IOC consensus statement supplements (part 5)

Indirect performance enhancers

Some supplements improve a crucial element that is not necessarily directly linked to performance, but by improving that specific element, the supplement will improve your overall performance in the long run. Some examples to get the idea:

  • Supplements that enhance recovery: Athletes that recover faster, can get more training units in.
  • Supplements that can manipulate body composition: Athletes usually aim for low-fat mass and high fat-free mass. Some supplements can aid you to achieve this goal.
  • Supplements that boost your immune system: Athletes that don’t get sick will be able to follow their training schedule without interruptions.

The list of supplements that may have an indirect effect on performance is very long. The problem is that most studies are done on regular people and there is no guarantee that athletes will respond the same way. Therefore extra research is needed to proof their true benefits for the more active population.

Below we listed the most commonly known. Are you wondering about a different supplement, feel free to send us a message.

Vitamin D

There is a reason to believe that vitamin D can improve your immune system, overall health, bone strength and adaptive response to exercise. The best way to get sufficient amounts of vitamin D is simply by spending enough time in the sun. Indoor athletes and athletes living in countries where there is not enough sunlight are at high risk for a vitamin D deficiency. Vitamin D is a fat-soluble vitamin, therefore when you take vitamin D as a supplement do so with a meal that contains some fat.


More and more evidence shows that our gut bacteria play an important role in our lives. Probiotics are live micro-organisms that can increase the number the “good bacteria” in our gut. It is recommended to ingest a daily dose of probiotics. The main examples of probiotics are Lactobacillus and Bifidobacterium which can be found in fermented food products like yogurt.

Vitamin C

Vitamin C is probably the most well-known vitamin to support the immune system. Some, but not all studies show a decrease in illnesses in people taking vitamin C supplementation. Vitamin C is also known as being an antioxidant, but research about its effectiveness in well-trained athletes remains unclear.


This is an essential mineral that is claimed to reduce the incidence and duration of common colds. Zinc deficiency is common in athletes and results in impaired immunity system. Before you start swallowing Zinc supplements be aware that too much Zinc is just as bad as a deficiency. Therefore perform regular blood checks and supplement accordingly.


Glutamine is a non-essential amino acid and an important energy substrate for immune cells. After prolonged exercise and very heavy training, the glutamine in the blood is decreased. It seems logical that taking extra glutamine as a supplement will boost the immune system, but there is no real evidence in athletes. In the general population, the immune-supportive effect of glutamine seems to be much more profound in vegetarians and vegans.


Echinacea is an herbal extract claimed to enhance immunity. There are some studies done in a lab supporting this, but real-life researches have ended with contradicting results. In other words, more research is required.

Beta-hydroxy beta-methyl butyrate (HMB)

HMB is a metabolite of the amino acid leucine and has very promising claims. The main idea is that HMB can enhance the adaptive response to exercise. Its clinical use looks very promising, reducing muscle atrophy caused by extended times of bed rest. However, the effectiveness in athletes remains unclear and the same results are likely to be obtained from a normal high protein diet.

Omega-3 fatty acids

Omega 3 is commonly known to promote healthier blood lipids. Less known are its beneficial effects related to neurology, reduced muscle damage after exercise, anti-inflammatory effect and possible appetite suppression. When choosing an omega 3 supplement, check for EPA and DHA on the package, as they indicate the quality of the product.


Curcumin, a constituent of the spice turmeric, is often ingested for anti-inflammatory effects. Studies are promising and show a decrease in inflammation and sense of pain, however, these studies were not done on athletes and further research should be done before it can be recommended for athletes.

Protein isolate

Protein isolate can be used either to gain weight, increasing muscle mass, or to retain lean body mass during weight loss. The benefit of protein isolate is that it gives your body the necessary amounts of protein without having to co-ingest carbohydrates and fat as is often the case in regular food.

Green tea catechins

Green tea is an antioxidant, has an anti-inflammatory effect and is a potential fat burner. Most studies have shown an increase in fat oxidation after drinking green tea, however some people respond better than others. This might have to do with being a regular coffee drinker or not. People that don’t drink coffee tend to have a greater fat-burning effect from green tea catechins.


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Based on the latest consensus statement of the IOC regarding supplements.