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Low transferrin saturation, hemoglobin and plasma zinc values in female alpine skiers
Science & Sports, 4 (1989) 243-244 © Elsevier, Paris
243
Communication
Low transferrin saturation, hemoglobin and plasma zinc values in female alpine skiers F. COUZY, C.Y. GUEZENNEC and H. LEGRAND
Metabolic" and Hormonal Physiology Laboratory, CERMA-LCBA, 75731 Paris Cedex 15, France
Transferrin saturation, hemoglobin and plasma zinc were assayed in a national team of 20 female alpine skiers (age: 2 2 + 3 . 5 years, mean SD), 1 m o n t h after the beginning of the season. These analysis were part o f a routine examination. Blood was drawn from an antecubital vein, in the morning betwen 9 and l0 A.M. The subjects were not on a fasting state as this particular day was a racing day. Care was taken to avoid hemolysis and contaminations. Samples were stored at-20°C prior analysis. Plasma zinc was assayed after protein precipitation by flame atomic spectroscopy. Transferrin saturation was calculated after serum iron and total iron binding capacity determination (Serifer-kit and TIBC-additif, respectively, bio M6rieux, Charbonni~res-les-Bains). Whole blood hemoglobin (Hb) was assayed using the cyanmethemoglobin reaction. The results shown on Table I indicate that none o f the athietes was relevant of the definition of sport anemia with hemoglobin value below 12 g/dL, even if the (World Health Organisation) limit value of 12 g / d L is corrected for altitude (Hb < 12.5 g / d L at 1 000 m). However, 7 (35%) athletes had transferrin saturation lower than 16%, and therefore could be considered as borderline iron-deficient (Cook and Finch, 1979). The low observed mean transferrin saturation of 20.75 + 1.8% could be related to the relatively high iron deficiency rate in the female population, and especially in the athletic female population (Nickerson et aL, 1985). These parameters of iron metabolism suggest that the studied group stands below the lower limit of normal range. Moreover, 6 (30%) had plasma zinc lower than 0.70 m i c r o g r a m / L : this value has previously been used as a threshold to characterize zinc deficiency, Pilch and Senti (1985). Hemodilu-
Table 1. Hemoglobin, % transferrin saturation and plasma zinc individual values in female athletes.
Subject Hemoglobin (g/dL) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 !5 16 17 18 19 20 m _+SD
14.0 13.3 13.4 13.6 14.7 12.9 13.4 14.0 14.2 12.5 14.0 13.8 13.0 12.8 14.2 13.5 14.5 14.4 14.2 14.0 13.72+0.13
% transferrin saturation
Plasmazinc (tzg/L)
33 22 33 32 25 27 25 33 12 24 16 10 8 20 21 15 22 14 10 13 20.75_+1.8
0.75 0.76 0.73 0.85 0.65 0.55 0.86 0.66 0.86 0.86 0.90 0.54 0.64 0.68 0.70 0.82 0.81 0.88 0.77 0.81 0.74+002
tion could be ruled out as a cause for low iron and zinc values, as serum protein concentrations Were all within the normal range (68-87 g / L , data not shown). Low serum zinc values have already been observed in the athlete (Dressendorfer and Sockolov, 1980). This is generally explained by an increase in the zinc losses through urine and sweat, w h i c h would lead to an alteration in the zinc status.
244
F. C o u z y et al.
Elsewhere these athletes received a daily oral magnesium c o m p l e m e n t a t i o n of 3 g. High magnesium intake could decrease intestinal Zn absorption by a competitive mechanism. Finally, no definite conclusions can be drawn from our study (as the measurements were not done in standard conditions), but these data confirm previous studies expressing concern about some micronutrient status in the athlete. The effect of decreased iron and Zn status on work capacity is actually an area of discussion.
