How Food Intolerances Can Be Part Of A World Title
The field of medicine that I am most passionate about is human performance optimization - seeking and adopting strategies to surpass limits, stay ahead of competition, and reach the pinnacle. I'm fascinated by endurance and athletes who are capable of repeatedly pushing the boundaries of human potential. Particularly those who can swim 3.8 km in open waters, cycle 180 km, and finish with a marathon run.
If I already found it incredible that they could achieve this feat in a single day, how can I describe someone who accomplishes it in 8 hours?!
Lucy Charles-Barclay (fonte: Instagram @lucycharles93)
One of the athletes I follow on social media is Lucy Charles-Barclay, a former British swimmer turned triathlete, who recently became the world champion of Ironman 70.3 after several second-place finishes. In a video on her YouTube channel, she shared that she recently underwent a test for food intolerances. While the results may not have been surprising, they would require a significant alteration to her dietary plan.
According to Lucy, the goal was to try to gain a 1 to 2% performance improvement.
When competing at the highest level, any performance gain cannot be underestimated. Despite seeming like a small percentage, gaining 1 or 2% over an 8-hour race can result in a real time improvement of 5 to 10 minutes, which can be the difference between victory and defeat (in the 2019 Ironman World Championships in Kona, Hawaii, the difference between the first and fourth male finishers was just over 11 minutes).
I lack any kind of inside knowledge that would allow me to know the real impact of this change and its relationship to the world title. All that remains is for me to dive into the science and attempt to reach some conclusions. That's exactly what I tried to do.
Why do food intolerances arise?
Food intolerance occurs when the body reacts against certain components of a food, triggering an immune response of varying magnitude and clinical impact.
When everything is functioning well, we ingest food and are able to digest it. The digestive process proceeds normally, breaking down the food into progressively simpler components that can be absorbed in the intestines. This absorption occurs in the correct location, using specific receptors, allowing the nutrients to enter our system.
After passing through the intestinal mucosa (the physical barrier of cells), the absorbed components are scrutinized by the resident immune system, the GALT - gut-associated lymphoid tissue. This system scans everything that has just entered, ensuring that no enemies or reasons for alarm are present.
When all is well, the nutrients are allowed to enter our system freely, to be utilized by our cells.
SIBO Doctors
This process occurs every time we eat or drink. It is of paramount importance to our health, and a significant portion of our immune cells are located in the intestines to ensure that we can distinguish between friend and foe.
This is how we maintain safety.
However, when this process deviates and the immune system identifies some of the components as dangerous or foreign, a defense reaction against these "invaders" is triggered. We become intolerant to these foods, and there can be several reasons for this to happen. Regardless of the cause, the reaction that follows is the same:
The release of pro-inflammatory mediators, such as IL6 or TNF-alpha, increases;
The mobilization and activation of immune cells, such as neutrophils and M1 macrophages, increase;
A local inflammatory state is created, which can potentially become systemic.
These imbalances should be of concern to those seeking to achieve their highest level of performance, whether they are world-class athletes like Lucy or weekend warriors striving to surpass themselves, those concerned with maintaining health, or even corporate athletes.
What is their impact?
The impact of food intolerances on physical and mental performance is due to the influence they exert on the central process of recovery from physical effort and adaptation to training: inflammation.
Athletes train to evolve, become stronger, and better withstand fatigue. They strive for each training session to lead them closer to their goals. To achieve this, biochemical and physiological changes and adaptations need to occur cumulatively, resulting in performance gains.
This logic underlies all types of training. Taking running as an example, long runs below the maximum aerobic function (MAF) improve cardiovascular efficiency and mitochondrial function, while sprints lead to an increase in mitochondrial density and muscle fiber speed. Both types of training stimulate some level of cellular muscle adaptation and support structure adaptation, such as bones, tendons, and ligaments, which together yield improved running times.
Despite these being extremely different types of training - different muscle fibers are recruited, energy production systems vary, and even mental effort differs - the gains only occur if the system takes a step forward toward performance improvement.
This journey is composed of continuous cycles of destruction and reconstruction, initiated by each training session, each stimulus. The success of this process depends on the perfect orchestration of the two phases of the cycle, both in terms of magnitude and timing. If destruction is too severe, reconstruction becomes more difficult and time-consuming. If reconstruction is slow, the new state won't be better or stronger.
What's the controlling force behind this process of evolution, gain, and progression? Inflammation.
Long gone are the days when inflammation was seen solely as a malevolent force that destroyed and eradicated any gains from training. This view wasn't without basis: there are data supporting this destructive effect, particularly the catabolic effect resulting from chronic systemic inflammatory conditions. In fact, this is an important point in terms of performance, which we'll come back to.
Inflammation controls the entire training adaptation cycle. The secret lies in the perfect orchestration between the two phases, balancing pro-inflammation, which triggers destruction; and anti-inflammation, which triggers recovery. Let me use the muscle as an example of how this process unfolds.
When we train, we aim to cause damage to muscle fibers; only then can we trigger the processes of adaptation and tissue regeneration. This damage is the first step in a series of events that result in the creation of new muscle cells from specific stem cells called satellite cells.
