Nutrients of concern for older people

Globally, the population is ageing, a process which is associated with a range of physiological changes linked to increased morbidity, with consequent increases in healthcare expenditure. Malnutrition is common in older adults due to a myriad of factors including physiological changes of ageing; thus, with growth in numbers, we can expect the burden of malnutrition and associated negative outcomes such as impaired immunity, loss of physical function, and independence to increase. Both malnutrition and the physiological changes of ageing can manifest in poor nutritional status, due to simple starvation, either through poor food intake or through changes in absorption and metabolism of nutrients in the body. Good nutrition is a modifiable factor which can help to minimize the effects of nutrient deprivation and reduce the impact of ageing on individuals and the community, as well as the healthcare budget. This chapter explains the importance of nutrition in the ageing population and present evidence of the consequences of malnutrition. The older generation is a heterogeneous group who are quite different to younger people. Yet, there is a lack of specific nutrient reference values especially for adults in advanced age and recommendations are often based on evidence extrapolated from younger adults. Energy needs vary across age groups based on gender, age, and level of activity; however, in older adults, the variation is exacerbated by the physiological changes of ageing and inflammation from illness. Further, many of the assumptions behind calculations of energy requirements, often based on younger people, are not valid in the older population; thus, assessments may not be accurate. Protein requirements are known to be higher in this group, at the very least to attempt to preserve muscle mass, but there is insufficient research to be able to establish guidelines. Fat is an important energy source particularly for older adults whose appetite may be diminished. The evidence suggests that adults of advanced age eat fat in excess of recommendations; however, there are no age-specific guidelines to help interpret the implications of this overconsumption. Generally, if older people eat a healthy balanced diet, they will meet micronutrient requirements. Micronutrient deficiencies can nevertheless arise from decreased food intake often due to the aforementioned physiological changes of ageing, poor health, and polypharmacy. Key micronutrients of interest in older adults are calcium, magnesium, selenium, zinc, and iron, vitamin B12, vitamin D, and folate. Of particular concern is vitamin D as food sources are limited and exposure to sunlight is often reduced. Given the need for vitamin D for adequate calcium absorption and the roles of calcium in the body, not least for bone strength, older adults may benefit from routine vitamin D supplementation.