The randomized, double-blind, placebo-controlled trial used the GKK1 strain provided by Taiwan-based Grape King Bio Ltd. Forty eight men were randomly assigned to receive either the probiotic or placebo for four weeks, and then underwent an exercise-induced muscle damage protocol.
Researchers from several Taiwanese universities and Grape King Bio Ltd reported that, compared with placebo, participants receiving the probiotic had lower levels of post-exercise creatine kinase (CK), myoglobin, hs-CRP (high-sensitivity CRP) and TBARS (Thiobarbituric Acid Reactive Substances). These are biomarkers associated with muscle damage, inflammation and oxidative stress.
Based on their findings and previous research, they suggested the mechanisms of action related to the anti-inflammatory, muscle-protective, metabolic and neuroendocrine effects of the probiotic.
“These findings suggest that GKK1 may be a safe nutritional strategy to facilitate functional recovery, attenuate secondary inflammatory responses and modulate urinary markers associated with muscle breakdown following muscle-damaging exercise in healthy young men,” the authors wrote in Nutrients.
Probiotics for athletics
Lactobacillus species are among the most abundant beneficial bacteria in the gut microbiome.
At the same time, interest in probiotics for sports nutrition has grown as evidence suggests certain strains may influence inflammation, recovery and exercise performance through interactions with the gut-muscle axis.
One study of L. plantarum TWK10 indicated the strain increases skeletal muscle mass, enhances muscle strength, and improves endurance capacity in both murine models and humans by optimizing energy metabolism and facilitating neuromuscular adaptation.
Further, studies with L. plantarum PS128 indicate the strain expedites exercise-capacity recovery following half-marathon, and attenuates muscle damage, oxidative stress, and systemic inflammatory responses in endurance athletes.
Prior research indicates L. plantarum GKK1 contains genetic features linked to immune regulation and anti-inflammatory activity, including pathways involved in nitric oxide production and the stimulation of immune signaling molecules.
These characteristics suggest the probiotic could help reduce inflammation and support recovery from exercise-induced muscle damage, although evidence from human trials remains limited.
The study
A total of 48 healthy, sedentary adult male participants were randomly assigned to either the placebo group (n = 24) or the GKK1 group (n = 24).
After the four week intervention, they attended the lab where they underwent a standardized, high-intensity plyometric protocol consisting of 100 maximal vertical jumps.
Countermovement jump (CMJ) assessments, isometric mid-thigh pull (IMTP) assessments, and the 30 s Wingate Anaerobic Test (WAnT) were systematically implemented at baseline as well as at 3, 24, and 48 h post-EIMD.
Blood samples were collected pre-EIMD and 3 h, 24 h, and 48 h post-EIMD to assess muscle damage and inflammation biomarkers, including CK, myoglobin, and hs-CRP. Endocrine and stress-related biomarkers including testosterone, cortisol, and dopamine.
Researchers additionally took urine samples to assess markers of muscle protein degradation.
Resulting data indicated, compared with placebo, the intervention led to smaller post -exercise decrements in countermovement jump (CMJ) rate of force development, relative peak force, jump height, IMTP relative peak force and peak RFD, and Wingate anaerobic performance.
GKK1 appeared to attenuate increases in CK and myoglobin, as well as hs-CRP and TBARS.
Blood sample analysis further indicated the intervention was associated with a more favorable stress response, as indicated by testosterone, HGH, catecholamine, and dopamine responses.
“GKK1 supplementation significantly mitigated the severe exercise-induced depletion of serum dopamine observed in the placebo group while attenuating acute adrenaline spikes,” the report said.
Inferring a mechanism of action via the biomarker changes, the researchers suggested GKK1 reduced post-exercise fatigue and muscle damage through a combination of anti-inflammatory, muscle-protective, metabolic and neuroendocrine effects.
The authors noted several limitations, including the limited demographic represented, the short intervention period, and the lack of gut microbiome analysis.
Source: Nutrients, doi: 10.3390/nu18172782, “Effect of Lactiplantibacillus plantarum GKK1 Supplementation on Exercise-Induced Fatigue, Muscle Damage, and Recovery in Healthy Men: A Randomized, Double-Blind, Placebo-Controlled Trial”, Authors: Lee, M.C. et al
