05 December 2023
2 minute read
Key takeaways:
- Twins assigned to the vegan diet had significant reductions in LDL seen as early as 4 weeks.
- According to the researchers, vegan nutrition was generalizable and accessible to everyone.
According to published findings, among 22 pairs of twins randomly assigned to a vegan diet, those twins assigned to a healthy omnivore diet showed improvements in several cardiovascular measures. JAMA Network Open.
“Based on these results and thinking about longevity, many of us could benefit from switching to a more plant-based diet.” Christopher Gardner, PhD, Rehnborg Farquhar Professor and a professor of medicine at Stanford University said in a press release.
Data derived from: Landry M, et al. JAMA Netw On. 2023;doi:10.1001/jamanetworkopen.2023.44457.
Gardner and colleagues noted that most previous studies on vegan diets were epidemiological studies and were subject to “bias from self-determined vegans, who may differ from non-vegans in factors that may influence diet and health.”
“Additionally, a poorly formulated vegan diet may include low-quality plant foods such as refined carbohydrates and added sugars,” they wrote.
The researchers aimed to overcome these obstacles by conducting a study with 22 pairs of identical twins (mean age, 39 years; 77.3% female); One twin from each pair was randomly assigned to a healthy vegan diet and the other twin to a healthy omnivore. Both groups were placed on the diet for 8 weeks, exposing them to legumes, vegetables, fruits, nuts, whole grains, and seeds. Participants were weighed and had their blood checked at baseline, weeks 4 and 8.
Twins assigned to the vegan diet experienced significant mean decreases (SD) at week 8 compared to their counterparts:
- LDL cholesterol (LDL-C) concentration (SD = 13.9 mg/dL; 95% CI, 25.3 to 2.4);
- fasting insulin level (SD = 2.9 IU/mL; 95% CI, 5.3 to 0.4); And
- body weight (SD = 1.9 kg; 95% CI, 3.3 to 0.6).
Specifically, “as early as 4 weeks, we observed a significant decrease in the mean LDL-C level in vegans compared to carnivores,” the researchers wrote.
However, consumers on the vegan diet had lower dietary satisfaction, protein intake, and dietary cholesterol intake, but higher vegetable servings and dietary iron intake.
Gardner added that the study “used a generalizable diet that is accessible to everyone, as 21 out of 22 vegans followed the diet.”
“This shows that anyone choosing a vegan diet can improve their long-term health within 2 months, with the most change seen in the first month,” he said.
Researchers acknowledged multiple study limitations. For example, while the cohort was generally healthy and therefore potentially not generalizable to other populations, the duration of the trial was considered short.
Still, Gardner noted that “a vegan diet may provide additional benefits, such as increasing gut bacteria and reducing telomere loss, which slows aging in the body.”
“What’s definitely more important than going vegan is adding more plant-based foods to your diet,” she said. “Fortunately, having fun with vegan multicultural foods like Indian masala, Asian stir-fries, and African lentil-based dishes can be a great first step.”
References:
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Descriptions:
Gardner reported receiving funding from Beyond Meat for studies outside the study. Please see the work for all relevant financial disclosures from other authors.
Perspective
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Kelli Davenport, RD, MS, CDCS
I thought this study was unique in that they used identical twins and assigned one twin to the vegan group and the other to the omnivore group. I liked that they made sure that both groups ate “healthy” food and were not allowed to choose foods on their own. Simply following a vegan diet can still allow for poor nutritional choices and therefore result in weight gain if you do not choose nutritious alternatives. Proper planning through a meal delivery service and consultation with health advisors during the first 4 weeks was a great way to provide the “healthy” and nutritious diet needed to make this a valid study. I also liked that they didn’t aim for this to be a weight loss study and encouraged participants to “eat until they’re full.”
I’m wondering if there are any reports on whether participants ate more or less than the meals provided during the first 4 weeks and how actual intake varied among participants. As expected, LDL-C and vitamin B-12 were significantly reduced in the vegan group. Since B-12 comes only from animal food sources and is not found in any plant-based foods unless fortified, this would be the main clinical consequence of following a strict vegan diet. B-12 supplementation is indicated in a person following a strict vegan diet because it is an essential nutrient. Another thing I’m wondering about might be the changes in calcium and iron in the vegan group, since we know that vegan diets can lead to reduced intake of both nutrients (this could also be a clinical consequence).
Kelli Davenport, RD, MS, CDCS
Registered dietitian, Top Coaching Nutrition
Descriptions: Davenport did not disclose any relevant financial disclosures.
