Vitamin & Mineral Supplementation
- To examine vitamin and mineral requirements for adult athletes (focusing on iron, antioxidants, calcium)
- Dietary micronutrients intake versus vitamin/mineral supplementation
- Vitamin/mineral supplements enhancing athletic performance
Athletes and the general population are often deficient
in many micronutrients, usually due to an inadequate
diet. Low total caloric, low fat, and low red meat diets
may not provide essential micronutrients, including
vitamins (Venkatraman, Pendergast 2002:332).
Vitamin and mineral deficiency also occurs after intense,
maintained physical activity (esp. decrease of serous
iron), which indicates that micronutrient demands for
athletes are higher than daily requirements for physically
inactive individuals (Mehlenbeck et al. 2004).
However, athletes do not necessarily require vitamin/mineral
supplements if they consume sufficient energy from a
variety of foods to maintain their weight (Dressendorfer
Vitamin/mineral supplements are encouraged in some cases
(e.g. for athletes on low fat, low energy diets and
vegetarians). Although micronutrient oral supplementation
can be beneficial, it would not have been indicated
for performance enhancement (Dresendorfer 2002: 64).
Vitamin and mineral requirements for athletes
Iron plays an important role in exercise and energy metabolism.
Long duration exercise induces a physiological reaction
similar to an acute phase immune response. Acute phase
immune response includes redistribution of iron from
extra-to intracellular compartment. In presence of reactive
oxygen intermediates, iron catalyses the generation
of hydroxyl radicals, which damage membrane lipids,
proteins, and nucleic acids. Cells have to control intracellular
iron levels in order to minimise iron toxicity and to
satisfy their metabolic needs (Aguilo et al. 2004).
The iron deficiency after intense physical activities
is common in athletes and is usually associated with
the reductions in hematocrit, hemoglobin and serum iron
which is known as a sport anemia
(Aguilo et al. 2004).
An antioxidant diet supplementation prevents the decrease
of serous iron and iron saturation index; and positively
influences iron metabolism (Aguilo et al. 2004).
Intestinal iron absorption may be increased by vitamin C
intake (Aguilo et al. 2004).
Strenuous exercise causes an oxidative stress
when high oxidative metabolism increases production
of oxygen free-radicals and lipid peroxidation in skeletal
muscles. Rise in level of oxygen free-radicals that
exceed the antioxidant defense capacity of the cells
causes damage to DNA, proteins, enzymes and subcellular
organs, resulting in possible muscle fatigue and soreness
following exercise. Endogenous antioxidant enzymes
and antioxidant vitamins
scavenge reactive oxygen species, produced during
oxidative stress. Vitamin- mineral supplements enhance
activity of antioxidant enzymes
, which fight against free radicals and decrease
Antioxidant supplements help to decrease oxidative-stress
status and preserve neutrophil ratio (Aquilo et al.
Supplementation with antioxidant vitamins is beneficial
for athletes on low-energy-balanced diets or vegetarians;
otherwise, the requirements can be met through an energy
balanced diet (Venkatraman, Pendergast 2002:326).
Supplementation with single antioxidant nutrients
is not recommended because of hazards caused by excessive
fat-soluble vitamins, or peroxidation and pro-inflammatory
responses caused by excess ascorbic acid. The enhanced
intake of vitamin B, ascorbic acid, tocopherol (vitamin
E) and carotenoid- and flavonoid- rich foods is suggested
to raise daily intakes to above RDAs for sedentary individuals.(Venkatraman,
To decrease production of oxygen- free radicals, athletes sometimes overdose vitamin supplements (10 to 1000 RDA), however this is not useful and may be harmful (Venkatraman, Pendergast, 2002:326).
Adequate calcium intake is necessary for optimizing
the peak bone mass, an important determinant of osteoporosis
risk, in young athletes. Calcium supplementation enhances
bone accrual in young adults. Inadequate calcium intake
is often found in young adult female athletes although
the daily calcium intake requirements are even greater
for competitive athletes (Mehlenbeck et al. 2004).
Calcium intake influences an achievement of peak bone
mass during adolescence and young adulthood; an inadequate
calcium intake increases risk of stress fractures in
physically active individuals (Mehlenbeck et al. 2004).
Dietary micronutrients intake versus vitamin/mineral supplementation
Strenuous endurance training does not affect plasma
mineral status when dietary micronutrient intakes are
adequate. Well- balanced diets prevent the development
of mineral deficiencies in most athletes, however, the
daily use of multivitamin/mineral supplements is not
discouraged because high sweat losses may increase
requirement of selected minerals, e.g. magnesium and
iron (Dressendorfer et al. 2002:63).
Low- energy, low- fat, low red meat, or vegetarian
diets may not provide essential micronutrients, including
vitamins. Athletes following the abovementioned
diet plans are often deficient in vitamin B12, iron,
zinc, selenium, copper, and calcium (Venkatraman, Pendergast,
Vitamin B12, zinc, and iron are the key supplements in treating female athlete triad (disordered eating, amenorrhea and osteoporosis).
