Vegan diets for the prevention of cardiovascular disease

https://www.cochrane.org/CD013501/VASC_vegan-diets-prevention-cardiovascular-disease Vegan diets for the prevention of cardiovascular disease Background It is well known that diet plays a major role in cardiovascular disease risk. This review assesses the effects of providing dietary advice to follow a vegan diet (excluding all meat, fish, eggs, dairy and honey) or providing foods relevant to the diet (or both) to healthy adults, to people at increased risk of cardiovascular disease and to those with cardiovascular disease, in order to prevent new or recurrent cardiovascular disease, and to reduce the risk factors associated with it. Study characteristics We searched key databases of medical studies up to February 2020 and found 13 randomised controlled trials (RCTs) (in 38 papers) that met our criteria. We grouped studies into the following three categories to help us with our interpretation of the results: 1. Vegan dietary intervention compared to no intervention or a minimal intervention to prevent the onset of cardiovascular disease; 2. Vegan dietary intervention compared to another dietary intervention to prevent the onset of cardiovascular disease; 3. Vegan dietary intervention compared to another dietary intervention for people with existing cardiovascular disease, to prevent recurrence. Key results None of the trials reported on the occurrence of cardiovascular disease either in those with or without disease to begin with. Risk factors for cardiovascular disease were reported in the included studies. There was moderate-certainty evidence for some small reductions in lipid levels with the vegan diet compared to no or minimal intervention in people without disease, but also some very small changes in measures in the opposite direction for cardiovascular benefit. In people who already had cardiovascular disease there was very limited information, as only one trial met our criteria. Four trials reported on side effects of the diet, which were either absent or minor. Certainty of the evidence Most studies had limitations in study design, so the evidence should be interpreted cautiously. In particular, the overall number of people who took part in the studies was too small to rule out the possibility of chance findings, and too small to pick up any differences in effect on our measures. Conclusions The review concludes that there is no information currently about the effects of a vegan diet on cardiovascular disease occurrence. There is limited information on the effects of the diet on those who already have cardiovascular disease, and mixed results about risk factors for those without disease. We found eight studies that are still ongoing, and when we have the results from these we will incorporate them into the review to help reduce the uncertainty. Authors' conclusions: Studies were generally small with few participants contributing to each comparison group. None of the included studies report on CVD clinical events. There is currently insufficient information to draw conclusions about the effects of vegan dietary interventions on CVD risk factors. The eight ongoing studies identified will add to the evidence base, with all eight reporting on primary prevention. There is a paucity of evidence for secondary prevention.