Much emphasis is placed on the importance of good diet, usually in relation to concern about the health risks of obesity. However it has been generally agreed that the risk of undernutrition rather than overnutrition is the main cause for concern in elderly people, particularly those who are hospitalised or institutionalised. Malnutrition has been shown to have important effects on recovery in a broad range of patients and conditions. It has been associated strongly with impaired immune response, impaired muscle and respiratory function, delayed wound healing, overall increased complications, longer rehabilitation, greater length of hospital stay and increased mortality. Oral protein and energy supplements are potentially safer and easier to administer than nasogastric enteral feeds and are therefore particularly suited to elderly people and are also widely used. However, there may be problems with the willingness and ability of older people to consume oral supplements, and supplements may not be used effectively. Even if supplements are prescribed, they may not always be given, or are given but not consumed. In addition to taste, the composition and timing of administration in relation to meals may be important. Efforts also need to be made to provide normal meals and snacks which meet the needs of elderly people and to provide assistance with feeding if required.
A total of 10,187 randomised participants from the 62 trials has been included. Maximum duration of intervention was 18 months. The reviewers suggest that supplementation appears to produce a small but consistent weight gain. There was no evidence in this updated review of a beneficial effect on mortality overall, but there may be a beneficial effect on mortality in people who are undernourished. Supplementation may also reduce the number of complications. The reported acceptance of supplements was variable between trials. Some adverse effects such as nausea or diarrhoea were reported. However, there were problems of study design and quality. More studies are required to confirm the beneficial effect on the number of complications, to establish whether there is a beneficial effect on mortality for undernourished elderly people and to provide evidence about whether protein and energy supplements can improve morbidity and functional status in frail older people.