Micronutrients and supplementation in triathlon

In your opinion, what are the biggest challenges when it comes to the diet of a female and male triathlete?

For women, it is often difficult to consume enough energy effectively when training volumes are high. Iron deficiency is also common, as women can lose a lot of iron during menstruation. Another challenge, particularly for younger athletes, is a long journey to training. It’s important to plan in advance what you can eat before and after training so you don’t have to wait for long periods on the way home. This requires good planning and it’s worth looking into this specifically.

Unlike cycling and running, nutrition during swimming is only of limited use. What do you recommend in that case?

You have to make a clear distinction between training and competition. During training, you can easily position a water bottle at the edge of the pool containing a mixture of easily digestible carbohydrates. In competition, over the Olympic distance, it is not possible to refuel; however, this usually lasts around 20 minutes, which is manageable when you consider that you can make up for it afterwards on the bike.
It’s a bit trickier over longer distances. Take the IRONMAN, for example, where you’re out there for a good hour. Here, you need to think it through properly beforehand and prepare accordingly. Energy intake only starts there once you switch to the bike.

The significantly increased physical activity leads to the acceleration and activation of many metabolic processes in athletes. Which micronutrients are frequently lacking in endurance sports?

Iron is particularly common in women, but calcium is also sometimes lacking, as some people cannot tolerate milk or explicitly exclude it from their diet. One should always pay close attention to specific diets that are not based on sound principles. It is important that athletes who choose a specific diet consider what they might be missing out on due to the exclusion of certain foods, and then address this specifically.

When should micronutrient testing or a sports medicine check-up ideally be carried out?

Athletes at national or regional squad level must undergo an annual sports check-up in order to be eligible to compete internationally. These check-ups sometimes include blood tests. This is not mandatory and is generally optional, particularly for regional squad athletes. However, it certainly makes sense, if you are training at a competitive level, to have this checked once a year, focusing on the most important nutrients – vitamin B12 and iron. Vitamin D is no longer included, as it is generally recommended to supplement this. Of course, if there is a drop in performance, you must also investigate specifically what might be causing this. It is often overlooked that nutrients can compete with one another when absorbed. For example, taking magnesium or calcium at the same time as iron is not particularly advisable. Similarly, not everyone is aware that magnesium should preferably be taken in the evening, as it can have a muscle-relaxing effect.

As a sports doctor, what do you look out for when recommending dietary supplements?

I ensure that the focus is on areas where there is increased demand, or conversely, where the athlete is not consuming enough due to their diet or where a deficiency exists. Furthermore, it is important to examine nutrients more closely in the case of specific complaints or during periods of injury. This is highly individual and varies from person to person.

Are there any myths regarding sports nutrition and dietary supplements that you’d like to dispel?

It has to be said that athletes often think that improved performance can be achieved simply by improving their diet or taking supplements. I believe this is not the case, and studies also show this. In principle, a healthy and balanced diet is the key. A difference can be made if one’s diet is very unbalanced and unhealthy, if certain foods are omitted, or if energy intake is too low. But if one has a balanced diet and there are no deficiencies, then dietary supplements will not improve performance.

To what extent should nutrition differ during training and competition?

It is important to test any products you plan to consume during competition in training beforehand. Some athletes are very sensitive to the intake of various carbohydrate mixtures and need to know exactly how much they can consume per hour and what the composition should be. You also need to consider whether, during a competition, you require a longer interval between eating and the event itself than you do in training. In training, you might also deliberately do one or two sessions where your energy stores are not fully replenished. However, if you do this too often, it can lead to a drop in performance. Training is also no longer as effective in such situations.

What might an optimal diet look like before a competition, and which foods are particularly suitable for after the competition?

Ideally, something that really tops up your energy stores. Carbohydrates that are easy to digest, which don’t weigh you down or cause bloating. Generally speaking, things you know you can tolerate well during a competition.
After the race is before the race. If you have another race coming up shortly afterwards, many athletes can still get a bit more out of themselves if they have a bottle of a carbohydrate/protein mix ready immediately after crossing the finish line, to replenish their stores as quickly as possible. We know that this helps you recover much faster and get back to full strength. If, on the other hand, you cool down, shower, etc. first and only eat something at the hotel hours later, you unnecessarily prolong the recovery time. This is not conducive to a good performance or a smooth return to training afterwards.

What should athletes following a vegetarian or vegan diet pay particular attention to when it comes to ensuring an adequate intake of micronutrients?

With a vegetarian diet, you need to make sure you replace or supplement iron, vitamin B12 and zinc where necessary, and have these levels checked at regular intervals. With a vegan diet, you need a great deal of knowledge to ensure you get enough of all nutrients. It is probably possible, but not entirely straightforward. You need to meet your entire protein requirement, and when it comes to micronutrients, there are others to consider that are mainly found in meat and dairy products, such as calcium, which mustn’t be forgotten. It really does become very difficult to consume these in sufficient quantities.

Dietary supplements are freely available and a major topic, particularly in elite sport. Do you often come across situations where people are taking too many supplements?

This is an issue I raise very frequently. You should take great care to ensure that the products do not come from a company that also manufactures other products found on a doping list. You can really cause yourself a great deal of harm with them. My motto is therefore: it’s better to take fewer products and not believe any advertising that promises to boost performance. There’s a very high risk that they contain something on the doping list. Products from Swiss manufacturers you can trust are a better choice.
In elite sport, it is less common for athletes to take too many supplements. This happens mainly at a lower level, among people who want to boost their performance quickly and with as little effort as possible in order to reach a goal faster. These methods are not very sensible.   

Which micronutrients do athletes often take in greater quantities than necessary?

It is important that athletes ensure they do not deliberately take various micronutrient supplements at the same time, as these may even interfere with each other’s absorption. Generally speaking, too little attention is paid to what one really needs and what is actually beneficial.

Does recovery nutrition play an important role? What do you think constitutes optimal recovery?

Recovery is very important because the next training session is usually just around the corner. The effect of training is more efficient if all recovery, repair and adaptation processes can take place by ensuring the body has sufficient energy available. A persistent state of energy deficiency can clearly lead to a decline in performance in the long term, which should not be the aim. It may be that you are overweight – in which case you need to tackle this specifically to lose weight. Generally speaking, however, in endurance sports and triathlon, weight is rarely the problem. The problem is usually rather that there is too little energy available, and this can pose a health risk in the long term.

Thank you very much, Sibylle, for taking the time to do this interview.