from eating disorders nutrient intake of female elite athletes … · 2017. 12. 18. ·...

International journal of Sport Nutrition, 1993, 3, 431 -442 0 1993 Human Kinetics Publishers, Inc.

Nutrient Intake of Female Elite Athletes Suffering From Eating Disorders

Jorunn Sundgot- Borgen

This study assessed the nutrient intake and eating behavior in Norwegian female elite athletes suffering from eating disorders (ED) who met the criteria for anorexia nervosa (AN), anorexia athletica (AA), or bulimia nervosa (BN). The subjects included 7 AN, 43 AA, 42 BN, and 30 controls. Three-day and 24-hr food records were used to assess energy and nutrient intake. Results revealed that a significant number of AN and AA athletes have diets too low in energy and nutrients, the mean intake for energy and CHO being lower than recommended for active females. A significant number did not reach the protein level recommended for athletes. In addition, there were low intakes of several micronutrients, most notably calcium, vitamin D, and iron. The energy and nutritional inadequacy, combined with the use of purging, are of major concern since the athletes in this study were relatively young. It is unknown whether the abnormal eating pattern is a consequence of ED or is typical of top level athletes.

Key Words: eating behavior, anorexia nervosa, anorexia athletica, bulimia nervosa

Aside from the limits imposed by heredity and the physical improvements associated with training, no factor plays a bigger role in exercise performance than nutrition (7). A proper diet can help athletes' maximize performance (5). Nonetheless, poor habits that may limit performance and promote injury often prevail, even among top competitors (6). A significant number of female athletes diet and practice pathogenic weight control methods, causing high rates of eating disorders (ED) (33). Little is known about the nutrient intake and eating behavior of athletes who meet the criteria for ED: anorexia nervosa (AN), anorexia athletica (AA), and bulimia nervosa (BN). Describing the dietary patterns of elite female athletes with ED may lead to a better understanding of their nutritional habits. Such knowledge can then be used in counseling the athletes. Nutritional counseling combined with cognitive behavioral therapy has been found effective in the treatment of ED (16).

Jorunn Sundgot-Borgen is with the Dept. of Biology and Sportsmedicine, The Norwegian University of Sport and Physical Education, P.O. Box 40 Kringsjaa, 0807 Oslo 8, Norway.

The aims of this study, therefore, were to determine the nutrient intake and eating behavior in Norwegian elite female athletes who met the criteria for AN, AA, or BN. These athletes follow the general eating pattern of elite female athletes in most western countries. Accordingly, it is felt that the data obtained in this study are representative of western elite female athletes in general.

Methods

Screening of Subjects

The data discussed here were collected as part of a larger study that was done to determine the prevalence of ED and investigate etiological factors and conse- quences of ED among elite female athletes. Written information explaining the procedures of the study, the Eating Disorder Inventory (EDI) (15), and a self- developed questionnaire were given to all 603 elite female athletes in Norway and to 522 age-matched and community-matched controls; ages ranged from 12 to 35 years. All participants had to complete a signed informed consent statement. In addition, anyone younger than 18 had to present written confirmation of parental consent to participate. Eighty-one athletes were excluded from the study: 41 did not meet the inclusion criteria, 4 were in treatment for ED and did not want to participate, and 36 did not respond for reasons unknown. Thus, final responses from 522 athletes and 448 controls were analyzed (33). Only the athletes will be discussed in this paper.

A total of 117 athletes were classified by the ED1 score as being at risk for developing ED. Of these athletes, 92 met the criteria for AN (I), BN (I), or AA (33). The control group comprised 30 athletes who were not classified as at risk and who matched the at-risk athletes on age, community, and sport. Thus, 92 ED athletes and 30 athletic controls were included in this study.

Dietary Recall

All athletes monitored their food intake by 24-hr dietary recall, since it was considered the least time consuming method for the subjects who, due to their training regimes, are very busy. This method was also chosen because clinical experience indicates that athletes, even those suffering from ED, report they have minimal day-to-day variations in food and nutrient intake. The athletes received both written and oral instructions for determining portion sizes and recording all dietary intake for 24 hrs.

