In patients at high risk of cardiovascular disease, what is the effect of specific diets on mortality and cardiovascular events?
This meta-analysis, which did not include low-carbohydrate/high-fat diets or intermittent fasting (for lack of research), found the Mediterranean diet (increased fish, fruit, and vegetable intake and A LOT of olive oil) and low-fat dieting to be associated with a small benefit on reducing mortality and cardiovascular disease in patients with at least 2 risk factors. The small net benefit makes me wonder whether we should devote so much time to asking about and trying to affect diet, even in patients at high risk of adverse cardiovascular outcomes.
Meta-analysis (randomized controlled trials)
Self-funded or unfunded
These investigators searched 6 databases, including Cochrane CENTRAL and a clinical trials database, and identified 40 English-language randomized studies that enrolled more than 35,000 participants across 7 dietary programs: low fat, 18 studies; Mediterranean, 12; very low fat, 6; modified fat, 4; combined low fat and low sodium, 3; Ornish, 3; and Pritikin, 1. All participants had at least 2 risk factors for cardiovascular disease. There were no studies of low-carbohydrate/high-fat diets or intermittent fasting included in this analysis since these have not been directly studied for their effects on cardiovascular disease and overall mortality. Two investigators independently selected studies for inclusion and extracted the data. The Mediterranean diet was associated with a small decrease in overall mortality (1.7%), as was a low-fat diet (0.9%). These diets were the most studied approaches in this analysis. The Mediterranean Diet also decreased, slightly, the risk of cardiovascular mortality (1.3%), stroke (0.7%), and nonfatal myocardial infarction (1.7%). The investigators rated the certainty of evidence as moderate for these approaches.
Allen F. Shaughnessy, PharmD, MMedEd
Professor of Family Medicine