The Role of Probiotic Supplementation in Preventing Gastrointestinal and Immune System Problems Arising from Intense Physical Activity: A Traditional Review

Öz

The bidirectional relationship between physical activity and gut health indicates that regular physical activity supports the gut microbiota, whereas prolonged and intense exercise may increase intestinal permeability, leading to gastrointestinal issues. Common symptoms, such as stomach cramps, nausea, and diarrhea, are observed in 20–40% of endurance athletes. In addition to gastrointestinal problems, intense and prolonged physical activity may increase inflammation and oxidative stress in the body, leading to suppression of immune function. Therefore, in recent years, probiotic supplementation has gained prominence as a means to support athletes’ health and enhance their performance. Probiotics contain live microorganisms that help balance the gut microbiota, providing beneficial effects on digestion, immunity, and metabolism. Microorganisms like Lactobacillus and Bifidobacterium enhance immune functions, reducing the incidence of upper respiratory tract infections and accelerating recovery. Studies have shown that, in marathon runners, probiotic supplementation reduces gastrointestinal complaints, increases maximal oxygen consumption, and supports post-exercise recovery. Moreover, consuming probiotic-enriched yogurt has been reported to improve both performance and immune function in athletes. The beneficial effects of probiotics on athletes may vary depending on individual differences, the strain type used, dosage, and duration of use. However, there some studies have reported that probiotics do not have a significant effect on performance or the immune system. This highlights the need for more comprehensive and long-term studies. In conclusion, regular probiotic supplementation shows significant potential for reducing health issues, strengthening immunity, and enhancing athletic performance. Nonetheless, individualized planning and further scientific investigation in this field are recommended.

Anahtar Kelimeler

• gastrointestinal microbiome
• Probiotics
• exercise
• athletic performance

Şiddetli Fiziksel Aktiviteye Bağlı Ortaya Çıkan Gastrointestinal ve Bağışıklık Sistemi Problemlerinin Önlenmesinde Probiyotik Takviyesinin Rolü: Geleneksel Derleme

Öz

Fiziksel aktivite ile bağırsak sağlığı arasındaki çift yönlü ilişki, düzenli fiziksel aktivitenin bağırsak mikrobiyotasını desteklediğini, ancak şiddetli ve uzun süreli fiziksel aktivitelerin bağırsak geçirgenliğini artırarak gastrointestinal problemlere neden olabileceğini göstermektedir. Dayanıklılık sporcularında %20-40 oranında görülen mide krampları, bulantı ve ishal gibi semptomlar, bu problemlerin en yaygın örneklerindendir. Gastrointestinal problemlerin yanı sıra şiddetli ve uzun süreli fiziksel aktiviteler, vücutta inflamasyon ve oksidatif stresi artırarak bağışıklık fonksiyonlarının zayıflamasına neden olabilir. Bu nedenle, sporcuların sağlığını desteklemek ve performanslarını iyileştirmek amacıyla probiyotik takviyeleri son yıllarda ön plana çıkmıştır. Probiyotikler, bağırsak mikrobiyotasını dengeleyerek sindirim, bağışıklık ve metabolizma üzerinde olumlu etkiler sunan canlı mikroorganizmalar içerir. Lactobacillus ve Bifidobacterium gibi mikroorganizma türleri, bağışıklık fonksiyonlarını güçlendirerek üst solunum yolu enfeksiyonlarının sıklığını azaltmakta ve iyileşme sürecini hızlandırmaktadır. Çalışmalar, probiyotik takviyelerinin maraton koşucularında gastrointestinal şikayetleri azalttığını, maksimum oksijen tüketimini artırdığını ve fiziksel aktivite sonrası toparlanmayı desteklediğini göstermektedir. Ayrıca, probiyotik içeren yoğurt tüketiminin sporcularda hem performansı artırdığı hem de bağışıklık sistemini güçlendirdiği rapor edilmiştir. Probiyotiklerin sporcular üzerindeki bu olumlu etkileri bireysel farklılıklar, kullanılan suş türü, dozaj ve kullanım süresi gibi faktörlere bağlı olarak değişiklik gösterebilmektedir. Bununla birlikte, probiyotiklerin performans ve bağışıklık sistemi üzerinde önemli bir etki yaratmadığını bildiren bazı çalışmalar da mevcuttur. Bu durum, daha geniş kapsamlı ve uzun vadeli araştırmaların gerekliliğini ortaya koymaktadır. Sonuç olarak, probiyotik takviyelerinin düzenli kullanımı, sporcuların sağlık sorunlarını azaltma, bağışıklık sistemini güçlendirme ve spor performanslarını iyileştirme açısından önemli bir potansiyel sunmaktadır. Her bireyin özel ihtiyaçlarına uygun planlamalar yapılması ve bu alanda daha fazla bilimsel araştırmaya odaklanılması önerilmektedir.

