After analyzing the results, the team found vegans were the healthiest, compared to the other groups. Those on vegan diets had more omega-3 fatty acids, higher levels of antioxidants and higher levels of compounds known to decrease inflammation. High levels of inflammation have been linked to diseases, including cancer.
Overall, vegans had more biomarkers that prevent diseases such as cancer, heart disease and hypertension.
"An awareness that a healthier biomarker profile is obtained with a plant-based diet should motivate people to be proactive about dietary habits that promote good health and prevent disease," co-author Fayth Miles said in a statement.
Lacto-ovo vegetarians nearly tied with pesco-vegetarians for the second healthiest diet. And semi-vegetarians were only slightly healthier than non-vegetarians.
"Overall, results for semi-vegetarians look very similar to non-vegetarians," Miles said. "This research helps ... paves the way for future studies elucidating mechanisms linking diet patterns to disease."
Want to learn more about the findings? Take a look at the full assessment here.