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Nutrition & Food Science Vol. 36 No. 5, 2006 pp. 343-348

EEmerald Group Publishing Limited 0034-6659 DOI 10.1108/00346650610703199

The current issue and full text archive of this journal is available at www.emeraldinsight.com/0034-6659.htm

have been highlighted as being particularly important in supporting growth (National Dairy Council, 1995).

As well as the energy requirements of exercise and growth there are many factors that affect food intake including access, availability, individual circumstances such as living conditions and nutritional knowledge. Whilst many football players are aware of the importance of diet very few actually employ ideal dietary practice. In fact studies on footballers have shown that most (Ingram and Davies, 1996) do not consume a diet considered compatible with peak physical performance and leave much room for improvement.

The aim of this study was to determine some of the factors including nutritional knowledge and residential status that influence the diets of a group of professional football players from a Premier division and a 1st division football clubs youth squads.

Methodology

Thirty five players were recruited mid-season from two professional football clubs; one club was in the English premier league and the other in the first division. Twenty- two players with a median age of 17 years (range 16–19 years) completed the study. For comparative purposes, 20 controls who did not participate regularly in sport were also recruited. The participants were provided with verbal and written instructions on how to complete a 7 day food diary, which they were asked to carry with them at all times and record everything they ate and drank. A full description of the foods consumed was requested, including the type and brand, how the food was cooked and the amount consumed. The diaries were then analyzed using Diet 5 (Univation, Aberdeen). To eliminate the possibility of under-reporting, the basal metabolic rate (BMR) of all participants was calculated using the FAO/WHO/UNU (1985) equations. These are equations based on individual body weights. If energy intakes are less than 1.5 times BMR, this suggests that unless there is a loss in body weight, that the subjects are not recording all foods consumed. Any subjects thought to be under- reporting were eliminated from the study.

The participants were interviewed about their exercise and training schedules, living situation and were asked to complete a questionnaire, tailored for football players, which tested their knowledge of nutrition. This entailed ten multiple choice questions and ten questions in a true/false format. Questions were included from the following categories: energy, macronutrients, vitamins and minerals, supplements, hydration and weight control. For the multiple choice section of the questionnaire correct responses were scored as 1 and incorrect as 0. For the true or false section correct answers scored 1 whereas incorrect answers scored 21. This method prevented artificially high scores since random responding would tend to sum to zero rather than 50 per cent. Both sections of the questionnaire were combined and presented as a percentage; the maximum possible score was therefore 100 per cent. This score was then used in subsequent analyses. The questionnaire was piloted using university students studying nutrition. There was a significant difference (p , 0.05) in the mean scores of the nutrition students and the football players.

Body mass was measured with a digital balance (Seca, Germany) to the nearest 0.1 kg. The balance was calibrated for accuracy with known weights. Height was measured using a portable stadiometer to the nearest 0.5 cm. Subjects were measured bare footed, heels together with heads in the Frankfort plane. To estimate body fat,

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skinfolds were measured using Harpenden calipers (British Indicators, UK) to the nearest 0.1 mm. Total body fat was estimated from the sum of four skinfold values taken at the biceps, triceps, sub-scapular and supra-iliac and calculated using the Durnin and Womersley (1974) equations.

All data are presented as mean values ¡ standard deviation (SD). T-tests and Pearsons correlations were calculated using SPSS (v 10.1) and graphed using Excel (Microsoft Corporations) software. A significance level of p,0.05 was adopted. Results

The participants’ anthropometric characteristics are presented in Table I. There was no significant difference in age between the two groups, however the football players were significantly (p , 0.05) lighter, had a lower body mass index and less body fat than the controls.

Results of energy intake and macronutrient consumption are shown in Table II, and show that the football players ate significantly (p , 0.05) less than the controls and their intakes were below the 11.54 MJ day21 recommended for adolescents (Department of Health, 1996) as well as the guideline of 14–15 MJ day21_{for football}

players (Shepherd, 1999). In addition, the macro-nutrients were not consumed in optimal proportions. The football players consumed significantly (p , 0.05) more carbohydrate as a percentage of energy intake than the controls, although both groups would benefit by increasing their intakes. The football players consumed 51 per cent of their energy from carbohydrate and an equivalent of 4.3 grams per kilogram of body weight per day (g kg21_day21_{). This is below the recommendations for football}

players whereby more than 55 per cent of the diet should be made of carbohydrate rich foods, or 6 g kg21 _day21 _{(Economos et al., 1998). A difference of 4 per cent}

Variable Football players Controls

TableI. Anthropometric characteristics of youth football players and controls (mean ¡ SD) Height (m) 1.75 ¡ 0.07 1.80 ¡ 0.04

Weight (kg) 72.3 ¡ 4.1 87.1 ¡ 3* Body Mass Index (kg m22_{) 23.6 ¡ 1.2 26.9 ¡ 1.6*}

Body fat (per cent) 15.0 ¡ 5 24.1 ¡ 3* Note: * p,0.05.

Nutrient Football players Controls

TableII. The energy and macronutrient intakes of youth football players and controls (mean ¡ SD) Energy (MJ) 10.26 ¡ 1.8 13.89 ¡ 0.7*

Carbohydrate (per cent) 51 ¡ 4* 44.9 ¡ 5.0 Carbohydrate (g) 310.05 ¡ 22 373 ¡ 32 Protein (per cent) 17 ¡ 2 15.1 ¡ 2.3 Protein (g) 104.1 ¡ 16 135 ¡ 13 Fat (per cent) 32 ¡ 3 31.7 ¡ 5

Fat (g) 87.7 ¡ 4 117 ¡ 2*

Alcohol (per cent) 0.3 ¡ 1 6.73 ¡ 0.6** Alcohol (g) 0.9 ¡ 1 31.9 ¡ 11** Notes: *p , 0.05. **p , 0.01.