Anahtar Kelimeler

• bağırsak mikrobiyotası
• fiziksel aktivite
• Probiyotik
• sporcu performansı

Kaynakça

1. Gasbarrini G, Bonvicini F, Gramenzi A. Probiotics history. J Clin Gastroenterol. 2016;50:116-9. DOI: 10.1097/mcg.0000000000000697.
2. Latif A, Shehzad A, Niazi S, Zahid A, Ashraf W, Iqbal MW, et al. Probiotics: mechanism of action, health benefits and their application in food industries. Front Microbiol. 2023;14:1216674. DOI: 10.3389/fmicb.2023.1216674.
3. openknowledge.fao.org [Internet].Probiotics in food Health and nutritional properties and guidelines for evaluation. London, Ontario, Canada: FAO/WHO; 2002 [cited 2025 January 14]. Available from: https://openknowledge.fao.org/server/api/core/bitstreams/382476b3-4d54-4175-803f-2f26f3526256/content
4. Guarner F, Sanders ME, Szajewska H, Cohen H, Eliakim R, Herrera-deGuise C, et al. World Gastroenterology Organisation Global Guidelines: Probiotics and prebiotics. J Clin Gastroenterol. 2024;58(6):533-53. DOI: 10.1097/mcg.0000000000002002.
5. Jan T, Negi R, Sharma B, Kumar S, Singh S, Rai AK, et al. Next generation probiotics for human health: An emerging perspective. Heliyon. 2024;10(16):e35980. DOI: 10.1016/j.heliyon.2024.e35980.
6. Aziz Q, Doré J, Emmanuel A, Guarner F, Quigley EMM. Gut microbiota and gastrointestinal health: Current concepts and future directions. Neurogastroenterol Motil. 2013;25(1):4-15. DOI: 10.1111/nmo.12046.
7. Kerry RG, Patra JK, Gouda S, Park Y, Shin H-S, Das G. Benefaction of probiotics for human health: A review. J Food Drug Anal. 2018;26(3):927-39. DOI: 10.1016/j.jfda.2018.01.002.
8. Bodke H, Jogdand S. Role of probiotics in human health. Cureus. 2022;14(11):e31313. DOI: 10.7759/cureus.31313.

