Comparative analysis of fatty acid profiles across omnivorous, flexitarians, vegetarians, and vegans: insights from the NuEva study.

Background: Different dietary choices can influence blood fatty acid profiles, which are crucial for maintaining physiological health and reducing disease risk. In particular, the exclusion of animal foods in vegetarian diets is associated with a higher risk of undersupply of long-chain omega (n)-3 fatty acids, which could, potentially, have a negative effect on inflammation. This study aimed to examine differences in plasma and erythrocyte fatty acid profiles as well as inflammation-related biomarkers between various plant-based diets and a regular omnivores diet.

Methods: The Nutritional Evaluation (NuEva) study is a is a parallel-designed trial. Here screening data was used to investigate differences in plasma and erythrocyte fatty acid profiles across omnivores (Western diet; n = 62), flexitarians (n = 69), vegetarians (n = 64) and vegans (n = 57). Furthermore, markers associated with inflammation are investigated and correlated with selected fatty acids.

Results: Flexitarians showed lower erythrocyte saturated fatty acids (SFA) than omnivores, while vegans had the lowest plasma SFA. Vegans had higher erythrocyte monounsaturated fatty acids proportions, like oleic acid, than flexitarians and vegetarians. n-6 fatty acids, particularly linoleic acid, were highest in vegans and vegetarians. Conversely, omnivores had higher arachidonic acid in erythrocytes. Vegans had lower n-3 fatty acids in both plasma and erythrocytes, also reflected in a lower n-3 index (eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA)) values, indicating a trend with restriction of animal foods: omnivores/flexitarians > vegetarians > vegans. While interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor (TNF)-α and high-sensitive C-reactive protein (hsCRP) did not differ between groups, and vegans had lower leptin levels compared to omnivores.

Conclusions: The NuEva study revealed significant impact of dietary patterns on fatty acid profiles, with vegans and vegetarians displaying lower concentrations of SFA and n-3 fatty acids, including EPA and DHA, compared to omnivores and flexitarians. Despite the clear differences in fatty acid profiles across the diets, the inflammatory markers measured in our healthy collective are comparable.

Trial registration: Registered under ClinicalTrials.gov Identifier no. NCT03582020.