18•Iglesias-Gutiérrez, García-Rovés, et al.
1Facultad de Medicina, Dept. de Biología Funcional (Fisiología), Univ. de Oviedo,
Oviedo, Asturias, Spain; 2Dept. of Internal Medicine, Washington Univ. School of Medi-
cine, St. Louis, MO 63163-4899, USA; 3Servicio de Análisis Clínicos del Hospital
Universitario Central de Asturias (Silicosis), Oviedo, Asturias, Spain.
Food Habits and Nutritional Status Assessment
of Adolescent Soccer Players. A Necessary
and Accurate Approach
Eduardo Iglesias-Gutiérrez1, Pablo M. García-Rovés2, Carmen Rodríguez3,
Socorro Braga3, Pedro García-Zapico1, and Ángeles M. Patterson1
Iglesias-Gutiérrez, E.; García-Rovés, P.M.; Rodríguez, C.; Braga, S.; García-Zapico, P.;
and Patterson, Á.M. (2005). Food habits and nutritional status assessment of adolescent
soccer players. A necessary and accurate approach. Can. J. Appl. Physiol. 30(1): 18-32 ©
2005 Canadian Society for Exercise Physiology.
Key words: young athletes; association football; dietary, anthropometric, biochemical, he-
matological, and functional measures
Mots-clés: jeunes athlètes; association de soccer; diète, donnés anthropométriques,
biochimiques, hématologiques, et functionnelles
The aim of this study was to assess the food habits and nutritional status of high level
adolescent soccer players (N = 33; ages 14–16 yrs) living in their home environment. Body
composition (height, mass, skinfolds), biochemical and hematological parameters, perfor-
mance in soccer-specific tests (sprinting, jumping, intermittent endurance), and dietary
intake (weighed food intake method) and related behaviors (nutrient supplement use, daily
activity profile) were assessed. Daily energy expenditure and energy intake were 12.5 MJ
and 12.6 MJ, respectively. Protein (16% of energy intake; 1.9 g/kg of body mass), lipid
(38%), and cholesterol (385 mg) intake were above recommendations, while carbohydrates
(45%) were below. The food intake of these adolescents was based on cereals and derivates;
meat, fish, and eggs; milk and dairy products; biscuits and confectionery; and oil, butter
and margarine, which provided 78% of total energy intake, 85% of proteins, 64% of carbo-
Adolescent Soccer Players• 19
hydrates, 90% of lipids, and 47% of fiber. Although diet provided sufficient iron, 48% of
individuals showed iron deficiency without anemia. Based on these results, a well designed
nutrition intervention would be advisable for optimizing performance, and especially for
promoting healthy eating habits in adolescent soccer players.
Dans cette étude, on cherche à tracer le portrait des habitudes alimentaires et de l’état
nutritionnel de joueurs de soccer de haut niveau (N = 33; 14 à 16 ans) vivant dans leur
environnement domestique. Les données suivantes sont obtenues: composition corporelle
(taille, masse, et plis cutanés), variables biochimiques et hématologiques, tests de perfor-
mance spécifiques au soccer (sprint, saut, endurance intermittente), apport alimentaire
(pesée des aliments consommés), et comportements apparentés (suppléments alimentaires,
pratique quotidienne d’activité). La dépense énergétique et l’apport énergétique sont de
12,5 MJ et 12,6 MJ, respectivement. Les apports protéiques (16% de l’apport énergétique;
1,9 g/kg de masse corporelle), lipidiques (38%), et de cholestérol (385 mg) sont supérieurs
aux normes alors que celui des sucres (45%) est inférieur. Les nutriments proviennent des
produits céréaliers; de la viande, du poisson, des oeufs; des produits laitiers; des biscuits et
friandises; de l’huile, du beurre, et de la margarine, et comptent pour 78% de l’apport
énergétique total: 85% des protéines, 64% des sucres, 90% des lipides, et 47% des fibres.
Même si l’apport alimentaire inclut des quantités suffisantes de fer, 48% des joueurs affi-
chent une carence en fer sans pourtant être anémiques. Selon ces observations, il serait
indiqué d’élaborer un bon plan d’intervention nutritionnel pour optimiser la performance,
et notamment pour favoriser de saines habitudes de vie chez les adolescents qui jouent au
In recent years there has been a lively interest in the literature in determining the
physical, physiological, and psychological attributes that may be helpful in the
early identification of talented soccer players (Reilly et al., 2000; Williams and
Reilly, 2000). However, there is little information on the nutritional status and
food habits of adolescent soccer players (Boisseau et al., 2002; Leblanc et al.,
2002; Rico-Sanz et al., 1998), as is true for male adolescent athletes in general
(Berning et al., 1991; Parizková, 2000). It is well known that proper nutrition and
regular physical activity during adolescence are crucial for optimal growth and
development, as well as for promoting good health in the short and long term.
Energy and nutrient needs increase during adolescence and are higher than at any
other time in life (Giovannini et al., 2000; Spear, 2002). Adolescent athletes have
special nutrient needs due to the additional demands of training and competition.
