Energy and macronutrient intake in growth hormone-deficient adults: the effect of growth hormone replacement

Objective: To assess the energy intake and the macronutrient composition of the diet in 25 growth hormone-deficient (GHD) patients before, and after 3 and 6 months replacement with recombinant human growth hormone (rhGH). Design: The study had a randomised double-blind placebo-controlled design. Energy intake was assessed by the 4-day food record and 24-h urine total nitrogen excretion was used as a check on the validity. The energy and macronutrient intake of the GHD patients at baseline were compared with the data obtained in the Dutch Nutritional Survey. Fat-free mass (FFM) and body fat (BF) were assessed by bioelectrical impedance analysis (BIA). Plasma thyroid hormones and insulin-like growth factor-I (IGF-I) were studied in relation to energy and macronutrient intake. Setting: Department of Endocrinology, University Hospital Utrecht, Utrecht. The Netherlands. Subjects: 25 GHD patients, aged 21-60 years. Results: GHD adults, compared to controls, have a lower energy intake. During the first 3 months of rhGH replacement therapy, there is a trend for energy intake to increase, no change in macronutrient intake, whereas plasma T3, IGF-I and FFM increase and body weight does not change, hence BF decreases. The positive relationship between the increase in energy intake and the rise in plasma total T3 level during rhGH replacement therapy indicates that in addition to the GH-induced changes the increase in energy intake and specifically in carbohydrate intake might contribute to the enhanced conversion of thyroxine. Protein intake calculated from the 4-day food record was significantly correlated with protein intake calculated from 24-h urine nitrogen. Conclusion: GHD patients have a lower energy intake. Notwithstanding the fact that FFM and plasma T3 increase and body weight does not change, a significant increase in energy intake is not found with the use of the 4-day food record method.