What we wanted to know

Weight loss, malnutrition and dehydration are common problems for people with dementia and can occur at any stage of the illness. People with dementia often develop psychological symptoms or behaviours which cause them to eat or drink less. In the later stages of the illness, they become dependent on others to help them eat or drink. We wanted to investigate how to keep people with dementia eating and drinking as well as possible. We looked for studies which changed the way food and drink are presented to people with dementia, and for studies which attempted to change the behaviour of people with dementia or of those helping them to eat. We called these environmental and behavioural modifications respectively, though some interventions include aspects of both. We were mainly interested in the effect on how much people with dementia ate and drank and on measures of how well-nourished they were (e.g. body weight or body mass index (BMI)), but we also looked for effects on eating behaviour, symptoms of dementia and quality of life.

How we tried to answer the question

We searched for all the randomised controlled trials (RCTs) which were relevant to our question. In these trials, some people with dementia got an environmental or behavioural modification intended to improve their eating and drinking and were then compared with other people who had not had the intervention (the control group). Whether someone got the intervention or not was decided at random. We found nine RCTs to include in our review. In total, there were 1502 people in these trials. They had varying degrees of dementia, probably mostly due to Alzheimer’s disease. Seven of the trials took place in care homes. In one trial, people were given extra snacks between meals and encouraged to eat them. In three trials, people with dementia were given education about diet and eating. In two trials, people with dementia were taught skills to help them to eat independently. In three trials, training was given to the carers responsible for helping people with dementia to eat.

What we found out

All the trials we found tested different interventions and measured their effects in different ways. Generally, the trials were small and there were problems with the way they were done, which reduced our confidence in the results. For some interventions, the quality of the evidence was so low that we could not draw any conclusions. For others, there was a mixture of positive and negative effects.

What we concluded

Because of the amount and quality of the evidence we found, we cannot at the moment, identify any specific environmental or behavioural modifications for improving food and fluid intake in people with dementia.