A comparison of systemic inflammation pre- and post- exercise between vegans and omnivores : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Auckland, New Zealand

Abstract

Introduction: Exercise-induced muscle damage (EIMD) triggers an inflammatory response essential for muscle repair and recovery. The impact of habitual dietary patterns on this response is not well understood. Aim: This study investigated whether nutrient source (i.e., vegan or omnivorous diet) has an impact on the systemic inflammatory response or muscle damage markers following an eccentric exercise protocol. Methods: Three vegans (2 males; 32.3 ± 5.78 years; 63.4 ± 16.9 kg; 173.7 ± 9.5 cm; 20.8 ± 3.4 BMI) and seven omnivores (6 females; 25.0 ± 5.34 years; 70.9 ± 8.5 kg; 167.9 ± 8.2 cm, 24.1 ± 2.5 BMI) underwent an eccentric exercise protocol involving 200 drop jumps. Muscle damage marker CKM, and inflammatory biomarkers IL-1β, IL-6 and IL-10 were analysed from plasma collected at baseline and 0 h, 1 h, 3 h, 24 h, 48 h, 72 h post-exercise. Participants followed a macronutrient-matched meal plan and consumed a standardised meal post-exercise. Results: IL-6 increased over time (P= 0.005), however there was no difference between diets (P= 0.225). IL-1β, IL-10 and CKM did not change over time (P= 0.371, P=0.097 and P=0.491, respectively) or differ between diets (P= 0.925, P= 0.821 and P= 0.296, respectively). Dietary analysis of participants’ habitual diets showed vegans had significantly lower intakes of cholesterol (P= 0.007), and dietary folate equivalents (P= 0.040). Dietary analysis of participants’ intake during the trial showed vegans had significantly lower intakes of cholesterol (P= 0.010), niacin equivalent (P= 0.028), and vitamin B6 (P= 0.032). Daily intake of fibre, folate, vitamin A, omega-3 polyunsaturated fatty acids, selenium, calcium, and zinc were below recommended levels for the vegans. Whereas daily intake of calcium was below recommended levels for the omnivores. Conclusion: The study found no significant differences in systemic inflammatory or muscle damage markers between habitual vegan or omnivorous diets following eccentric exercise. Despite significant differences in nutrient intake between diets, the eccentric exercise protocol was not strenuous enough to produce notable systemic stress detectable by the biomarkers measured. The small sample size limited the study’s power, highlighting the need for further research with larger samples and more comprehensive assessments, including, for example, muscle ultrasound for assessment of muscle damage, additional inflammatory biomarkers (e.g., IL-4 and IL-1ra), and plasma lipid panels and plasma nutrient levels. Future studies should continue to explore the effects of whole dietary patterns on muscle recovery and inflammation without inducing nutrient deficiencies or excessive supplementation.