Calcium intake and its relationship with adiposity and insulin resistance in post-pubertal adolescents.
BACKGROUND
Dietary calcium intake has been described as being a negative contributor to adiposity. In adolescents, this relationship is not well established. The objectives of the present study were to compare the calcium intake of normal-weight and obese adolescents and to evaluate its relationship with adiposity and insulin resistance.


METHODS
A cross-sectional analysis of 96 post-pubertal adolescents; 47 normal weight and 49 obese, mean age 16.6 (SD +/- 1.3) years. Body composition was assessed by dual-energy X-ray absorptiometry. Dietary intake was evaluated using a 3-day dietary record. The biochemical evaluation comprised the measurements of serum lipids, lipoproteins, glucose and insulin. Insulin resistance was calculated using the Homeostasis Model Assessment of Insulin resistance (HOMA-IR).


RESULTS
The mean calcium intake, adjusted for energy, was lower in obese adolescents, 585.2 (+/-249.9) mg, than in normal weight adolescents, 692.1 (+/-199.5) mg. Only 4% of adolescents had an adequate intake of calcium. Calcium intake was inversely associated with body trunk fat, insulin and HOMA-IR in the obese group. The quartile analysis of calcium intake provided evidence that girls in the highest quartile had decreased adiposity and insulin resistance.


CONCLUSIONS
This study showed a negative relationship between calcium intake and body fat and insulin resistance, mainly in obese girls, and demonstrates the importance of an increased dietary calcium intake.
dos Santos
L C
LC
Nutrition Department, School of Public Health, São Paulo University, São Paulo, Brazil.
de Pádua Cintra
I
I
Fisberg
M
M
Martini
L A
LA
D015502:Absorptiometry, Photon / Q000379:methods; D050154:Adiposity / Q000187:drug effects*; D000293:Adolescent; D017195:Adolescent Nutritional Physiological Phenomena; D001823:Body Composition / Q000187:drug effects; D015992:Body Mass Index; D050071:Bone Density Conservation Agents / Q000008:administration & dosage; D002136:Calcium, Dietary / Q000008:administration & dosage*; D003430:Cross-Sectional Studies; D015930:Diet Records; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D009751:Nutritional Requirements; D009765:Obesity / Q000378:metabolism*; D013851:Thinness / Q000378:metabolism*
D050071:Bone Density Conservation Agents; D002136:Calcium, Dietary