Providing Nutrition Supplements to Institutionalized Seniors
Objectives: To examine whether providing a midmorning nutrition supplement increases habitual energy intake in seniors with probable Alzheimer's disease (AD) and to investigate the effects of body weight status and cognitive and behavioral function on the response to the intervention.
Design: Randomized, crossover, nonblinded clinical trial.
Setting: A fully accredited geriatric teaching facility affiliated with the University of Toronto's Medical School with a home for the aged.
Participants: Thirty-four institutionalized seniors with probable AD who ate independently.
Intervention: Nutrition supplements were provided between breakfast and lunch for 21 consecutive days and compared with 21 consecutive days of habitual intake.
Measurements: Investigator-weighed food intake, body weight, cognitive function (Severe Impairment Battery and Global Deterioration Scale), behavioral disturbances (Neuropsychiatric Inventory–Nursing Home Version), and behavioral function (London Psychogeriatric Rating Scale).
Results: Relative to habitual intake, group mean analyses showed increased 24-hour energy, protein, and carbohydrate intake during the supplement phase, but five of 31 subjects who finished all study phases completely compensated for the energy provided by the supplement by reducing lunch intake, and 24-hour energy intake was enhanced in only 21 of 31 subjects. Compensation at lunch was more likely in subjects with lower body mass indices, increased aberrant motor behavior, poorer attention, and increased mental disorganization/confusion.
Conclusion: Nutrition supplements were least likely to enhance habitual energy intake in subjects who would normally be targeted for nutrition intervention–those with low body weight status. Those likely to benefit include those with higher body mass indices, less aberrant motor problems, less mental disorganization, and increased attention.

Although there is an unacceptably high prevalence of involuntary weight loss in the elderly in general, weight loss is more likely to occur in seniors with probable Alzheimer's disease (AD) than in healthy elderly and is considered a clinical feature consistent with the diagnosis of AD. Prevention of involuntary weight loss is important because weight loss and low body weight status are predictors of morbidity, mortality, and poor quality of life. The origin(s) of weight loss in the population with AD has yet to be definitively established, but a decline in food intake may be a contributor. Nutritional supplements are often prescribed, especially to nursing home residents, as an intervention for weight loss, despite the fact that further research is needed to establish their effectiveness.

The integrity of appetite regulatory systems signaling hunger and satiety will, in part, govern the ability of nutritional supplements to enhance daily food intake. To successfully increase food intake, compensation (a phenomenon whereby intake of habitual foods is reduced to adjust or compensate for energy provided by the intervention/test food) cannot occur. Although the lack of compensatory responses to additional foods would suggest dysfunctional appetite regulatory signals, this could potentially be beneficial to seniors at risk for undernutrition, if appropriately exploited.

Most, but not all, studies suggest that the elderly, including those with AD, have an impaired ability to regulate food intake, and associate the provision of excess energy with reductions in habitual food intake, but not of sufficient magnitude to completely compensate for the energy contained in the intervention foods. Studies demonstrating enhanced energy and protein intake through the provision of oral supplements for 15 days to hospitalized critically ill elderly patients and weight gain in 12-week supplementation studies in institutionalized demented seniors also suggest impaired compensatory responses.

However, studies suggesting that a simultaneous reduction in the habitual diets of institutionalized frail seniors offsets high compliance in consumption counter these studies that support the potential success of nutritional supplements to enhance intake. Part of the problem may be the lack of understanding of the appropriate provision of supplements, with a recent study suggesting that providing dietary supplements to seniors between meals rather than with meals may be more effective in increasing energy intake.

Features of disease progression are likely to influence the integrity of appetite regulatory mechanisms in seniors with AD. Not only are age-related physiological changes that result in the failure to adequately regulate food intake, the so-called anorexia of aging, likely to affect seniors with AD, but atrophy in regions of the brain such as the mesial temporal cortex is also likely to affect food intake, and possible neurotransmitter abnormalities associated with appetite regulation can also occur. Furthermore, behavioral and cognitive deterioration that accompany the disease process are likely to negatively affect food intake. For example, studies on institutionalized seniors with AD suggest that the ability to recognize appropriate appetite signals may vary depending on time of day, level of behavioral difficulties of the individual, and body weight status.

Based upon the need to expand current understanding of appetite regulation and the effectiveness of nutrition supplements in seniors with AD, the goals of this investigation were to determine whether providing a nutrition supplement between breakfast and lunch influences habitual energy intake and to determine the effects of patient characteristics such as body weight status, cognitive performance, behavioral disturbances, and behavioral function on intervention response.