by December 05, 2023
2 minutes to read
Key takeaway shops:
- Twins assigned to a vegan diet had significant LDL reductions seen as early as 4 weeks.
- According to researchers, the vegan diet was universal and accessible to anyone.
Among 22 pairs of twins, those randomly assigned to a vegan diet had improvements in several cardiovascular measures vs. twins assigned to a healthy omnivore diet, according to findings published in JAMA Open Network.
“Based on these findings and considering longevity, most of us would benefit from a more plant-based diet,” Christopher Gardner, PhD, Professor Rehnborg Farquhar and professor of medicine at Stanford University, said in a press release.
Gardner and colleagues noted that most previous studies of vegan diets have been epidemiological examinations, which are subject to “the bias of self-identified vegans who may differ from non-vegans in factors that may influence have on diet and health.”
“In addition, a poorly formulated vegan diet may contain low-quality plant foods, such as refined carbohydrates and added sugars,” they wrote.
The researchers aimed 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 assigned the another one for the healthy omnivore. diet for 8 weeks, with both groups exposed to legumes, vegetables, fruit, nuts, whole grains and seeds. Participants were weighed and their blood checked at baseline, 4 weeks and 8 weeks.
Twins assigned to a vegan diet experienced significant mean (SD) reductions – compared to their counterparts – at 8 weeks in:
- LDL cholesterol concentration (LDL-C) (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 reduction in the mean LDL-C level among vegans compared to omnivores,” the researchers wrote.
However, vegan diet consumers had lower dietary satisfaction, protein intake and dietary cholesterol intake but higher intake of vegetable servings and dietary iron.
Gardner added that the study used a generalizable diet “that is accessible to anyone, as 21 of the 22 vegans followed the diet.”
“This suggests that anyone who chooses a vegan diet can improve their long-term health in 2 months, with the biggest change seen in the first month,” he said.
The researchers acknowledged multiple study limitations. For example, the cohort was generally healthy and therefore may not be generalizable to other populations, and the duration of the trial was considered short.
However, Gardner noted that “a vegan diet can provide additional benefits such as an increase in gut bacteria and a decrease in telomere loss, which slows down aging in the body.”
“What’s more important than going strictly vegan is adding more plant-based foods to your diet,” he said. “Fortunately, having fun with multicultural vegan foods like Indian masala, Asian stir-fry and African lentil-based dishes can be a great first step.”
References:
Sources/Disclosure
Reduce
Disclosure: Gardner reports that he has received funding from Beyond Meat for work outside of the study. Please see the study for relevant financial disclosures of all other authors.
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Kelli Davenport, RD, MS, CDCS
I thought this study was unique in that 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 both groups had a “healthy” diet and were left to choose foods on their own. Following a vegan diet can allow poor dietary choices, which can lead to weight gain if you don’t make other nutritional choices. Having the proper planning through the meal delivery service for the first 4 weeks, along with counseling from health advisors, was a great way to get as much of the “healthy” and nutritious diet needed to make this a valid study. I also like that this was not intended to be a weight loss study and encouraged the participants to “eat until they are satisfied.”
I am curious if there were any reports of participants eating more or less of the meals provided during the first 4 weeks and how the actual intake varied among participants. As expected, LDL-C and vitamin B-12 were significantly reduced in the vegan group. This is the main clinical implication of following a strict vegan diet, as B-12 only comes from animal food sources and is not found in any plant-based foods unless it is fortified. B-12 supplementation would be indicated in someone following a strict vegan diet as it is an essential nutrient. My other questions would be changes in calcium and iron in the vegan group, as we know that vegan diets can lead to a reduced intake of both nutrients (this is a clinical implication too).
Kelli Davenport, RD, MS, CDCS
Registered dietitian, Top Nutrition Nutrition
Disclosure: Davenport reports no relevant financial disclosures.
