Micronutrients and Sport: Do I need to supplement?
To maintain normal health, a wide range of vitamins and minerals must be present in your daily diet (3). Micronutrients play namely many important roles in the body, including hemoglobin synthesis, maintenance of bone health, adequate immune function, and protection of body tissues from oxidative damage (3). So, it is very important to get sure that you meet all vitamins and minerals. Therefore, the Institute of Medicine provides reference values, known as Dietary Reference Intakes (DRIs), of suggested intake of micronutrients to prevent deficiency and provide optimal nutrition (3). The DRIs vary among gender and age groups, and importantly, these values represent what is needed for the “normal” individual (3). The DRIs consist of four different components: recommended dietary allowance (RDA), adequate intake (AI), estimated average requirement (EAR), and tolerable upper intake level (UL). The RDA, as the most important value, provides a dietary intake level that is sufficient to meet the requirement for 98 % of healthy individuals (3). As you maybe already know, the consumption of minerals and vitamins has an optimal level. So, you can eat too little and also too much of a specific micronutrient. This fact is very important for your daily life. A lot helps a lot is here not the case. So, don´t consume a lot of supplements as a normal person, only when a medicine person recommends it. Summarized, Figure 1 will present you an overview of the previously discussed DRIs.
Figure 1 Dietary Reference Intakes (Source: https://els-jbs-prod-cdn.jbs.elsevierhealth.com/cms/attachment/9183684a-b76d-4493-ad54-100b49102888/gr1_lrg.jpg, Retrieved from 28.04.4041)
The next what we must consider is that micronutrient needs change with increased physical activity. So, as I already told you, the RDA represents the amount of each specific micronutrient for a normal person with a normal activity level. This means, that regular intense exercise training increases all nutrient requirements by increasing turnover and decreasing absorption (3). Moreover, high intakes of micronutrients may be required to cover needs related to tissue maintenance and repair (3). However, after we now know what we must consider by consuming micronutrients, let us look at the different micronutrients, beginning with the vitamins.
Vitamin is an organic compound, naturally found in small amounts in food products. In addition, vitamins are essential nutrients because they cannot be synthesized by the body in amounts that are necessary to support normal physiological function (3). So, we need to consume these with a balanced diet. Furthermore, vitamins can be differentiated into water-soluble and fat-soluble vitamins. On the one side, water-soluble vitamins (Vitamin B1, B2, B3, B6, B12, Vitamin C, Folate, Biotin, Pantothenic acid) dissolve readily in water and are lost daily in the urine (3). We need water-soluble vitamins for energy production during exercise (mainly mitochondrial energy metabolism), production of red blood cells, protein synthesis, and tissue repair and maintenance (2, 3). Fat-soluble vitamins (Vitamin A, D, E, K) on the other side, stored for extended periods when consumed in excess. So, they create a greater risk for toxicity than water-soluble vitamins (3). But, fat-soluble vitamins are necessary for antioxidant activity and bone formation (3).
Summarized, there will be no real deficiency for water- and fat-soluble vitamins for people who eat balanced and get their energy requirements. Although it is thought that exercise may only slightly increase the need for these vitamins, but the demands can usually be met by the increased energy intakes required for physically active persons to maintain energy balance (3). So, in general, the benefits of vitamin supplementation regarding increased exercise needs or improved athletic performance are assumed inconclusive (3). If you want more detailed information about the different vitamins then check out my vitamin list on Friday. Here you will get more information about the function, nutritional sources, and reference values for each vitamin.
Minerals are chemical agents which are required by living organisms to maintain physical health (3). There are various roles involved in enzyme regulation, maintenance of acid-base balance, nerve and function, and cellular growth (3). Here we also can differentiate between macrominerals and microminerals. Macrominerals, on the one hand, are required in amounts greater than 100 mg/day and include calcium, phosphorus, magnesium, sulfur, potassium, sodium, and chloride (3). On the other hand, microminerals are required in amounts less than 100 mg/day and include iron, zinc, copper, selenium, iodine, fluoride, chromium, manganese, molybdenum, boron, and vanadium (3). Deficiencies of all these elements are theoretically possible, but in practice, deficiencies are generally uncommon, with the possible exceptions of iron, calcium, and in some parts of the world, iodine (2). However, a balanced diet with a sufficient energy intake will normally supply all the minerals in the required amounts (2). You will see an overview of a balanced diet below in Figure 2.
Figure 2 Balanced Diet (Source: https://www.nutrition.org.uk/images/Eatwell_Guide.jpg, Retrieved from 28.04.2021)
But are there any deficiencies of minerals under athletes? For example, iron and calcium may be consumed in low amounts by athletes (3). Also, during strenuous activity or exercise in a hot environment, elevated sweat losses may result in increased dietary requirements of sodium and chloride (3). In the end, deficiencies in iron and chromium may lead to performance impairment and deficiencies in calcium, magnesium, and phosphorus may decrease bone health (3). Overall, when well-nourished athletes are supplemented with vitamins and minerals, no improvements will be reached (3). So, try firstly to eat balanced during the day.
In the end, it is very important to consider that those deficiencies can only be established by biochemical investigation (2). So, supplement only the micronutrient if there is a detected deficiency. Otherwise, you will reach no improvements. Moreover, you can decrease your performance or get ill. So, vitamin supplementation is generally unnecessary, but further research into the requirements of athletes is required (2). You will also get later also a mineral list with the specific function, requirements, and nutritional sources for each mineral. But not this week.
Have a nice week and we see us on Friday!
(1) Gleeson, M. (2016). Immunological aspects of sport nutrition. Immunology and cell biology, 94(2), 117-123.
(2) Maughan, R. J. (1999). Role of micronutrients in sport and physical activity. British medical bulletin, 55(3), 683-690.
(3) Serra, M. C., & Beavers, K. M. (2015). Essential and nonessential micronutrients and sport. In Nutritional Supplements in Sports and Exercise (pp. 77-103). Springer, Cham.
Caballero, B. (2009). Guide to nutritional supplements. Academic Press.
Castell, L. M., Stear, S. J., & Burke, L. M. (Eds.). (2015). Nutritional supplements in sport, exercise and health: An AZ guide. Routledge.