Iron Status of Highly Active Adolescents: Evidence of Depleted Iron Stores in Gymnasts

Abstract

Much attention has focused on the nutrition and hematological profile of female athletes, especially gymnasts. The few studies on iron status of male adolescent athletes found a low incidence of iron deficiency. The present studies investigated the iron status of male and female gymnasts (G) and compared it with athletes of other sports. Subjects were 68 elite athletes (43 M, 25F) ages 12-18, of four sports: gymnasts (11M,12F), swimmers (11M,6F), tennis players (10M,4F), and table tennis players (11M,3F). All lived in the national center for gifted athletes, trained over 25 hr a week, ate in the same dining room, and shared a similar life style. Mean levels of hemoglobin (Hb), red blood cell indexes, serum ferritin, serum iron, and transferrin were measured in venous blood. There was no difference in mean Rb among gymnasts (G) and nongymnasts (NG). However Hb was less than 14g/dL in 45% of MG vs. only 25% in NG, and less than 13g/dL in 25% of premenarcheal FG vs. 15% in NG. Low transferrin saturation (<20%) was detected in 18% of MG and 25% of FG vs. 6% and 8% in male and female NG, respectively (p<.05). The percentage of males suffering from low ferritin level (<20 ng/ml) was twice as high in G (36%) vs. NG(19%), and about 30% in all females. In summary, iron stores were consistently lower in MG vs. NG. Adolescent athletes of both genders, G in particular, are prone to nonanemic iron deficiency, which might compromise their health and athletic performance.

Prevalence of iron deficiency in male elite athletes

“…Sinclair at al [23] found higher sTfR/logFerr index (above 4.5) in only 6% subjects (recreationally active men). Constantini et al [8] reported an iron deficiency incidence in male gymnasts equal to 36% (the criterion was ferritin <20 µg/L). This was the most close to our values, although still much lower.…”

“…Even iron-deficient erythropoiesis, without symptoms of anaemia, may affect work capacity by impairing energy generation [3,6,7]. Moreover, latent iron deficiencies may impair thermoregulation, as well as decrease mental performance, and affects the immunological defence [8,25].…”

“…Individuals subjected to high physical loads are at risk of iron deficiency [3,8,17,19]. A negative iron balance in athletes might be due to a combination of malnutrition and/or malabsorption-induced decreased absorption of iron, and by increased loss of iron in faeces, sweat and urine [1,20].…”

Discrimination of Athletes and Non-athletes Based on the Latent Structure of Some Biometric Variables

“…This may be caused by a combination of factors, including iron loss in sweat, blood loss from the urinary tract or gastrointestinal system and the breakdown of the red blood cells in the circulation from heavy foot striking (foot-strike hemolysis). Approximately, 25% of female and 10% of male athletes have iron deficiency (Constantini et al, 2000;Dubnov & Constantini, 2004). Even if, athletes are more sensitive to the effects of iron deficiency because they depend on the body's ability to transport oxygen to the muscles, among them, the prevalence of iron depletion without anemia seems to be significantly higher than among the general population (Constantini et al).…”

Iron supplementation maintains ventilatory threshold and improves energetic efficiency in iron-deficient nonanemic athletes

“…The prevalence of iron deficiency is lower among male subjects compared with female subjects, estimated to be 2% (Looker et al, 2002). Iron deficiency is more common among physically active individuals compared with their sedentary counterparts (Magnusson et al, 1984;Blum et al, 1986;Balaban et al, 1995;Chatard et al, 1999;Malczewska et al, 2000Malczewska et al, , 2002Sinclair and Hinton, 2005), affecting 25-35% of adolescent and female athletes and 10-11% of male subjects (Constantini et al, 2000;Dubnov and Constantini, 2004). The negative functional and clinical consequences of anemia have been well documented, including fatigue and decreased maximal and submaximal work capacity (Gardner et al, 1977;Celsing and Ekblom, 1986;Celsing et al, 1988).…”