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between the average amount of carbohydrate consumed and the recommendations may seem minor but for some individuals this deficit was as much as 15 per cent and such an amount is likely to affect performance (Brouns, 2002).

Both protein and fat were consumed in appropriate amounts by both groups, however the controls consumed significantly (p , 0.05) more fat. Alcohol was consumed in very small quantities by the football players and significantly (p , 0.01) less than the controls.

Adequate intakes of all vitamin and minerals were consumed (Table III), with the exception of calcium, which was below recommendations for both groups (Department of Health, 1996).

There was a disparity between nutritional knowledge and the nutritional practices employed by the players. For example, you would expect the more a player knew about nutrition the greater they would understand the need for high intakes of carbohydrate. Correlation between carbohydrate intake and nutritional knowledge score was determined by carrying out a Pearsons correlation. From this it was revealed that carbohydrate intake and nutritional knowledge were poorly correlated (R 5 0.2, p , 0.07). Energy intake and nutritional knowledge score were also weakly correlated (R 5 0.3, p , 0.06). Similar patterns were seen in the control subjects.

When player living situation was investigated, it was revealed that players who resided in the club hostel had significantly greater energy intakes, consumed more carbohydrate and less fat (p , 0.05) than players who lived in their parental home. This was not the case for the control subjects. There were no significant differences in the diets consumed by the players from the premier division club and those from the first division club.

Discussion

Measurements of body composition are necessary in order to assess appropriate nutritional intakes and the fact the football players were lighter and had less body fat may account for and be a result of the differences in energy intakes between the two groups. The football players could do with increasing their energy intakes inline with recommendations for athletes (Economos et al., 1998). It is also recommended that the football players increase their carbohydrate intakes since low carbohydrate intakes are also associated with less distance covered and lower speeds during matches (Rico-Sanz et al., 1998). Although protein was consumed in adequate amounts it was still below the 142 g day21consumed by elite soccer players reported by Rico-Sanz et al. (1998). Fat intakes were also appropriate in both groups but for a comparison were less than the 158 g day21_{consumed by Greek football players (Hassapidou et al.,}

2000). The controls reported drinking alcohol between two and four times a week, however the football players rarely drunk. This is probably a sensible decision on behalf of the football players since even small quantities of alcohol can produce a

TableIII. The micronutrient intakes of youth football players and controls (mean ¡ SD)

Nutrient Football players Controls Vitamin C (mg) 90.1 ¡ 4.6 82.9 ¡ 6 Vitamin E (mg) 4.82 ¡ 3.1 5.5 ¡ 4.5 Calcium (mg) 665 ¡ 189 626 ¡ 320 Iron (mg) 11.14 ¡ 3 17.82 ¡ 48

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negative effect on aerobic performance, although anaerobic performance may not be affected (O’Brien, 1993).

In accordance with the findings of Rockwell et al. (2001), who studied female university athletes, there was a disparity between nutritional knowledge and the nutritional practices employed by the players. Even in those clubs which do provide a good level of nutritional education perhaps in conjunction with a college based training programme this knowledge does not always manifest itself into a good diet. In theory nutritional education should have an impact on the adequacy of food choices however, in reality this rarely occurs. Many studies have shown even when life and/or livelihood dependant, subjects are still reluctant to alter their habitual diets (Webb, 2002). Yet this is no reflection on their level of education or the dietary information provided, hence generally there is a large disparity between nutritional knowledge and the dietary practices employed (Packman and Kirk, 2000). This discrepancy may be due to the fact that most subjects are over optimistic about their own diets, and do not relate general nutritional advice to their own lifestyle habits (Fieldhouse, 1998). Yet when given accurate information about their own individual intakes, it more likely improvements will be made (Raats et al., 1999). There is a need to improve understanding of personal dietary intakes in order to improve personal attitudes towards and desire to modify dietary habits. These dietary changes can then in turn lead to an improvement in the football players’ physical condition, provide better protection against injuries, faster recovery, maintain growth and ultimately better performance on the pitch.

Conclusions

It is apparent that the players need assistance in the implementation of their knowledge of nutrition to their own diets, to increase their nutritional intakes in line with recommendations. Nutritional guidance may be particularly beneficial to those who live away from the scrutiny of the football club.

References

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Fieldhouse, P. (1998), Food and Nutrition: Customs and Culture, Routledge, London.

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Hassapidou, M.N., Grammatikopoulou, L. and Liarigovinos, T. (2000), ‘‘Dietary intakes of Greek professional football players’’, Nutrition and Food Science, Vol. 30 No. 4, pp. 191–4. Ingram, L. and Davies, J. (1996), ‘‘Nutritional awareness of professional football teams with

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Rico-Sanz, J., Frontera, W., Mole, P., Rivera, M., Rivera-Brown, A. and Meredith, C. (1998), ‘‘Dietary and performance assessment of elite soccer players during a period of intense training’’, International Journal of Sports Nutrition, Vol. 8 No. 8, pp. 230–41.

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Webb, G. (2002), Nutrition a Health Promotion Approach, Arnold, London. Corresponding author

Yvonne Jeanes can be contacted at: [email protected]

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