Detoxification pathways and their importance in exercise

To many people, detoxification conjures up ideas of trendy health farms with herbal teas and juices. It is not immediately associated with sporting performance. However, this potentially ‘hidden’ physiological pathway is essential for many elite amateur athletes. One of the many challenges of being a very good athlete, but also needing to work full time, is that you have many demands on your energy levels. Understandably, these athletes don’t readily make the connection between the energy demands of their training and the energy demands of their life: they see their sporting pursuits as the place where they burn energy, but don’t consider the additional load created by other aspects of their lives.

Introducing Ed

Ed was one such athlete, barely making the connection between food and exercise, let alone specific physiological processes within energy production and general performance. Ed was a triathlete who was working, training and playing hard. He approached me after he had joined a newly formed triathlon team. From his point of view, he was ready to go; the only aspect he felt he hadn’t given consideration to was his nutrition. 

Starting nutrition support

During the initial call Ed expressed concern about a small amount of fatigue he experienced, but more importantly he was seeking my advice to “gain a competitive edge”. During the first consultation, however, he presented slightly differently than I had expected. He was very low in mood and clearly tired. He had been up that morning at 5 a.m., on the turbo trainer for 90 minutes. By 6 p.m., when I arrived for the consultation, he had not eaten since breakfast and was helping to prepare food for his family. He was already very daunted by the early start tomorrow to continue his relentless training regime. Ed worked for an agricultural company as an agronomist, and being very busy, he regularly missed lunch, instead drinking coffee. Additionally, he didn’t feel particularly hungry at breakfast after early morning training. Table 1 shows a typical daily pattern of eating for him.

Typical food consumption before my nutrition intervention:

As I continued with the consultation, the cracks started to appear. It came to light that Ed had been experiencing drops in performance over the last six months, which were causing significant stress/anxiety due to the pressure of racing for the new team. He admitted to being exhausted, struggling with headaches, injuries and poor sleep. Additionally, he was very stressed at work and was relying more and more on alcohol to help him sleep. It also became clear that Ed’s low mood had been something that he’s been battling with for a few months. He also said that he had been trying to lose weight, but instead was putting it on, despite low food intake and a heavy training schedule. Table 2 is an example of a training week for Ed.

Typical training week

Due to his poor eating patterns, I suspected that Ed may be deficient in many micronutrients. He admitted to drinking a lot of coffee, fruit cordial and alcohol, plus he exercised heavily most days. He could sustain this training schedule for a month or so, but then he would ‘crash’, leading to a week off work.

Often when deciding on the first steps of an intervention, I try to pull together all the case information and group the symptoms together. The functional medicine matrix really helps with this process. After completing this with Ed, I hypothesized that he may be struggling with his detoxification processes.  From his timeline, I could see that Ed’s symptoms coincided with a promotion at work that resulted in additional responsibility and more travelling time meeting clients. He also had a busy social life, often staying up late drinking with friends on the weekend and the usual demands of a young family at home, with two children under 10 years old.

Why detoxification?

Detoxification processes happen throughout the body, but primarily in the liver. In simple terms, detoxification consists of two phases: phase 1 which is focused on transformation of compounds, an intermediate phase, and phase 2 which is focused on excretion of compounds. Like all physiological processes, detoxification pathways require nutrients to work optimally. Ed was potentially low on many of these nutrients. A detailed analysis of his food diary suggested that he was low in protein, B-vitamins, and antioxidants, all of which are vital for detoxification. Some of Ed’s other practices, such as a high caffeine intake, processed food consumption, plus regular alcohol intake, would challenge his detox pathways further since their clearance from the body can be nutrient-depleting.

Caffeine can up-regulate phase 1 detoxification processes (1), which in theory may help, but Ed’s diet lacked vital amino acids to clear phase 2 metabolites, potentially leading to a back-up in the intermediary phase of detoxification. Poor clearance, which has been linked to low protein status, can cause an increase in ammonia, which is toxic at high levels and has been linked to fatigue (2). A lack of amino acids in the system can mean that ammonia remains in the muscle and causes fatigue; the amino acid citrulline, for instance, has been shown to increase time to fatigue by assisting with the excretion of ammonia via the urea cycle (3). 

