How food intolerances can be part of a world title
The area of medicine that I am most passionate about is optimising human performance, seeking and adopting strategies to overcome limits, stay ahead of the competition and reach the top. I am fascinated by endurance and athletes who are able to exceed human limits several times over, in particular those who can swim 3.8km in open water, cycle 180km and finish by running a marathon.
If I already think it's incredible that they can do it in one day, how can I call someone who can do it in 8 hours?
Lucy Charles-Barclay (source: Instagram @lucycharles93)
One such athlete I follow on social media is Lucy Charles-Barclay, former British swimmer turned triathlete, who congered a few days ago as Ironman 70.3 world champion, after having placed second several times. In a video on her Youtube channel, she shared that she had recently taken a food intolerance test. While not necessarily surprising, the results would require a significant change in her eating plan.
The aim, Lucy says, would be to try and gain 1 to 2 per cent performance.
When competing at the highest level, any performance gain cannot be underestimated. Although it may seem like a small amount, gaining 1 or 2% over 8 hours of racing can represent a real gain of 5 to 10 minutes which is the difference between winning or not winning (at the 2019 Ironman world championships in Kona, Hawaii, the difference between first and fourth place in the men's race was just over 11 minutes).
I don't have any kind of inside knowledge that would allow me to know the real impact of this change and the relationship it had with the world title. I can only delve into the science and try to come to some conclusion. That's exactly what I tried to do.
Why are food intolerances common?
A food intolerance arises when the body reacts against part of a food, triggering an immune reaction of greater or lesser magnitude, with greater or lesser clinical impact.
When all is well, we ingest a food and are able to digest it. The digestive process proceeds normally and we are able to break it down into progressively simpler parts so that they can be absorbed in the intestine, in the right place, by the right channel or receptor, thus actually entering our body.
After passing through the intestinal mucosa (the physical barrier of cells), the absorbed components are analysed by the resident immune system, the GALT - gut-associated lymphoid tissue, which scans everything that has just entered, making sure that it does not find any enemies or cause for alarm.
When it does, it lets it enter our system freely, so that it can be used by our cells.
Source: SIBO Doctors
This process occurs every time we eat or drink. It is so important for our health that most of our immune cells are located in the gut to ensure that we can discern friend from foe.
This is how we keep ourselves safe.
However, when this process does not occur in this way and theimmune system identifies some of the compounds as dangerous or enemies, we trigger a defence reaction against these 'aggressors'. We become no longer tolerant to these foods, and there are several reasons why this might happen. Whatever the reason, the reaction they cause is the same:
increased release of pro-inflammatory mediators such as IL6 or TNFa;
increased mobilisation and activation of immune cells, such as M1 neutrophils and macrophages
the creation of a local inflammatory state with the possibility of developing into a systemic picture.
These imbalances should be the focus of anyone looking to reach their best level of performance, from the world's best like Lucy, to weekend warriors looking to excel, to those concerned with staying healthy or even corporate athletes.
What impact do they have?
The impact of food intolerances on physical and mental performance is due to their influence on the process at the heart of recovery from physical effort and adaptation to training: inflammation.
Athletes train to evolve, become stronger and better resist fatigue. They try to make each training session result in one more step towards their goal. For this to happen, it has to result in biochemical and physiological changes and adaptations which, cumulatively, will lead to a gain in performance.
This logic underpins all types of training. Using running as an example, long workouts below MAF heart rate improve cardiovascular efficiency and mitochondrial function while sprints result in an increase in mitochondrial density and muscle fibre speed. Both stimulate some level of adaptation of muscle cells and supporting structures such as bone, tendons and ligaments, which together resulted in better running times.
Although they are extremely different workouts - the muscle fibres recruited, the energy production systems and even the mental effort are different - the gains are only there if the system takes a step forward towards improved performance.
This journey is made of continuous cycles of destruction and reconstruction, triggered by each training, by each stimulus. The success of this process depends on the perfect orchestration of the two phases of the cycle, both in magnitude and timing: if the destruction is too great, the reconstruction will be more difficult and time-consuming; if the reconstruction is slow, the new state will not be better or stronger.
What is the controlling force of this process of evolution, gain and progression? Inflammation.
Long gone are the days when inflammation was seen only as an evil force that destroyed and eliminated any gains resulting from training. It was not an unreasonable or meaningless view: there is data to support this destructive effect, in particular the catabolic effect resulting from chronic systemic inflammatory conditions. Incidentally, this is an important point in terms of performance, to which we will return.
Inflammation controls the entire cycle of adaptation to training. The secret lies in the perfect orchestration between the two phases, in the balance between pro-inflammation, which triggers destruction, and anti-inflammation, which triggers recovery. Let me use the muscle as an example of how it all occurs.
When we train, we (want to) cause damage to the muscle fibres; only in this way can we trigger the phenomena of tissue adaptation and regeneration. It is the first step in a series of events that will result in the creation of new muscle cells from specific stem cells, the satellite cells.