9. Jan T, Negi R, Sharma B, Kour D, Kumar S, Rai AK, et al. Diversity, distribution and role of probiotics for human health: Current research and future challenges. Biocatal Agric Biotechnol. 2023;53:102889. DOI: 10.1016/j.bcab.2023.102889.
10. Obayomi OV, Folakemi Olaniran A, Olugbemiga Owa S. Unveiling the role of functional foods with emphasis on prebiotics and probiotics in human health: A review. J Funct Foods. 2024;119:106337. DOI: 10.1016/j.jff.2024.106337.
11. Varghese S, Rao S, Khattak A, Zamir F, Chaari A. Physical exercise and the gut microbiome: A bidirectional relationship influencing health and performance. Nutrients. 2024;16(21): 3663. DOI: 10.3390/nu16213663.
12. de Oliveira EP, Burini RC, Jeukendrup A. Gastrointestinal complaints during exercise: Prevalence, etiology, and nutritional recommendations. Sports Med. 2014;44(1):79-85. DOI: 10.1007/s40279-014-0153-2.
13. Jäger R, Mohr AE, Carpenter KC, Kerksick CM, Purpura M, Moussa A, et al. International Society of Sports Nutrition Position Stand: Probiotics. J Int Soc Sports Nutr. 2019;16(1):62. DOI: 10.1186/s12970-019-0329-0.
14. Leite GSF, Resende AS, West NP, Lancha AH. Probiotics and sports: A new magic bullet? Nutrition. 2019;60:152-60. DOI: 10.1016/j.nut.2018.09.023.
15. Monda V, Villano I, Messina A, Valenzano A, Esposito T, Moscatelli F, et al. Exercise modifies the gut microbiota with positive health effects. Oxid Med Cell Longevity. 2017;2017(1):3831972. DOI: 10.1155/2017/3831972.
16. Karl JP, Margolis LM, Madslien EH, Murphy NE, Castellani JW, Gundersen Y, et al. Changes in intestinal microbiota composition and metabolism coincide with increased intestinal permeability in young adults under prolonged physiological stress. Am J Physiol Gastrointest Liver Physiol. 2017;312(6):G559-G71. DOI: 10.1152/ajpgi.00066.2017.
17. Aya V, Flórez A, Perez L, Ramírez JD. Association between physical activity and changes in intestinal microbiota composition: A systematic review. PLoS One. 2021;16(2):e0247039. DOI: 10.1371/journal.pone.0247039.
18. Clauss M, Gérard P, Mosca A, Leclerc M. Interplay between exercise and gut microbiome in the context of human health and performance. Front Nutr. 2021;8: 637010. DOI: 10.3389/fnut.2021.637010.
19. Archer E, Blair SN. Physical activity, exercise and non-communicable diseases. Res Exerc Epidemiol. 2012;14(1):1-18. DOI: 10.24804/ree.14.1.
20. ter Steege RWF, Kolkman JJ. Review article: the pathophysiology and management of gastrointestinal symptoms during physical exercise, and the role of splanchnic blood flow. Aliment Pharmacol Ther. 2012;35(5):516-28. DOI: 10.1111/j.1365-2036.2011.04980.x.
21. Costa RJS, Snipe RMJ, Kitic CM, Gibson PR. Systematic review: exercise-induced gastrointestinal syndrome—implications for health and intestinal disease. Aliment Pharmacol Ther. 2017;46(3):246-65. DOI: 10.1111/apt.14157.
22. Ribichini E, Scalese G, Cesarini A, Mocci C, Pallotta N, Severi C, et al. Exercise-induced gastrointestinal symptoms in endurance sports: a review of pathophysiology, symptoms and nutritional management. Dietetics. 2023;2(3):289-307. DOI: 10.3390/dietetics2030021.
23. Gaskell SK, Rauch CE, Costa RJS. Gastrointestinal assessment and therapeutic intervention for the management of exercise-associated gastrointestinal symptoms: A case series translational and professional practice approach. Front Physiol. 2021;12:719142. DOI: 10.3389/fphys.2021.719142.
24. Parnell JA, Wagner-Jones K, Madden RF, Erdman KA. Dietary restrictions in endurance runners to mitigate exercise-induced gastrointestinal symptoms. J Int Soc Sports Nutr. 2020;17(1):32. DOI: 10.1186/s12970-020-00361-w.
25. Costa RJS, Mika AS, McCubbin AJ. The impact of exercise modality on exercise-induced gastrointestinal syndrome and associated gastrointestinal symptoms. J Sci Med Sport. 2022;25(10):788-93. DOI: 10.1016/j.jsams.2022.07.003.