Participants were asked to indicate whether they regarded the eating epi- sodes as a binge and whether they had used vomiting, laxatives, diuretics, and/ or excessive exercise afterward for the previous 7 days. They were all told that some would be asked to do a 3-day recall after the interview session, and that this report, in addition to the results from the interview, was important for preparing the treatment program. Since the semistructured interview (33) included questions about the athletes' eating behavior during the preceding weeks, the 24-hr recall was discussed at that time. In connection with the interview session, all athletes underwent clinical examination; height and weight were measured and relative percent fat was estimated via skinfold measurements (32).

Due to the relatively low number of anorectics and controls, all the AN athletes and the controls, as well as 22 BN and 21 AA athletes, were randomly

Athletes and Eating Disorders / 433

chosen to do the 3-day recall. This method was used in addition to the 24-hr record to examine whether the latter was a valid tool for assessing the energy and nutrient intake in this special group of athletes. Since it is one's usual diet that should be assessed, it was stressed that their "usual" diet was being investigated and that they should not use the opportunity, for example, to restrict energy intake or not report binges. All subjects were given written and oral instructions as well as demonstrations of how food should be weighed. The record book was explained in detail. Subjects involved in the 3-day weight records were asked to select 1 day of the weekend and 2 weekdays.

A total of 23 ED athletes and 10 controls had extensive experience in keeping food records, since they had kept food records for similar studies; in addition, 18 ED athletes and 5 controls had kept records in other connections previously. Each subject was instructed to eat as usual and to record, as accurately as possible, the quantity and type of food and drink consumed, including supplements. The dietary data were analyzed using the Norwegian Nutritional Analysis Program (36), which is based on the Norwegian Food Composition Tables (37). Statistical analysis and plot procedures were done according to SAS (29). No significant differences were found in energy or nutrient intake between the 3- day recall and 24-hr recall. Results from the latter are used in this paper, therefore, since all athletes employed this method.

In addition to recording their food intake, the athletes were asked to note at which times they had eaten, the frequency and time of all binges, and the use of purging methods (specifying vomiting, use of laxatives, diuretics, fasting, or excessive exercise) during the day or days of dietary recall and the 6 or 3 following days. The athletes were also asked about the type and duration of training and competitions. The nutritive value of their food intake was compared with the Nordic nutrition recommendation daily intake (NNRDI) for highly active people (2.0 x BMR) (38). The NNRDI does not include recommendations for the intake of CHO, therefore CHO intake among the athletes was compared with previously published values (7).

Categorization of Athletes

For part of the analysis, the athletes were divided into the three diagnostic groups of AN, AA, and BN, and one group of controls. The athletes represented 35 sports. For other parts of the analyses, these 35 sportlevents were divided into the following five groups: technical, endurance, aesthetic, weight-dependent, and ball-game sports. One of the athletes representing the power sports met the ED criteria. She was excluded from the statistical analyses concerning sport groups but is included in the analyses concerning the diagnostic groups. Only ED athletes were categorized into different sport groups.

Statistical Methods

All results are expressed as mean with 95% confidence intervals (95% CI) unless otherwise stated. For construction of the CI, the student procedure was used. Analysis of variance was used for comparison of the groups (30). Two-tailed tests were said to be statistically significant if the p values were less than or equal to 5%. Pairwise comparisons were performed via Duncan's multiple range test (30).

434 / Sundgot-Borgen

Table 1

Characteristics of the Athletes (mean and total range)

Age (yrs) 1 7b 14-18

Body mass (kg) 47b 38-56

Body fat (%)" 1 Ob 4-1 1

Training vol. (hrslweek) 20e 18-24

aFrom Ref. 32. Significantly different %om AA, BN, and C, pcO.01; Yrom BN and C, ~ 0 . 0 1 ; dfrom C; *om BN, pc0.01; and C, ~ 0 . 0 5 .

Characteristics of the ED athletes and the controls are given in Table 1. Analyses showed an overall difference between groups on all variables included in Table 1 0) < 0.01). Forty percent of the athletes representing the AN and AA groups and 17% of the BN athletes were younger than 18 yrs. The AN and AA athletes trained significantly more than the BN group (p < 0.01) and the controls O, < 0.05). The mean energy intake of the ED athletes and the controls are shown in Figure 1. No significant differences were found between the two reporting methods.

Except for the bulimics, the mean energy intake for the ED athletes and the controls were below the NNRDI for highly active women 19 to 30 years of age (1 1.6 + 1.6 MJIday). It has been reported previously that 27% of the controls were dieting (34). The caloric intake for the anorectic groups and the controls was made up of 60% CHO, 20% fat, and 20% protein, as compared to 60% CHO, 30% fat, and 10% protein for the BN group. Nutrient intake for the ED groups and controls are given in Table 2.

