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By Belinda Reynolds, BSc Nut&Diet (Hon)


Do you find that you come down with a cold following intense exercise? Or that your athletic performance is compromised by digestive issues or training in a new climate? If you answered ‘yes’ to any of these questions, taking a specific probiotic blend may be worth looking into.

Previously, the school of thought has been that athletes experience reduced performance and fatigue simply due to ‘overtraining’. However, this is not always the case, as emerging research implies that poor gut integrity can also play a role.

While you probably know that exercising in a warm climate can encourage dehydration and muscular issues, you may not be aware of the impact it can have on the digestive system. Heat stress can encourage inflammation and swelling of the intestinal lining, causing gaps to develop between the ‘tight junctions’ (TJs), complex structures that lie between the epithelial cells of the intestines[1] [2]. A potential result of this is gastrointestinal hyper-permeability, also known as ‘leaky gut’.

Gastrointestinal hyper-permeability involves weakening of the gastrointestinal walls which consequently enables the harmful bacteria, bacterial toxins, or partially digested food particles to crossover from the digestive tract into the bloodstream. This can trigger an immune or inflammatory reaction, potentially disrupting the functioning of cells and organs, and activating a range of systems involved in cell signaling.

In the initial stage of damage to the intestinal walls, digestive enzyme production is compromised. Subsequently, incompletely digested food undergoes fermentation, providing a ‘feeding ground’ for undesirable bacteria which can then proliferate and extend the degree of inflammation, alongside the first stage symptoms of leaky gut, which may include:

·         Gas

·         Bloating

·         Constipation

·         Diarrhoea

·         Stomach cramps

·         Indigestion

·         Food sensitivities

These digestive symptoms are often ignored; however, if treatment is not sought inflammation is likely to worsen.

As intestinal permeability progresses into the advanced stages, the intestinal cells and TJs undergo degeneration, resulting in the formation of larger gaps in the intestinal lining. The symptoms stemming from this are hard to dismiss, and may include:

·         Headaches

·         Migraines

·         More severe food allergies

·         Worsening digestive problems

·         Chronic fatigue

·         Painful joints

What can we do to reduce our risk of or potentially prevent leaky gut?

One important measure may be to take a high quality probiotic. Billions of microflora - the beneficial microbes of the gut - can play an important part in maintaining intestinal integrity.

Groundbreaking research has revealed that not only may certain probiotics improve the general health of athletes, they also may improve their performance under hot conditions.

When choosing a probiotic, the lactobacilli and bifidobacteria species are the ones to look out for as they encourage an acidic environment in the gastrointestinal tract via their production of short-chain fatty acid (SCFA). Probiotics can stimulate the immune system and synthesise bacteriocins, substances that serve as natural antibiotics[3] [4] [5] [6]. And due to their involvement in regulating pro- and anti-inflammatory cytokines, gastrointestinal microflora also influence intestinal and systemic inflammatory processes.

Recently, a high-quality Tasmanian study (with double-blind, placebo-controlled, randomised crossover methods) demonstrated the potential benefits of probiotics on athletic performance in 12 trained male runners[7]. For one month, six of the runners were administered a daily probiotic consisting of nine strains and 45 billion colony forming units (CFUs). The remaining six runners were administered a placebo. This was followed by a three-week ‘washout’ period (allowing for probiotic elimination in the treatment group), after which participants swapped treatments for another month.

Before and after probiotic or placebo treatment, athletic performance was examined under conditions of 35C heat and 40% humidity, in which participants ran on a treadmill at 80% of their ventilatory threshold.

Remarkably, the runners on probiotic treatment had a decline in gastrointestinal permeability, immune markers and systemic inflammation. This was confirmed upon looking at intestinal permeability markers and the amount of lipopolysaccharide (LPS) in the bloodstream, both of which indicate how much harmful bacteria have leaked from the GIT. Upon taking the multi-strain probiotic, levels of LPS post-exercise had declined.

And if that were not enough, the probiotic treatment also seemed to improve heat tolerance. Athletes receiving probiotic treatment could run for 14% longer than placebo participants.

Ideally, prior to competing in a hostile climate, you need one to two weeks of exposure to that climate; 100 minutes of daily exercise in the new climate is also required. However, this is not an opportunity of which we all have the luxury.

Our athletic performance largely depends on good all-round health and a threshold for unfamiliar climates. A high quality probiotic may just be the solution we need for the digestive and immunosuppressive symptoms that can occur with high intensity exercise in the heat.

Speak to your healthcare practitioner for more information about choosing the right probiotic. When taking supplements, make sure to always read the label and use only as directed. If symptoms persist, see your healthcare practitioner.

Belinda Reynolds graduated with an Honours Degree in Nutrition and Dietetics in 2003. She has been involved in the complementary medicine industry for nearly 14 years - nine of these working for BioCeuticals, Australia’s leading provider of practitioner-only nutritional and therapeutic supplements, as a Practitioner Sales Consultant, Team Leader, Presenter, Educator and Writer, with an involvement in Marketing and Product Development. Outside of this Belinda has spent time working in hospitals and lectured at the Australasian College of Natural Therapies.

Belinda’s greatest passion is assisting practitioners in developing their knowledge by presenting new research in the area of integrative medicine. Now a mother of two, pre- and postnatal, infant and child health have evolved as subjects particularly close to her heart.

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[1] Ulluwishewa D, Anderson RC, McNabb WC, et al. Regulation of tight junction permeability by intestinal bacteria and dietary components. J Nutr 2011;141(5):769-76.

[2] Wells JM, Rossi O, Meijerink M, et al. Epithelial crosstalk at the microbiota-mucosal interface. Proc Natl Acad Sci U S A 2011;108 Suppl 1:4607-14..

[3] Salminen S, Deighton MA, Benno Y, et al. Lactic acid bacteria in health and disease. In: Salminen S, von Wright A (Eds), Lactic acid bacteria: microbiology and functional aspects, 2nd ed (pp.211-53). New York: Marcel Dekker, 1998.

[4] Allen SJ, Martinez EG, Gregorio GV et al. Probiotics for treating acute infectious diarrhoea. Cochrane Database Syst Rev 2010;(11):CD003048.

[5] Isolauri E, Sutas Y, Kankaanpaa P, et al. Probiotics: effects on immunity. Am J Clin Nutr 2001:73(2 Suppl):s444-50.

[6] Corr SC, Hill C, Gahan CG. Understanding the mechanisms by which probiotics inhibit gastrointestinal pathogens. Adv Food Nutr Res 2009;56:1-15.

[7] Shing CM, Peake JM, Briskey D, Lim F, Vitetta F. Response to exercise in the heat following a period of probiotics supplementation. School of Human Life Sciences. University of Tasmania, 2011 (unpublished report).

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