26. Gaskell SK, Burgell R, Wiklendt L, Dinning PG, Costa RJ. Impact of exercise duration on gastrointestinal function and symptoms. J Appl Physiol (1985). 2023;134(1):160-71. DOI: 10.1152/japplphysiol.00393.2022.
27. Pugh JN, Kirk B, Fearn R, Morton JP, Close GL. Prevalence, severity and potential nutritional causes of gastrointestinal symptoms during a marathon in recreational runners. Nutrients. 2018;10(7):811. DOI: 10.1007/s00421-019-04136-3.
28. Smith KA, Pugh JN, Duca FA, Close GL, Ormsbee MJ. Gastrointestinal pathophysiology during endurance exercise: endocrine, microbiome, and nutritional influences. Eur J Appl Physiol. 2021;121(10):2657-74. DOI: 10.1007/s00421-021-04737-x.
29. Stuempfle KJ, Hoffman MD. Gastrointestinal distress is common during a 161-km ultramarathon. J Sports Sci. 2015;33(17):1814-21. DOI: 10.1080/02640414.2015.1012104.
30. Furness JB. The enteric nervous system and neurogastroenterology. Nat Rev Gastroenterol Hepatol. 2012;9(5):286-94. DOI: 10.1038/nrgastro.2012.32.
31. Gribble FM, Reimann F. Enteroendocrine cells: chemosensors in the intestinal epithelium. Annu Rev Physiol. 2016;78(1):277-99. DOI: 10.1146/annurev-physiol-021115-105439.
32. de Oliveira EP, Burini RC. Food-dependent, exercise-induced gastrointestinal distress. J Int Soc Sports Nutr. 2011;8(1):12. DOI: 10.1186/1550-2783-8-12.
33. Erdoğmuş, TN. Egzersizle ilişkili semptomların oluşum mekanizması. Aras D, editor. Sporcularda gastrointestinal sorunlar.Yayın 1. Ankara: Ankara Üniversitesi Yayınevi; 2023. p. 16-18.
34. Simpson RJ, Campbell JP, Gleeson M, Krüger K, Nieman DC, Pyne DB, et al. Can exercise affect immune function to increase susceptibility to infection? Exerc Immunol Rev. 2020;26:8-22.
35. Kurowski M, Seys S, Bonini M, Del Giacco S, Delgado L, Diamant Z, et al. Physical exercise, immune response, and susceptibility to infections—current knowledge and growing research areas. Allergy. 2022;77(9):2653-64. DOI: 10.1111/all.15328.
36. Nieman DC, Wentz LM. The compelling link between physical activity and the body's defense system. J Sport Health Sci. 2019;8(3):201-17. DOI: 10.1016/j.jshs.2018.09.009.
37. Nieman DC. Exercise, upper respiratory tract infection, and the immune system. Med Sci Sports Exerc. 1994;26(2):128-39. DOI: 10.1249/00005768-199402000-00002.
38. Malm C. Susceptibility to infections in elite athletes: the S-curve. Scand J Med Sci Sports. 2006;16(1):4-6. DOI: 10.1111/j.1600-0838.2005.00499.x.
39. Mårtensson S, Nordebo K, Malm C. High training volumes are associated with a low number of self-reported sick days in elite endurance athletes. J Sports Sci Med. 2014;13(4):929-33.
40. Walsh NP, Gleeson M, Shephard RJ, Gleeson M, Woods JA, Bishop NC, et al. Position statement part one: immune function and exercise. Exerc Immunol Rev. 2011;17:6-63.
41. Nielsen HG, Øktedalen O, Opstad P-K, Lyberg T. Plasma cytokine profiles in long-term strenuous exercise. J Sports Med (Hindawi Publ Corp). 2016;2016(1):7186137. DOI: 10.1155/2016/7186137.
42. Campbell JP, Turner JE. Debunking the myth of exercise-induced immune suppression: Redefining the impact of exercise on immunological health across the lifespan. Front Immunol. 2018; 9:648. DOI: 10.3389/fimmu.2018.00648.
43. Walsh NP, Gleeson M, Pyne DB, Nieman DC, Dhabhar FS, Shephard RJ, et al. Position statement. Part two: Maintaining immune health. Exerc Immunol Rev. 2011;17:64-103.
44. Perna FM, Schneiderman N, LaPerriere A. Psychological stress, exercise and immunity. Int J Sports Med. 1997;18 Suppl 1:S78-83. DOI: 10.1055/s-2007-972703.
45. Alotiby A. Immunology of Stress: A Review Article. J Clin Med. 2024;13(21):63-94. Epub 20241025. DOI: 10.3390/jcm13216394.
46. Clow A, Hucklebridge F. The impact of psychological stress on immune function in the athletic population. Exerc Immunol Rev. 2001;7:5-17.
