Mediterranean diet and its components in relation to all-cause mortality: meta-analysis

The beneficial association of the Mediterranean diet (MedDiet) with longevity has been consistently demonstrated, but the associations of MedDiet components have not been accordingly evaluated. We performed an updated meta-analysis of prospective cohort studies published up to 31 December 2017, to quantify the association of adherence to MedDiet, expressed as an index/score (MDS) and of its components with all-cause mortality. We estimated summary relative risks (SRR) and 95 % CI using random effects models. On the basis of thirty studies (225 600 deaths), SRR for the study-specific highest/lowest and per 1sd MDS increment were 0·79 (95 % CI 0·77, 0·81, Ι 2=42 %, P-heterogeneity 0·02) and 0·92 (95 % CI 0·90, 0·94, Ι 2 56 %, P-heterogeneity <0·01), respectively. Inversely, statistically significant associations were evident in stratified analyses by country, MDS range and publication year, with some evidence for heterogeneity across countries overall (P-heterogeneity 0·011), as well as across European countries (P=0·018). Regarding MDS components, relatively stronger and statistically significant inverse associations were highlighted for moderate/none-excessive alcohol consumption (0·86, 95 % CI 0·77, 0·97) and for above/below-the-median consumptions of fruit (0·88, 95 % CI 0·83, 0·94) and vegetables (0·94, 95 % CI 0·89, 0·98), whereas a positive association was apparent for above/below-the-median intake of meat (1·07, 95 % CI 1·01, 1·13). Our meta-analyses confirm the inverse association of MedDiet with mortality and highlight the dietary components that influence mostly this association. Our results are important for better understanding the role of MedDiet in health and proposing dietary changes to effectively increase adherence to this healthy dietary pattern.

May the Mediterranean diet attenuate the risk of type 2 diabetes associated with obesity: the Seguimiento Universidad de Navarra (SUN) cohort

It is likely that the Mediterranean diet (MedDiet) may mitigate the adverse effects of obesity on the incidence of type 2 diabetes mellitus (T2DM). We assessed this hypothesis in a cohort of 18 225 participants initially free of diabetes (mean age: 38 years, 61 % women). A validated semi-quantitative 136-item FFQ was used to assess dietary intake and to build a 0-9 score of adherence to MedDiet. After a median of 9·5-year follow-up, 136 incident cases of T2DM were confirmed during 173 591 person-years follow-up. When MedDiet adherence was low (≤4 points), the multivariable-adjusted hazard ratios (HR) were 4·07 (95 % CI 1·58, 10·50) for participants with BMI 25-29·99 kg/m2 and 17·70 (95 % CI 6·29, 49·78) kg/m2 for participants with BMI≥30 kg/m2, (v.4 points), these multivariable-adjusted HR were 3·13 (95 % CI 1·63, 6·01) and 10·70 (95 % CI 4·98, 22·99) for BMI 25-30 and ≥30 kg/m2, respectively. The P value for the interaction was statistically significant (P=0·002). When we assessed both variables (BMI and MedDiet) as continuous, the P value for their interaction product-term was marginally significant (P=0·051) in fully adjusted models. This effect modification was not explained by weight changes during follow-up. Our results suggest that the MedDiet may attenuate the adverse effects of obesity on the risk of T2DM.