Beneficial effect on ApoB, LDL-C, and total cholesterol
ApoB is the main apolipoprotein in LDL-C (“bad” cholesterol), the researchers note. Previous studies have shown that LDL-C and apoB-containing particles are associated with increased risk of ASCVD.
They aimed to estimate the effect of vegetarian or vegan diets on blood levels of total cholesterol, LDL-C, triglycerides, and apoB in people randomized to a vegetarian or vegan diet versus an omnivorous diet (that is, including meat and dairy).
They identified 30 studies published between 1982 and 2022 and conducted in the United States (18 studies), Sweden (2), Finland (2), South Korea (2), Australia (1), Brazil (1), Czech Republic (1), Italy (1), Iran (1), and New Zealand (1).
The diet interventions lasted from 10 days to 5 years with a mean of 29 weeks (15 studies ≤ 3 months; 12 studies 3-12 months; and three studies > 1 year). Nine studies used a crossover design, and the rest used a parallel design whereby participants followed only one diet.
The studies had 11 to 291 participants (mean, 79 participants) with a mean BMI of 21.5-35.1 kg/m2 and a mean age of 20-67 years. Thirteen studies included participants treated with lipid-lowering therapy at baseline.
The dietary intervention was vegetarian in 15 trials (three lacto-vegetarian and 12 lacto-ovo-vegetarian) and vegan in the other 15 trials.
On average, compared with people eating an omnivore diet, people eating a plant-based diet had a 7% reduction in total cholesterol from baseline (–0.34 mmol/L), a 10% reduction in LDL-C from baseline (–0.30 mmol/L), and a 14% reduction in apoB from baseline (–12.9 mg/dL) (all P < .01).
The effects were similar across age, continent, study duration, health status, intervention diet, intervention program, and study design subgroups.
There was no significant difference in triglyceride levels in patients in the omnivore versus plant-based diet groups.
Such diets could considerably reduce greenhouse gases
Senior author Dr. Frikke-Schmidt noted: “Recent systematic reviews have shown that if the populations of high-income countries shift to plant-based diets, this can reduce net emissions of greenhouse gases by between 35% to 49%.”
“Plant-based diets are key instruments for changing food production to more environmentally sustainable forms, while at the same time reducing the burden of cardiovascular disease” in an aging population, she said.
“We should be eating a varied, plant-rich diet, not too much, and quenching our thirst with water,” she concluded.
The study was funded by the Lundbeck Foundation, the Danish Heart Foundation, and the Leducq Foundation. The authors, editorialists, Ms. Parker, Dr. Cassidy, and Dr. Storey have reported no relevant financial relationships. Dr. Mellor has disclosed that he is a vegetarian.
A version of this article first appeared on Medscape.com.