IMPACT: Immune and Musculoskeletal Physiological Adaptations to Combined Exercise Training & Nutrition

Individuals with overweight often have higher levels of inflammation, which can increase the risk of developing many health conditions. As adults with overweight represent a growing proportion of the Canadian population, research that emphasizes lifestyle interventions to help manage inflammation is warranted. Our proposed research combines both exercise and nutritional interventions along with detailed assessment of inflammation and immune responses in adults with overweight. This study aims to determine whether different dairy products can positively influence inflammation and immune function when consumed during a structured exercise training program.

Exercise training is known to reduce inflammation, and these positive effects may be bolstered by nutritional strategies, particularly through the consumption of dairy products. Dairy products such as milk and Greek yogurt (GY) are widely accessible, nutrient-dense foods, that contain anti-inflammatory constituents that may reduce systemic inflammation. Indeed, the chronic consumption of dairy in adults with overweight has been shown to reduce inflammatory and increase in anti-inflammatory markers, in the absence of exercise training. Importantly, GY and milk may have differential effects on inflammation due to differences in their preparation and constitution. GY is a fermented dairy product with bacterial cultures that may influence the gut, whereas milk is fortified with vitamin D, which most GY in Canada lacks. With respect to exercise, new and (currently) unpublished work from our group has demonstrated some differences in the acute inflammatory response to a single exercise bout following milk or GY consumption. Yet, longer-term exercise training studies with nutrition interventions, particularly ones that explore different dairy products, are seldom designed with inflammation as the primary outcome. Moreover, most studies assess inflammation only using circulating markers and do not examine dynamic responses such as how immune cells themselves adapt over time.

Rationale: Our study will help determine whether consuming different dairy products during a structured exercise training program influences inflammation and adaptations in immune responses in adults with overweight. Evidence exists for: 1) the role of exercise training in reducing inflammation in humans and inducing anti-inflammatory adaptions in immune cells in animal models, and 2) the effects of chronic dairy consumption on modulating inflammatory markers at rest. By comparing exercise training combined with milk consumption, exercise training with GY consumption, and exercise training with a habitually low-dairy diet, this study will assess whether the chronic consumption of different dairy products differentially modulate the effects of exercise training on comprehensive measures of inflammation and immune responses.

• Milk (Dietary supplement): 2 servings of 1% MF milk (1 serving = 250 mL) on non-training days and 3 servings on training days, integrated into habitual diet.
• Greek Yogurt (Dietary supplement): 2 servings of plain or flavoured GY (1 serving = 175 g) on non-training days, and 3 servings of GY on training days, integrated into your habitual diet.
• Exercise training (Behavioral): 12-week structured exercise training program. Exercise sessions will take place three times per week and will last approximately 60 minutes per session. Sessions will be conducted at York University in the Exercise Research Lab. Each session will be facilitated by a certified personal trainer and/or kinesiology student

Primary outcomes

• Inflammatory Cytokines assessed from blood samples via Elisa [week 0 and week 12]: e.g., Interleukin-6 (IL-6)
• Body Composition determined via Bodpod [week 0 and week 12]: e.g., Lean mass
• Bone turnover assessed from blood samples via Elisa [week 0 and week 12]: e.g., Procollagen type 1 N-propeptide (P1NP)

Secondary outcomes

• Immune system function (ex vivo cellular leukocyte analyses) via flow cytometry [week 0 and week 12]: e.g., monocyte cell counts
• Body Composition determined via Bodpod [week 0 and week 12]: Body fat mass
• Body Composition determined via Bodpod [week 0 and week 12]: % body fat
• Muscle thickness determined by ultrasound [week 0 and week 12]: Thickness and Cross-sectional area

Sex: All, ages: 18 Years to 50 Years, accepts healthy volunteers

Inclusion Criteria:

* Between the ages of 18 and 50 years
* Overweight BMI (25.0-29.9) kg/m2
* 'Overweight' body fat percentage (males: ≤30%; females: ≤42%)
* Low to moderately physically active (0-2 times/week)
* Habitual low dairy consumption (≤ 1 serving/day, assessed via baseline food record)

Exclusion Criteria:

* Peri- or postmenopausal status (female)
* Dairy protein allergy or lactose intolerance
* Use of vitamin D and/or calcium supplements
* Any musculoskeletal, autoimmune, or inflammatory conditions
* Use of medication related to a chronic condition

• Nicholas Cheng, MSc, Study director, York University
• Andrea Josse, PhD, Principal investigator, York University
• Ali Abdul-Sater, PhD, Principal investigator, York University