A posteriori healthier dietary patterns and several nutrients have been associated with lower risks of depression in various studies; however, evidence is lacking with regard to the prospective association between adherence to nutritional recommendations (food-based and nutrient-based recommendations) and incident depression or depressive symptoms. In this study, we investigate such associations in the NutriNet Santé cohort. The study sample included 26 225 participants (aged 18–86 years) who were initially free of depressive symptoms. Adherence to nutritional recommendations was measured by four scores namely modified French Programme National Nutrition Santé-Guideline Score (mPNNS-GS), Alternative Healthy Eating Index-2010 (AHEI-2010), Probability of Adequate Nutrient Intake Dietary Score (PANDiet) and Diet Quality Index-International (DQI-I), using non-consecutive dietary record data during the first 2 years of follow-up (mean number of recording days=8, sd 2). Depressive symptoms were defined by a Center for Epidemiologic Studies Depression Scale (CES-D) score ≥17 for men and ≥23 for women. We used Cox proportional hazards models to estimate hazard ratios and 95 % CI, modelling the dietary scores as standardised continuous variables and as tertiles. Over a mean follow-up of 6 years, we identified 2166 incident cases of depressive symptoms. All dietary scores with the exception of the AHEI-2010 were significantly inversely associated with incident depressive symptoms. In the fully adjusted model, an increase of 1 sd in the mPNNS-GS, PANDiet and DQI-I was, respectively, associated with an 8 % (95 % CI 4, 13), 5 % (95 % CI 1, 9) and 9 % (95 % CI 5, 13) reduction in the risk of depressive symptoms. Overall, these findings suggest that diet in accordance with national or international guidelines could have beneficial effects with regard to mental health.

Although nutrition has been advocated as a major determinant of healthy ageing (HA), studies investigating the link between dietary quality and HA are scarce. We investigated the association between adherence to French food-based and nutrient-based guidelines at midlife, as assessed by three dietary scores, and HA. HA was assessed in 2007–2009, among 2329 participants of the SUpplémentation en Vitamines et Minéraux AntioXydants study aged 45–60 years at baseline (1994–1995) and initially free of diabetes, CVD and cancer. HA was defined as not developing any major chronic disease, good physical and cognitive functioning, no limitations in instrumental activities of daily living, no depressive symptoms, no health-related limitations in social life, good overall self-perceived health and no function-limiting pain. Data from repeated 24-h dietary records provided at baseline permitted the computation of the modified French Programme National Nutrition Santé-Guideline Score (mPNNS-GS), the Probability of Adequate Nutrient Intake Dietary Score (PANDiet) and the Diet Quality Index-International (DQI-I). Associations of these scores with HA were assessed by logistic regression. In 2007–2009, 42 % of men and 36 % of women met our criteria of HA. After adjustment for potential confounders, higher scores of the mPNNS-GS (ORquartile 4 v. quartile 1 1·44; 95 % CI 1·10, 1·87; Ptrend=0·006) and the PANDiet (1·28; 95 % CI 1·00, 1·64; Ptrend=0·03) were associated with higher odds of HA. We observed no association between DQI-I and HA. In conclusion, this study suggests a beneficial long-term role of high adherence to both food-based and nutrient-based French dietary guidelines for a HA process.

Personalised, genotype-based nutrition is a concept that links genotyping with specific nutritional advice in order to improve the prevention of nutrition-associated, chronic diseases. This review describes the current scientific basis of the concept and discusses its problems. There is convincing evidence that variant genes may indeed determine the biological response to nutrients. The effects of single-gene variants on risk or risk factor levels of a complex disease are, however, usually small and sometimes inconsistent. Thus, information on the effects of combinations of relevant gene variants appears to be required in order to improve the predictive precision of the genetic information. Furthermore, very few associations between genotype and response have been tested for causality in human intervention studies, and little is known about potential adverse effects of a genotype-derived intervention. These issues need to be addressed before genotyping can become an acceptable method to guide nutritional recommendations.