Nutrient intake of community dwelling adolescents with anorexia

Nutrition Research Newsletter, Nov, 2006

Eating disorders are the third most common chronic illness in adolescent girls. Anorexia nervosa (AN) occurs in 0.7% to 1.3% of female adolescents, and 50% of 5th to 12th grade adolescents report dieting in an effort to improve their appearance. There are many medical consequences of AN including cardiac arrhythmias, electrolyte imbalances, vitamin and mineral deficiencies, osteoporosis, and hormonal changes.

Few studies have examined nutrient intakes, particularly micronutrient intakes, in adolescent girls with AN. There is even less data regarding nutrient intakes in community-dwelling girls with AN being followed by caregivers as outpatients. A recent investigation aimed to describe patterns of macronutrient and micronutrient intakes in community-dwelling girls with AN. Given the high incidence of low bone density in AN, intakes of vitamins and minerals that relate to bone health were investigated.

Seventy-eight adolescent girls were enrolled in the study (39 meeting DSM-IV criteria for AN and 39 healthy adolescents). The mean chronologic age of the girls with AN was 15.9 [ or -] 0.3 yrs and of the healthy adolescents was 15.0 [ or -] 0.3 yrs. Subjects were assessed during an outpatient visit. Height and weight were measured and BMI was calculated. Bone age was determined. Following an overnight fast, blood samples were obtained for the measurement of adiponectin, leptin, ghrelin, insulin, and insulin-like growth factor I (IGF-I) concentrations. Resting energy expenditure (REE) was determined by indirect calorimetry. Estimated REE was also determined by using the Harris-Benedict equation, the modified Harris-Benedict equation for AN, and World Health Organization recommendations. Finally, researchers used an equation incorporating weight, height, age, and physical activity to calculate estimated energy expenditure. A modifiable activity questionnaire was administered to determine activity level. All participants were instructed by a registered dietitian on the completion of a 4-day food record of three weekdays and one weekend day. Body composition was determined with whole-body dual-energy X-ray absorptiometry.

In contrast with the control group, the AN group consumed fewer calories from fats and more from carbohydrates and proteins. Intake of individual fat components was lower and of dietary fiber higher in the AN group. No significant between-group differences were observed in dietary intakes of calcium, zinc, and iron; however, total intake was greater in the AN group because of greater supplement use. The AN group had greater intakes of vitamins A, D, and K and of most of the B vitamins, and significantly more girls with AN met the DRI for calcium and vitamin D from supplement use. Fat intake predicted ghrelin, insulin, and IGF-I concentrations; carbohydrate intake predicted adiponectin. REE was lower and leisure activity levels higher in the AN group.

Despite ongoing outpatient care, community-dwelling adolescents with AN continue to have lower fat and higher fiber intakes than do healthy adolescents, resulting in lower caloric intake.

M. Misra, P. Tsai, E. Anderson, et al. Nutrient Intake in Community-Dwelling Adolescent Girls with Anorexia Nervosa and in Healthy Adolescents. Am J Clin Nutr; 84:698-706 (October, 2006). [Correspondence: M Misra, BUL 457, Neuroendocrine Unit, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114. E-mail: mmisra@partners.org.]