Therefore, if a proper food intake and nutritional status is essential for any adoles-
cent, it will be even more so for those who exercise regularly.
Nowadays there is no information about the nutritional status and eating
habits of adolescent soccer players under usual and realistic circumstances (i.e.,
training and competing while living at home). In the available literature these young
athletes have usually been assessed during a period of training at a specialized
center, not in their home environment (Leblanc et al., 2002; Rico-Sanz et al., 1998),
which is the major influence on eating behaviors (Story et al., 2002). What is
more, most of these studies include only dietary (sometimes as additional data to
the main purpose of the study) and body composition assessment (Boisseau et al.,
20• Iglesias-Gutiérrez, García-Rovés, et al.
2002; Leblanc et al., 2002; Rico-Sanz et al., 1998). Having in mind that dietary
assessment does not characterize nutritional status per se, studies on dietary intake
must be combined with anthropometric, biochemical, hematological, and func-
tional measures, as well as with the measure or calculation of daily energy expen-
diture, to characterize actual nutritional status (Magkos and Yannakoulia, 2003;
The aim of this study was to accurately assess the food habits and nutritional
status of high level adolescent soccer players living in their home environment
during the competitive season. For this purpose we assessed food and nutrient
intake, daily activity profile, and biochemical and hematological parameters, as
well as body composition and performance in soccer-specific tests, which consti-
tutes a necessary global approach.
Subjects and Methods
Thirty-three male soccer players, ages 14–16 years, were recruited from the junior
teams of a Spanish First Division Soccer League club. They competed in the high-
est national division of their age group and three of them were also members of the
Spanish National Soccer Team (under –15). At the time of the study they were in
regular training the first half of the season. They trained for 4 days a week, 2 hours
a day. Every training session involved physical (sprinting, intermittent endurance),
technical, and tactical exercises, but alternately emphasizing some of these ele-
ments in each session in order to resemble match-play situations as much as pos-
sible. There was no position-specific training, except for goalkeepers once a week.
At least one competitive match was played each week, resulting in a total of 52
matches per season.
Written consent was obtained from each of the participating soccer players
and their families, according to the study design approved by the Committee on
Ethical Research of the Oviedo University Hospital, Spain.
Height (Añó Sayol stadiometer, precision 1 mm) and mass (Seca scale, precision
100 g) were measured and body mass index (BMI) was calculated as the Quetelet
Index (kg/m2). Seven skinfolds (biceps, triceps, subscapular, suprailiac, abdomi-
nal, front thigh, and medial calf) were measured using a Holtain caliper and stan-
dard techniques. The sum of the seven skinfolds was also calculated to be used as
an index of subcutaneous adiposity (Reilly and Doran, 2003). The equation of
Lohman (1981) was used to calculate body density, and the percentage of body fat
(% BF) was estimated using the equation of Brozek (1966).
DIETARY INTAKE AND ENERGY EXPENDITURE
The soccer players recorded their daily dietary intake for a 6-day period (a whole
week, excluding the match-day) using the weighed food intake method (Bingham,
1987). This method provides the most accurate estimation of usual individual in-
take (Buzzard, 1998) and it has been successfully applied to elite athletes (García-
Adolescent Soccer Players• 21
Rovés et al., 1998; 2000a; 2000b). What is more, it permits the data obtained to be
analyzed by nutrients, by individual foods, by any food grouping scheme desired,
or by meals (Buzzard, 1998). However, it requires a high level of motivation and
effort, and it has been suggested that subject motivation falls off as the number of
days of data collection increases (Buzzard, 1998). A 6-day record is therefore a
good balance between the desired accuracy of the assessment and the effort re-
quired for its completion.
All the players and their families were given food record questionnaires and
digital food-weighing scales (Philips precision HR 2388, maximum 5 kg, preci-
sion 1g). They also received specific oral guidelines and detailed written instruc-
tions about how to put this method into practice, and they were specifically asked
not to alter their usual dietary behavior during this period. A telephone number
was available for all players in case they had any questions. Food records were
carefully reviewed immediately after completion, and subjects were contacted to
clarify ambiguous information. Dietary assessment data were analyzed using a
nutrient analysis program (Alimentación y Salud, BitASDE, Huesca, Spain).
For a thorough dietary assessment, a specific questionnaire was designed in
order to gather information on usual eating patterns and related behaviors (nutrient
supplement use, food preferences and dislikes, weight-control practices, subjec-
tive body image assessment). Information about the subject’s daily activity profile
was also compiled in order to estimate total daily energy expenditure (TDEE).
TDEE consists of three components: the resting metabolic rate (RMR); the energy
cost of physical activity (PA); and the thermic effect of food (TEF) (Leenders et
al., 2001). RMR was calculated using the equation of Schofield (1985) for adoles-
cents. For calculating the energy cost of PA, subjects were asked to estimate the
number of hours during the food recording period they spent sleeping, eating, at-
tending class (specifying the hours in physical education), studying, and training.