R~f6rences Cook J.D. & Finch C.A. (1979) Assessing iron status of a population. A m . J. Clin. Nutr. 32, 2115-2119 Dressendorfer R.H. & Sockolov R.A. (1980) Hypozincemia in runners. Sports med. 8, 97-100 Nickerson H.J., Holubets M., Tripp A.D. & Pierce W.E. (1985) Decreased iron stores in high school female runners. A m . J. Dis. Child. 139, 1115-1119 Pilch S.M. & Senti F.R. (1985) Analysis of zinc data from the second national health and nutrition survey (NHANES II). J. Nutr. 115, 1393-1397
243
Communication
Low transferrin saturation, hemoglobin and plasma zinc values in female alpine skiers F. COUZY, C.Y. GUEZENNEC and H. LEGRAND
Metabolic" and Hormonal Physiology Laboratory, CERMA-LCBA, 75731 Paris Cedex 15, France
Transferrin saturation, hemoglobin and plasma zinc were assayed in a national team of 20 female alpine skiers (age: 2 2 + 3 . 5 years, mean SD), 1 m o n t h after the beginning of the season. These analysis were part o f a routine examination. Blood was drawn from an antecubital vein, in the morning betwen 9 and l0 A.M. The subjects were not on a fasting state as this particular day was a racing day. Care was taken to avoid hemolysis and contaminations. Samples were stored at-20°C prior analysis. Plasma zinc was assayed after protein precipitation by flame atomic spectroscopy. Transferrin saturation was calculated after serum iron and total iron binding capacity determination (Serifer-kit and TIBC-additif, respectively, bio M6rieux, Charbonni~res-les-Bains). Whole blood hemoglobin (Hb) was assayed using the cyanmethemoglobin reaction. The results shown on Table I indicate that none o f the athietes was relevant of the definition of sport anemia with hemoglobin value below 12 g/dL, even if the (World Health Organisation) limit value of 12 g / d L is corrected for altitude (Hb < 12.5 g / d L at 1 000 m). However, 7 (35%) athletes had transferrin saturation lower than 16%, and therefore could be considered as borderline iron-deficient (Cook and Finch, 1979). The low observed mean transferrin saturation of 20.75 + 1.8% could be related to the relatively high iron deficiency rate in the female population, and especially in the athletic female population (Nickerson et aL, 1985). These parameters of iron metabolism suggest that the studied group stands below the lower limit of normal range. Moreover, 6 (30%) had plasma zinc lower than 0.70 m i c r o g r a m / L : this value has previously been used as a threshold to characterize zinc deficiency, Pilch and Senti (1985). Hemodilu-
Table 1. Hemoglobin, % transferrin saturation and plasma zinc individual values in female athletes.
Subject Hemoglobin (g/dL) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 !5 16 17 18 19 20 m _+SD
14.0 13.3 13.4 13.6 14.7 12.9 13.4 14.0 14.2 12.5 14.0 13.8 13.0 12.8 14.2 13.5 14.5 14.4 14.2 14.0 13.72+0.13
% transferrin saturation
Plasmazinc (tzg/L)
33 22 33 32 25 27 25 33 12 24 16 10 8 20 21 15 22 14 10 13 20.75_+1.8
0.75 0.76 0.73 0.85 0.65 0.55 0.86 0.66 0.86 0.86 0.90 0.54 0.64 0.68 0.70 0.82 0.81 0.88 0.77 0.81 0.74+002
tion could be ruled out as a cause for low iron and zinc values, as serum protein concentrations Were all within the normal range (68-87 g / L , data not shown). Low serum zinc values have already been observed in the athlete (Dressendorfer and Sockolov, 1980). This is generally explained by an increase in the zinc losses through urine and sweat, w h i c h would lead to an alteration in the zinc status.
244
F. C o u z y et al.
Elsewhere these athletes received a daily oral magnesium c o m p l e m e n t a t i o n of 3 g. High magnesium intake could decrease intestinal Zn absorption by a competitive mechanism. Finally, no definite conclusions can be drawn from our study (as the measurements were not done in standard conditions), but these data confirm previous studies expressing concern about some micronutrient status in the athlete. The effect of decreased iron and Zn status on work capacity is actually an area of discussion.
R~f6rences Cook J.D. & Finch C.A. (1979) Assessing iron status of a population. A m . J. Clin. Nutr. 32, 2115-2119 Dressendorfer R.H. & Sockolov R.A. (1980) Hypozincemia in runners. Sports med. 8, 97-100 Nickerson H.J., Holubets M., Tripp A.D. & Pierce W.E. (1985) Decreased iron stores in high school female runners. A m . J. Dis. Child. 139, 1115-1119 Pilch S.M. & Senti F.R. (1985) Analysis of zinc data from the second national health and nutrition survey (NHANES II). J. Nutr. 115, 1393-1397