ASSESSMENT OF DIETARY BEHAVIOUR OF YOUNG WOMEN PARTICULARLY VULNERABLE TO EATING DISORDERS

Karolina Łagowska
Dietetic Division, Department of Human Nutrition and Hygiene, Poznań University of Life Sciences, Poznań, Poland

ABSTRACT

Abnormal eating habits are very frequent among ballet dancers and female athletes. Recent studies have suggested that students of dietetics also fall into this group.

Key words: dietary behaviour, ballet dancers, students, female athletes.

INTRODUCTION

Incorrect nutritional practices are more often found in women than in men. Abnormal eating habits may be the result of a consciously applied dietary regimen that even includes self-provoked vomiting and the taking of laxatives and diuretics. Such practices are particularly dangerous, as they may become the basis for clinical nutritional disorders that are associated with problems assessing one’s own body shape, emotional status, and interpersonal relations (reference is needed). Anorexia nervosa is one of the most extreme clinical forms of nutritional disorder. According to DSM IV (Diagnostic and Statistical Manual of Mental Disorders, the standard classification of mental disorders used by mental health professionals in the United States), subjects suffering from this condition will starve themselves even when their body weight is as much as 15% below the ideal body mass. On the other hand, the behaviors associated with bulimia include alternating cycles of extremely limited food intake and of compulsive eating, followed by purging.

Nutritional disorders are also frequently diagnosed in physically active subjects, including elite female athletes. The pressure to maintain a slim figure is very great in the case of aesthetic disciplines, including among ballet dancers, for whom low body weight is essential [13, 14, 18]. There are also studies drawing attention to another group particularly prone to improper dietary practices: students of dietetics and nutrition, who tend to be women, appear to be particularly vulnerable to the development of eating disorders. This increased risk may be due to their knowledge of food, weight control, and body composition. However, there are still few studies on this subject [12].

The aim of this study is to evaluate the eating behavior and nutritional habits among young ballet dancers, athletes, and dietetics students – all women considered to have a specific risk of developing an eating disorder.

MATERIALS AND METHODS

Subjects
45 well-trained female athletes (rowers, synchronized swimmers, and triathlonists) from various sports clubs in Poznań, 27 ballet dancers from the Poznań Ballet School, and 34 dietetics student from Poznań University of Life Sciences were recruited to the study. 31 athletes, 21 ballet dancers, and 30 students completed the study.

One of inclusion criteria for the athletes was that they had taken part in national-level sport competitions during the last 12 months. The dancers were all ballet students and the students were dietetics students. All women with training volumes of over 10 hours per week and who had been training for more than three yearsin total were eligible. The exclusion criteria were a diagnosed nutritional disorder or pregnancy. Written informed consent was obtained from all participants and their parents. The study was approved by the Poznań Medical Ethics Committee (no. 334/09).

Body weight and body composition measurements
In order to evaluate nutritional status, anthropometrical indices of height and body weight (BW) were measured using an anthropometer coupled with a WPT 200 OC calibrated medical scale (Rad Wag). The body mass index (BMI, kg/m2) was calculated as the body weight divided by the square of the body height. Participants wore minimal clothing during measurements, which were rounded to the nearest 0.5 kg and 0.5 cm. Measurement of body fat mass (FM) and fat-free mass (FFM) was performed in the morning after an overnight fast, with the subjects lying in a supine position, using a Bodystat 1500 analyzer. All subjects had empty bladders at the time of measurements and had been instructed to abstain from caffeine and alcohol for 24 hours prior to the measurement, as well as to refrain from performing strenuous exercise on the day prior to measurement. The measurement was not performed during menstruation. Body composition measurement was conducted, taking into account individual and environmental factors [7]. The bioelectrical impedance method potentially raises some controversies. However, the DEXA method was not used, due to the young age of the study participants and the potential for adverse UV effects.

Nutritional habits
Seven consecutive days of dietary records were obtained under the supervision of dieticians. All meals (including recipes and item masses), nonmeal foods, beverages, and fluids were recorded in diary form with the assistance of a “Photographic Album of Dishes” [19]. Participants met regularly with a registered dietician to receive training in accurately recording their dietary intake and to review the completed energy and nutrient intake logs. The participants received written guidelines regarding proper measurement and reporting of food portions and preparation. Their daily diets were analyzed for energy and nutrient levels (fat, protein, and carbohydrate) using the Dietetyk software package based on Polish food composition tables [10].

