Comparison of nutrient intake between dieters and non-dieters in students aged 12 through 19 years

Comparison of nutrient intake between dieters and non-dieters in students aged 12 through 19 years Ni Ketut Aryastami Center for Health Services Research and Health Technology National Institute of Health Research and Development Ministry of Health of the Republic of Indonesia (was a research fellow for the CIP Program in the Department of Community Medicine, West Virginia University) ABSTRACT Adolescence is a period when nutrient intake is of utmost importance. Not only is it a time of physical growth, but also a period when lifestyle behaviors are learned.the objective of this study was to compare nutrient intakes, physical activity levels and methods for weight control in adolescent dieters to non dieters.a cross-sectional survey was conducted in adolescents from thirteen high schools (n=1092) in West Virginia, USA. The average age of students (n=416 males, 676 females) was 15.35 years (sd=1.163, range of 14-20 years). A 40% of males and 32% of females were overweight or at-risk for overweight. More females (63%) reported dieting than males (31%). Dieters were more likely to be overweight or at-risk for overweight (55.8%) than non dieters (16%; p<0.01). Dieters had a significantly lower intake of nutrients compare to non-dieters except for the calories. Dieters were more likely to consume the recommended amounts of cholesterol, and calorie from fat, than the non dieters. Dieting behavior relatively impacted nutrient intakes. To facilitate weight loss, students need education about nutrient dense foods to ensure optimal growth. Keywords: Nutrients intake, dieting, students ABSTRAK Perbandingan asupan zat gizi dengan dan tanpa diet pada murid sekolah usia 12-19 tahun Usia remaja merupakan periode yang memerlukan asupan zat gizi yang sangat tinggi. Pada periode ini bukan saja merupakan masa pertumbuhan tetapi juga periode pembelajaran pola hidup. Studi ini bertujuan untuk membandingkan asupan zat gizi, tingkat kegiatan fisik dan metode dalam mengontrol berat badan pada remaja yang sengaja menjalankan diet dan tanpa diet. Rancangan potong silang (cross-sectional) digunakan pada remaja usia sekolah (n=1092) di West Virginia, Amerika Serikat. Usia rata-rata siswa sekolah (416 laki-laki dan 676 wanita) adalah 15,35 tahun (SD =1,16, interval 14-20 tahun). Sebanyak 40% remaja laki-laki dan 32% remaja wanita mengalami obesitas atau dalam resiko obesitas. Lebih banyak wanita (63%) menjalankan diet daripada laki-laki (31%). Remaja yang menjalankan diet cenderung memiliki berat badan lebih (obesitas) atau berisiko kegemukan (55,8%) dibandingkan dengan mereka tanpa diet (16%; p<0,01). Remaja yang berdiet secara signifikan memiliki asupan zat gizi yang lebih rendah dibandingkan dengan mereka yang tidak berdiet, kecuali untuk kalori. Remaja yang melakukan diet cenderung memiliki tingkat konsumsi yang sesuai dengan rekomendasi untuk kolesterol dan kalori yang berasal dari lemak dibandingkan dengan mereka tanpa diet. Perilaku diet pada remaja secara relatif mempengaruhi asupan zat gizi. Kata kunci: Asupan, zat gizi, diet, murid sekolah 51

Aryastami Comparison of nutrient intake INTRODUCTION The prevalence of overweight in youth is increasing at alarming rates. The inclination from 1663 to 1980 was 5 to 6%. In the years 1999-2000, 15% of 12-19 year olds were overweight, (1) a 30% increase. The Youth Risk Behavior Surveillance System for West Virginia, USA showed, on average, 35% of the adolescence describe themselves as slightly or very overweight. Of those subjects, 65% of the females and 30% of males reported trying to lose weight. (2) Regardless of how they look to others, adolescents are seldom satisfied with their appearance. As might be expected, girls often view their weight and body shape with disfavor, but boys also visualize enviable masculine physiques that often do not coincide with their own. These disparities between the perceived and the desired often leads to inappropriate eating behavior. Adolescents may be dieting even when they are not overweight. (3) Body weight based on selfperceived weight status in adolescents is poorly correlated with their actual weight. Significantly more girls (52%) than boys (25%) who considered themselves overweight, were in fact normal weight. (4) Even adolescents who are not dieting are at-risk for poor nutrient intakes. Adolescence is a period when nutrient intake is of utmost importance. Not only is it a time of physical growth, but also a period when lifestyle behaviors are learned. During this period, there are changes and increasing demand for nutrients related to physical growth and development; changing life-style and food habits as well as special nutrient needs associated with participation in sports, pregnancy, development of eating disorder, excessive dieting, use of alcohol and drugs, or other situation common to adolescents. Unfortunately, it is also the period, where despite an increased need, it has been demonstrated that intake is poor and high in foods with poor nutrient density. (5) There are barriers for adolescence when it comes to healthy eating. On the Minnesota Adolescence Health Survey (MAHS) in 1986-1987, a high prevalence rate for inadequate intakes of certain food groups such as fruits, vegetables and dairy products and overweight was found, particularly among ethnic subgroups of the population. In addition, dieting and disorder eating behaviors were prevalent among the female adolescents. (6) Data for the current study were taken from the West Virginia Eating and Activity Teen Survey (WVEATS) in 2003, an epidemiological study of diet and physical activity levels in adolescent. The purpose of this study was to compare nutrient intakes, physical activity levels, and methods for weight control in adolescent between dieters to non-dieters. It hypothesized that students who are dieting are more likely to have inadequate dietary intakes. In addition, the study will attempt to determine difference in body mass index, body weight status, sport participation as well as the weight control practice between the dieters and non-dieters. METHODS Study design A cross-sectional design was conducted using sample of students in West Virginia, USA. Subjects Students range of aged 12 through 19 years recruitment was communities dependent. 52

