The aim of this systematic review and meta-analysis was to synthesize the knowledge about the relation between intake of 12 major food groups and risk of type 2 diabetes (T2D). We conducted a systematic search in PubMed, Embase, Medline (Ovid), Cochrane Central, and Google Scholar for prospective studies investigating the association between whole grains, refined grains, vegetables, fruits, nuts, legumes, eggs, dairy, fish, red meat, processed meat, and sugar-sweetened beverages (SSB) on risk of T2D. Summary relative risks were estimated using a random effects model by contrasting categories, and for linear and non-linear dose–response relationships. Six out of the 12 food-groups showed a significant relation with risk of T2D, three of them a decrease of risk with increasing consumption (whole grains, fruits, and dairy), and three an increase of risk with increasing consumption (red meat, processed meat, and SSB) in the linear dose–response meta-analysis. There was evidence of a non-linear relationship between fruits, vegetables, processed meat, whole grains, and SSB and T2D risk. Optimal consumption of risk-decreasing foods resulted in a 42% reduction, and consumption of risk-increasing foods was associated with a threefold T2D risk, compared to non-consumption. The meta-evidence was graded “low” for legumes and nuts; “moderate” for refined grains, vegetables, fruit, eggs, dairy, and fish; and “high” for processed meat, red meat, whole grains, and SSB. Among the investigated food groups, selecting specific optimal intakes can lead to a considerable change in risk of T2D.

Background: Despite growing evidence for food-based dietary patterns' potential to reduce cardiovascular disease risk, knowledge about the amounts of food associated with the greatest change in risk of specific cardiovascular outcomes and about the quality of meta-evidence is limited. Therefore, the aim of this meta-analysis was to synthesize the knowledge about the relation between intake of 12 major food groups (whole grains, refined grains, vegetables, fruits, nuts, legumes, eggs, dairy, fish, red meat, processed meat, and sugar-sweetened beverages [SSB]) and the risk of coronary heart disease (CHD), stroke and heart failure (HF). Methods: We conducted a systematic search in PubMed and Embase up to March 2017 for prospective studies. Summary risk ratios (RRs) and 95% confidence intervals (95% CI) were estimated using a random effects model for highest versus lowest intake categories, as well as for linear and non-linear relationships. Results: Overall, 123 reports were included in the meta-analyses. An inverse association was present for whole grains (RR_CHD: 0.95 (95% CI: 0.92–0.98), RR_HF: 0.96 (0.95–0.97)), vegetables and fruits (RR_CHD: 0.97 (0.96–0.99), and 0.94 (0.90–0.97); RR_stroke: 0.92 (0.86–0.98), and 0.90 (0.84–0.97)), nuts (RR_CHD: 0.67 (0.43–1.05)), and fish consumption (RR_CHD: 0.88 (0.79–0.99), RR_stroke: 0.86 (0.75–0.99), and RR_HF: 0.80 (0.67–0.95)), while a positive association was present for egg (RR_HF: 1.16 (1.03–1.31)), red meat (RR_CHD: 1.15 (1.08–1.23), RR_stroke: 1.12 (1.06–1.17), RR_HF: 1.08 (1.02–1.14)), processed meat (RR_CHD: 1.27 (1.09–1.49), RR_stroke: 1.17 (1.02–1.34), RR_HF: 1.12 (1.05–1.19)), and SSB consumption (RR_CHD: 1.17 (1.11–1.23), RR_stroke: 1.07 (1.02–1.12), RR_HF: 1.08 (1.05–1.12)) in the linear dose-response meta-analysis. There were clear indications for non-linear dose-response relationships between whole grains, fruits, nuts, dairy, and red meat and CHD. Conclusion: An optimal intake of whole grains, vegetables, fruits, nuts, legumes, dairy, fish, red and processed meat, eggs and SSB showed an important lower risk of CHD, stroke, and HF.

