Aline Lopes Bueno

The importance for growth of dietary intake of calcium and vitamin D

OBJECTIVE To investigate the role of dietary calcium and vitamin D in the process of growth and development of children and adolescents, focusing in particular on the prevention and treatment of delayed growth caused by nutritional deficiency. SOURCES Information was gathered from articles published in the last 2 decades, from searches on the databases SciELO, PubMed and Medline, technical books and publications of international organizations. SUMMARY OF THE FINDINGS Growth is influenced by intrinsic (genetic and metabolic) and extrinsic factors (environmental factors such as diet, health, hygiene, housing and access to health services). Among the nutritional factors are vitamin and oligoelement deficiencies which may be associated with malnutrition or caused by insufficient absorption. Since calcium is one of the main mineral components of bone tissue, it is essential for adequate bone formation and, considering that vitamin D plays an important role in calcium metabolism, a diet with insufficient quantities of these nutrients can impact on the formation of the skeleton and on the process of growth and development. CONCLUSIONS In children and adolescents, low intake or low absorption of calcium and vitamin D may limit their statural growth, and it is necessary to supply sufficient quantities of both during the critical growth phases.

Calcium and vitamin D intake and biochemical tests in short-stature children and adolescents

Background:Growth is highly dependent on the absorption of nutrients. Inadequate calcium and vitamin D intake may compromise bone mineralization and growth. There is a great deal of concern regarding calcium and vitamin D intake, as well as biochemical changes in children and adolescents, which led us to investigate calcium and vitamin D levels during growth.Methods:Fifty-eight children and adolescents with short stature (z-score <3 s.d.) were evaluated from September 2005 to February 2007. Blood biochemical analyses and 24-h urine tests were performed and were used to evaluate calcium, phosphorus, creatinine, sodium, alkaline phosphatase, parathyroid hormone (PTH) and 25(OH)D levels. Dietary inquiries, repeated three times, were used to estimate the actual intake of these substances.Results:A reduced calcium (608.6 mg/day) and vitamin D (72.5 IU/day) intake was observed. Calcium excretion in 24-h urine (56 mg/24 h) and calcium excretion by weight (2.0 mg/24 h/kg) showed scores that were below normal. A negative correlation between PTH and both dietary vitamin D (r=−0.46; P<0.01) and calcium intake (r =−0.41; P<0.001) was observed.Conclusions:The low calcium and vitamin D intake observed in short-stature children and adolescents was associated with biochemical results, and suggested that PTH and calcium excretion may be useful screening tests for evaluating dietary calcium and vitamin D.