The remaining hours were deemed to be spent in activity of light intensity.
Standardized values of energy expenditure were asigned to the various ac-
tivities (Ainsworth, 2000). Thus sleeping, eating, attending class (physical educa-
tion), studying, training, and light intensity activity were categorized as 0.9, 1.5,
1.8 (4.0), 1.8, 7.0, and 1.5 METs, respectively. TEF can be calculated as the sum of
the thermic effect of nutrients, which is considered to be 25–30% for proteins, 6–
8% for carbohydrate (CHO), and 2–3% for lipids (Jéquier, 1995), expressed as a
percentage of their energy content.
BIOCHEMICAL AND HEMATOLOGICAL ANALYSIS
After an overnight fast, blood samples were taken from an antecubital vein, using
standardized material and techniques. Hematological parameters were measured
using a Coulter counter model S analyzer (Coulter Electronics, London, England).
Biochemical parameters were determined by colorimetric (triglycerides, choles-
terol, HDL-cholesterol, iron, and albumin) or UV (glucose and CK) methods
(Roche/Hitachi 717 autoanalyzer). Transferrin was measured by immuno-
turbidimetry. Ferritin was determined by enzyme immunoassay (Abbott AxSym).
LDL-cholesterol was calculated using the Friedewald formula. All samples were
taken and processed by the Servicio de Análisis Clínicos del Hospital Universitario
Central de Asturias (Silicosis), Spain.
22• Iglesias-Gutiérrez, García-Rovés, et al.
Soccer-specific field tests were conducted during the first half of the season, as
part of the team’s training routine. All subjects were familiarized with these tests
by at least one pretest. Sprinting ability (10, 20, and 30 m) was assessed using a
system of photoelectric cells. Three types of vertical jump (Bosco, 1994) were
used to evaluate the muscular strength of the lower limbs: squat jump (SJ), coun-
termovement jump (CMJ), and countermovement jump with free hands (CMJF).
Jumps were performed on a touch-sensitive mat connected to a timer. The Yo-Yo
intermittent endurance test was used to evaluate an individual’s ability to repeat-
edly perform intense exercise intervals over a prolonged period of time (Bangsbo,
All data are reported as mean and range. Descriptive statistical analysis was
performed using SPSS (version 11.0) for Windows.
The anthropometric characteristics of the adolescent soccer players assessed are
shown in Table 1. As expected, a high heterogeneity was observed for most param-
eters and indexes, as is shown, for example for height (range 1.60–1.91 m), mass
(54.3–87.8 kg), or the sum of seven skinfolds (37.4–96.6 mm).
DIETARY INTAKE AND ENERGY EXPENDITURE
The subjects’ energy expenditure, energy and macronutrient intake, recommended
values for adolescent athletes (Bar-Or and Unnithan, 1994; Boisseau et al., 2002;
Giovannini et al., 2000), and the percentage of individuals below and above these
recommendations are shown in Table 2. Mean TDEE was estimated to be 12.5 MJ
(2,983 kcal), being PA 4,842 kJ (1,158 kcal). Daily protein, lipid, and cholesterol
(N = 33)
Anthropometric Characteristics of the Adolescent Soccer Players
Body Mass Index (kg/m2)
Sum of 7 skinfolds a
% Body fat b
1.60 – 1.91
54.3 – 87.8
18.0 – 24.2
37.4 – 96.6
7.4 – 15.9
a Sum of 7 skinfolds: biceps, triceps, subscapular, suprailiac, abdominal, front thigh, and
medial calf. b Body density calculated via Lohman (1981) equation; % Body fat estimated
via Brozek (1966) equation.
Adolescent Soccer Players• 23
cent Soccer Players (N = 33) Compared to Recommended Values (RV)
Daily Energy Expenditure and Macronutrient Intake of the Adoles-
below RVMean RangeRVa
% Energy intake
% Energy intake
% Energy intake
% Energy intake
% Energy intake
% Energy intake
5938 – 7815
4394 – 5783
852 – 1474
11.3 – 14.8
2705 – 3545
9.4 – 16.7
113 – 258
2261 – 4007
90 – 177
1.2 – 2.6
11 – 20
12 – 15
258 – 508
3.4 – 8.1
37 – 55
24 16 – 4319 – 21964
83 – 181
29 – 47
13 – 88
4 – 23
8 – 33
2 – 10
15 – 54
5 – 13
174 – 714
20 – 30
Note: RMR = resting metabolic rate; PA = energy cost of physical activity; TEF = thermic
effect of food; BM = body mass; MUFA = monounsaturated fatty acids; PUFA = polyunsatu-
rated fatty acids; SFA = saturated fatty acids. a RV taken from Bar-Or and Unnithan (1994),
Giovanni et al. (2000), and Boisseau et al. (2002).
