Vegan dietary pattern for the primary and secondary prevention of cardiovascular diseases.

Rees K, Al-Khudairy L, Takeda A, Stranges S (2021)

Cochrane - DOI: 10.1002/14651858.CD013501.pub2.

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Evidence Categories

• Care setting: College/University Setting
• Care setting: Community setting
• Care setting: Commercial food environment
• Population group: Students
• Population group: Adults living with overweight and obesity
• Intervention: Intra-/Inter-personal: Food provision
• Outcome: Healthy Eating: Fruit and veg intake
• Outcome: Healthy Eating: Fibre intake
• Outcome: Healthy Eating: Fat intake
• Outcome: Healthy Eating: Protein intake
• Outcome: Healthy Eating: Whole diet quality

Type of Evidence

Systematic Review

Aims

The authors state:

"To determine the effectiveness of following a vegan dietary pattern for the primary and secondary prevention of CVD."

Findings

The authors state:

• "A vegan dietary pattern excludes meat, fish, eggs, dairy and honey; the intervention could be dietary advice, provision of relevant foods, or both."
• "We selected randomised controlled trials (RCTs) in healthy adults and adults at high risk of CVD (primary prevention)."
• "We conducted three main comparisons: 1. Vegan dietary intervention versus no intervention or minimal intervention for primary prevention; 2. Vegan dietary intervention versus another dietary intervention for primary prevention;"
• "Thirteen RCTs (38 papers, 7 trial registrations) and eight ongoing trials met our inclusion criteria. Most trials contributed to primary prevention: comparisons 1 (four trials, 466 participants randomised) and comparison 2 (eight trials, 409 participants randomised)."
• "Four trials reported on acceptability of the vegan diet and six trials reported on adherence. These studies found the vegan diet to be acceptable and did not find differences in acceptability with comparison groups, with good overall adherence, and some reported that this was higher for the vegan intervention than for comparison diets."
• "One study used thresholds of cholesterol intake and fat intake as indicators of adherence to the vegan dietary intervention, and found significantly reduced intakes compared to the control group (GEICO 2013). A further study used dietary indiscretions measured over three days as an adherence measure (Wright 2017), but did not define these. In the vegan group dietary indiscretions increased during the six-month intervention period (Wright 2017)."
• "Turner-McGrievy 2015 defined adherence as the absence of prohibited foods on dietary recall or <40% fat for the omnivorous diet group where they found that adherence to the dietary recommendations did not differ by diet group at six-month followup."
• "In Barnard 2009, dietary adherence to the vegan group was defined as the absence of meat, poultry, fish, dairy, or egg intake reported on 24-hour recalls and three-day dietary records of saturated fat <5% and total fat <25% of energy, and average daily cholesterol intake <50 mg. This study found diet adherence criteria were met by 67% of the vegan group compared to 44% of adherence criteria for the comparison diet at 22 weeks follow-up (P = 0.019)."
• "Jenkins 2014 looked at adherence to the three principal cholesterol-lowering components (vegetable proteins (soy and gluten), nuts and viscous fibres) of the low-carbohydrate vegan diet which was estimated from the seven-day food records. When the amount consumed was equivalent to the amount prescribed a 33.3% compliance would be recorded for that component. Overall adherence (of 100%) to the vegan dietary intervention at six months was 33.6% (95% CI 22.1 to 45.2)."
• "In Lee 2016, dieticians deducted points from a daily 10-point scale of self-assessed dietary recording, for the consumption of prohibited foods or whenever daily food consumption had not been maintained according to the prescribed food exchange lists. The mean compliance score (a maximum of 10 points) during the overall intervention period was 9.2 ± 1.6 and 8.2 ± 1.5 in the conventional diet group and vegan diet group, respectively (P = 0.002)." 
• "Most studies included in this review were at unclear risk of bias for many of the 'Risk of bias' domains, so results should be interpreted cautiously."

Conclusions

The authors state:

"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."