Vitamin/mineral supplements enhancing athletic performance
Iron is essential for oxygen delivery to the tissues
as a compartment of hemoglobin and myoglobin, and acts
as an enzyme cofactor involved in energy production.
Adequate iron status is crucial to the optimal physical
performance as well as immune function of athletes (Clark
et al. 2003:318). Iron- deficiency anemia impairs athletic
performance. In this case, iron supplementation together
with hematopoietic nutrients additional intake can enhance
athletic performance. Iron synergy with hematopoietic
nutrients (folate, zinc, cobalamin- vitamin B12, pyroxidine-
vitamin B6, ascorbate- vitamin C, tocopherol- vitamin
E) can result in improved hematological status, increased
VO2max, and increased performance (Colgan 1993:261).
In athletes with normal iron status, iron supplementation
does not enhance performance.
Essential minerals deficiency, production of oxygen free-radicals
and oxidative tissue damage, occurring during exercise,
increase need for vitamins (e.g. antioxidants), and
minerals in athletes. Although oral vitamin/mineral
supplementation can be beneficial, it is usually not
necessary. In a well-balanced eating plan, the daily
requirements for vitamins and minerals are easily met.
Vitamin/mineral supplementation can possibly enhance performance only if the performance has been decreased due to micronutrient deficiency (e.g. anemia). If the athlete’s mineral status is normal, supplementation is not going to increase performance.
- Aguilo, Antoni, Fuentespina, Emilia, Tauler, Pere et al. (2004). Antioxidant Diet Supplementation Influences Blood Iron status in Endurance Athletes. International Journal of Sport Nutrition & Exercise Metabolism, 14 (2), (accessed September 20, 2004, from Academic Search Elite database).
- Cavas, L., Tarhan, L. (2004). Effects of Vitamin- Mineral Supplementation on Cardiac Marker and radical Scavenging Enzymes and MDA Levels in Young Swimmers. . International Journal of Sport Nutrition & Exercise Metabolism, 14 (2), 133- 145.
- Clark, Mandy, Reed et al. (2003). Pre- and Post- Season Dietary Intake, Body Composition, and Performance Indices of NCAA Division I Female Soccer Players. International Journal of Sport Nutrition & Exercise Metabolism, 13 (3), 303-319.
- Dressendorfer, R.H., Petersen, S.R., Moss Lovshin, S.E., Keen, C.L. (2002). Mineral Metabolism in Male Cyclists During High- Intensity Endurance Training. International Journal of Sport Nutrition & Exercise Metabolism, 12, 63- 72.
- Lukaski, H.C., Bolonchuk, W.W., Klevay, L.M., Milne, D.B., Sandstead, H.H. (2001). Interactions Among Dietary Fat, Mineral Status, and Performance of Endurance Athletes. International Journal of Sport Nutrition & Exercise Metabolism, 11, 186- 198.
- Mehlenbeck, R.S., Ward, K.D., Klesges, R.C., Vukadinovic, CH.M. (2004). A Pilot Intervention to Increase Calcium Intake in Female Collegiate Athletes. International Journal of Sport Nutrition & Exercise Metabolism, 14 (1), (accessed September 20, 2004, from Academic Search Elite database).
- Peake, J.M. (2003). Vitamin C: Effects of Exercise and Requirements with Training. International Journal of Sport Nutrition & Exercise Metabolism, 13 (2), (accessed September 20, 2004, from Academic Search Elite database).
- Venkatraman, J.T., Pendergast, D.R. (2002). Effects of Dietary Intake on Immune Function in Athletes. Sports Medicine, 32(5), 323-337.
- Colgan M.(1993). Optimum Sports Nutrition, NY: Advanced Research Press.
Sports anemia features are low iron plasma levels and storage (Aguilo et al., 2004) which leads to decreased hemoglobin production, and thus decreased maximum oxygen uptake. Decline in maximum oxygen uptake causes decreased ability of muscle to use oxygen which is a cause of decreased athletic performance.
During physical exercise, a large amount of oxygen is inhaled into the body; the body is subjected to oxidative stress (Cavas, Tarhan, 2004:143).
Body fights back against oxidation with 3 main endogenous antioxidants- superoxide dismutase SOD, catalase CAT and glutathione peroxidase GSH-Px (Cavas, Tarhan, 2004:134).
Antioxidant vitamins- A, C, E, Beta- carotenesCoenzyme Q10, selenium
E.g. iron and copper influence positively SOD and CAT activity (Cavas, Tarhanm, 2004:134).
E.g. overdosing vitamin C can cause diarrhea, joint pain, kidney stones; high levels of vitamin A intake can cause toxic effects and liver damage (Venkatraman, Pendergast, 2002: 326).