Mean values for CHO intake per kilogram (kg) body mass (BM) were below the level recommended (7). Mean values for protein per kg BM were within the recommended level of the NNRDI for all groups. An overall difference was observed between the groups on protein, CHO, fat, calcium, and vitamins D and B, (Table 2). No overall difference was observed in nutrient intake (Table 3). ED athletes competing in aesthetic sports had a significantly lower protein intake than those competing in ball-game sports (p < 0.05). An overall difference in training volume was observed between the sport groups (Table 3). Athletes competing in endurance and aesthetic sports had a significantly higher training volume than those competing in technical, weight-dependent, and ball-game sports (p < 0.01 for each) (Table 3).


2 4 hr. / 3-day recal l

Mega Joule

30.0 -7-

24 fir. 3-day 24 Ilr. 3-day. 24 hr. 3-day 24 hr. 3day AN M BN C

Diagnostic groups

Figure 1 - The mean energy intake (95% CI) of athletes with anorexia nervosa, anorexia athletica, and bulimia nervosa, and the controls. The marked area is the recommended daily energy intake for highly active females, ages 19-30 (37).


Table 2

Intake of Protein, CHO, Fat, and Micronutrients per Day for ED Athletes and Controls

AN A A BN C

Protein (g/kgBM) 0.7

CHO' (g/kgBM) 9-1 0

Fat (ClfkSBM)

Iron (mg) 12-1 8

Calcium (mg) 800

Vitamin C (mg) 60

Vitamin A (ug) 1000

Vitamin D ( 4 ) 5

Vitamin B, (mg) 1 .O

Vitamin B, (mg) 1.3

M CIM M CIM M CIM M CIM M CIM M CIM M CIM M CIM M CIM M CIM

*From Ref. 7. Note. Values are given as mean with 95% confidence interval of mean (CIM). The Nordic nutrition recommended daily intake (NRDI) for protein and micronutrients are given. Significantly different afrom AN, AA, and C; %om AA, EN, and C; %om BN.

Table 4 shows the reported number of meals per day for each diagnostic group. The typical Norwegian meal pattern is four daily meals (breakfast, lunch, dinner, and evening meal). But 29% of the AN athletes, 14% of the AA, 60% of the BN, and 13% of the controls reported having two or less meals a day. Bulimic athletes had significantly fewer meals per day than AA athletes ( p < 0.05). For athletes who had breakfast, lunch, and an evening meal, the mean duration (total range) between breakfast and lunch and between lunch and the evening meal was 5 (3-6) hrs and 9 (7-11) hrs, respectively. An evening meal usually contains bread and is the last meal of the day in Norway. For those who had breakfast, lunch, and dinner, the mean duration between breakfast and lunch was 4 (3-6) hrs, and from lunch to dinner it was 5 (3-7) hrs.

Fifty-five athletes (40 BN and 15 AA) reported bingeing and purging on a regular basis. The average number (total range) of binges per week was 4 (2-12). A full 83% of the bulimics binged after the last meal of the day. In addition, 12 of the 21 bulimics who reported consuming two meals a day claimed that they often binged at both meals. All the bulimics vomited after bingeing.


Table 3

Energy, Protein, CHO, and Fat Intake per Kg Body Mass for Each Sport Group

Weight- Ball game Technical Endurance Aesthetic dependent sports

(n=13) (n=24) (n=22) (n=11) (n=21)

Energy (K~/kg)

Protein (g/kg)

CHO (glkg)

Fat (g/kg)

Train. vol. (hrslweek)

Note. Values given as mean with 95% confidence interval of mean. aSignificantly different afrom ball games; %om all other groups; Yrom the technical, weight- dependent, and ball-game sports.

Table 4

Reported No. of Meals Eaten by Each Diagnostic Group per Day

Meals

Groups n 1 2 3 4

Anorexia nervosa 7 2 4 1 Anorexia athletics 43 1 5 11 26 Bulimia nervosa 42 4 21* 11 6 Controls 30 4 6 20

--

*BN athletes had significantly fewer meals per day compared to AA athletes and controls.