24• Iglesias-Gutiérrez, García-Rovés, et al.
intake were above nutritional recommendations for most individuals, while CHO
intake was below. On the other hand, mean fiber intake and the relative contribu-
tion of saturated fatty acids (SFA) to total energy intake were within recommended
The relative contribution (%) of different food groups to total daily energy
and macronutrient intake is listed in Table 3. The food intake of these adolescent
soccer players was based on the following groups of foods: cereals and derivates;
meat, fish, and eggs; milk and dairy products; biscuits and confectionery; and oil,
butter, and margarine, which provided 78% of total daily energy intake, 85% of
proteins, 64% of CHO, 90% of lipids, 90% of SFA, and 47% of fiber. Vegetables,
fruit and natural fruit juices, and legumes and nuts provided another 47% of fiber
intake, but only 11% of total energy intake.
Average daily micronutrient intake compared to the Dietary Reference In-
takes for Vitamins and Minerals (Food and Nutrition Board, 2002) is shown in
Figure 1. All vitamins and minerals were above recommendations except folate,
vitamin E, calcium, magnesium, and zinc. With regard to nutrient supplement use,
none of the soccer players in this study reported the use of supplements during the
food-recording period. However, 76% of them admitted a sporadic use of vitamin,
mineral, or vitamin-mineral supplements, especially iron supplements (64% of
individuals), due to medical advice (72%), their own decision (16%), or both rea-
Macronutrient Intake of the Adolescent Players (N = 33)
Relative Contribution (%) of Food Groups to Total Daily Energy and
Food groupsEnergy Proteins CHO LipidsSFA Fiber
Cereals and derivates
Meat, fish, and eggs
Milk and dairy products
Biscuits and confectionary
Oil, butter, and margarine
Fruits and natural fruit juices
Legumes and nuts
Sport beverages and soft drinks
Sugar, honey, and jam
Note: CHO = carbohydrates; SFA = saturated fatty acids. a Includes salty snacks, mayon-
naise, coffee, etc.
Adolescent Soccer Players• 25
BIOCHEMICAL ANALYSIS AND PERFORMANCE ASSESSMENT
Mean serum biochemical and hematological parameters are listed in Table 4, to-
gether with reference values for each parameter (taken from the Servicio de Análisis
Clínicos del Hospital Universitario Central de Asturias, Spain), and with the per-
centage of individuals below or over these references. Mean values for most pa-
rameters were within reference values, although lower-than-reference ferritin and
cholesterol levels, and higher CK and HDL-cholesterol values, were found in a
high percentage of individuals.
Results on sprinting (10, 20, 30 m) and jumping (SJ, CMJ, CMJF) ability, as
well as intermittent endurance capacity (Yo-Yo test), are shown in Table 5.
The present study constitutes an extensive, realistic, and necessary approach to the
complexity of eating habits and nutritional status of adolescent soccer players,
showing differences with previous studies and enriching the scarce existing infor-
mation on nutritional status and eating habits of adolescent athletes in general.
Heterogeneity in body size is one of the main physical characteristics of
= 33) compared to the dietary reference intakes (% of DRI) (Food and Nutrition Board,
Average daily vitamin and mineral intake of the adolescent soccer players (N
26• Iglesias-Gutiérrez, García-Rovés, et al.
Soccer Players (N = 33) Compared to Reference Values (RV)
Serum Biochemical and Hematological Parameters of the Adolescent
below RV above RV MeanRangeRVa
Creatin kinase (µkat/L)
35.9 28.0 – 44.0
327 – 109
9.3 7.9 – 10.2
44 38 – 50
5.4 4.5 – 6.2
4.01.6 – 13.0
0.3 – 1.5
2.6 – 5.0
1.0 – 2.0
2.1 – 4.9
1.2 – 3.4
6.4 – 28.5
0.4 – 1.4
3.4 – 4.9
0.9 – 1.4
3.3 – 5.0
1.2 – 4.9
10.6 – 28.3
21.7 – 41.2
30 – 300
8.7 – 11.2
42 – 52
4.2 – 6.1
0.6 – 3.2
a RV from the Servicio de Análisis Clínicos del Hospital Universitario Central de Asturias
(N = 33)
Soccer-Specific Tests and Intermittent Endurance Assessment
Intermittent endurance (m)
1.70 – 2.01
2.98 – 3.32
4.10 – 4.64
30 – 43
31 – 44
35 – 52
21211240 – 2920
Note: SJ = squat jump; CMJ = countermovement jump; CMJF = countermovement jump,
Adolescent Soccer Players• 27
soccer teams (Al-Hazzaa et al., 2001; Casajús, 2001; Wisløff et al., 1998) and it is
especially evident during adolescence (Rico-Sanz et al., 1998), due to the fact that,
for training and competition, athletes are grouped by chronological age, not by
any other maturation related criteria. Our results are in accord with this evidence,
as can be seen in Table 1. Although more appropriately the dual expression of the
summed skinfolds and % BF should be used as indexes of subcutaneous adiposity
(Reilly and Doran, 2003), alone the expression of % BF has been widely adopted
in the literature, and wide differences among studies have been reported regarding
this index in young soccer players (Leblanc et al., 2002; Rico-Sanz, 1998). In fact,
the mean values reported for players ages 13–18 years ranged from 7.6 to 15.0%,
our data (9.6%) being within this observed range. The equation selected, the ath-
letic level of the soccer players, and even race could explain these differences.