47. van Paridon KN, Timmis MA, Nevison CM, Bristow M. The anticipatory stress response to sport competition; a systematic review with meta-analysis of cortisol reactivity. BMJ Open Sport Exerc Med. 2017;3(1):e000261. Epub 20170917. DOI: 10.1136/bmjsem-2017-000261.
48. İsmailoğlu Ö, Öngün Yılmaz H. Probiyotik kullanımının bağırsak mikrobiyotası üzerine etkisi. Bandırma Onyedi Eylül Üniversitesi Sağlık Bilimleri ve Araştırmaları Dergisi 2019;1(1):38-56.
49. Montrose DC, Floch MH. Probiotics used in human studies. J Clin Gastroenterol. 2005;39(6):469-84. DOI: 10.1097/01.mcg.0000165649.32371.71.
50. Penner R, Fedorak RN, Madsen KL. Probiotics and nutraceuticals: Non-medicinal treatments of gastrointestinal diseases. Curr Opin Pharmacol. 2005;5(6):596-603. DOI: 10.1016/j.coph.2005.06.009.
51. Pyne DB, West NP, Cox AJ, Cripps AW. Probiotics supplementation for athletes – Clinical and physiological effects. Eur J Sport Sci. 2015;15(1):63-72. DOI: 10.1080/17461391.2014.971879.
52. Díaz-Jiménez J, Sánchez-Sánchez E, Ordoñez FJ, Rosety I, Díaz AJ, Rosety-Rodriguez M, et al. Impact of probiotics on the performance of endurance athletes: A systematic review. Int J Environ Res Public Health. 2021;18(21):11576. DOI: 10.3390/ijerph182111576.
53. Rawson ES, Miles MP, Larson-Meyer DE. Dietary supplements for health, adaptation, and recovery in athletes. Int J Sport Nutr Exerc Metab. 2018;28(2):188-99. DOI: 10.1123/ijsnem.2017-0340.
54. Vaisberg M, Paixão V, Almeida EB, Santos JMB, Foster R, Rossi M, et al. Daily intake of fermented milk containing Lactobacillus casei Shirota (Lcs) modulates systemic and upper airways immune/inflammatory responses in marathon runners. Nutrients. 2019;11(7):1678. DOI: 10.3390/nu11071678.
55. Michalickova D, Minic R, Dikic N, Andjelkovic M, Kostic-Vucicevic M, Stojmenovic T, et al. Lactobacillus helveticus Lafti L10 supplementation reduces respiratory infection duration in a cohort of elite athletes: a randomized, double-blind, placebo-controlled trial. Appl Physiol Nutr Metab. 2016;41(7):782-9. DOI: 10.1139/apnm-2015-0541.
56. Strasser B, Geiger D, Schauer M, Gostner JM, Gatterer H, Burtscher M, et al. Probiotic supplements beneficially affect tryptophan–kynurenine metabolism and reduce the incidence of upper respiratory tract infections in trained athletes: A randomized, double-blinded, placebo-controlled trial. Nutrients. 2016;8(11):752. DOI: 10.3390/nu8110752.
57. Kearns RP, Dooley JSG, Matthews M, McNeilly AM. "Do probiotics mitigate GI-induced inflammation and perceived fatigue in athletes? A systematic review". J Int Soc Sports Nutr. 2024;21(1):2388085. DOI: 10.1080/15502783.2024.2388085.
58. Pugh JN, Sparks AS, Doran DA, Fleming SC, Langan-Evans C, Kirk B, et al. Four weeks of probiotic supplementation reduces GI symptoms during a marathon race. Eur J Appl Physiol. 2019;119(7):1491-501. DOI: 10.3390/nu10070811.
59. Komano Y, Fukao K, Shimada K, Naito H, Ishihara Y, Fujii T, et al.Effects of ingesting food containing heat-killed Lactococcus lactisstrain plasma on fatigue and immune-related indices after hightraining load: A randomized, double-blind, placebo-controlled, andparallel-group study. Nutrients. 2023;15(7):1754. DOI:10.3390/nu15071754.
60. Schreiber C, Tamir S, Golan R, Weinstein A, Weinstein Y. The effectof probiotic supplementation on performance, inflammatorymarkers and gastro‐intestinal symptoms in elite road cyclists. J IntSoc Sports Nutr. 2021;18(1):36. DOI: 10.1186/s12970-021-00432-6.
61. Kuyulu Bozdoğan FB, Tazeoğlu A. Sporcularda probiyotik takviyesive mikrobiyatanin performansa etkisi. Spor ve PerformansAraştırmaları Dergisi. 2022;13(2):217-230. DOI:10.17155/omuspd.1077375.
62. Şahin A, Şenel Ö. Probiyotik tüketiminin dayanıklılık sporcularındaatletik performans üzerine etkileri. Gazi Beden Eğitimi ve SporBilimleri Dergisi. 2020;25(1):41-53.
63. Mazur-Kurach P, Frączek B, Klimek AT. Does multi-strain probioticsupplementation impact the effort capacity of competitive roadcyclists? Int J Environ Res Public Health. 2022;19(19):12205. DOI:10.3390/ijerph191912205.
