Inadequate Micronutrient Intakes: Exploring the Vitamin and Mineral Intakes and Food Sources of New Zealand Aged-Care Residents

Abstract

Introduction: Dependent older adults in residential aged care are at increased risk of inadequate micronutrient intakes. Knowledge of dietary intakes in this group is needed to inform clinical decision making and guide nutrition policy and menu planning. This study aimed to determine the usual intake and food sources of micronutrients of New Zealand aged-care residents.

Methods: A cross-sectional survey of nutrition and health was conducted in 16 residential aged-care homes across New Zealand. Dietary intake data were extracted from a single 3-day weighed food record. Vitamin and mineral intakes were adjusted for intra-individual variation and the Estimated Average Requirement (EAR) cut-point used to establish the prevalence of inadequate intakes. Individual foods were categorised according to the broad food-grouping classification that was used in the 2008/09 New Zealand Adult Nutrition Survey. The contribution of these food groupings to vitamin and mineral intake was also examined.

Results: Data were available for 309 residents who had a mean (SD) age of 85.1 (7.6) years. Two-thirds (67.6%) of participants were women, and the majority were of European ethnicity (97.7%). Median usual intakes of multiple minerals (calcium, selenium, magnesium, and zinc (males only)) and B-6 were below the EAR. More than 80% of participants had inadequate calcium, selenium, magnesium, and vitamin B-6- intakes, while thiamine and folate intakes were also inadequate for between 30% and 50% of participants. Inadequate zinc intakes and intakes of vitamin E below the Adequate Intake were more prevalent in males than females (89% vs. 46% and 94% vs. 62% respectively). Plant- and animal-based food groupings were important sources of many nutrients. Milk, red meat, and fish & seafood were important sources of minerals. Three-quarters of participants consumed breakfast cereals which were ranked amongst the five richest food sources of B-vitamins. Despite being consumed by less than 10% of residents, oral nutritional supplements was ranked amongst the top three sources for all six minerals and nine vitamins studied. Similarly, the other meats grouping was ranked amongst the top 10 food group sources of B vitamins, vitamin A, iron, zinc, selenium and copper despite being consumed by few (< 6%) of participants.

Conclusions: Older residents had a high prevalence of inadequate usual intakes of multiple micronutrients. Both animal and plant-based food groups were important sources of vitamins and minerals, and further work is needed to develop practical policies and methods of ensuring nutritional adequacy in this setting.

Keywords: dietary intake; food groups; older adults; residential aged‐care; vitamins and minerals.

Figure 1

Proportion of participants with inadequate mineral (A), vitamin (B) and combined mineral and vitamin intakes (C).