by December 5, 2023
2 minutes of reading
Key takeaways:
- The twins assigned to a vegan diet had significant decreases in LDL that were observed as early as 4 weeks.
- According to the researchers, the vegan diet was generalizable and accessible to anyone.
Among 22 pairs of twins, those who were randomly assigned to a vegan diet had improvements in several cardiovascular measures compared to their twin who was assigned to a healthy omnivorous diet, according to findings published in Open JAMA Network.
“Based on these results and with longevity in mind, most of us would benefit from adopting a more plant-based diet.” Christopher Gardner, PhD, Professor Rehnborg Farquhar and a Stanford University medicine professor said in a news release.
Gardner and colleagues noted that most previous studies on vegan diets are epidemiological examinations, which are subject to the “bias of self-identified vegans who may differ from non-vegans on factors that may influence diet and health.”
“In addition, a poorly formulated vegan diet may include low-quality plant foods, such as refined carbohydrates and added sugars,” they wrote.
The researchers set out to overcome these barriers by conducting a study with 22 pairs of identical twins (mean age, 39 years; 77.3% female) where one twin in each pair was randomly assigned to a healthy vegan diet and the other to an omnivorous diet. healthy. diet for 8 weeks, with both groups exposed to legumes, vegetables, fruits, nuts, whole grains and seeds. Participants were weighed and had a blood test at the start of the study, 4 and 8 weeks.
Twins who were assigned to a vegan diet, compared to their counterparts, experienced significant mean (SD) decreases at 8 weeks in:
- 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).
In particular, “as early as 4 weeks, we observed a significant decrease in the mean LDL-C level among vegans compared to omnivores,” the researchers wrote.
However, vegan diet consumers had lower dietary satisfaction, protein and dietary cholesterol intake, but higher intakes of vegetable servings and dietary iron.
Gardner added that the study used a generalizable diet “that is accessible to anyone, because 21 of the 22 vegans followed the diet.”
“This suggests that anyone who chooses a vegan diet can improve their long-term health within 2 months, with the most changes seen in the first month,” he said.
The researchers acknowledged multiple limitations of the study. For example, the cohort was generally healthy and therefore potentially not generalizable to other populations, while the duration of the trial was considered short.
Still, Gardner noted that “a vegan diet may confer additional benefits, such as increasing gut bacteria and reducing telomere loss, which slows the body’s aging.”
“What’s more important than going strictly vegan is including more plant-based foods in your diet,” he said. “Fortunately, having fun with multicultural vegan foods like Indian masala, Asian stir-fries, and African lentil-based dishes can be a great first step.”
References:
Sources/Disclosures
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Disclosures: Gardner reports receiving funding from Beyond Meat to work outside of the studio. She consults the study for relevant financial disclosures from all other authors.
Perspective
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Kelli Davenport, RD, MS, CDCS
I thought this study was unique because they were able to use identical twins and assign one twin to the vegan group and one to the omnivore group. I like how they made sure both groups had a “healthy” diet and weren’t left to choose foods on their own. Simply following a vegan diet could still allow for poor dietary choices and could therefore result in weight gain if nutritious alternatives are not chosen. Having proper planning through the meal delivery service for the first 4 weeks, along with advice from health coaches, was a great way to ensure as much of the “healthy” and nutritious diet needed to make this a valid study. I also like how they didn’t intend this to be a weight loss study and encouraged participants to “eat until full.”
I’m curious if there were reports that participants ate more or less of the meals provided during the first 4 weeks and how actual intake varied between participants. As expected, LDL-C and vitamin B-12 were significantly reduced in the vegan group. This would be the main clinical implication of following a strict vegan diet, since B-12 comes only from animal sources and is not found in any plant-based foods unless it has been fortified. Supplementation with B-12 would be indicated for a person who follows a strict vegan diet, since it is an essential nutrient. The other curiosity I have would be the changes in calcium and iron in the vegan group, since we know that vegan diets could result in a lower intake of both nutrients (this would also have a clinical implication).
Kelli Davenport, RD, MS, CDCS
Registered Dietitian, Top Coaching Nutrition
Disclosures: Davenport does not report any relevant financial disclosures.
