed T2DM, 70 of whom reported low MD diet adherence. Logistic regression analyses confirmed these results, revealing that MD adherence was associated with a significantly lower risk of T2DM that was independent of age and sex.  

Adherence to MD appeared significant and inversely associated with new cases of T2DM only in the group of subjects without weight gain at follow-up, which showed 2.17 to 2.9 times less likelihood of developing T2DM compared to those with low adherence."

Conclusions

Long-term and consistent MD intake can significantly reduce the risk of T2DM, even when this risk is exacerbated by preexisting MAFLD. In the current study, the long-term follow-up data of over 700 Spanish adults revealed that individuals adhering to MD were significantly less likely to develop T2DM than those who did not, with men showing stronger pattern associations than women.

Nevertheless, additional studies are needed to confirm the efficacy of MD, particularly in individuals residing outside of the Mediterranean region, and how the observed health benefits compare with those associated with other healthy dietary patterns.

These results support nutritional recommendations about the utility of MD as the dietary pattern of choice in MAFLD patients and also as preventive therapy for the development of T2DM.”