Responses to nutrition interventions aimed at increasing food intake in seniors with Alzheimer's disease and their associations with body mass index, cognitive impairment, and behavioural difficulties

Unintentional weight loss is commonly observed in seniors with probable Alzheimer's disease (AD) and is increasingly likely to occur with disease progression. My previous work demonstrated that a decline in food intake likely contributes. Despite this recognition, increasing food intake remains a challenge, partly because the design of nutrition interventions have not, to date, taken into account the progressive alterations in food intake patterns that occur with AD. The objectives of this thesis were to examine nutrition interventions aimed at increasing intake, whose designs were based on changes in food consumption patterns that occur with increasing behavioural difficulties in this population. These were achieved by conducting a randomized, cross-over, non-blinded clinical trial of two nutrition interventions: (1) encouraging the consumption of a nutrition supplement between breakfast and lunch; and (2) providing foods traditionally served at breakfast for dinner, to residents of a nursing home with probable AD. Further, the associations between the responses to the interventions and body mass index (BMI), cognitive and behavioural difficulties were examined. Overall, 24-hour energy intake increased significantly with both interventions, compared to habitual intakes. Although most individuals had enhanced intakes with, at minimum, one intervention, those with higher BMIs tended to increase intakes to a greater degree relative to those with lower BMIs for both interventions. Less cognitive impairment and less behavioural problems predicted a greater increase in energy intake from the supplement intervention relative to those with more cognitive and behavioural problems. Cognitive and behavioural status were also associated with the response to the breakfast foods for dinner intervention, but in the opposite direction. These results suggest although seniors with AD residing in a nursing home with low BMIs had proportionately smaller increases in intake relative to those with higher BMIs, the cognitive and behavioural profile of the individual may be used to predict the intervention most probable to result in enhanced intake. The longer-term implications of this research are to increase food intake and prevent weight loss in seniors with AD by implementing nutrition interventions that are most likely to enhance consumption, based upon the characteristics of the individual.