Detoxification processes within the body require a greater amount of ATP, the body’s energy source, than any other biochemical processes. Exercise also causes an additional stress on our detoxification pathways (4). These two factors, coupled with Ed’s caffeine and excessive alcohol consumption, could mean that his liver was having to work overtime. What’s more, he was consuming a multitude of additional sweeteners, flavourings, preservatives, stabilisers, colours and emulsifiers with the consumption of processed junk foods; ironically mostly in the pursuit of more energy. Also, with Ed’s high stress levels, he would need effective detoxifying processes to help excrete hormones created by this stress. 

The initial intervention – food and health first

We started by making some significant changes to Ed’s diet, introducing more colourful vegetables because they contain the nutrients needed to optimise detoxification among others listed below. Additional considerations are shown in table 3.

Nutrients that support optimum detoxification

An interesting aspect to this case was Ed’s job, which required him to meet clients on arable farms, potentially exposing him to pesticides. Having explained the potential links, I managed to convince Ed to complete a genetic test focused on detoxification processes. The results were fascinating: he had polymorphisms for three of the family of enzymes responsible for phase one detoxification, CYP450. The test results gave more weight to my suspicions, plus also meant that we had identified potential health challenges within all phases of detoxification. 

The genetics report was the final straw for Ed, who threw himself wholeheartedly into nutrition and healthy eating. I embarked on a process of educating Ed about how food impacts his physiological functioning so he could understand the importance of what he ate.

Ed also started to take rest seriously. When we summed up his symptoms, he had been experiencing low mood, fatigue, drops in performance, poor sleep, headaches, and injuries for longer than he cared to remember. He was tired of feeling tired. As I explained to him that the functioning of the liver, not just skeletal muscles, is essential to exercise performance (5) he began to see the value of working with a nutritional therapist.

The next phase – sports nutrition specifics

The next phase of Ed’s training focused on running fitness. His goal was a marathon in under 3 hours 30 minutes. Already a competent distance runner, a 12-week training plan was designed by his coach to help him achieve his goal. He would run a marathon event at the end of the 12 weeks and this would form part of his wider training toward an Ironman distance triathlon.

Having worked with Ed on the initial assessment of his diet and made changes that had really supported him in his life, not just his training, Ed was keen to continue the work we were doing together into the next phase of his training, particularly focusing on body composition.

I like to think this was where the sports specific nutrition advice started. We did energy calculations based on the Cunningham equation of estimated calorific requirements. We estimated Ed’s required calories, to meet both daily lifestyle and athletic demands, to be 2,761 kcal per day (6). Using the analysis of Ed’s current food consumption that I had done in stage 1, however, I found his estimated intake to be only 1,808 kcal per day. This was significantly below his estimated expenditure but yet Ed had struggled to shift weight, which by conventional wisdom didn’t add up.

In terms of an energy intake strategy, the simplistic approach would be to continue a low-calorie intake to help reduce body weight, particularly fat. However, I was reluctant to continue with this low-calorie approach as, based on the evidence I had so far, this was proving to be an ineffective strategy. Research has demonstrated that a calorie deficit doesn’t always result in weight loss (19) although under-reporting can sometimes be a factor. 

Nutrient timing

My working hypothesis was that Ed was under-nourished and I therefore felt that an improved diet was a higher priority than further food restrictions. I also felt that there would be greater benefits from a weight loss perspective in implementing a strategic nutrient timing approach rather than a calorie-in versus calorie-out approach. If we could achieve a good nutrient timing strategy, I thought that he would find body fat loss easier, while also effectively supporting his detoxification pathways.

My particular focus was to use foods with a higher carbohydrate content specifically around training. This goes against conventional wisdom, but anyone involved in sports knows that sugar gives energy. This was shown in Ivy and Portman’s work on nutrient timing that demonstrated that exercise can create an insulin sensitive metabolic state (7). This means that glucose uptake is improved during this time; avoiding body fat storage pathways and leading to greater energy throughput at a cellular level. This would help to increase Ed’s falling energy levels and hopefully address recent performance decrements.

