This article aims to focus sports-medical and scientific nutrition standards for athletes as it was ruled out by the DOSB (Deutsche Olympische Sportbund) and its suborganisation ‘AG Ernahrungsberatung an den Olympiastatzpunkten’. The basics for this issue are the presentations of the authors during the Sochi international meeting (may 2013) on nutrition standards for athletes related to the 2014 Olympic Winter Games located in Sochi (Russia).
Methods for the identification of metabolic pathways
A relevant method for the measurement of metabolic pathways is the ‘Double Labeled Water’ (DWL-) method by labeling water using H- and O-isotopes. By this way you can identify the development of specific metabolites by using mass spectrometry or radioactive measurements. It is differentiated in case of athlete analyses between the RMR (Resting Metabolic Rate) and the BMR (Basic Metabolic Rate). The resting or the basic characteristics of the metabolism are compared to the conditions revealed during training and racing .
The assessments for adequate nutrition are the biochemical criteria for nutrition values, energy balance, supplementation and the recommendations of the ‘AG Ernahrungsberatung of the DOSB’ at the different Olympic National Bases.
Everything is related to the metabolic processes of the athletes’, organism after food intake and consuming. The total degradation of fat (elements:
C, H), carbohydrates (elements: C, H, O) and proteins (elements: C, H, O, N etc.) produces finally carbon dioxide, water and nitrogen containing end products (Fig. 1). Glucose is the most important substrate for the total metabolism. Acetyl-CoA is the central metabolite. From here the fatty acid pathways are developed as well as the so-called Krebs-Cycle.
In case of sufficient oxygen supply - the aerobic pathways - the respiration chain is induced by the Krebs-Cycle. In this case the biochemical energy equivalent (ATP = Adenosine triphosphate) is produced and activated. The maximum amount of ATP-molecules can be produced after intake of food (e.g. glucose) aerobically. If there is not enough oxygen supply in the metabolic pathways O 2 cannot be integrated into the heme factors of the blood. The consequences are well known. E.g. lactose is produced - the end product of the anaerobic metabolism. This phenomenon is not optimal for the athletes and they try to avoid this effect.
In the anaerobic pathways there is no sufficient ATPproduction and the energy efficacy is not satisfactory for the athletes.
The ‘high-mountain-training’ is one of the proper methods to overcome this handicap. The organism produces a higher amount of red blood cells in the higher level air. Therefore, heme can bind more O 2 and guaranty a better oxygen supply for the energy metabolism.
This is permitted. However, the consumption of drugs with a similar effect is forbidden in most of the cases.
Supplementation of natural ingredients like vitamins, minerals and trace elements is also permitted, a supplementation which guaranties the most effective metabolism by optimizing energy development and potentiation of the immune system. By this way the risk of infections is also avoided (Tab. 1).
Supplementation using naturally occuring alcaloids like vincamines, 5-hydroxytryptophan and the Pygeum Africanum Extract can also be very useful for the athletes. Endocrine, tissue and blood factors as well as blood vessel functions are stimulated and the athletes are stabilized in critical and race stress situations (Calvo F., Diduk N., Sochi, 2013).
As it is outlined in Table 2 the nutrition guidelines for staying power sports like cross-country skiing (Langlauf) focus mainly carbohydrates (55-60%).
Fat follows (25-30%) and protein (10-15%). In case of the weight lifter sports the recommendation increases the protein proportion to become 15-20%.
The daily food intake of carbohydrate, fat and protein is totally managed and related to the specific individual type and weight of the athlete and the type of sport discipline (Tab. 3). As it is outlined, the nutrition guidelines have not to be utilised in a strict manner.
Dependent on the individual physes and the specific environmental conditions it can be varified and modulated .
It can be stated that the healthy metabolism obtains a wide range of flexibility. Surplus and deficiency in between the different biochemical types of food stuff is replaceable and can be balanced out.
The calculation of the energy production (energy equivalent ATP) from 1 mol glucose results 38 Mol ATP (Fig. 2).
Experiences show that irreversible energy consumption of maximal 7000-8000 kcal/day (29,000-34,000 kJ/day) are possible which are derived via nutrition. Long-term sportsmen can produce up to about 3000 kcal/day derived from the own body fat. That leads to loosing weight and growing thin, and has to be recompensated by an additional food intake.
The metabolism is defined to be a ‘flowing equilibrium’ and should always been kept in a proper balance (Fig. 1).
The strongly different energy demands which are depending on the athletes’ individual sport disciplines are demonstrated in Fig. 3.
It can be outlined that the normal cross-country skiing or cycling reveals 5-fold less energy consumption than it is measured during extreme olympic race conditions. Such a difference in the energy demand cannot be recognized between the normal and maximum stress situation in case of disciplines like fencing and billiard.
Obviously vitamins and minerals cannot be synthesized by the human organism (Tab. 1). In case of Health Food nutrition there exists the guaranty of sufficient supply of those important food ingredients. Therefore, the ‘AG Ernahrungsberatung der DOSB’, recommends avoidance of any supplementation. Even the addition of iron for female athletes during their menstruation phases is risky in case of surplus doses and competition to other metal and trace elements in the organism. That has been improved in cases of Mg and Zn metabolites.
Another problem exists concerning wrong influences on the endocrine glands after substitution using contraceptive drugs. Water-soluble vitamins and folic acid have to be substituted or vitamin D if the female athlete is suffering from a lack of sun light.
The group of very young athletes of about e.g. 13 years are fed normally at their individual homes together with their parents. Those children suffered in average from increased diseases and metabolic disorders as a consequence of too much ingredient supply and synthetic substances as it has been improved from a survey by Braun . Young athletes, parents and teachers have to be aware of this with the exception of certain natural nutraceutical ingredients as mentioned above.