64. Salarkia N, Ghadamli L, Zaeri F, Sabaghian Rad L. Effects of probioticyogurt on performance, respiratory and digestive systems of youngadult female endurance swimmers: a randomized controlled trial.Med J Islam Repub Iran. 2013;27(3):141-6.
65. Salehzadeh K. The effects of probiotic yogurt drink on lipid profile,CRP and record changes in aerobic athletes. Int J of Life Sciences.2015:9;32-7. DOI: 10.3126/ijls.v9i4.12672.
66. Owens DJ, Twist C, Cobley JN, Howatson G, Close GL. Exercise-induced muscle damage: What is it, what causes it and what are thenutritional solutions? Eur J Sport Sci. 2019;19(1):71-85. DOI:10.1080/17461391.2018.1505957.
67. Yeh W-L, Hsu Y-J, Ho C-S, Ho H-H, Kuo Y-W, Tsai S-Y, et al.Lactobacillus plantarum PL-02 supplementation combined withresistance training improved muscle mass, force, and exerciseperformance in mice. Front Nutr. 2022;9:896503. DOI:10.3389/fnut.2022.896503.
68. Wang C, Zhu H, Cheng Y, Guo Y, Zhao Y, Qian H. Aqueous extract ofBrassica rapa L.’s impact on modulating exercise-induced fatigue viagut–muscle Axis. Nutrients. 2023;15(22):4737. DOI:10.3390/nu15224737.
69. Lee M-C, Ho C-S, Hsu Y-J, Huang C-C. Live and heat-killed probioticLactobacillus paracasei PS23 accelerated the improvement andrecovery of strength and damage biomarkers after exercise-inducedmuscle damage. Nutrients. 2022;14(21):4563. DOI:10.3389/fmicb.2023.1216674.
70. Tavares-Silva E, de Aquino Lemos V, de França E, Silvestre J, dosSantos SA, Ravacci GR, et al. Protective effects of probiotics onrunners’ mood: Immunometabolic mechanisms post-exercise.Nutrients. 2024;16(21):3761. DOI: 10.3390/nu16213761.
71. Wang L, Meng FJ, Jin YH, Wu LQ, Tang RY, Xu KH, et al. Effects ofprobiotic supplementation on 12 min run performance, moodmanagement, body composition and gut microbiota in amateurmarathon runners: A double-blind controlled trial. J Exerc Sci Fit.2024;22(4):297-304. DOI: 10.1016/j.jesf.2024.04.004.
72. Crowson MM, McClave SA. Does the intestinal microbiome impactathletic performance? Curr Gastroenterol Rep. 2020;22(11):53. DOI:10.1007/s11894-020-00790-2.
73. Vitetta L, Bambling M, Alford H. The gastrointestinal tractmicrobiome, probiotics, and mood. Inflammopharmacology.2014;22(6):333-9. DOI: 10.1007/s10787-014-0216-x.
74. Salleh RM, Kuan G, Aziz MNA, Rahim MRA, Rahayu T, Sulaiman S, etal. Effects of probiotics on anxiety, stress, mood and fitness ofbadminton players. Nutrients. 2021;13(6):1783. DOI:10.3390/nu13061783.
75. Carbuhn AF, Reynolds SM, Campbell CW, Bradford LA, Deckert JA,Kreutzer A, et al. Effects of probiotic (Bifidobacterium longum 35624)supplementation on exercise performance, immune modulation,and cognitive outlook in division I female swimmers. Sports (Basel).2018;6(4):116. DOI: 10.3390/sports6040116.
76. Townsend JR, Bender D, Vantrease WC, Sapp PA, Toy AM, WoodsCA, et al. Effects of probiotic (Bacillus subtilis DE111)supplementation on immune function, hormonal status, andphysical performance in division I baseball players. Sports (Basel).2018;6(3):70. DOI: 10.3390/sports6030070.
77. Cox AJ, Pyne DB, Saunders PU, Fricker PA. Oral administration of theprobiotic Lactobacillus fermentum VRI-003 and mucosal immunityin endurance athletes. Br J Sports Med. 2010;44(4):222-6. DOI:10.1136/bjsm.2007.044628.
78. Gill SK, Teixeira AM, Rosado F, Cox M, Costa RJS. High-doseprobiotic supplementation containing Lactobacillus casei for 7 daysdoes not enhance salivary antimicrobial protein responses toexertional heat stress compared with placebo. Int J Sport Nutr ExercMetab. 2016;26(2):150-60. DOI: 10.1123/ijsnem.2015-0171.
79. Toohey JC, Townsend JR, Johnson SB, Toy AM, Vantrease WC,Bender D, et al. Effects of probiotic (Bacillus subtilis)supplementation during offseason resistance training in femaledivision I athletes. J Strength Cond Res. 2020;34(11):3173-81. DOI:10.1519/JSC.0000000000002675.