The average period from the end of the binge to the start of vomiting was 15 (3-45) min. Fourteen of the bulimics also used laxatives, and 3 used diuretics.

The average number of binges per week for the AA athletes was 1 (1-4). They all reported bingeing in connection with the last meal of the day, and 12 reported that vomiting always followed a binge. The time period from the end of the binge until vomiting started was 21 (6-38) min. Five of the bingeing AA athletes and 19 nonbingeing AA athletes reported using laxatives an average of 2 (1-5) times a week. Four reported using diuretics at least once a week in the morning prior to the required weight controls arranged by the coaches in connection with the training. Some 23% of the ED athletes (16 AA, 4 BN, and 1 AN) and 57% of the controls used different supplements (supplement intake is not included in Table 2).

Discussion

The food intake of the athletes in the two anorectic groups (AN and AA) was too low in calories and nutrients, in view of the NNRDI. The caloric and nutrient intake of the bulimics, as a group, was within the recommended level for highly active females (38). The sport groups with the highest energy intake, ball-games and endurance sports, have the highest percentage of bulimics, 81% and 58%, respectively. However, the number of calories that the athletes retained in their gastrointestinal tract after vomiting was not calculated. Vomiting can reduce caloric retention by 50% (19). Thus the caloric inadequacy of the ED athletes is even more pronounced when one considers the significant number who practice regular vomiting, the intense training regimen, the normal energy expenditure of the athletes representing the different sport groups (10, 11,24), and the number of maturing girls which is not taken into account in the NNRDI for females ages 19-30 yrs.

Mean caloric intake of AA.and controls was similar, perhaps because 27% of the controls were dieting during the diet recording period. The energy expenditure for AA athletes should be higher than that of the controls, since there was a significant difference in training volume (Table 1). Excluding the dieters who had a mean energy intake of 5.2 MJ/day, the remaining controls had a mean energy intake of 10.2 (total range 6.0-13.1) MJ/day. The dietary intake of the nondieting controls was within the limits of the NNRDI. The fraction of dieting athletes among the controls is similar to previous reports (34). This finding only confirms that even athletes with no symptoms of ED consume too few calories and nutrients.

Even though CHO intake expressed as energy percent was within the recommended level for all groups (7), the CHO intake in glkg BM was below the recommended intake except in the BN group. This confirms previous findings by Erp-Baart et al. ( l l ) , that many athletes have a relatively low CHO intake. Erp-Baart et al. also reported that about 35% of the energy intake of top Dutch athletes was derived from snacks. Others have reported similar findings (20). The ED athletes in this study, however, did not have snacks between meals, probably because they were afraid of losing control like other ED patients (13). Snacking in connection with meals (lunch and/or dinner) was reported by 28 athletes. For them, snacking was usually defined as one fruit, one ice cream, or a cookie. The restrictive caloric intake and the lack of snacking could contribute


to the low CHO intake per kg BM. The importance of the CHO intake has been illustrated in a number of studies (7, 17). Although most research is focused on endurance sports, it is reasonable to assume that athletes competing in other sports and who train intensively also need a CHO-rich diet (1 1).

The mean values for the reported protein intake were within the recommended level for all groups. However, 17% of the AN athletes had a protein intake below the amount recommended for athletes (21). Since protein needs are higher during a weight reduction program, and since lack of protein may contribute to amenorrhea (18, 25), it has been suggested that female athletes should have as much as 1.2-1.4 gmkg BMIday (21). Thus some of the AN athletes may have had a negative nitrogen balance.

It is not surprising that athletes who consume few calories have a low nutrient intake as well (Table 2). Similar findings have been reported among professional ballet dancers and gymnasts (2, 4, 6, 23). Erp-Baart et al. (12) concluded that vitamin and mineral intake is sufficient for top level athletes when food consumption ranges between 10 and 20 MJIday. Only the mean values for the BN group reached this level. Some athletes used nutritional supplements, but on a very irregular basis. Most likely, therefore, the supplements did not make up for the dietary deficiencies. The low number of ED athletes who used nutritional supplements is in contrast to previous reports on athletes (4) and ED patients (6), perhaps due to misconceptions about the caloric content of the different supplements. In addition, the bulimics felt that taking supplements was a waste of money, since they often vomited.

