A recent investigation into identical twins explored how diet impacts heart health. The study, published in JAMA Network Open, followed pairs where one twin adopted an omnivorous diet while the other pursued a vegan plan. The goal was to see how two seemingly healthy eating patterns could influence cardiovascular factors when all other variables were kept similar.
The trial took place from May through July 2022 and involved 22 twin pairs, all without signs of cardiovascular disease at the outset. Each pair began with a shared baseline goal of healthy eating that emphasized vegetables, fruits, legumes, and whole grains while avoiding sugar and refined starches. During the initial four weeks, meals were prepared and delivered through a food service, totaling 21 meals per week with seven meals each for breakfast, lunch, and dinner. In the final four weeks, participants cooked for themselves and recorded every meal in a diary to capture real-world eating habits and consistencies.
Results showed that participants following the vegan plan experienced notably lower levels of LDL cholesterol, a key marker of heart disease risk, as well as reduced insulin levels and modest weight loss compared to their omnivorous twins. These shifts point to improvements in overall cardiovascular and metabolic health among the vegan group.
Baseline data indicated a mean LDL level of 110.7 mg/dL for vegans and 118.5 mg/dL for omnivores. By the study’s end, vegan participants averaged 95.5 mg/dL, while omnivores averaged 116.1 mg/dL. An LDL level under 100 mg/dL is broadly considered favorable for heart health. Insulin levels decreased by almost 20 percent among vegan participants, a change associated with a lower risk of developing diabetes. Additionally, vegans lost about two pounds more on average than the omnivorous group during the study period.
These findings add to a growing body of evidence suggesting that well-planned vegan diets can support heart and metabolic health in adults, even when compared with a healthy omnivorous pattern that emphasizes whole foods. The twin design strengthens the comparison by minimizing genetic and early-life environmental differences, helping to isolate the impact of dietary choices on measurable health outcomes.
Experts note that individual responses to diet can vary and that long-term adherence, nutrient adequacy, and practical factors play important roles. Nevertheless, the study underscores that specific dietary patterns featuring vegetables, fruits, legumes, and whole grains can meaningfully influence LDL cholesterol, insulin sensitivity, and body weight, which together influence cardiovascular risk. Future research could explore how these diet types interact with physical activity, sleep, and other lifestyle factors to shape long-term health outcomes.
For individuals considering dietary changes, a gradual approach that emphasizes nutrient-dense foods and minimizes processed sugars and refined starches may offer cardiovascular benefits similar to those observed in the vegan group within the study context. Consulting with a healthcare professional or a registered dietitian is advisable to ensure balanced nutrition while pursuing any major dietary shift.