High schools were randomly selected based on student enrollment in schools, i.e., A (N=3), AA (N=4), and AAA (N=6). In most cases an entire class was invited to participate. Classes were health science, biology, anatomy, health care management, anatomy, sports medicine, physical education, family consumer sciences, and business. Only one school had voluntary participation during the independent research periods. Active consent was decided by the school, and obtained accordingly. Active consent involved parental signatures on consent forms. Procedure Questionnaire was given to the student to complete and a dietary interview was scheduled. Question in the survey referred to the students perception of their weight, food frequencies and physical activity. Height and body weight were measured using the National Health and Nutrition Examination Survey (NHANES) method. (7) BMI was calculated as weight (kg) divided by height (m 2 ). This was plotted on age and gender specific growth charts. Classifications for students were: overweight as BMI >=95 th percentile, at risk of overweight as BMI >=85 th to 95 th percentile, normal weight as BMI between the 5 th and 84 th percentile, and underweight as BMI <5 th percentile. Dieters were defined as the number of students trying to lose weight. The computerized 24-hour recalls were conducted by trained nutritionists using the University of Minnesota Nutrition Data System software version 4.05-33, released in 2002. A multiple pass method is use to help subjects with memory retrieval. In the first pass, subjects are asked to list all foods and drinks consumed without providing any detail. After a subject listed all consumed items, the interviewer queried for details on the foods reported (portions, brand, names, recipes, etc.) as well as for any additional foods that may have not been recalled in the first pass. In the last pass, the interviewer reads the detailed intake back to the respondent and inquires if anything else was added or anything else consumed. To determine portions, respondents used the Food Portion visual poster, the portion photos of popular foods, (7) and actual measuring tools (standardized measuring cups, spoons, and drinking glasses). Nutrients assessed included energy (kcal), total fat (percentage of total energy), carbohydrate (percentage of total energy), protein (percentage of total energy), cholesterol, saturated fat (percentage of total energy), total dietary fiber (g), vitamin D (mcg), vitamin E (mg), vitamin C (mg), vitamin B6 (mg), vitamin B12 (mcg), calcium (mg), iron (mg), zinc (mg), sodium (mg), vitamin A (mcg), folate (mcg). The estimated average requirement (EAR) was used to compare the nutrient intake and requirements. A nutrient intake estimated to meet the requirement for a specified indicator of adequacy of half the health individuals in a particular life stage and gender group. EAR represents an estimated median requirement that is exceeding the requirements of half the group, and falls below the requirements of the other half. (8) Statistical analysis The data was analyzed using SPSS version 11. Chi-square test was done to assess the proportion of males and females meeting the Dietary Reference Intake based on the EAR. Independent t-tests were done to test mean difference in nutrient intake between dieters and non-dieters. 53