Wide differences in energy expenditure and in energy and macronutrient
intake have been reported for adolescent soccer players (Boisseau et al., 2002;
Leblanc et al., 2002; Rico-Sanz et al., 1998). The estimated mean daily energy
expenditure observed in this study (12.5 MJ or 2,983 kcal) was lower than the
3,833 kcal reported by Rico-Sanz et al. (1998) and higher than the 2,175 kcal
observed by Boisseau et al. (2002) for adolescent soccer players. It is well known
that, during adolescence, intake should not be balanced just to expenditure; posi-
tive energy balance is the desired state for growth and development in young per-
sons (Thompson, 1998). Rico-Sanz et al. (1998) and Boisseau et al. (2002) agreed
that the daily energy expenditure reported was slightly lower than energy intake
(3,833 vs. 3,952 and 2,175 vs. 2,345 kcal), and the same was observed in the
present study (2,983 vs. 3,003 kcal).
Our results show an average daily energy intake (12.6 MJ or 3,003 kcal)
higher than the intake reported by Boisseau et al. (2002) and Leblanc et al. (2002)
for different groups of French adolescent soccer players (2,345 kcal and 2,352;
2,757; and 2,420 kcal, respectively), but considerably lower than the 3,952 kcal
observed by Rico-Sanz et al. (1998) for players from Puerto Rico. The differences
reported in energy intake are very important since macronutrient intake recom-
mendations for adolescent athletes have been traditionally expressed in terms of
percentage of energy intake.
In this sense, none of the players assessed in the present study followed the
recommended CHO intake for adolescent soccer players (>55% of daily calories)
(Bar-Or and Unnithan, 1994), and the mean CHO intake observed (45% of energy
intake) was the lowest of all the previous studies on this topic (from 52.0 to 56.6%).
The main CHO sources of these adolescents were cereals and derivates (39% of
total CHO) and biscuits and confectionery (15%).
Oxidation of proteins contributes less than 10% of the total energy produc-
tion during match-play (Bangsbo, 1994a; Lemon, 1994). However, proteins are
also needed to repair exercise-induced damage to muscle fibers and to support
gains in lean mass. Taking this into account, nitrogen balance studies in adolescent
soccer players have suggested a daily protein intake of 1.4 to 1.7 g/kg body mass
(Boisseau et al., 2002), which coincides with the recommendations for adult play-
ers (Lemon, 1994). Wide differences among studies have been observed in protein
intake (from 13.1 to 17.5% of energy intake, and from 1.4 to 2.3 g/kg BM). Our
results (1.9 g/kg BM and 16% of energy intake) are within this range and show a
28• Iglesias-Gutiérrez, García-Rovés, et al.
higher than recommended protein intake, mainly related to high daily meat, fish,
and egg consumption (16% of total energy and 43% of total protein intake).
Although a greater reliance on fat as an energy source during exercise has
been described for young athletes (Bar-Or, 2001), there are no data to suggest that
adolescent soccer players require a higher lipid intake than adults (Bar-Or and
Unnithan, 1994). Our results (38% of total energy intake) are significantly higher
than the values observed by other authors (from 29.1 to 32.8%). Nevertheless,
more important than the quantity is the qualitative distribution of fats, considering
that foods containing monounsaturated fatty acid (MUFA) and polyunsaturated
fatty acid (PUFA) are basic for a healthy diet (Hu and Willett, 2002). Only the
study of Boisseau et al. (2002) included the analysis of MUFA, PUFA, and SFA
intake, showing a remarkably higher percentage of energy intake from SFA (25.6%)
compared to our results (9%). This is related to the use of olive oil as the main
added fat, which has been traditionally observed in Mediterranean populations
(Agudo et al., 1999; Moreno et al., 2002). In fact a high contribution of MUFA to
total energy intake (13%) has been observed, while there is a low PUFA intake
(5%), which is related to a virtually nonexistent use of vegetable oils containing
PUFA, and mainly to a low daily fish intake (2% of total energy intake), compared
to consumption of meat, poultry, and meat derivates (12% of total energy intake).
Only the data reported by Boisseau et al. (2002) are available about fiber
intake of adolescent soccer players (17.1 g). We found a significantly higher fiber
intake (24 g), closely related to consumption of cereals and derivates (22% of total
energy intake and 35% of total fiber intake) and legumes and nuts (3% and 19%).
Yet the consumption of whole grain foods, and especially vegetables, should be
promoted, as it is well known that a plant based diet has great potential to lower
the risk of chronic diseases, mainly due to ample amounts not only of fiber but also
of vitamins and minerals contained in these foods (Fung and Hu, 2003).
