The Effect of Kefir Supplementation on Improving Human Endurance Exercise Performance and Antifatigue

Abstract

Kefir is an acidic, carbonated, and fermented dairy product produced by fermenting milk with kefir grains. The Lactobacillus species constitutes an important part of kefir grains. In a previous animal study, kefir effectively improved exercise performance and had anti-fatigue effects. The purpose of this research was to explore the benefits of applying kefir to improve exercise performance, reduce fatigue, and improve physiological adaptability in humans. The test used a double-blind crossover design and supplementation for 28 days. Sixteen 20–30 year-old subjects were divided into two groups in a balanced order according to each individual’s initial maximal oxygen uptake and were assigned to receive a placebo (equal flavor, equal calories, 20 g/day) or SYNKEFIRTM (20 g/day) every morning. After the intervention, there were 28 days of wash-out, during which time the subjects did not receive further interventions. After supplementation with SYNKEFIRTM, the exercise time to exhaustion was significantly greater than that before ingestion (p = 0.0001) and higher than that in the Placebo group by 1.29-fold (p = 0.0004). In addition, compared with the Placebo group, the SYNKEFIRTM administration group had significantly lower lactate levels in the exercise and recovery (p < 0.05). However, no significant difference was observed in the changes in the gut microbiota. Although no significant changes in body composition were found, SYNKEFIRTM did not cause adverse reactions or harm to the participants’ bodies. In summary, 28 days of supplementation with SYNKEFIRTM significantly improved exercise performance, reduced the production of lactic acid after exercise, and accelerated recovery while also not causing any adverse reactions.

Protective and Recovery Effects of Resveratrol Supplementation on Exercise Performance and Muscle Damage following Acute Plyometric Exercise

“…During the measurements, the subjects kept their arms open, which left their trunk at a 30° angle, and did not speak or move. All subjects were asked to fast for at least 8 h before the test [ 24 ].…”

Plasma Metabolomics Reveals β-Glucan Improves Muscle Strength and Exercise Capacity in Athletes

“…Muscle strength and quality are key factors to maintain the athletic performance of athletes [ 1 , 2 ]. Nutritional supplementation, mainly including whey protein, creatine, glutamine, l-carnitine, and other nutritional supplements [ 3 , 4 ], is a pivotal means to maintain and enhance muscle function. At the same time, more and more research evidence has shown that natural molecular products play a regulatory role in the process of myocyte proliferation and differentiation [ 5 ].…”

Impact of probiotics on muscle mass, muscle strength and lean mass: a systematic review and meta‐analysis of randomized controlled trials

“…37,39,40,42,[44][45][46][51][52][53]55,56 Eight studies were conducted in adults with overweight and/or obesity, [42][43][44][45][46]49,50,56 seven in untrained and non-athletic healthy populations, 37,40,41,51,54,55,59 one in resistance-trained individuals, 53 one in individuals with metabolic syndrome and type 2 diabetes 48 or hypertension, 60 one in people with frailty, 38 one in people with low bone mineral density, 58 one in patients with chronic heart failure, 57 one in participants with non-displaced distal radius fracture, 47 one in triathletes 39 and one in volleyball and soccer players. 52 Eleven studies had a treatment duration of 12 weeks, [41][42][43][44][45][46]49,50,54,55,57 three of ...…”

“…60 Nine studies assessed muscle mass 37,39,40,42,43,48,54,59,60 and one study assessed appendicular lean mass, 57 and 12 studies assessed total lean mass. 38,41,[44][45][46][49][50][51][52][53]56,58 Body composition assessment was performed via bioelectrical impedance (BIA) in 12 studies 37,[40][41][42][43][48][49][50]52,57,59,60 and dual energy X-ray absorptiometry (DXA) in eight studies, 38,39,[44][45][46]51,53,58 whereas two studies did not report details. 54,56 Three studies assessed handgrip strength, 38,47,57 two bench press 52,…”