Background: To conduct a secondary analysis of Stanford University’s Study With Appetizing Plantfood - Meat Eating Alternatives Trial (SWAP-MEAT) by assessing the effects of consuming plant-based meats versus animal meats on biomarkers of inflammation (clinical trials.gov registry: NCT03718988). We hypothesized that biomarkers of inflammation would be improved for the plant-based meats compared to the animal meats.
Methods: SWAP-MEAT was a randomized crossover trial that involved participants eating 2 or more servings of plant-based meats for 8 weeks (i.e. Plant-based phase) followed by 2 or more servings of animal meats for 8 weeks (i.e. Animal phase) or vice versa. Participants’ biomarkers of inflammation were assessed from blood samples collected every 2 weeks in the intervention. Using the Olink platform, changes in 92 biomarkers of inflammation were compared between baseline and the end of each dietary phase (week 8 and 16). Linear mixed effect models were conducted to assess if the changes were significantly different for the Plant phase compared to the Animal phase.
Results: A total of 36 participants completed the intervention and provided complete data. They were 67% women, 69% Caucasian, had an average age of 50±14 years and body mass index (BMI) of 28±5 kg/m2. The results of the linear mixed effect models indicated only 4 out of the 92 biomarkers reached statistical significance.
Conclusions: The results were contrary to our hypothesis, since we expected relative improvements in biomarkers of inflammation during the Plant-based phase. It is possible that 8 weeks of reducing animal meat consumption are not enough to observe any significant improvements in systemic inflammation or that plant-based meat products themselves are not sufficient enough to improve inflammation compared to an overall, healthy plant-based dietary pattern.