Methodological differences among studies on nutritional intake of adoles-
cent soccer players could be on the basis of the wide disparities observed, espe-
cially the environment in which these young athletes were assessed. When assess-
ing at a training center (Leblanc et al., 2002; Rico-Sanz et al., 1998), the influence
of the family environment on dietary habits is obviated. What is more, the possi-
bility of selecting foods is limited since meals usually follow a set menu and it is
difficult to choose foods based on individual preferences, which is one of the stron-
gest predictors of food choices (Story et al., 2002). This influences not only food
selection but also nutrient intake. In this sense it can be seen that those adolescent
soccer players assessed during a period of training at a specialized center, where
meals usually follow a set menu, showed a nutritional intake closer to the current
recommendations than those assessed in their home environment.
Very little is known about the dietary micronutrient intake of adolescent
soccer players. The results on vitamin and mineral intake (Figure 1) should be
carefully analyzed due to the fact that most micronutrients present a high day-to-
day variability. The observed lower than recommended (Food and Nutrition Board,
2002) intake of folate, vitamin E, calcium, magnesium, and zinc should be consid-
ered, therefore, as a reference for further in-depth analysis. In this sense, although
none of the soccer players in the present study reported the use of vitamin/mineral
supplements during the food-recording period, most of them (76%) admitted its
Adolescent Soccer Players• 29
use, especially iron supplements (64%), and mainly following medical advice (72%)
based on the biochemical and hematological assessment. The assessment of bio-
chemical and hematological parameters during the first half of the season was a
common practice in this soccer club, and the medical team used the results to
prescribe vitamin and/or mineral supplements in order to prevent or correct defi-
Most studies to date on the nutritional status of adolescent soccer players
have focused only on the dietary and anthropometrical evaluation (Boisseau et al.,
2002; Leblanc et al., 2002), although its complete assessment should include other
determinations such as biochemical, hematological, and functional measurements
(Magkos and Yannakoulia, 2003). Biochemical and hematological assessment was
included in the present study, and iron deficiency (low ferritin levels) without ane-
mia was observed in 48% of the players, although diet provided sufficient amounts
of iron (143% of the dietary reference intake) (Food and Nutrition Board, 2002).
This condition has often been described among adolescent athletes (Constantini et
al., 2000) and is probably related to the increase in myoglobin mass that occurs
during adolescence due to high muscular development (Eichner, 2000).
Furthermore, a high intravascular hemolysis during training and competi-
tion has been described for soccer players (Resina et al., 1991), which can lead to
higher iron losses. Low total cholesterol (21% of our subjects), high HDL-choles-
terol levels (24% of subjects), and a regular cholesterol/HDL-cholesterol ratio were
observed, which is a positive physiological consequence of exercise as also previ-
ously described for adolescent athletes (Eisenmann, 2002; Eisenmann et al., 2001)
and adult soccer players, although very few studies have been made in this regard
(Lehtonen and Viikari, 1980; Wirth et al., 1983). CK levels slightly above refer-
ence values were observed in most individuals (57.6%). These CK values, while
elevated, are not really high compared to that reported by Thompson et al. (1999)
after prolonged intermittent high-intensity shuttle running, or by Féasson et al.
(2002) after 30 min downhill treadmill running. The elevation observed probably
means there has been some limited damage associated with regular training and
competition; it may actually indicate some form of remodeling of muscle, not
simply damage that needs to be repaired (Féasson et al., 2002).
With regard to performance on soccer-specific tests, our results (Table 5)
show a lower level of aerobic fitness (2,121 m) compared to data provided by
Malina et al. (2004) for the Yo-Yo intermittent endurance test. From a practical
point of view, the use of soccer-specific tests (as with the Yo-Yo intermittent en-
durance test) seems to be necessary for the determination of intermittent exercise
performance as part of a team’s training routine (Bangsbo, 1994a). On the other
hand, better performance was observed in explosive activities involving high power
output (like jumping or sprinting), although the players in the present study per-
formed no specific strength training, which usually is incorporated into training
schedules from this age onward.
Summarizing, the results of this study show that the nutritional intake and
eating habits of high-level adolescent soccer players living in their home environ-
ment do not follow the nutritional recommendations for age and physical activity,
although further research is needed in order to determine the actual nutritional
needs and recommendations for adolescent soccer players. Overall, as discussed
30• Iglesias-Gutiérrez, García-Rovés, et al.
previously, those adolescent soccer players assessed during a period of training at
a specialized center (where meals usually follow a set menu) showed a nutritional
intake closer to the current recommendations than those living at home. Therefore,
it is necessary to understand the nutritional status and food habits of adolescent
athletes under typical circumstances, and its accurate assessment should be en-
couraged. This information is useful for designing nutrition education programs
that can be of great interest for these adolescents, in order to optimize performance
and especially to promote healthy eating habits, taking into account that only a few
high-level adolescent athletes reach the top adult level.