Aryastami Comparison of nutrient intake Table 1. Characteristics of subjects RESULTS A total of 1092 students (416 males and 676 females) participated in the study. Of these, 1035 had completed the 24 hour-recall. Approximately half of the population reported dieting. Significantly more females (n=422, 63%) than males (n=130, 31%) reported dieting. The average means age of the participants was 15.35 years (SD=1.16, range 14-20). More than half of participants were among 14-15 years age group (males=66.6%; females=68.0%). There was no significant difference between the percentage of males and females and their respective ages. Most of the students (n=652, 59.7%) had a normal weight (5-84.9 percentile of the BMI). However, the percentage of overweight and at-risk to overweight comprised one third of the study population (n=372, 35.9%). (Table 1) Table 2 showed, that there was significant different in dieting over body weight status (p=0.00). Among the dieters, 55.8% (n=290) were overweight and at-risk to overweight as compared to 15.9% (n=82) of the non-dieters. There was no significance difference in sport participation between the dieters and nondieters. Percentage of dieters who participated in sports was 62% and 64.9% of the non dieters. There was a significantly greater proportion of dieters reported exercising (n=488, 88.4%, p<0.01), eating less food (n=363, 65.9%, p<0.01), and fasting to control weight (n=97, 17.6%, p<0.01). There was no significance difference of physical activities (PA) namely vigorous PA (exercise for three or more days per week for 20 minutes per occasion without breathing hard) and moderate PA (exercise at least 30 minutes on five or more of the previous seven days) between dieters and non dieters. The macronutrient content of the adolescent s diet 54

Table 2. Characteristics of adolescent dieters and non dieters showed that males consumed higher calorie levels and all macronutrients when compared to females. Non-dieters consumed in between males and the total population levels. (Table 3) To compare the intake of nutrients and the nutrient requirements, the dietary Reference Intake (DR1) of estimated average requirement (EAR), adequate intake (AI) and the recommended dietary allowance (RDA) between males and females were combined. The adolescent intake of 24 hours recall to the NHANES dietary intake in order to get the depict picture of day to day variation of our students was adjusted. Fourteen types of nutrients including macro and micro nutrients which most related to the students growth and requirements were selected. Especially for the macro nutrients, the analysis was based on the percentage of recommended dietary allowance (RDA). Females consumed significantly less intake than males in all selected nutrients i.e. cholesterol, vitamin A, vitamin E, vitamin C, vitamin B6, vitamin B12, folate, calcium, iron, and zinc, except calories from carbohydrates (Table 4). Table 3. Median and standard deviation of macro intakes in adolescents Note: Using Mann-Whitney test, all were significantly different at p<0.001 55

Aryastami Comparison of nutrient intake Table 4. Adjusted Median intake of nutrients compare to the Dietary Reference Intake (DRI) between males, females and dieters and non dieters * Estimated Average Requirement; Based on the Recommended Dietary Allow as no reference for EAR available; Significance determined by Mann-Whitney 12-19 years of age (9) ; ** Students 14-18 years of age (10-12) The number in brackets refers to the number of references Comparing to the DRI, the West Virginia s adolescences have significantly higher consumption in vitamin A, vitamin B6, vitamin B12, folatc, iron and zinc (p<0.01). However, intakes of vitamin E and calcium were lower than RDI. Note, the percent calorie from saturated fat with the DRI could not be compared as there were no references to it. The macro nutrient intake, such as percent calorie from fat and percent calorie from protein of both males and females, was slightly skewed. Dieters have significantly lower intakes of nutrients compare to non-dieters, except for the calories. Both groups have especially lower intakes of vitamin E and calcium compared to DRI. On the other hand, they had higher intakes of dietary folate and iron. The calorie intakes were not significantly different for both groups. Hence, the calories from carbohydrates has almost the same median compared to the DRI. Table 5 showed, there was a strong different of nutrient intakes towards gender and dieting status (p<0.01). In general, females have significantly higher percentage of not meeting EAR than males, especially for vitamin A, vitamin E, vitamin C, vitamin B6, vitamin B12, folate, calcium, iron, zinc and calorie from carbohydrate and protein. On the other hand, males have also higher percentage in not meeting the EAR for cholesterol and 56

Table 5. Proportion (%) of adolescences not meeting the dietary recommended intake calorie from fat. When comparing males and females, only the calorie intakes (from fat and carbohydrate) were not significantly different. The intakes of vitamin E and calcium were very critical for both groups especially for females. Vitamin C and folate were much less consumed by females as can be seen that 51.4% of females compared to 3.7% of males had not met their vitamin C requirement. Furthermore, 42.7% of females compared to 9.0% of males had not met their folate intakes. There was significant difference in proportion of nutrients intake between dieters and non dieters (p<0.01). Dieters met more dietary requirements for cholesterol (84.1%), calorie from fat (62.2%), and calorie from protein (81.7%). On the other hand, they met less requirements for vitamin A, vitamin E, vitamin C, vitamin B6, vitamin B12, folate, calcium, iron, zinc, and calorie from carbohydrate. There was no significant difference of protein intakes between dieters and non dieters. Proportion of intakes of vitamin E and calcium were the most unmet need for both dieters and non dieters. The intakes of macro nutrients especially fat and carbohydrate were significantly different in meeting the requirement between males and females. Only 46.1% of the dieters met the requirement of saturated fat, compared to 35.2% of the nondieters. DISCUSSION In general, the prevalence of overweight and at-risk of overweight among the West Virginia adolescent were slightly higher than YRBSS 1999 for West Virginia and the overall USA (34.1; 34.7; 30.0). (13) In total, the prevalence of overweight and at-risk of overweight in the study was 35.9% which is almost comparable to the YRBSS (34.7%). More males than females are overweight and at-risk of overweight (40.8% compare to 57

