Growth hormone and IGF-I plasma concentrations and macronutrient intake measured in a free-living elderly population during a one-year period

Objective: To determine seasonal variations in circulating concentrations of growth hormone and IGF-I in healthy, free-living elderly and to identify correlates between dietary intake, growth hormone and IGF-I concentrations in this population. Methods: Seven-day diet records and plasma samples were collected throughout a 1-year period. Plasma growth hormone and IGF-I were determined by RIA. Dietary macronutrient intake was determined using Nutritionist TV. Results: The dietary intake of the population corresponded to the established recommendations for percentage of fat, carbohydrate and protein. Carbohydrate intake differed significantly during the year, but protein and fat did not. Hormone concentrations were constant throughout the year, with no significant differences observed. No correlation between plasma growth hormone and IGF-I was observed. Growth hormone and IGF-I concentrations did not correlate with macronutrient intake, however subjects with the lowest energy intakes tended to have higher growth hormone and lower IGF-I than those with higher energy intakes. Conclusion: This study provides important information on the dietary intake and hormone concentrations in normal, healthy elderly which will be useful in comparison with persons of similar age with complicating illnesses or nutrient deficiencies.