Agudo, A., Amiano, P., Barcos, A., Barricarte, A., Beguiristain, J.M., Chirlaque, M.D.,
Dorronsoro, M., González, C.A., Lasheras, C., Martínez, C., Navarro, C., Pera, G.,
Quirós, J.R., Rodríguez, M., and Tormo, M.J. (1999). Dietary intake of vegetables
and fruits among adults in five regions of Spain. Eur. J. Clin. Nutr. 53: 174-180.
Ainsworth, B.E., Haskell, W.L., Whitt, M.C., Irwin, M.L., Swartz, A.M., Strath, S.J., O’Brien,
W.L., Bassett, D.R., Jr., Schmitz, K.H., Emplaincourt, P.O., Jacobs, D.R., Jr., and
Leon, A.S. (2000). Compendium of physical activities: An update of activity codes
and MET intensities. Med. Sci. Sports Exerc. 32: S498-S504.
Al-Hazzaa, H.M., Almuzaini, K.S., Al-Refaee, A., Sulaiman, M.A., Dafterdar, M.Y., Al-
Ghamedi, A., and Al-Khuraiji, K.N. (2001). Aerobic and anaerobic power character-
istics of Saudi elite soccer players. J. Sports Med. Phys. Fitness 41: 54-61.
Bangsbo, J. (1994a). The physiology of soccer—With special reference to intense intermit-
tent exercise. Acta Physiol. Scand. 150: 1-156.
Bangsbo, J. (1994b). Fitness Training for Football: A Scientific Approach. Copenhagen:
H O + Storm.
Bar-Or, O. (2001). Nutritional considerations for the child athlete. Can. J. Appl. Physiol.
Bar-Or, O., and Unnithan, V.B. (1994). Nutritional requirements of young soccer players. J.
Sports Sci. 12: S39-S42.
Berning, J.R., Troup, J.P., VanHandel, P.J., Daniels, J., and Daniels, N. (1991). The nutri-
tional habits of young adolescent swimmers. Int. J. Sport Nutr. 1: 240-248.
Bingham, S.A. (1987). The dietary assessment of individuals; Methods, accuracy, new tech-
niques and recommendations. Nutr. Abstr. Rev. (Series A) 57: 705-742.
Boisseau, N., Le Creff, C., Loyens, M., and Poortmans, J.R. (2002). Protein intake and
nitrogen balance in male non-active adolescent and soccer players. Eur. J. Appl.
Physiol. 88: 288-293.
Bosco, C. (1994). Aspectos Fisiológicos de la Preparación Física del Futbolista [Physi-
ological aspects of physical preparation for soccer]. Barcelona: Paidotribo.
Brozek, J. (1966). Body composition: Models and estimation equations. Am. J. Phys.
Anthropol. 24: 239-246.
Buzzard, M. (1998). 24-hour recall and food record methods. In: W.C. Willett (Ed.), Nutri-
tional Epidemiology, pp. 50-73. New York: Oxford University Press.
Casajús, J.A. (2001). Seasonal variation in fitness variables in profesional soccer players. J.
Sports Med. Phys. Fitness 41: 463-469.
Adolescent Soccer Players• 31
Constantini, N.W., Eliakim, A., Zigel, L., Yaaron, M., and Falk, B. (2000). Iron status of
highly active adolescents: Evidence of depleted iron stores in gymnasts. Int. J. Sport
Nutr. Exerc. Metab. 10: 62-70.
Eichner, E.R. (2000). Minerals: Iron. In: R.J. Maughan (Ed.), Nutrition in Sport, pp. 326-
338. Oxford: Blackwell Science.
Eisenmann, J.C. (2002). Blood lipids and lipoproteins in child and adolescent athletes. Sports
Med. 32: 297-307.
Eisenmann, J.C., Womack, C.J., Reeves, M.J., Pivarnik, J.M., and Malina, R.M. (2001).
Blood lipids in young distance runners. Med. Sci. Sports Exerc. 33: 1661-1666.
Féasson, L., Stockholm, D., Freyssenet, D., Richard, I., Duguez, S., Beckmann, J.S., and
Denis, C. (2002). Molecular adaptations of neuromuscular disease-associate pro-
teins in response to eccentric exercise in human skeletal muscle. J. Physiol. 543:
Food and Nutrition Board, Institute of Medicine. (2002). Dietary Reference Intakes for
Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Man-
ganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC:
National Academy Press.
Fung, T.T., and Hu, F.B. (2003). Plant-based diets: What should be on the plate? Am. J.
Clin. Nutr. 78: 357-358.
García- Rovés, P.M., Terrados, N., Fernández, S.F., and Patterson, A.M. (1998). Macronu-
trients intake of top level cyclists during continuous competition—Change in the
feeding pattern. Int. J. Sports Med. 19: 61-67.
García-Rovés, P.M., Fernández, S., Rodríguez, M., Pérez-Landaluce, J., and Patterson, A.M.
(2000b). Eating pattern and nutritional status of international elite flatwater pad-
dlers. Int. J. Sport Nutr. Exerc. Metab. 10: 182-198.