Aryastami Comparison of nutrient intake 32.8%), which was consistence with the prevalence reported by the West Virginia Department of Health and Human Sciences (males = 32.3%; females = 23.7%). Unfortunately, this prevalence seems to be higher as compared to the overall United States (males = 29.4%; females = 22.3%). (14) More than half of the students were dieting and one third of them belong to the 14-15 years age group. This study found 31% of males and 62.5% of females were reported trying to lose weight which was comparable to the YRBSS (30.1% of males; 65% of females). Hence, this study found 44.2 % of the dieters were among those who have a normal weight, in addition, 28.4% of the students perceived themselves overweight, in fact normal weight which was also reported by other study. (4) Thus, overestimating would bring about risky behavior that consequently would affect students health status in the long run. Reduction of body weight involves loss of protein, fat and other nutrients. Steady weight loss over a longer period favors reduction of fat stores and limits the loss of vital protein tissue. The most behavioral concern in the dieting adolescent was exercising almost two times higher than the non dieters; eating less food (almost five times higher in dieters) and fasting (almost six time higher in dieters). The relationship between physical activity and dietary behaviors may have important implications for physical development, thus, may affect the incidence of chronic diseases in the long run. The contribution of these two evidences would significantly influence the cost for health. Sport participation, physical activities and sedentary activities were significantly different between dieters and non-dieters. It was assumed that more dieters participate sport activities and spend less time watching at television in terms of being more active than the non-dieters. They may better understand the value of sport participation to keep healthy or reduce weight, or otherwise, dieting is done just because of the body images motive. (3,6) Furthermore, dietary intake was significantly associated with most sedentary behaviors. (14) Females consumed significantly less nutrient intake, especially vitamins and some minerals. This is unlikely happening with the macro nutrients both for males and females as well as dieters and non dieters. The comparison of median intake between males and females of some nutrients appeared quite interesting. Unlike the other vitamins, the intake of vitamin E was hardly being met by our students. More than eighty percent of the females and or dieting students did not meet their requirements, and there were significant differences between males and females. The main sources of vitamin E are the plantation products and oils such as wheat germ oil, sunflower oil, almonds, corn oil, soybean oil, mayonnaise and margarine. When analyzing adolescents food consumption, significance difference existed between those consuming total grains and vegetables without fried foods to vitamin E. The latter has a fundamental role in the normal metabolism of all cells. Therefore, its deficiency can affect several different organ systems related to the adolescences growth and development. There was significant difference in vitamin C intake between males and females as well as dieters and non-dieters. Male students consumed higher quantities of vitamin C as compared to the EAR. Unfortunately, only half of the female population met the requirements. Furthermore, more dieters had not met the vitamin C requirement. Vitamin C is a water 58

