Midway through the Soccer World Cup 2018 – Granted, the author of this article (that’s me) is addicted to soccer on several levels. For one, I have played football (same as soccer for the world outside the US) as a goal keeper myself; not at the highest performance levels, but nevertheless. Second, me too, I was
following and admired the idols of soccer at my time, beginning with Lew Yashin (a goal keeper from today’s Russia), then Gordon Banks from Great Britain, right through to greats such as Dino Zoff from Italy, Oliver Kahn of Germany, Gigi Buffon from Italy, and today’s Manuel Neuer, again from Germany. Of course, I always also admired players from the other side of the coin (from the perspective of a goal keeper, notabene) like midfielders and strikers of the formats of Pele, Maradonna, Netzer, Beckenbauer, Platini, Zidane, Socrates, Eto’o fils, Messi, and CR7, to just name a few and leaving out many others for no particular reason.
Having entered into an academic rather than a professional soccer career path, and having developed into somebody who is professionally interested in and personally addicted to all aspects of life where our individual genetic outfit may impact on us, and may be responsible for what we are and what we have become as an individual in our lifetime, I always wondered how these geniuses in soccer come about?
How would these privileged individuals compare to normal folks with respect to a) athletic capability (particularly endurance aspects), b) in management of the coordination of complex and multidimensional movements, c) capability of outmost fast physical regeneration, d) susceptibility for injuries (e.g. tendonitis), e) capability of spatial and time orientation, and f) particularly for goal keepers, fabulously short reaction times for general and targeted reflexes? Then there are team issues such as, for example, handling Individual and collective psychological pressure, such as being the favourite team in the upcoming decisive elimination game against an assumed “underdog” team?
There is limited and not yet conclusive evidence that genetics may play an important role in at least some of the listed aspects above in order to providing all the ingredients necessary to become a soccer player (and later on a coach) of the format of Zinédine Zidane, for example. Here, we have to acknowledge that the athlete Zinédine Zidane, and all like him, are very complex phenotypes, of whom not all phenotypic parameters are easily to characterise, to standardise, and to quantify. This means that even if there existed genetic predispositions for becoming an competitive world class athlete, soccer player in this case, there most probably are many environmental factors contributing to the forming of such an athlete. Such factors may involve the socio-economic environment in childhood (e.g., are my friends going to soccer or the ballet or golf, the latter two being much more likely in better situated neighbourhoods than the former), finding expert coaches for soccer, and/or finding a team or franchise with the capability to let a player develop up to his maximal potential.
There have been efforts to find genetic variations that would associate and provide advantages to carriers of such variations when becoming athletes. Thus, genomic variants of the ACE, BDKRB2, NOS3, HIF1, and VEGF genes may influence maximal oxygen consumption and energy supply of aerobic metabolism, enhance oxygen supplies to muscle tissues, and increase endurance performance. Polymorphisms of the gene HBB, involved in the production and function of red blood cells, may increase oxygen supply to muscles whereas CHRM2 genomic variants genetically influences cardio-respiratory fitness and heart rate recovery ability. Moreover, the gene ACTN3 is involved in athletic performance and function of skeletal muscle fibers. In fact, muscle strength and performance may be differently influenced by genes involved in supplying oxygen to muscles, including NOS3, HIF-1, ACE, and ACTN3. In addition, a nonsense variant in the gene AMPD1 is associated with acute exercise intolerance. This is a genetic barrier to intense muscle performance and, in sedentary patients, may predispose to cramps, easy fatigability, and myalgia after exercise. Specifically, muscle fatigue depends on removal of lactic acid, which is influenced by a variant in the MCT-1 gene, determinant for lactate transport capability and intensity of performance. On the contrary, a gene variant in DIO1 affects positively anaerobic exercise phenotypes, enhancing muscular strength.
Genetic predisposition and increased risk for tendinopathies and sports-related injuries is conferred by the genetic variants in genes encoding various collagen types such as COL1A1, COL5A1, since collagen is the main structural component of tendons and ligaments. The specific variant in the MMP3 gene encoding a matrix metalloproteinase interacts with COL5A1, and is associated with increased risk to develop Achilles tendinopathy, which is further increased in individuals who have unfavorable variants in both COL5A1 and MMP3 genes.
The association between genomic variants and susceptibility, predisposition and increased risk for bone injury is limited. However multiple association studies link Bone Mineral / Mass Density to functional genomic variants in the Vitamin D receptor gene (VDR, which mediates calcium absorption).
Physical activity is beneficial not only for athletes but also for the population at large in terms of body weight management and BMI reduction. Depending on the DNA profile for genes involved in body mass composition, physical activity alone might not be sufficient to achieve optimal lean body mass, maintain a good BMI and improve sports performance, but proper nutrition and nutritional supplementations may be useful for individuals with at-risk DNA profiles.
The main purpose of nutritional genomics is to determine for each individual their personalized and individualized nutritional needs, essential and beneficial to promote optimal health and well-being. The vitamin B complex has a key role (folic acid, vitamin B6, vitamin B12) in cell metabolism and especially DNA synthesis and repair processes, as well as many variants in genes responsible for the metabolism of these vitamins (MTHFR, MTR, MTRR, etc.). Often increased iron intake and supplementation are needed, especially in athletes involved in endurance sports, but genetic profiles may be indicative of increased risk for hemochromatosis, when specific variants of the HFE gene are present. In these subjects, an increased iron intake may lead to toxic effects on tissues.
Intensive exercise may increase the risk for inflammation, which is further intensified by functional genomic variants in genes such as TNF-α, IL-6 and CRP), with the need to enhance anti-inflammatory bioactive compounds in their diet. Accumulation of variants in genes affecting anti-oxidation and detoxification (among other GSTT1, GPX1, CAT) may compromise the defense against free radical damage and oxidative stress insults. Nutritional programs for athletes are traditionally designed to accommodate the nutritional demands of the sport of choice on various biochemical markers that indicate specific nutritional needs. A well-structured dietary program, meeting the dietary and energy requirements for the particular athlete and sport is crucial to success, and DNA profiling may be taken into account when designing and implementing these programs.
There is a comprehensive review on most of these aspect accessible here. Overall, there will be some more time until a comprehensive prospective genetic profile will be established, which will help in the early selection of young individuals (possibly girls and boys alike) for the development into world class soccer players. However, despite all these associated incertitudes, the are companies such as Soccer Genomics (see here) offering prospective soccer carrier DNA-profiling for young talents and their (sometimes overly) aspiring parents. The latter may be understandable giving the 100 to 200 Million price tag of top soccer players of today. However, total determination and very hard work (training) might still get you there, before genetics productively my help you out.