After testing a range of diets, researchers conclude that vegan and vegetarian diets produce the healthiest levels of diet-related biomarkers. Scientists are steadily unpicking how plant-based diets can improve health. It is clear that there are many factors involved.
One obvious place to start is that vegetarians and vegans do not eat red meat or processed meat products, both of which experts consider to increase the risk of cancer. As well as choosing not to eat meat, people who follow a plant-based diet also tend to consume more vegetables, fruits, and nuts. With this increase in plant matter comes a similar increase in nutrients, fiber, and other potentially beneficial compounds.
Vegetarians and vegans also typically have higher levels of compounds with anti-inflammatory and antioxidant activity, such as carotenoids and flavonoids, in their bodies. According to the team behind the new study, these chemicals protect against cell damage and chronic diseases.
Also, vegetarians are likely to have higher levels of lignans and isoflavones in their blood serum; experts believe that both of these can protect against cardiovascular disease and cancer. Recently, a group of researchers at Loma Linda University School of Public Health in California took a detailed look at the metabolic changes that a vegetarian diet can bring. They published their findings in The Journal of Nutrition.
The scientists wanted to understand whether dietary choices made a significant difference to the levels of disease-fighting markers in blood, urine, and fat tissue. To explore, they recruited 840 participants from five dietary categories:
vegans, who consume no animal products
lacto-ovo vegetarians, who consume eggs and dairy more than once per month but consume no meat or fish
pesco-vegetarians, who consume fish once or more times each month but avoid meat
semi-vegetarians, who eat meat more than once per month but less than once each week
nonvegetarians, who eat meat at least once each weekThe scientists analyzed plasma, urine, and adipose (fatty) tissue from each of the participants. They tested for a range of markers, including carotenoids, isoflavonoids, saturated fat and unsaturated fats, and vitamins.
As expected, the vegan group had the highest levels of bioactive markers that prevent disease. For instance, the highest levels of carotenoids, isoflavones, and enterolactone were present in the vegans, followed closely by vegetarians.
Vegans also had the highest levels of omega-3 and the lowest levels of fatty acids.Also, interestingly, Miles explains that the “results for semi-vegetarians look very similar to [those of] nonvegetarians.”