All groups had mean values below the NNRDI for vitamin D intake (Table 2). Selective abstention from certain foods can account for some of the low vitamin A and D intake of some athletes. Many of those competing in aesthetic and endurance sports avoided foods such as butter and margarine. Based on their food choices, it was concluded that the endurance athletes in this study tended to eat a vegetarian diet. Athletes with vegetarian food habits usually eat more non-heme-bound iron in combination with fiber-rich food (1 1). The resulting negative influence on iron intake could therefore help explain why all groups, except the bulimics, had mean values below the NNRDI for iron intake.

For a significant number of the athletes, the reported calcium intake was far below the NNRDI (Table 2). It has been postulated that inadequate calcium intake may be partly responsible for the high frequency of stress fractures reported in female athletes (25). A possible link between eating disorders, secondary amenorrhea, and bone mineral loss has been suggested (40). Some 59% of the ED athletes had amenorrhea or irregular menses (35). Simultaneous low protein and fat intake magnify the problem (8). Drinkwater et al. (8) advise a calcium intake of 1,500 mglday for amenorrheic athletes, which calls for an energy intake of at least 13.2 MJIday to meet such a high demand (12). In this study, only bulimics had such a high energy intake.

It is difficult to explain how these ED athletes can continue to compete at their high performance level in spite of their undernutrition. Poor growth and impaired maturation has been reported in a group of children and adolescents who regularly restricted calories because they were afraid of becoming obese (22, 26). Fohlin et al., on the other hand (14), claims that it cannot be assumed that the pathophysiology of AN is directly comparable to that of involuntary undernutrition. The fact that these ED athletes can compete at a high performance


level could suggest that their bodies have become metabolically more efficient in an attempt to conserve energy stores. That is, their resting metabolic rate and thermic response to food are attenuated, and therefore they may be able to perform physical activity with exceptionally low energy expenditure (3).

However, Schulz et al. (31) did not support the hypothesis that distance training results in metabolic adaptations that lower energy requirements in women. Furthermore, it is noteworthy that most of the AN and AA athletes represented aesthetic and weight dependent sports. Some AN athletes also performed well in the endurance sports. Few meals per day, and spaced too far apart, were reported by a significant number of the ED athletes. These have been termed trigger factors for the development of bingeing and purging (3, 16). In spite of this, most of the BN athletes seem to have more control of their eating behavior than BN nonathletes (27), possibly due to the strict training schedule they must follow. Yet their eating pattern is far from acceptable for athletes (9).

Although the reported eating pattern could be due to their eating disorders, a significant number of the controls also reported a similar eating pattern (Table 4), and the ED athletes reported that they had irregular eating schedules even before the ED developed. Therefore, this may be an adapted and "normal" eating pattern for these female athletes, and as such, a possible risk factor for the development of ED.

The accuracy of the data could have been influenced by the diet record methods, the nutrient comparison standard of the NNRDI, and the data base. Although it is tempting to attribute these low intakes to the underreporting of food intake or undereating during the diet recall period, low caloric intakes have been observed for a variety of sports and appear to be consistent across a number of studies (28). Since we did not monitor weight during the 3-day recall period, we do not know whether the athletes were weight stable and cannot rule out the possibility of underreporting or undereating during the registration period.

Our second area of concern was that using the NNRDI as a standard is open to criticism, since the NNRDIs do not represent individual requirements. They are merely recommendations for population groups and can only estimate needs. However, when the proportion of individuals with low intake for several nutrients is as extensive as we found, the risk of deficiency in the study group is high. Individual counseling seems effective in improving the nutrition of female athletes and ED patients (39). Therefore it is suggested that guidelines be developed to help athletes attain a desirable weight and body fat ratio without resorting to dangerous dietary practices.

Summary

The study showed that the ED athletes, except the BN group, consume a diet that is too low in energy and nutrients. The mean levels of energy and CHO intake for AN and AA athletes are lower than recommended for active females, and a significant number of the athletes did not reach the protein level recommended for athletes. In addition, low intakes of several micronutrients were reported, most notably calcium, vitamin D, and iron. The energy and nutritional inadequacy, combined with the use of different purging methods, are of major concern in athletes who are so young.


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Acknowledgment This study was supported by a grant from The Norwegian Research Council for

Science and the Humanities. The authors are obliged to Sverre Maehlum, M.D., Ph.D., at The Norwegian Univer-

sity of Sport and Physical Education for valuable help and advice with the manuscript.

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