Three-Factor Eating Questionnaire (TFEQ)
The Three-Factor Eating Questionnaire (TFEQ) was used to evaluate dietary restrictions [17]. The questionnaire contained 36 items in a true-or-false response format and 15 questions for which it was necessary to select one of the following descriptors: never, seldom, often, or always. All item responses were dichotomized and aggregated into three scales: cognitive restraint, with 21 items; hunger, with 14 items; and disinhibition, with 16 items.

The Food Frequency Questionnaire (FFQ)
We used the FFQ consumption frequency questionnaire for certain product groups and foods. These were combined into groups of products of similar energetic and nutritional values. Respondents participating in the survey were required to indicate what products they consumed and how often they had eaten them in the last month, selecting one of the following answers: A: 4–5 times a day; B: 2–3 times a day; C: once a day; D: 4–6 times a week; E: 2–3 times a week; F: once a week; G: 2–3 times a month; H: once a month; J: rarely or never.

The YHEI nutritional quality index
Based on data collected from the FFQ questionnaire, the Youth Healthy Eating Index (YHEI) was calculated, following the procedures outlined in the work of Feskanich et al. [4].The overall YHEI score ranges from 0 to 100 and is made up of 13 components, with up to 10 points contributed by each of components 1 to 7 and up to 5 points contributed by each of components 8 to 13. Intermediate scores are calculated to reflect the level of attainment toward the recommended goal.

STATISTICAL ANALYSIS
The means and standard deviations of the quantitative variables were calculated. The normality of the distribution was then checked. Comparisons between data were carried out using an independent t-test and Pearson's correlation. Statistical analysis was performed using Statistica 8.0 software (StatSoft, 2008). P-values of less than 0.05 were considered statistically significant.

RESULTS

Study subjects
Significant differences were observed between anthropometric parameters and body composition in the groups. There were significant differences in BW, BMI, and FM% between subjects, with BW being the lowest in the dancers; there were significant differences between dancers and athletes (p < 0.05). BMI was also lowest among the dancers. FM% was highest in the students and significant differences were observed between the students, dancers, and athletes (Tab. 1).

Dietary habits of subjects
The ballet dancers obtained the highest scores on the TFEQ and there were significant differences between the dancers and the students (p < 0.01). In the group of dancers, energy, fat, protein, and carbohydrateintake were the lowest, but sugar intake was lowest in the student group.A negative energy balance was observed in all groups, but was lowest in the dancers (Tab. 2).

The YHEI demonstrated the presence of errors in the diets of the study subjects. The ballet dancers had the lowest YHEI and significant differences were observed between the study groups. The students had the highest intake of foods of high nutritional value, including vegetables, fruits, wholegrain products, and the lowest intake of sweets, cereals, snacks, ready meals, sweet drinks, energy drinks, and isotonic drinks. The students also showed the highest consumption of water and the lowest of energy drinks (Tab. 3).

The correlation analysis shows that the higher the degree of nutritional limitation (as evaluated by the TFEQ), the lower was the power consumption, the more negative the energetic balance, and the lower the YHEI – which also correlated well with lower levels of body fat.

The energy values of the diets of the women also correlated positively with their intake of other nutrients, including protein, fat, and carbohydrates. At the same time, it has been shown that with the increase in energy intake, body mass and the nonfat mass were also higher (Tab. 4).

DISCUSSION

Despite reports suggesting that groups such as female athletes, female dancers,and femalestudents of nutrition and dietetics have an increased risk of developing eating disorders,very little work including these three seemingly very different population groups had been done. Astrength of the present work is thus that it describes research comparing the nutritional behavior and the nutritional and energetic values of the daily diets of three groups of young women: ballet dancers, athletes of various disciplines,and dietetics students. It was demonstrated that ballet dancers, when compared to athletes and dietetics students, more often chose questionnaire responses indicating improper eating habits. In the work of Castelo-Branco et al. [1], 87% of participating ballerinas indicated that they employed restrictive eating behaviors, primarily by reducing the number of meals, reducing energy consumption, and switching to a diet of low-fat products only. Herbrich et al. [6] stated that, among ballet dancers, as compared to the control group, there was a significantly higher risk of developing eating disorders. It has been demonstrated that the dancers, more so than other women, continually strive to achieve an even slimmer figure and show a high degree of dissatisfaction with their appearance. Furthermore, they tend to treat the everyday training involved in their occupation as an opportunity to improve their appearance. Also noted in this group were a significantly lower energy availability and a lower energy balance than in the control group. These observations are confirmed in this study because, in addition to displaying a higher degree of inappropriate eating behavior than the athletes and dietetics students, the ballerinas were characterized by the greatest negative energy balance. Moreover, the YHEI nutritional quality indicator for this group was also the lowest, indicating the incorrect composition of daily food rations among its members.

