Probiotics to boost Sport nutrition
What do sportsmen and women look for?
Sportsmen and women face specific physiological challenges. During physical activity, our body is responding to different needs like energy and endurance.
When gaining in intensity, exercise can be the source of occasional physiological and psychological stress and the body’s natural defenses can be impaired. The relationship between the intensity of exercise and immunity is a J-shaped curve. It appears that people are more prone to cold and flu-like episodes following intense training. This phenomenon can last for up to 72 hours. Lowered immunity, combined to hyperventilation that naturally occurs during exercise, contributes to a higher susceptibility to upper respiratory tract (URT) disorders in sportsmen and women. URTI-like symptoms are a common cause for missing training or even a competition and can affect performance.
The benefits of certain probiotic strains on immune defenses are now well described. One particular strain, Lactobacillus helveticus Lafti® L10, has been clinically tested in athletes and shows immune support benefits.
A clinical study was published in 2016 that confirmed the benefits of Lactobacillus helveticus Lafti® L10 in training athletes during winter. Based on this and previous clinical studies, the Canadian health authorities (Health Canada) has granted claims such as “Promotes gastrointestinal health in physically active adults” and “Helps reduce the incidence of cold-like symptoms in adults with exercise-induced stress” for this unique probiotic strain. The 39 elite athletes enrolled in this study were aged 18-28 years, training for over 11 hours per week in various sports and followed the probiotic treatment, or placebo, for 14 weeks in the winter period. This randomized, double-blind placebo-controlled study looked at the severity, the incidence and the duration of URTI-like episodes using a validated scale, and monitored biological immune markers.
The study showed that L. helveticus Lafti® L10 supplementation:
- Significantly shortened by 3.4 days the average duration of URTI-like episodes (7.25 days with the probiotic vs. 10.64 with placebo, P<0.05) (Fig. 2).
- Significantly decreased the number of URTI-like symptoms by around 29% (4.92 symptoms with the probiotic vs. 6.91 with placebo, P<0.05. URTI severity tended to decrease (P=0.078).
- Increased the self-rated sense of vigor and tended to reduce the proportion of athletes reporting impaired training.
Moreover, several changes in immune markers have been recorded during the study in the probiotic group: for example, Interferon-γ was significantly higher in the probiotic group suggesting a better prevention of URTI-like symptoms.
This new study reinforces previous findings on the immunological benefits of L. helveticus LAFTI® L10 supplementation in athletes and shows that probiotics could help address the increased URTI-like episode risks linked to training and intense exercise and help support a well-functioning immune system. The first sports study conducted with this strain was a pre-post intervention study conducted in two groups of well-trained recreational athletes: 18 ‘healthy’ athletes and 9 fatigued athletes, the suffering of fatigue, recurrent cold-like symptoms, and impaired performance. In this study, L. helveticus LAFTI® L10 helped overtrained athletes to recover a healthy immune balance: after one month of probiotic administration, CD4+ T cells secretion of IFN-g in fatigued athletes was restored. For the healthy group, IFN-g level in saliva also increased.
Gastro-intestinal (GI) functions
They are also affected during exercise. The body mobilizes its blood supply to the lungs and heart, to the detriment of other organs. This phenomenon can lead to perturbations in gut motility and damages to intestinal epithelial cells increasing gut permeability. Exercise-induced GI disturbances can impair training and performance.
Probiotics’ ability to help balance and restore the intestinal microbial ecosystems is public knowledge. Their modes of action are increasingly well apprehended. It has been shown that probiotic bacteria can adhere to the gut epithelium, preventing the adhesion of opportunistic microorganisms. Certain strains have the ability to enhance the gut barrier function through various mechanisms.
“A healthy mind in a healthy body”
While sport is part of a healthy lifestyle, it can also generate occasional stress, for example when overtraining or preparing for a competition. If a certain level of stress can be beneficial to keep oneself competitive and help push the limits, excessive stress can affect exercise and performance and in turn gastro-intestinal health, as we are now aware that the gut is our second brain.
The role of the digestive microflora and probiotic supplementation on the brain-gut axis has recently gained momentum. In 2008 the first clinical trial was published linking probiotics to stress-like symptoms. A double-blind, placebo-controlled, randomized study was conducted over a 3-week period on stress-induced gastrointestinal symptoms in healthy volunteers, using either a specific probiotic preparation (Lactobacillus helveticus Rosell®-52 and Bifidobacterium longum Rosell®-175 in a stick format – Probio’Stick®-) or a placebo. After three weeks of daily administration of the probiotic, two important stress-induced occasional symptoms, were significantly reduced by half as compared to the placebo group. This study indicated that the probiotic could bring benefits to occasionally stressed individuals, reducing significantly gastro-intestinal symptoms of stress. Later on, another unique clinical study assessed the effect of this probiotic combination on psychological occasional stress in healthy humans, using tests commonly used to evaluate anxiolytic drugs. A one-month daily administration of the probiotic had a beneficial effect on psychological symptoms related to stress and general signs of anxiety. These positive results were verified by the decrease of the biological marker for stress.