Researchers discovered that young men who ate Greek yogurt after training showed lower levels of inflammation than those who consumed a carb pudding, highlighting the power of fermented dairy in recovery.
Study: Resistance Exercise Training and Greek Yogurt Consumption Modulate Markers of Systemic Inflammation in Healthy Young Males—A Secondary Analysis of a Randomized Controlled Trial. Image credit: Oksana Mizina/Shutterstock.com
A recent study in Nutrients used an isoenergetic carbohydrate pudding (CP) control to assess the effects of post-exercise Greek yoghurt (GY) consumption on markers of systemic inflammation during an exercise training intervention.
Exercise, dietary supplementation, and anti-inflammatory markers
Post-exercise nutrition plays a key role in recovery and maximizing the benefits of training. Long-term exercise training lowers inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6, although acute bouts can temporarily raise them. The type of nutrition consumed after workouts may amplify these benefits.
Dairy products are excellent post-exercise supplements due to their carbohydrate, protein, and electrolyte content. They also have anti-inflammatory and anti-oxidative constituents and have been linked to lower inflammation markers like C-reactive protein (CRP).
Research has extensively studied milk, but given the widespread consumption of yoghurt, it may be worthwhile studying its effects as a source of post-exercise nutrition. This is particularly true for GY, given its additional bioactive components, higher protein content than milk, and fermented nature. This may lower nuclear factor kappa B (NF-kB) activity and alter the gut microbiome, lowering circulating inflammatory cytokines. Furthermore, research has yet to investigate the short- and long-term effects of GY consumption and exercise training.
About the study
This study used an isoenergetic CP control to assess the short-term (1 week) and long-term (12-week) effects of progressive resistance exercise training and GY supplementation on markers of systemic inflammation (CRP, IL-1 beta [IL-1β], TNF-α, IL-6, IL-10, and IL-1 receptor antagonist (IL-1ra)). The effect of a change in body composition on inflammatory markers after a workout was also analyzed.
The participant sample comprised 30 healthy Canadian males aged between 18 and 25, randomly assigned to either the GY or CP group. They performed resistance exercise training infrequently, had normal body fat percentages, and had not taken dietary supplements in the last six months. During the intervention, both groups underwent high-intensity, high-impact resistance and plyometric exercise training three times a week for twelve weeks.
On training days, the GY group received 200 g of 0% fat yoghurt supplementation three times a day. On non-training days, the quantity was reduced to 150 g twice daily. The CP group was given 47g of CP made in-house. Venous blood samples were collected at baseline, week 1, and week 12 of the intervention.
Study findings
Regarding average daily dietary intake, both groups increased their daily magnesium, potassium, and energy intake. By week 12, the GY group consumed more protein, calcium, and phosphorus than the CP group. The concentrations of IL-1ra and CRP increased at week 1 compared with baseline, and IL-1ra remained elevated at week 12 compared with baseline, while CRP returned closer to baseline.
Relative to the baseline, the concentrations of IL-1β at weeks 1 and 12 were lower. The concentration of IL-6, relative to baseline and week 1, was lower at week 12 in the GY group, but not in the CP group. The week 12 TNF-α concentration and the TNF-α ratio to IL-10 increased in CP but not GY.
Linear regressions were estimated to gauge the change in each inflammatory marker. During the intervention period, greater decreases in IL-1ra and IL-1β were predicted by higher baseline levels of IL-1ra and IL-1β, respectively. Over the intervention period, a greater increase in fat mass predicted a decrease in IL-1β. GY predicted a reduction in IL-6, compared to CP. Furthermore, an increase in IL-6 over the intervention period was indicated by an increase in fat-free mass.
The change in TNF-α predicted increases in IL-10 over the intervention, while the baseline concentration of IL-10 predicted decreases. It was also noted that GY predicted an increase in IL-10 (a non-significant trend, p = 0.081) and a decrease in TNF-α, compared to CP. A greater reduction in CRP was predicted for individuals with a higher baseline concentration of CRP. Finally, an increase in IL-10 predicted a rise in TNF-α.
Conclusions
Exercise training provided anti-inflammatory benefits, notably reducing IL-1β and showing a short-term increase at week 1 that returned to baseline by week 12. Consumption of GY enhanced these benefits by lowering IL-6 and preventing increases in TNF-α and the TNF-α/IL-10 ratio seen in CP. In the future, more research should be conducted to understand the key predictors of changes in inflammatory markers, in addition to exercise and nutrition.
A key limitation of the study is the inability to detect differences between the CP and GY groups since the study was not primarily designed to investigate systemic inflammation. Furthermore, the generalizability of the findings to other populations cannot be established because the study participants were all young, healthy, and lean individuals without higher resting levels of inflammation.