The aim of the present systematic review and meta-analysis was to gain further insight into the effects of adherence to Mediterranean Diet (MedD) on risk of overall cancer mortality, risk of different types of cancer, and cancer mortality and recurrence risk in cancer survivors. Literature search was performed using the electronic databases PubMed, and Scopus until 25 August 2017. We included randomized trials (RCTs), cohort (for specific tumors only incidence cases were used) studies, and case-control studies. Study-specific risk ratios, hazard ratios, and odds ratios (RR/HR/OR) were pooled using a random effects model. Observational studies (cohort and case-control studies), and intervention trials were meta-analyzed separately. The updated review process showed 27 studies that were not included in the previous meta-analysis (total number of studies evaluated: 83 studies). An overall population of 2,130,753 subjects was included in the present update. The highest adherence score to a MedD was inversely associated with a lower risk of cancer mortality (RR_cohort: 0.86, 95% CI 0.81 to 0.91, I² = 82%; n = 14 studies), colorectal cancer (RR_{observational}: 0.82, 95% CI 0.75 to 0.88, I² = 73%; n = 11 studies), breast cancer (RR_RCT: 0.43, 95% CI 0.21 to 0.88, n = 1 study) (RR_{observational}: 0.92, 95% CI 0.87 to 0.96, I² = 22%, n = 16 studies), gastric cancer (RR_{observational}: 0.72, 95% CI 0.60 to 0.86, I² = 55%; n = 4 studies), liver cancer (RR_{observational}: 0.58, 95% CI 0.46 to 0.73, I² = 0%; n = 2 studies), head and neck cancer (RR_{observational}: 0.49, 95% CI 0.37 to 0.66, I² = 87%; n = 7 studies), and prostate cancer (RR_{observational}: 0.96, 95% CI 0.92 to 1.00, I² = 0%; n = 6 studies). Among cancer survivors, the association between the adherence to the highest MedD category and risk of cancer mortality, and cancer recurrence was not statistically significant. Pooled analyses of individual components of the MedD revealed that the protective effects appear to be most attributable to fruits, vegetables, and whole grains. The updated meta-analysis confirms an important inverse association between adherence to a MedD and cancer mortality and risk of several cancer types, especially colorectal cancer. These observed beneficial effects are mainly driven by higher intakes of fruits, vegetables, and whole grains. Moreover, we were able to report for the first time a small decrease in breast cancer risk (6%) by pooling seven cohort studies.

Background: Suboptimal diet is one of the most important factors in preventing early death and disability worldwide.

Diets of the highest quality have been associated with a significantly lower risk of noncommunicable diseases. It was the aim of this study to update a previous systematic review investigating the associations of diet quality as assessed by the Healthy Eating Index (HEI), Alternate Healthy Eating Index (AHEI), and Dietary Approaches to Stop Hypertension (DASH) score and multiple health outcomes. As an additional topic, the associations of these diet quality indices with all-cause mortality and cancer mortality among cancer survivors were also investigated. A literature search for prospective cohort studies that were published up to May 15, 2017 was performed using the electronic databases PubMed, Scopus, and Embase. Summary risk ratios (RRs) and 95% CIs were estimated using a random effects model for high vs low adherence categories. The updated review process showed 34 new reports (total number of reports evaluated=68; including 1,670,179 participants). Diets of the highest quality, as assessed by the HEI, AHEI, and DASH score, resulted in a significant risk reduction for all-cause mortality (RR 0.78, 95% CI 0.77 to 0.80; I2=59%; n=13), cardiovascular disease (incidence or mortality) (RR 0.78, 95% CI 0.76 to 0.80; I2=49%; n=28), cancer (incidence or mortality) (RR 0.84, 95% CI 0.82 to 0.87; I2=66%; n=31), type 2 diabetes (RR 0.82, 95% CI 0.78 to 0.85; I2=72%; n=10), and neurodegenerative diseases (RR 0.85, 95% CI 0.74 to 0.98; I2=51%; n=5). Among cancer survivors, the association between diets for the highest quality resulted in a significant reduction in all-cause mortality (RR 0.88, 95% CI 0.81 to 0.95; I2=38%; n=7) and cancer mortality (RR 0.90, 95% CI 0.83 to 0.98; I2=0%; n=7). In the updated meta-analyses, diets that score highly on the HEI, AHEI, and DASH were associated with a significant reduction in the risk of all-cause mortality, cardiovascular disease, cancer, type 2 diabetes, and neurodegenerative disease by 22%, 22%, 16%, 18%, and 15%, respectively. Moreover, high-quality diets were inversely associated with overall mortality and cancer mortality among cancer survivors.