Owing to improved healthcare practices over time, the increasing life expectancy in many countries is changing the age structure of populations. For instance, the number of adults above the age of 65 in the United States is projected to nearly double from 52 million in 2018 to 95 million by 2060, and the 65-and-older age group’s share of the total population is bound to rise from 16 percent to 23 percent. However, it is notable that the changes in life expectancy are not reflected directly by changes in healthy life expectancy, and in most countries, there have been increases in the number of healthy life years being lost to disability. The need to address this gap in morbidity has focused attention on the role of lifestyle and health behaviors, including nutrition, and their links to the ageing process, with a view to considering strategies to promote healthier ageing.
Causes of Malnutrition
Aside from the reducing activity levels that come with age, an age-related reduction in the amount of food consumption also occurs. The differences in energy intake across adulthood are significant. A recent study that analyzed the daily energy intake among healthy adults older (70 years and above) and younger (about 26 years) adults showed a difference in energy intake of approximately 16-20% was shown between the groups, amounting to a reduction of about 0.5% per year; this compares with previous estimates of a fall in energy intake of around 25-30% between young adulthood and older age. This was attributed to a number of age-related physiological changes, that include more rapid and longer satiation, dental and chewing problems, being less hungry and thirsty, and impairments in smell and taste, that can act to change eating behavior. The study also showed that older adults tend to eat more slowly, consume smaller meals, and snack less, leading to lower food consumption and ultimately, to weight loss. These changes may be compounded by effects of comorbidities and medication that cause loss of appetite.
Among the most significant aspects of nutrition among older adults is the recognition of deteriorating or poor nutritional status. A malnourished state is defined as any of the following:
- BMI < 18.5
- Unintentional weight loss > 10% within the last three to six months
- BMI < 20 and unintentional weight loss > 5% within the last three to six months
Aside from these parameters, there are several screening tools that are available for use in older adults. In the most commonly used screening tool is the Malnutrition Universal Screening Tool (MUST), a five-step screening tool that includes guidelines for the formulation of a care plan. MUST develops a risk of malnutrition score based upon current body mass index (BMI), known weight loss and the presence of acute disease/no nutritional intake for 5 days. Further information and instructions on the use of the MUST toolkit are available from: www.bapen.org.uk
Nutrition Support Strategies
Low fat and low sugar diets are among the most commonly recommended healthy eating options. However, older adults who are under-nutritioned often rely on fat and sugar as their sources of calories. The benefit of energy dense foods in these circumstances should be explained to patients and care-givers to assist compliance. Ideally fats should be heart healthy (oils, margarines, seeds and nuts) but with the priority being to ensure an energy dense intake. Calories from butter, cream, full fat milk and cheese can be utilized.
General suggestions for a Food First approach may include:
- Three small meals with snacks in-between every day
- Two courses for each of the three meals (see below for ideas)
- Add oil, butter, margarine, cream, cheese, dressings, sauces, sugar, honey and spreads to meals and snacks to boost energy intake
- Choose nourishing fluids such as milky drinks, soups or fruit juice instead of water or tea
- Make dessert a regular option rather than a treat
Oral Nutritional Supplements
Oral nutritional supplements are nutritionally complete liquid supplements that contain a mix of macro and micronutrients. These products are available from pharmacies in:
A powder form which is reconstituted with water or milk – brands include Ensure powder and Sustagen Hospital Formula
Ready-mixed liquid forms (often referred to as sip feeds) – brands include Ensure Plus and Fortisip
Evidence that oral nutritional supplements improve health outcomes is limited. A systematic (Cochrane) review of 62 trials, updated in 2009, concluded that there was evidence of small consistent weight gain following the use of oral nutritional supplements and that for undernourished patients, mortality is possibly reduced.