COMPLEX. VITAMIN COMPLEX WITH MAGNESIUM AND ZINC

Key conclusions

• Micronutrients play a significant role in processes important for physical exertion, from energy production to the synthesis of new cells and proteins. The authors note that an overt deficiency can impair training capacity, increase the risk of illness or injury, and reduce performance potential.
• Athletes can be more exposed to deficiencies of certain nutrients than the general population, among other reasons because of higher nutrient turnover, greater losses and the difficulty of assessing subclinical deficiencies.
• Among the nutrients that most often may require supplementation in athletes, the authors list iron, calcium and vitamin D. Iodine, folate and vitamin B12 may require supplementation in specific population groups, but these are not indications specific to athletes alone.
• A significant element of the position statement is also the risk associated with product quality and anti-doping safety. The authors point out that supplements may contain banned substances as undeclared ingredients or contaminants, which can lead to anti-doping rule violations even with unintentional use.

Magnesium
Why it matters in sport: the authors note that magnesium may have significance for the maintenance of muscle mass, power and selected markers of inflammatory status, although results regarding supplementation effects remain inconclusive. The response to supplementation may depend on dose, baseline magnesium status, intake level and exertion intensity.

Link to training load: the review describes observations suggesting that intensive exertion is associated with changes in magnesium concentration. For example, a higher share of very high intensity training was associated with lower magnesium levels in plasma, which the authors consider an indication of the significant role of muscle in magnesium metabolism during physiological stress.

What intervention studies show: in summary, the authors indicate that magnesium supplementation at a dose of approximately 300 to 500 mg per day over 1 to 4 weeks may beneficially affect dynamic indicators of muscle function, such as CMJ (countermovement jump), one repetition maximum (the maximum weight that can be lifted once), and resistance to fatigue. At the same time, no benefits were shown in terms of aerobic capacity or isokinetic tests.

Body response markers: the authors also describe studies in which magnesium supplementation was associated with changes in selected exertion response markers, including interleukin 6, cortisol, selected immunity-related blood parameters and markers of genetic material damage. They note, however, that the practical significance of these changes for sport performance requires further research.

Important limitation: despite a biologically justified potential, the authors state that there is currently no evidence confirming a beneficial effect of magnesium supplementation on typical indicators of aerobic capacity.

Zinc
Nature of the evidence: the authors found few studies that assessed zinc used independently and simultaneously analyzed direct indicators of performance or sport results. Most available work concerned physiological parameters that may indirectly relate to organism function under high exercise loads.

Aerobic capacity, results are inconsistent: in one study, six-week zinc supplementation at a dose of 30 mg per day was associated with an improvement in the estimated aerobic ceiling in futsal players, with a greater effect observed when combining supplementation with interval training. At the same time, other studies did not show improvement in this parameter after shorter supplementation, which led the authors to conclude that results regarding the effect of zinc on aerobic capacity are inconclusive. szacowanego pułapu tlenowego u zawodniczek futsalu, a większy efekt obserwowano przy połączeniu suplementacji z treningiem interwałowym. Jednocześnie inne badania nie wykazały poprawy tego parametru po krótszej suplementacji, dlatego autorzy podsumowują, że wyniki dotyczące wpływu cynku na wydolność tlenową są niejednoznaczne.

Caution in interpretation: the authors draw attention to interesting but preliminary data from a study in elite cyclists with zinc deficiency, in which improvement in zinc status was accompanied by changes in zinc:copper relationships and indicators related to glucose metabolism. They emphasize, however, that these results require cautious interpretation and confirmation in subsequent studies.