García- Rovés, P.M., Terrados, N., Fernández, S., and Patterson, A.M. (2000a). Compari-
son of dietary intake and eating behavior of professional road cyclists during training
and competition. Int. J. Sport Nutr. Exerc. Metab. 10: 82-98.
Giovannini, M., Agostoni, C., Gianní, M., Bernardo, L., and Riva, E. (2000). Adolescence:
Macronutrient needs. Eur. J. Clin. Nutr. 54: S7-S10.
Hu, F.B., and Willett, W.C. (2002). Optimal diets for prevention of coronary heart disease.
JAMA 288: 2569-2578.
Jéquier, E. (1995). Nutrient effects: Post-absorptive interactions. Proc. Nutr. Soc. 54: 253-
Leblanc, J.C., Le Gall, F., Grandjean, V., and Verger, P. (2002). Nutritional intake of French
soccer players at the Clairefontaine Training Centre. Int. J. Sport Nutr. Exerc. Metab.
Leenders, N.Y.J.M., Sherman, W.M., Nagaraja, H.N., and Kien, C.L. (2001). Evaluation of
methods to assess physical activity in free-living conditions. Med. Sci. Sports Exerc.
Lehtonen, A., and Viikari, J. (1980). Serum lipids in soccer and ice-hockey players. Me-
tabolism 29: 36-39.
Lemon, P.W.R. (1994). Protein requirements of soccer. J. Sports Sci. 12: S17-S22.
Lohman, T.G. (1981). Skinfolds and body density and their relation to body fatness: A
review. Hum. Biol. 53: 181-225.
Magkos, F., and Yannakoulia, M. (2003). Methodology of dietary assessment in athletes:
Concepts and pitfalls. Curr. Opin. Clin. Nutr. Metab. Care 6: 539-549.
32• Iglesias-Gutiérrez, García-Rovés, et al. Download full-text
Malina, R.M., Eisenmann, J.C., Cumming, S.P., Ribeiro, B., and Aroso, J. (2004). Matu-
rity-associated variation in the growth and functional capacities of youth football
(soccer) players 13-15 years. Eur. J. Appl. Physiol. 91: 555-562.
Moreno, L.A., Sarría, A., and Popkin, B.M. (2002). The nutrition transition in Spain: A
European Mediterranean country. Eur. J. Clin. Nutr. 56: 992-1003.
Parizková, J. (2000). Dietary habits and nutritional status in adolescents in Central and
Eastern Europe. Eur. J. Clin. Nutr. 54: S36-S40.
Reilly, T., Bangsbo, J., and Franks, A. (2000). Anthropometric and physiological predispo-
sitions for elite soccer. J. Sports Sci. 18: 669-683.
Reilly, T., and Doran, D. (2003). Fitness assessment. In: T. Reilly and A.M. Williams (Eds.),
Science and Soccer, pp. 21-46. London: Routledge.
Resina, A., Gatteschi, L., Giambernardino, M.A., Imreh, F., Rubenni, M.G., and Vecchiet,
L. (1991). Hematological comparison of iron status in trained top-level soccer play-
ers and control subjects. Int. J. Sports Med. 12: 453-456.
Rico-Sanz, J. (1998). Body composition and nutritional assessment in soccer. Int. J. Sport
Nutr. 8: 113-123.
Rico-Sanz, J., Frontera, W.R., Molé, P.A., Rivera, M.A., Rivera-Brown, A., and Meredith,
C.N. (1998). Dietary and performance assessment of elite soccer players during a
period of intense training. Int. J. Sport Nutr. 8: 230-240.
Schofield, W.N. (1985). Predicting basal metabolic rate, new standards and review of previ-
ous work. Hum. Nutr. Clin. Nutr. 39: 5-41.
Spear, B.A. (2002). Adolescent growth and development. J. Am. Diet. Assoc. 102: S23-
Story, M., Neumark-Sztainer, D., and French, S. (2002). Individual and environmental in-
fluences on adolescent eating behaviors. J. Am. Diet. Assoc. 102: S40-S51.
Thompson, D., Nicholas, C.W., and Williams, C. (1999). Muscular soreness following pro-
longed intermittent high-intensity shuttle running. J. Sports Sci. 17: 387-395.
Thompson, J.L. (1998). Energy balance in young athletes. Int. J. Sport Nutr. 8: 160-174.
Williams, A.M., and Reilly, T. (2000). Talent identification and development in soccer. J.
Sports Sci. 18: 657-667.
Wirth, A., Diehm, C., Kohlmeier, M., Heuck, C.C., and Vogel, I. (1983). Effect of pro-
longed exercise on serum lipids and lipiproteins. Metabolism 32: 669-672.
Wisløff, U., Helgerud, J., and Hoff, J. (1998). Strength and endurance of elite soccer play-
ers. Med. Sci. Sports Exerc. 30: 462-467.
Received January 5, 2004; accepted in final form July 12, 2004.