For runs less than 60 minutes in duration, I felt that the work we had done with his overall diet would be sufficient. However, for runs over 60 minutes I introduced 30 grams of carbohydrate 30 minutes before exercise and at 30-minute intervals throughout the session wherever practical. The evidence points to shorter time periods being optimal (8) but Ed felt that this wasn’t achievable for him. It is always important to give the athlete their say and I feel that I achieve greater adherence in the longer term with this approach, so I took on board his feedback and changed the plan, not sticking rigidly to the research. My main priority at this stage was not to get the grams of carbohydrate exactly right, but more to implement the spirit of the guidelines in a way that was achievable for him. I also wanted to focus on natural sources of carbohydrate and I knew that he would need to ‘train’ his gut to get used to what was being eaten (9). Table 4 shows some carbohydrate-rich training examples.

Examples of pre training natural foods

I also felt that Ed’s protein intake could be more strategic. Protein has been used to support recovery from exercise, plus during calorie deficit, it can help to maintain lean body mass while the body loses fat (10). Ed also needed to maintain a range of proteins from different sources to support his detoxification pathways (1). My recommendation was to maintain a moderately high protein intake at 2 grams per kg body weight (g/kg/bw) and to ensure an adequate intake at breakfast, lunch and evening meals (11). Although some research suggests that overall protein consumption through the day is more important than specific protein feeding episodes, I continued to emphasise post-training protein intake as I felt that this strategy would improve adherence to my overall plan. Sometimes people like to feel they are doing something different to support their goals. I recommended 20g of protein following exercise (12) combined with a carbohydrate source to help enhance absorption of both (13). 

An example meal plan to achieve protein recommendations

In general, I wanted to achieve a high polyphenolic diet. To this end, Ed was encouraged to eat more cruciferous and allium vegetables because they support detoxification pathways, and potentially have performance enhancing properties (14). Colourful fruits and vegetables were added to smoothies for the anti-inflammatory benefits. Citrulline, found in watermelon, pumpkin and cucumbers, was also encouraged due to its benefits in supporting ammonia clearance (1). 

Excessive training has been linked with limitations in muscle adaptation to exercise due to chronic stimulation of stress responses caused by the exercise itself (15). Prior to our consultation Ed was experiencing performance drops and a lack of adaptation to the training stimulus. To address this area, I focused on the emerging field of the gut-muscle axis (15). Our gut bacteria help us to absorb and break down proteins, making sure that we get the most out of what we are eating. Therefore, helping Ed to create a diverse gut bacteria environment was one of my priorities. To this end, I encouraged Ed to include fruits and vegetables such as asparagus, bananas, stewed apples, kale, onions and garlic in his diet.

There were many aspects to this case and as we continued to work together, we started to look more deeply into theories of overtraining and how these may apply to Ed.  This led us to record some interesting data, but more importantly meant that Ed was very focused on his own health and power he had in his own hands to make positive changes.  This was the aspect of working with Ed that gave me the most satisfaction and it’s a great message for everyone; we all have it within ourselves to make a positive impact on our health and performance, it just sometimes takes a little nudge first.

Avoiding overtraining and making lifestyle changes

It was very important to get Ed sleeping better.  Poor sleep has been linked with changes in glucose metabolism, increases in appetite and decreases in daily energy expenditure potentially making it harder for people to lose weight in these circumstances (16).  We decided to work on a pre-bed protocol that involved switching off all devices one hour before bed and introducing magnesium salt baths two to three times a week to aid muscle recovery and improve sleep.

Addressing sleep led me nicely into discussing strategies to avoid any reoccurrence of overtraining syndrome.  Ed was on-board with this following our initial consultation but more work was required to keep him on track, particularly as endurance athletes are more at risk than others (17).  We started to track morning heart rate, paying particular attention to any fluctuations.  One specific marker to pinpoint overtraining syndrome does not exist which makes it a very difficult condition to confirm (18) and therefore testing at this point didn’t seem appropriate.  However, after detailed discussions with Ed about potential warning signs we agreed that we would both be alert to any possible onset of the condition.

Ed felt well prepared in this cycle of his training programme and many nutritional aspects practiced at this stage would be carried through the season as he increased his training load leading to the Ironman in September.  He is still competing in triathlon and working hard but now spends more time at home relaxing with his family.  He works with his body rather than considering it a machine, making the connection between the demands of his life in total rather than just his sporting pursuits.  He certainly no longer considers trendy health farms as the only way to detox!!

References on request.