December 5, 2023
2 minutes reading
Key learning points:
- In twins who followed a vegan diet, there was a significant decrease in LDL levels, which was observed after just four weeks.
- According to researchers, the vegan diet was generalizable and accessible to everyone.
Among 22 twins, those randomly assigned to a vegan diet showed improvements in several cardiovascular measures compared to their twins who were assigned a healthy omnivore diet, according to findings published in JAMA network opened.
“Based on these results and thinking about longevity, most of us would benefit from a more plant-based diet,” Christopher Gardner, PhD, the Rehnborg Farquhar Professor and said a professor of medicine at Stanford University in a press release.
Gardner and colleagues noted that most previous studies of vegan diets are epidemiological studies, which are subject to “the bias of self-decided vegans who may differ from non-vegans in factors that may influence diet and health.”
“Additionally, a poorly formulated vegan diet may contain low-quality plant foods, such as refined carbohydrates and added sugars,” they wrote.
The researchers sought to overcome these barriers by conducting a study with 22 pairs of identical twins (average age 39 years; 77.3% female), where one twin from each pair was randomly assigned to a healthy vegan diet and the other was assigned to a healthy omnivore. diet for 8 weeks, during which both groups were exposed to legumes, vegetables, fruits, nuts, whole grains and seeds. Participants were weighed and had their blood checked at baseline, 4 weeks and 8 weeks.
Twins fed a vegan diet – compared to their counterparts – experienced significant mean decreases (SD) after 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).
Remarkably, “we observed a significant decrease in mean LDL-C levels among vegans compared to omnivores after just four weeks,” the researchers wrote.
However, consumers following a vegan diet had lower nutritional satisfaction, protein intake and dietary cholesterol intake, but higher intake of vegetable portions and dietary iron.
Gardner added that the study used a generalizable diet “that is accessible to everyone, as 21 out of 22 vegans followed the diet.”
“This suggests that anyone who chooses a vegan diet can improve their long-term health within two months, with the most change seen in the first month,” he said.
The researchers acknowledged several study limitations. For example, the cohort was generally healthy and thus may not be generalizable to other populations, while the duration of the study was considered short.
Still, Gardner noted that “a vegan diet may provide additional benefits, such as an increase in gut bacteria and the reduction of telomere loss, which slows aging in the body.”
“What’s more important than going strict vegan is incorporating more plant-based foods into your diet,” he 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:
Sources/Disclosures
To collapse
Disclosures: Gardner reports that he has received funding from Beyond Meat for work outside of research. See the study for relevant financial information for all other authors.
Perspective
Back upstairs
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. I like how they made sure that both groups were fed a ‘healthy’ diet and not just having to choose their own food. Simply following a vegan diet can still enable poor food choices, and thus lead to weight gain if nutritious alternatives are not chosen. Having the right planning through the meal delivery service for the first four weeks, along with guidance from health advisors, was a great way to ensure as much of the ‘healthy’ and nutritious food was needed to make this a valid study. I also like that they didn’t intend for this to be a weight loss study and that they encouraged participants to “eat until they were satisfied.”
I’m curious if there are any reports that participants ate more or less of the meals provided during the first four weeks and how actual intake varied between participants. As expected, LDL-C and vitamin B12 were significantly reduced in the vegan group. This would be the most important clinical implication of following a strict vegan diet, as B-12 only comes from animal food sources and is not found in any plant foods unless fortified. B12 supplementation would be indicated in someone following a strict vegan diet as it is an essential nutrient. The other curiosities I have are changes in calcium and iron in the vegan group, as we know that vegan diets can result in reduced intake of both nutrients (this would also be a clinical implication).
Kelli Davenport, RD, MS, CDCS
Registered Dietitian, Top Nutrition Coaching
Disclosures: Davenport reports no relevant financial disclosures.