The nutritional behavior data from the athlete group also show many irregularities in the intake of the energy and nutrients. The results we obtained were similar those presented byDoyle-Lucas et al. [3], Hoch et al. [8], and Tomten et al. [20], who also indicated the presence of negative energy balances in a group of young women undergoing increased exercise. Furthermore, the nutritional value of daily diets, as in the findings of Hoogenboom et al. [9], Manore [11], Quah et al. [15], points to a deficiency in the supply of most vitamins and minerals. In the case of the  ballerinas, it seems to be clear that the shortage of energy and nutrients in the daily diet is caused by the desire to maintain a slim figure and a low body weight (as is also demonstrated by the results of the TFEQ questionnaire). Similarly, for the athletes, it also seems to be possible to suggest that errors in the daily diet result not only from deliberate reductions in food intake, but also from insufficient knowledge of the proper composition of a diet for people with increased physical activity [21]. The inadequate energy intake of athletes may also be due to the suppression of hunger resulting from increased training. These results were compared with those from the evaluation of the nutritional behavior of the dietetics students. It can be stated that better knowledge of the proper composition of daily rations, better knowledge of the ingredients of food, and better awareness of the risks that can arise from an improperly balanced diet all act to improve the quality of nutrition, as in the group of dietetics students, the YHEI was significantly higher than for the athletes and ballerinas. However, the more frequent consumption of foods of high nutritional value and the limitation of processed foods of low nutritional value did not translate into a direct increase in energy intake in this group, since the energy balance remained negative and the consumption of a variety of vitamins and mineral remained insufficient. Diets with similarly low energy values were seen in the study of Głodek et al. [5], where the eating habits of 200 students with knowledge of proper nutrition were investigated. The study of Charkiewicz et al. [2] on dietetics students showed diets with low energetic values (containing only 52% of the recommended level), improper balance of macronutrients, and deficiencies of fiber, essential fatty acids, and vegetable protein. The study of Mealha et al. [12] described the risk of developing an eating disorder in students of dietetics and nutrition by comparing the nutritional behavior, eating habits, nutritional status, and physical activity with those of students from other faculties.A high risk of developing eating disorders was not demonstrated, with such tendencies being observed in only 4.2% of respondents. In comparison, the control group of dietitians and nutritionists was characterized by healthier eating habits and increased physical activity. Silva et al. [16] conducted an evaluation of the relationship between changes in dietary behaviors associated with dissatisfaction with appearance and the nutritional status of female dietetics students. 21.7% of the women were at high risk of eating disorders and 13.7% reported dissatisfaction with their own bodies. Those dietetics students who were overweight and who had a higher proportion of body fat and a greater waist circumference more frequently showed discontent with their own appearance and had a higher risk of developing an eating disorder.

This study has several limitations. Firstly, body composition swere determined using the electrical bioimpedance method, which is potentially controversial. However, the DEXA method was not used due to the young age of study participants, the frequency of the tests, and the potential adverse UV effects. Secondly, questionnaire methods can always underestimate. Apart from this, due to the small group, the results of the present study cannot be generalized to the entire population; they can, however, be treated as a preliminary study and, taking into account the results, it seems reasonable to plan further research involving a larger group and also including a control group consisting of young women who practice physical activity for leisure.

CONCLUSION

On the basis of our results, it can be inferred that a higher level of knowledge regarding the impact of nutrition on health affects the composition of that daily diet. As a result of this, it is important that knowledge of a proper diet becomes more widespread among athletes and ballet dancers. Doyle-Lucas et al. [3] also demonstrated that the appropriate educational programs can translate into a significant improvement in eating habits and can help increase the intake of energy and nutrients in the population of young athletes who are particularly vulnerable to the development of the female athlete triad.However, unlike in the reports of other authors, the results of our research do not unequivocally state that students of dietetics have an increased risk of developing an eating disorder.

ACKNOWLEDGEMENTS

The project was financed by the Polish Ministry of Science and Higher Education under grant number N N312 239738.

REFERENCES

Accepted for print: 19.02.2016

Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed 'Discussions' and hyperlinked to the article.