soluble vitamin that mainly comes from fruits, vegetables and organ meats. It functions as a protective agent and anti oxidant (reacts with free radicals), as well as promoting resistance to infection through the immunologic activity. The low percentage of vitamin C intake among women may relate to the eating behavior especially those who are dieting. In fact, a significant difference was found in the consumption of fruits and vegetables among dieters. The findings on intakes of vitamins B6, vitamin B12, iron and dietary folate were quite surprising. Most of those nutrient requirements were met by more than seventy percent of the students, except for females. It was assumed these intakes might come from the protein source of food, as it can be seen that percentage of calorie intake from protein met more than 80% of their requirement. In fact, fortifications are closely related to American processed food. Calcium intakes, on the other hand, seemed to meet a very low level of the requirements. Male students met 50% of the requirements, indeed females and the dieters met the requirements of a very low level. Further analysis for milk consumed showed a significant difference (p<0.01) between dieters and non-dieters in their consumption. Calcium is mainly found in milk and dairy products, soybeans as well as sea food. There was a reluctance to discuss about fish consumption in as much as this type of food is not common in West Virginia. However, there was more concerned for the dairy consumption such as milk, yoghurt, ice cream, etc. Soft drink consumption appeared to contribute to low intake of calcium, magnesium, riboflavin, vitamin A and vitamin C among teenagers. Low calcium intake and the resulting effect on bone health are a particularly critical issue for adolescent females. (15) Students incorporate twice the amount of calcium, iron, zinc, and magnesium into their bodies during the years of their growth spurt than at other times. This study revealed that only 19.6% of the dieters met their requirement for calcium. Although the statistics test showed a highly significant different of calcium intake, the non dieters have also a lacking consumption of calcium. Calcium intake tends to decline at 0-17 years of age. This analysis suggest that a significant effort has to be done to inform or educate the importance of calcium during the adolescent period. Iron has been recognized as an essential nutrient for more than a century. Nutritional iron deficiency and iron deficiency anemia are the greatest nutrition problems worldwide. Students, both male and female, have high requirements for iron. In the male adolescent, iron is needed for the build-up of muscle mass which is accompanied by greater blood volume, while in females students, iron is needed to maintain the iron lost during the menstruation periods. The most common nutritional anemia in the United States results from iron or folic acid deficiency. (16) Although the iron deficiency in this study may not yet result in anemia, it is suspected that it could slightly reduce the productivity of the adolescence either in their Grade Point Average or their daily activities. There was a significant difference of median intake of iron between dieters and non dieters. The dieters consumed less iron than the non-dieting, and both groups have failed to meet their requirement. Macro nutrients such as carbohydrate, fat and protein were adequately consumed by dieters as well as non dieters. In addition, there 59

Aryastami Comparison of nutrient intake was no significant difference for proportion of meeting the dietary reference intake for percent calorie from protein. Nonetheless, the significant difference for percent calorie from fat and carbohydrate was significant. More non-dieters met these requirements. The unmet requirement for calories from fat depicted higher than the calories from carbohydrate. In other words, the dieters met their calorie requirement more from carbohydrates than from fat. It was perceived that the dieters ate more zero calories than the natural food in their consumption. Otherwise, their dieting behavior would properly fulfill their diet requirements. CONCLUSIONS There was a strong relationship of nutrient intake toward gender and dieting status. Dieters had significantly lower intake of nutrients compared to non-dieters except for the calories. Both dieters and non-dieters had especially lower intake of vitamin E and calcium compared to DRI. Dieters met more dietary requirements for cholesterol, calorie from fat, and calorie from protein than the non dieters. Proportion of intakes of vitamin E and calcium were the most unmet need for both dieters and non dieters. Education on health and nutrition is recommended to facilitate weight control practices and to ensure optimal growth. ACKNOWLEDGEMENT Thanks to Dr. Debra Krummel, associate professor, Department of Community Medicine West Virginia University for her kindness and permission to use the WV-EATS data set for this analysis. My thanks also to Ms. Beth Semmens, college at the Center for Nutrition, Department of Community Medicine West Virginia University for her cooperation in preparing and cleaning the WV- EATS data set. Finally, thanks to the WV-CIP for the opportunity given in the International for the Young Professional Exchange Program. References 1. Center of disease control. Prevalence of overweight among children and adolescents: United States, 1999-2000. Reviewed September 23, 2003. Available at: http: //www.cdc.sov/ nchsiproducts puhspuhdhestats overwght99.htm. Accessed September 25, 2003. 2. National center for chronic disease prevention and health promotion. Adolescent and school health. Youth risk behavior surveillance system. 1999. West Virginia Dietary Behaviors. Available at: http//apps.nccd.cdc.gov/yrbss/ Graph V.asp. Accesssed September 30, 2003. 3. Emmons L. Predisposing factors differentiating adolescent dieters and non dieters. J Am Diet Assoc 1994; 94: 729-30. 4. Strauss, RS. Self-reported weight status and dieting in a cross-sectional sample of young adolescents. Arch Pediatr Adolesc Med 1999; 153: 741-7. 5. Cusatis DC, Shannon BM. Influences on adolescent eating behavior. J Adolescent Health 1996; 18: 27-34. 6. Neumark-Sztainer D, Story M, Resnick MD, Bloem RW. Lesson learned about adolescent nutrition from the minnesota adolescent health survey. J Am Diet Assoc 1998; 12: 1449-56. 7. Abbot, HM. Portion photos of popular foods. The American dietetics association and center for nutrition consulting enterprises. Morgan/ Posner; 1997. 8. Barr SI, Suzanne PM, Mary IP. Interpreting and using the dietary references intakes in dietary assessment of individuals and groups. J Am Diet Assoc 2002; 102: 780-8. 60

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