探討益生菌結合乳清蛋白於提升運動表現之功效

Abstract

於現代生活型態中，運動成為維持身體機能的必要方法，使運動逐漸受到重視。其中，運動表現是量化個體體能狀況的指標。運動表現受到許多因素的影響，包括肌肉質量、代謝能力等。運動時肌肉持續收縮而累積的氧化壓力，也會影響肌肉的正常收縮。依需求使用適當的營養補充品，或機能性食品，則對增進運動表現有一定的幫助。 許多研究證實適量服用益生菌，對宿主健康有益。在眾多益生菌機能性中，抗氧化與代謝調節能力日益被重視，因此在增進運動表現上，益生菌被認為具有潛力。乳清蛋白是乾酪生產的副產物，在營養上被視為優良的蛋白質來源。本研究目的為挑選具增進運動表現潛力之益生菌，亦將結合益生菌與乳清蛋白，觀察其是否能進一步改善運動表現。 試驗首先以細胞模式於體外挑選具有抗氧化潛力的菌株。建構細胞模式時，因過氧化氫並無法引起人類肝癌細胞株 (HepG2) 的氧化壓力，因此改以叔丁基過氧化氫 (tert-butyl hydroperoxide) 誘導人類結腸癌細胞株 (Caco2) 之氧化壓力。結果顯示，9株與Caco2進行共培養的乳酸菌中，僅Lactobacillus delbrueckii subsp. lactis BCRC 14033 表現出較高的抗氧化潛力，因此選擇此菌與先前本研究室發現在動物試驗中具有抗氧化能力的Lactobacillus kefiranofaciens HL1進行動物試驗。 動物試驗之結果顯示，僅有同時食用HL1與乳清蛋白（HWP組）六週的小鼠，在最大肌力方面的相對握力，較C組有顯著 (p < 0.05) 增加，而在有氧運動能力中，所有試驗處理並未對力竭游泳時間有幫助。BCRC 14033組中，所測定的運動表現項目與對照組比較皆無顯著的變化。HWP組小鼠則具有顯著較高的相對肌肉重量 (p < 0.05) ，代表最大肌力的增加，可能與肌肉量的增加有直接關係。血液生化指標結果顯示，僅HL1組小鼠具有顯著較高的血糖值與低的乳酸 (p < 0.05) 。HWP小鼠之肝臟有顯著較高的過氧化氫酶活性 (p < 0.05) ，但肌肉的超氧陰離子歧化酶活性卻顯著低於C組 (p < 0.05) 。在盲腸內容物則以HWP組小鼠具有顯著 (p < 0.05) 較低的乙酸濃度。 綜上所述，Lb. kefiranofaciens HL1與乳清蛋白之組合，在動物模式中，能夠增加動物之最大肌力與肌肉量，但對於長時間、強度較低的運動，此組合則不具有顯著提升的效果。Lb. kefiranofaciens HL1本身能夠調節能量物質的代謝，減少乳酸的堆積。雖然Lb. kefiranofaciens HL1與乳清蛋白之組盒並未如預期促進肌肉抗氧化酵素活性，但後續仍可測定肌肉纖維的組成，與肌肉中能量代謝相關基因的表現，以確立益生菌結合乳清蛋白增進運動表現的機制。

Exercise has become an important way to maintain physiological function in modern lifestyle, which makes exercise get more attension. Exercise performance can be used as an index to describe body fitness. Several factors are involved in determining exercise performance, including muscle condition and metabolism. Also, researches have indicated that increased oxidative stress during continuous exercise would interfere muscle contraction. Thus, use nutritional supplement or functional food would be helpful to improve exercise performance. Probiotics has been massively studied for its functionality in last few decades. Particularly, the antioxidative activity and metabolism-regulating effect make probiotics as potential material for boosting exercise performance. Besides, whey protein is a quality protein source, which is commonly used to support muscle growth. This study aims to screen the probiotics to improve exercise performance. The combining effect of probiotics and whey protein was also investigated. In vitro, we failed to find the proper condition to induce oxidative stress in the HepG2 cell model, so Caco2 cell and tert-butyl hydroperoxide were used instead. Results indicted that Lactobacillus delbrueckii subsp. lactis BCRC 14033 showed a higher antioxidant potential against tert-butyl hydroperoxide-induced cellular oxidative stress than other 8 strains. Therefore, this strain and Lb. kefiranofaciens HL1, which was previously identified with antioxidative and anti-aging effects, were selected for the further in vivo study. In vivo results showed that the mice receiving HL1 and whey protein (HWP group) significantly (p < 0.05) elevated relative grip strength as compared with C group. HWP mice also had significantly (p < 0.05) higher relative muscle mass, indicating the direct link between muscle strength and combined treatment. However, all treatments did not improve exercise performance in exhausted swimming test. In additional biochemical analysis, HL1 mice possessed higher blood glucose and lower lactate than other groups. Whereas, HWP mice had higher catalase activity, but muscle superoxide dismutase activity and cecal short chain fatty acid, acetate, was lower when compared with control group. In conclusion, the combination of Lb. kefiranofaciens HL1 and whey protein can improve muscle strength and mass, but not in prolonged, relatively low intensity exercise. However, only Lb. kefiranofaciens HL1 itself showed metabolic-regulating effect. Although this combination did not showed expected effect in improving muscular oxidative stress, we may further determine the muscular fiber composition and expression of metabolic-related gene in muscle to verify the underlying mechanism.