Abstract
Background: Life expectancy is improving and birth rates slowing, causing an increase in the population over 65 years of age. As a result of different lifetime exposures to risk factors causing disease manifestations, and medication use, this age group is a very heterozygous age group. Adequate nutrition is essential for good health at all ages and plays a role in the prevention and treatment of non-communicable diseases associated with ageing. Total energy intake declines, the prevalence of nutritional inadequacies increases, and diet quality may decline with age. The inclusion of nutrient dense foods in the diet is currently recommended, but there is no standard definition of nutrient density, or index by which to assess the nutrient density of single foods or whole diets. Therefore examination of the nutrient density of the older New Zealand population is essential to determine the quality of food choices and overall diets.
Objective: The three objectives of this study were: 1) to examine nutrient density scores of the diets of older New Zealanders 71 years and over (≥ 71 years) in comparison to other age categories 2) To examine the relationships between nutrient density scores and demographic variables for older New Zealanders 3) To discuss the implications of these results in relation to current recommendations for older New Zealanders.
Design: We analysed nationally representative, cross-sectional data from the 2008/09 Adult Nutrition Survey (ANS). Nutrient density scores were calculated for all ANS participants. Mean comparison tests were performed across the 5 age categories to identify differences in nutrient density. Linear regression was performed to determine whether demographic variables were related to nutrient density scores. Results for each nutrient were interpreted alongside Estimated Average Requirement (EAR) and percentage of inadequate intakes to formulate food based recommendations suitable for older New Zealanders.
Results: Mean zinc nutrient density scores were significantly higher for age category 5 (≥ 71 years) than age category 1 (15-18 years). Mean calcium, selenium and vitamin B6 nutrient density scores were all significantly higher for age category 5 than age categories 1 and 2 (19-30 years). Mean vitamin A nutrient density scores were higher for age category 5 than age categories 1, 2 and 3 (31-50 years). Both mean thiamin and riboflavin nutrient density scores were significantly higher in age category 5 than all other age categories. Vitamin B12 nutrient density was similar across all age categories. No demographic variable was related to all eight nutrient density scores, but some relationships between demographic variables and nutrient density scores were found.
Conclusion: Diet quality of older New Zealanders is as good if not better than younger New Zealanders. Therefore, older adults make good food choices but do not eat adequate total energy to maintain nutritional status. Consequently, recommendations for the careful selection of foods to be consumed from each food group have been suggested to maximise the nutrient density of older New Zealanders diets and address the high prevalence of nutritional inadequacies.