Vegetarian Nutrition (VN) DPG Public Library

Rees K, Al-Khudairy L, et al.
Journal: Cochrane Database Syst Rev.
Published: 2021

Key Points

• Aim: Evaluate the effectiveness of a vegan dietary pattern for both primary and secondary prevention of cardiovascular disease (CVD).

• Design: This systematic review and meta-analysis included 38 papers representing 13 RCTs (including 8 ongoing trials) evaluating a vegan dietary pattern in three populations: (1) healthy adults, (2) those at high risk of CVD (primary prevention), and (3) those with established CVD (secondary prevention). The vegan dietary pattern was compared either to (1) no or minimal intervention, (2) another dietary prevention aimed at preventing CVD onset, or (3) another dietary pattern for people with CVD to prevent a recurrent event.

• Outcomes: Primary outcomes included lipid levels and blood pressure. No studies reported on clinical endpoints (CVD events).

• Results: Moderate-certainty evidence that a vegan diet probably led to a small reduction in total cholesterol, LDL cholesterol, a very small decrease in HDL levels, and a very small increase in triglyceride levels compared to no or minimal intervention in people without CVD.

  • There is a lack of evidence for a significant effect on systolic and diastolic blood pressure and total cholesterol levels.

  • The studies showed little or no effect on LDL and HDL cholesterol levels or triglycerides compared to other dietary interventions.

  • There was insufficient evidence for a beneficial effect on lipid levels or blood pressure compared to other dietary interventions.

• Limitations: Studies in this review had small sample sizes and limitations in study design. Only one study was included with people who already had CVD. No study reported on CVD clinical endpoints (i.e., heart attack, heart failure, or stroke). Eight studies were ongoing so were unable to report final results.

Conclusion

Current evidence is insufficient to conclude the effects of vegan dietary interventions on CVD risk factors. Ongoing studies may provide more insights, particularly in the context of primary prevention.

Editor’s Note: Caution is needed in interpreting the findings due to study limitations and small sample sizes. A vegan dietary pattern is not necessarily a healthy dietary pattern and other studies have explored the different effects of healthy versus unhealthy plant-based diets. This review highlights the need for further research that includes CVD clinical endpoints, larger sample sizes, and populations with CVD. In addition, diet quality should be assessed to distinguish between healthful and unhealthful plant-based diet patterns so that accurate conclusions about the efficacy of a plant-based diet in preventing and reversing heart disease.