The first phase is the pro-inflammatory or degenerative phase. It is catalysed by the damage inflicted on muscle cells and the consequent release of inflammatory mediators, such as reactive oxygen species(ROS), IL6 and TNFa, and mobilisation of neutrophils and M1 macrophages, the main cells involved in this step. Together, they work to destroy the debris and debris from the damaged cell, ensuring that the ground is ready to be restored and strengthened.
The greater the damage, the greater the magnitude of the pro-inflammatory process triggered and, for this reason, the greater the intensity of the destruction and cleansing process.
When the cleansing is complete, the scenario changes significantly: pro-inflammation turns into anti-inflammation giving rise to the second phase, that of regeneration. The mediators of the process change (there is an increase in the amount of IL10, an anti-inflammatory cytokine), growth factors are released (HGH, TGF B1 and IGF-1) and the macrophages become M2, giving orders to the satellite cells (which have since increased in number through the action of M1) to transform themselves into muscle cells.
It is this balance between increased and decreased inflammation that we evolve. That's the key word: balance.
The success of this process depends on the existence of an inflammatory peak, caused by the increase in inflammatory mediators that signals the beginning of the first phase, which gives rise to an anti-inflammatory peak of a suitable magnitude in order to deal with the inflammatory signal emitted. Only then will the satellite cells transform into muscle cells, regenerating and strengthening the muscle.
Any disturbance in the magnitude of both peaks undermines the whole process:
If the inflammatory peak is too small, it may not be enough to trigger the cycle (if the effort and stress exerted is small, it will probably not lead to real gains)
If there is no anti-inflammatory capacity, it will not be possible to repair the damage
If the inflammatory spike is too great, the damage caused is likely to be too much to repair, requiring long and possibly imperfect work (which cumulatively can lead to overtraining syndrome).
There is yet another form of imbalance: the existence of a chronic state of inflammation.
In this state, there is constantly circulating information signalling the release of pro-inflammatory mediators, creating a state of chronic low-grade inflammation. This state is known to be associated with various chronic disease processes, from diabetes, depression, cardiovascular and even oncological diseases.
In the performance context, its impact is far from positive:
How can the impact be so far-reaching?
Because these chronic inflammatory conditions not only make it difficult for the structures to adapt to physical effort but also increase wear and tear and accumulated damage.
For the recovery and adaptation process to be triggered, there needs to be a certain increase in pro-inflammatory mediators, a certain delta, for the whole process to take place. Without this increase, the recovery cycle will not start.
However, when the amount of inflammatory mediators that exist in circulation is already chronically increased, the required post-workout elevation appears to be compromised. This has been shown for the cytokines most crucial in this process, such as IL6 and also TNFa.
If you can't get that post-exercise inflammatory peak, when it is actually mandatory, the whole process is compromised, leading to the conclusions that now seem obvious, as stated in this 2016 review article:
"Difficulties in post-exercise recovery may just be due to how difficult it is to increase pro-inflammatory cytokines in an already chronically inflamed individual "
Put another way, the increase in these cytokines, regardless of the reason or origin in our bodies, will hinder recovery and, by the same token, performance. Which brings us back to food intolerances and why they may have been a key part of Lucy Charles-Barclay's world title.
Every time Lucy ate foods she was intolerant to, she was giving rise to the same inflammatory mediators that she needs to get extremely under control in order to train, recover and compete at the highest level. If she ingests this food three times a day, this is how many times these messengers will be released. If we combine this data with the highly demanding training plan you follow, with 2 to 3 workouts a day (which also create spikes), the magnitude of the inflammatory status increases significantly.
The consequence, I predict based on everything I have described, will have been an unnecessary increase in these messengers over time, creating a chronically higher inflammatory state than would be desirable, potentially impacting negatively on your performance.
By the same token, when she removed her food intolerances from the plan, the now world champion will necessarily have achieved a greater immune balance with the potential to improve her performance, even if it has been 1-2%. Over the course of a four-hour race, that's crucial minutes gained.
The influence of food on performance, sporting or otherwise, goes far beyond the quantity of macro or micronutrients.
It is much more than fuel. The inflammatory effect of diet is probably a more important factor and has a greater influence on the ability and likelihood of achieving the best results, whether it's being a world champion or getting through a demanding day of meetings. It's not just about 'eating well' or 'having a clean diet' but about knowing what is best for each system, each athlete, each individual.
This is the only way we can reach our best potential. Isn't that what we are all looking for?
Two final notes:
In this article I have significantly simplified the physiology and biochemistry with the aim of making them better understood. This simplification has not however altered the veracity of the arguments described. If you want to dive into the details, I invite you to read the articles I reference throughout the text, they are fascinating).
The relationship between food sensitivities and sports, particularly endurance sports, is complex, particularly due to the impact on gastrointestinal health that long-duration races have. Cases of increased intestinal permeability as a result of physical exertion have been described, thereby increasing the inflammatory intestinal reaction, rather than the primary action caused by food. Although the cause is different and therefore the treatment of these conditions is different, even in these circumstances, food triggers immune reactions which may aggravate the condition. For this reason, and even if only temporarily, there are probably clear benefits in studying the food reactions and removing these foods from the diet).