Abstract

Introduction: There is much evidence that fat-modified and low-fat diets rich in vegetables, fruits, legumes, and nuts as well as either olive oil or mustard oil are protective against cardiovascular diseases (CVDs) and all causes of cardiovascular-induced mortality. This communication aims to ascertain the relative efficacy of structured named diet and for prevention of major cardiovascular events and death in patients at high risk of CVDs.

Study Design and Synthesis of Data: This is a systematic review and network meta-analysis of randomized controlled trials. The study searched Medline, Embase, AMED (Allied and Complementary Medicine Database), CENTRAL (Cochrane Central Register of Controlled Trials), CINAHL (Cumulative Index to Nursing and Allied Health Literature), and ClinicalTrials.gov up to Jan 2025. The comparison was made between dietary patterns with minimal intervention, such as healthy diet information sheet or alternative patterns with at least nine months of follow-up and reporting data on mortality or major cardiovascular events, such as stroke or non-fatal myocardial infarction in randomized trials. In addition to dietary intervention, dietary patterns could also include other behavioral risk factors and other secondary interventions such as drug therapy. The endpoints were individual cardiovascular events, including stroke, non-fatal myocardial infarction (NFMI), CVD mortality, all-cause mortality, and unplanned cardiovascular interventions.

Results: Of the 42 eligible trials (n = 36, 954), nine trials (n = 17, 632) studied a primary prevention population, and 33 trials (n = 17 916) studied a secondary prevention population. The study examined low fat (18 studies), Mediterranean (14), very low fat (6), modified fat (4), combined low fat and low sodium (3), Ornish (3), Pritikin (1) and Indo-Mediterranean (2) dietary patterns. Based on evidence of moderate certainty, follow-up revealed that the Mediterranean dietary pattern proved superior to minimal intervention for the prevention of all-cause mortality (odds ratio = 0.72, 95% confidence interval (CI): 0.56 to 0.92; patients at intermediate risk: risk difference 17 fewer per 1000 followed over five years), cardiovascular mortality (0.55, 0.39 to 0.78; 13 fewer per 1000), stroke (0.65, 0.46 to 0.93; 7 fewer per 1000), and non-fatal myocardial infarction (0.48, 0.36 to 0.65; 17 fewer per 1000). Based on moderate certainty evidence, low fat programs proved superior to minimal intervention for prevention of all-cause mortality (0.84, 0.74 to 0.95; 9 fewer per 1000) and NFMI (0.77, 0.61 to 0.96; 7 fewer per 1000). The results for the Indo-Mediterranean diet were much more pronounced. The absolute effects for these dietary patterns were greater for patients at high risk. There were no convincing differences between Mediterranean and low-fat programs for mortality or NFMI, however, the remaining five dietary patterns showed only minor benefit compared with minimal intervention.

Conclusions: It is concluded that evidence with moderate certainty shows that dietary patterns promoting Indo-Mediterranean and Mediterranean compared with low fat diets can reduce all-cause mortality and NFMI in patients with higher risk of CVDs. Moreover, Mediterranean-type diets may also decrease the risk of stroke.