• Vitamin A
  The authors describe vitamin A as a component important for immune function, the integrity of epithelial tissues and processes related to healing. In the context of exertion, they draw attention to its role as an antioxidant, indicating that adequate intake may support the neutralization of reactive oxygen species generated during intensive exercise.
• At the same time, the authors emphasize that excessive intake of preformed vitamin A from supplements can lead to hypervitaminosis, which is why supplementation should be conducted with caution.
• Vitamin E
  Vitamin E was described as an important element of protection against lipid peroxidation and oxidative stress, which may intensify during intensive exertion. The authors indicate that an appropriate antioxidant status may have significance for maintaining proper muscle function, particularly during recovery after intense and endurance exertion.
• In the section concerning sport, the authors cite studies in which supplementation increased alpha-tocopherol concentration in plasma, but note that the effect on lipid peroxidation markers was not unambiguous and requires further research. In the context of safety, the authors also describe that very high doses of alpha-tocopherol may affect clotting.
• Vitamin K
  The authors emphasize the classical functions of vitamin K, namely participation in the blood clotting process and the function of proteins important for bone metabolism. The paper also draws attention to the fact that vitamin K deficiency may be associated with an increased risk of vascular calcification and cardiovascular disease.
• The article also describes an 8-week intervention study with vitamin K2 in 26 athletes, in which supplementation was associated with improved cardiac output and a trend toward changes in heart rate and stroke volume compared with placebo.
• Vitamin B6
  The authors indicate that vitamin B6 is an important element of exercise metabolism, since it participates in the transformations of amino acids, lipids and carbohydrates. In the context of exertion, its role as a coenzyme in processes related to glycogen breakdown and amino acid metabolism is emphasized.
• The paper also draws attention to the role of vitamin B6 in homocysteine metabolism. Low vitamin B6 status was associated with hyperhomocysteinemia, which the authors describe as an unfavorable phenomenon from the perspective of vascular health, including the nervous system.
• The authors also note that in athletes, particularly women with a suboptimal diet, vitamin B6 intake may be too low. In the cited literature, this phenomenon was linked to poorer exertion capacity and a greater risk of fatigue or injury. At the same time, the authors recall that long-term use of very high supplemental doses may lead to adverse effects on the nervous system.

Key conclusions

• The authors indicate that masters athletes may be particularly exposed to oxidative stress, because with age the production of reactive oxygen species increases, while enzymatic mechanisms of antioxidant defense weaken. Intensive training may further intensify this load.
• Under conditions of predominant oxidation processes, damage to lipids, proteins and DNA may occur, and with age the efficiency of repair mechanisms also decreases. The authors also note that older muscle may be more sensitive to exercise-induced damage and less capable of full recovery.
• At the same time, the authors emphasize that with appropriately high energy intake and a well-balanced diet, vitamins and minerals can be supplied in sufficient amounts, which means that routine supplementation is not always necessary.
• The authors note that there are few studies conducted directly in masters athletes, and the results regarding the effect of supplementation on recovery, muscle function and exercise outcomes remain inconclusive.
• In summarizing the paper, they indicated that supplementation with vitamin C alone or vitamin E alone most often does not give convincing effects in limiting post-exercise muscle damage or in improving recovery.
• More promising results concerned antioxidant complexes containing several vitamins and minerals in doses not exceeding daily recommendations. In several small studies, including those involving masters athletes, such supplements were associated with better recovery of exercise capacity after exertion strongly loading the muscles, particularly those dominated by eccentric contractions. The authors note, however, that the mechanisms of these effects have not been well explained.
• The authors strongly emphasize caution in using high doses of antioxidants. Long-term supplementation with large doses may be unfavorable and potentially weaken training adaptations, which is why any supplementation should respect recommended daily intake and, if used, have rather a periodic character, for example in training blocks with a high share of eccentric work.

Key conclusions

• Vitamins and minerals are important for many processes relevant from the perspective of training and sport health, including energy metabolism, oxygen transport, red blood cell production, immunity, muscle growth and recovery, and bone health. The authors emphasize, however, that broad deficiencies of these components are not common if the athlete covers energy requirements and follows a well-balanced diet.
• The authors indicate that in athletes the risk of suboptimal micronutrient status may increase, among other reasons because of greater losses through sweat, urine and stool, increased nutrient turnover, impaired absorption in the digestive tract, and biochemical adaptations associated with training. The situation in which energy intake does not keep up with training load is of particular significance.
• The "food first" approach remains the foundation, but is not always sufficient. The authors note that in specific situations, such as limited energy intake, low diet quality, elimination diets, poor nutritional recovery between sessions or a high share of highly processed sport food at the cost of meal quality, a vitamin and mineral supplement can be considered as a supplement to the diet.
• The decision to supplement should not be automatic. The authors recommend an organized assessment including energy requirements, analysis of dietary patterns, evaluation of biological and clinical parameters, and environmental factors that may affect nutritional status in sport.
• The paper emphasizes that individual vitamins and minerals have significance in different practical situations. As examples, the authors list iron and B vitamins in the context of hematopoietic function, calcium and vitamin D in the context of bone health, and folate as a particularly important component in women.
• Women in sport require special attention, because they more often experience difficulties covering energy needs and have specific nutritional challenges, including those related to iron, folate and bone health. The authors also note that there is still a lack of good-quality research allowing precise determination of part of the recommendations specific to female athletes.
• Sednem podejścia autorów jest to, że suplement (jeśli jest stosowany) powinien uzupełniać The core of the authors' approach is that a supplement (if used) should complement a typical diet, not replace it. When planning supplementation, dose, duration of use, interactions with other dietary components or medications, the time needed to correct a deficiency, and the risks associated with supplement quality and contamination must also be considered.