By: Daisy Ochola
If you perform regular physical activity, the volume and intensity of your work out can induce temporary suppression to your immune system. There is extensive evidence of regular, moderate exercise’s beneficial effects in health and disease . However, strenuous exercise has been shown to result in extensive muscle damage, oxidative stress, and immunosuppression . To see the relationship between exercise and predisposition to infection, a “J-shaped curve” model  can be used to show how the severity of exercise can impact our immune system. The model suggests our immune system gains more benefits when we engage in regular, moderate levels of exercise. In contrast, prolonged, excessive levels of exercise impairs immune system function . Sport supplementation has become very popular in the past 2 decades with new products that suggest their ability to boost immune function during exercise.
Recent studies have showcased polyphenols have antioxidant, anti-inflammatory and anti-cancer effects. Polyphenols are anti-oxidant compounds found in foods such as green tea, blueberries, tannins, liginins etc . Protein shakes enriched with blueberry-green tea polyphenol soy protein complex (PSPC) were implemented to investigate the effects on predisposition of microbial infection due to strenuous exercise . The aim of the study was to compare runners on the protein powder enriched polyphenol administered group to placebo administered group. This was to find out if long distance runners administered a high dose of protein powder enriched with polyphenol would develop protective mechanisms against microbial infection after a 3 day intense training. Since the long distance runners had to do strenuous exercise it was normal for there to be an increase in production of reactive oxygen compounds which will build oxidative stress . Another argument is the use of PSPC protein powders in athletes to counter exercise induced physiologic stress. Endurance training has been shown to lead to muscle micro-trauma, and chronic inflammation. Moreover, their immune system will be compromised during the 3-day strenuous training making them more susceptible to contracting respiratory tract infections  and high profiles of cortisol, inflammation and oxidative stress .
So, immunity booster or immunity buster? In both studies  and , long distance runners were divided randomly into a control group who received 40g/day protein shakes enriched with blueberry-green tea polyphenol soy protein complex and the placebo group received soy protein and colorings. This was done for a duration of 17 days, with a 3-day period at day 14 dedicated to intensive running. Blood samples were collected pre and post 14 days of the respective supplementations and 14 hours immediately after the 3rd day of running. The results revealed that strenuous exercise stimulated E.Coli and S.aureus in the blood samples of both groups by 20-70% . Results from the metabolomics strategy assessed metabolic and physiologic responses  found high levels of cortisol, increase in white blood cell count and oxidative stress indicator (DHOME) in both groups 
The control group was significantly protected against microbial infections due to the soluble ingredients in PSPC protein shakes that possess ability to target microbial infections at various bodily points during strenuous exercise . Polyphenol in PSPC protein powders were found to have activated gut bacteria during the 3-day intense training. This increased “gastrointestinal permeability,”  resulted in an increase in fat oxidation. Increased fat oxidation allows for an increased breakdown of fatty acids . Metabolomics reveal that our immunity is still boosted because the gut-bacteria have anti-inflammatory and anti-oxidative significance during intense exercise .
Based on the current literature reviewed, it appears that protein supplements enriched with blueberry-green tea PSPC have anti-microbial, anti-inflammatory and anti-oxidative effects. Protein shakes enriched with PSPC are a potential immunity booster to take with you to your workout.
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