The first phase is the pro-inflammatory or degenerative phase. It is catalyzed by the damage inflicted on the muscle cells and the subsequent release of inflammatory mediators, such as reactive oxygen species (ROS), IL6, and TNFa, as well as the mobilization of neutrophils and M1 macrophages, the main cells involved in this step. Together, they work to destroy the debris and waste of the damaged cell, ensuring that the ground is prepared for restoration and strengthening.
The greater the damage, the greater the magnitude of the pro-inflammatory process triggered, and for that reason, the intensity of destruction and cleanup increases.
Once cleanup is completed, the scenario changes significantly: pro-inflammation transforms into anti-inflammation, giving rise to the second phase, regeneration. The mediators of the process change (there's an increase in the amount of IL10, an anti-inflammatory cytokine), growth factors are released (HGH, TGF B1, and IGF-1), and macrophages transition to M2, instructing satellite cells (which have increased in number due to M1 activity) to transform into muscle cells.
It's this balance between inflammation increase and decrease that leads to evolution. The keyword is indeed balance.
The success of this process depends on the existence of an inflammatory peak, caused by an increase in inflammatory mediators that signal the beginning of the first phase, leading to an anti-inflammatory peak of appropriate magnitude to counter the inflammatory signal emitted. Only in this way will satellite cells transform into muscle cells, regenerating and strengthening the muscle.
Any disturbance in the magnitude of both peaks impairs the entire process:
If the inflammatory peak is too small, it might not be sufficient to trigger the cycle (if the effort and stress exerted are small, real gains probably won't be achieved);
Without anti-inflammatory capacity, repairing damage becomes impossible;
If the inflammatory peak is too large, it's likely that the damage caused is too extensive to be repaired, requiring prolonged and potentially imperfect recovery (which cumulatively can lead to overtraining syndrome).
There's another form of imbalance: the existence of a chronic state of inflammation.
In this state, information circulates constantly, signaling the release of pro-inflammatory mediators, creating a state of low-grade chronic inflammation. This state is associated with various chronic disease processes, from diabetes and depression to cardiovascular and even oncological diseases.
In the context of performance, its impact is far from positive:
Reduced cardiovascular capacity, particularly in terms of VO2max;
Loss of muscle mass;
Increased risk of injury.
How can the impact be so extensive?
Because these chronic inflammatory conditions not only hinder the adaptation of structures to physical effort but also increase wear and accumulated damage. For the recovery and adaptation process to be initiated, a certain increase in pro-inflammatory mediators - a specific delta - required for the entire process to unfold. Without this increase, the recovery cycle won't begin.
However, when the amount of inflammatory mediators already circulating in the body is chronically increased, the necessary post-training elevation seems compromised. This has been demonstrated for the most crucial cytokines in this process, such as IL6 and TNFa.
If this post-effort inflammatory peak can't be achieved when it's really necessary, the entire process becomes compromised. This leads to the conclusions that seem obvious now, as stated in a 2016 review article:
"The difficulties of post-exercise recovery may be due only to the difficulty of increasing pro-inflammatory cytokines in an individual who is already chronically inflamed."
In other words, an increase in these cytokines, regardless of the reason or origin within our body, will hinder recovery and, for the same reason, performance.
This brings us back to food intolerances and the reason they might have been a key factor in Lucy Charles-Barclay's world title.
Every time Lucy ate foods to which she was intolerant, she was initiating an increase in the same inflammatory mediators she needs to have extremely controlled in order to train, recover, and compete at the highest level. If she consumes that food three times a day, that's the number of peaks in the release of these messengers. If we combine this data with her highly demanding training plan of 2 to 3 daily workouts (which also create peaks), the magnitude of her inflammatory status grows significantly.
As a consequence, based on everything I've described, there might have been an unnecessary increase in these messengers over time, leading to a chronically elevated inflammatory state higher than desirable, with potential negative impact on her performance. Likewise, when she removed her food intolerances from her diet, the now world champion likely achieved a better immune balance, with the potential to improve her performance, even if it's just by 1 to 2%. Over a 4-8 hour race, these are crucial minutes gained.
The influence of diet on performance, whether athletic or not, extends far beyond the quantity of macro or micronutrients. It's much more than fuel. The inflammatory effect of the diet is likely a more important factor with a greater influence on the ability and likelihood of achieving optimal results, whether becoming a world champion or getting through a demanding day of meetings. It's not just about "eating well" or having a "clean diet," but rather understanding what's best for each system, each athlete, each individual.
That's the only way we can reach our full potential. Isn't that what we all aim for?
Two final notes:
In this article, I've significantly simplified the physiology and biochemistry to make them more understandable. However, this simplification hasn't altered the accuracy of the arguments described. If you're interested in delving into the details, I encourage you to read the articles I reference throughout the text—they're fascinating.
The relationship between food sensitivities and sports, particularly endurance sports, is complex due to the impact on gastrointestinal health that long-duration races have. Cases of increased intestinal permeability resulting from physical exertion have been described, which increases intestinal inflammatory reactions - not due to primary action caused by diet. Despite the differing cause and treatment of these conditions, even in these circumstances, foods trigger immune reactions that can exacerbate the situation. For this reason, and albeit transiently, there are likely clear benefits in studying food reactions and removing those foods from the diet.
08/08/2023
Posted originally - 30/09/2021 (https://www.cristinasales.pt/blog)