3 NUTRITIONAL NEEDS OF OLDER ADULTS
Summary
This chapter briefly describes nutritional requirements which are specific to the older population.
Like the rest of the adult UK population older people should:
- eat less saturated fat and salt
- eat more fibre
- have a minimum of 6-8 glasses of fluid each day
In addition older people should:
- take a vitamin D supplement
3.1 The nutritional requirements for healthy people in the UK are covered in depth by the COMA report ( DH, 1991) and so are not included as part of this review. General guidance on a healthy diet for older people is provided by the Food Standards Agency ( http://www.eatwell.gov.uk/agesandstages/olderpeople/) including the proportions of foods which should be eaten "The Eatwell Plate". ( http://www.eatwell.gov.uk/healthydiet/eatwellplate/
3.2 In the main the nutritional requirements of the older adult are the same as those for the rest of the adult population although there are some specific recommendations for older people ( DH, 1991). As these recommendations may form the basis of some interventions they have been highlighted and are described below.
Energy
3.3 Due to a reduction in basal metabolic rate as a result of ageing, and a possible reduction in levels of activity, older people require less energy than younger adults. The level of energy required is dependant on a number of factors including age, gender, body composition, weight and activity levels. Generally energy requirements continue to decrease with increasing age due to loss of body muscle stores and reduction in activity levels. In those older people who have very low energy requirements there is a risk of their diet not meeting micronutrient (i.e. vitamin and mineral) requirements. The quality of the diet is therefore of prime importance to ensure that deficiencies do not develop. Like the rest of the UK adult population older people should be encouraged to meet their energy requirements through a healthy diet and some of the components of this are discussed below.
Fat
3.4 Although there are no specific recommendations outwith those for the adult population as a whole it is worth considering fat intake. Increased fat intakes are associated with higher levels of overweight and obesity, cardiovascular disease, some forms of cancer and diabetes mellitus. These conditions are associated with increased levels of morbidity and mortality and as such could impact on a person's ability to live independently. The older population are already at a higher risk of developing these conditions and high fat intakes may exacerbate this further. This is particularly so for saturated fat (animal type fats) with unsaturated fats (pure vegetable type fats) not being associated with the same risk. In view of this older people like the rest of the adult UK population should eat less fat and in particular less saturated fat.
Protein 4
3.5 The Reference Nutrient Intake ( RNI) i.e. requirement for protein, is equivalent to that of the younger adult population. However as muscle mass decreases in older people this intake will result in a relatively higher intake per kg lean body mass compared to younger adults. The UK adult population currently consumes more protein than is required and there is some evidence that excessive protein intakes are associated with health risks ( DH, 1991). Older people should therefore not eat excessive amounts of protein and their meals should instead be based around starchy foods.
Vitamin D
3.6 Vitamin D is primarily required for bone health in both children and adults with a deficiency resulting in rickets 5 in children and osteomalacia 6 in adults. Osteomalacia is associated with increased risk of fractures in older people. More recently low vitamin D status has been implicated in a range of diseases including osteoporosis, several forms of cancer, cardiovascular disease, tuberculosis, multiple sclerosis and type 1 diabetes ( SACN, 2007).
3.7 The majority of people in the UK obtain most of their vitamin D as a result of exposure to sunlight ( DH, 1991) and as little as 20% of the body's surface is sufficient to enable people to meet their requirements. This is difficult in the UK as there is no sunlight of appropriate wavelength from mid October to the beginning of April. During the remainder of the year 60% of effective UV radiation occurs between 11am and 3pm (although this will be less in Scotland due to a more northerly latitude). Older people tend to expose less skin even when there is adequate sunlight which results in lower plasma levels of 25( OH)D (the marker for vitamin D status). The body relies on stores and dietary vitamin D during winter months and so these stores and dietary vitamin D may not be adequate in older people.
3.8 It is extremely unlikely that people will meet their vitamin D requirements from diet alone and so exposure to sunlight is necessary (for detail on food sources of Vitamin D see 6.12.9). In view of this the Scientific Advisory Committee on Nutrition ( SACN) (2007) recommends that all adults aged over 65 years should take a vitamin D supplement to enable them to meet the requirement of 10µg vitamin D daily. (Vitamin D is discussed more fully in section 6.12.9).
Fibre (Non-starch polysaccharide ( NSP7))
3.9 There are no specific recommendations for NSP (more commonly thought of as fibre) intakes in older adults outwith those for the adult population. However COMA ( DH, 1991) recommends that those people who have a tendency to constipation are particularly encouraged to increase their NSP intake. As a result of slower gut movement, decreased activity levels and side effects of medications some older people could be considered to be a group who may have a tendency to constipation. Therefore, it is recommended that older people are advised to eat more fibre.
Fluid
3.10 Fluid requirements are not covered by the COMA report ( DH, 1991) however low fluid intake is a cause for concern in the older population and is therefore included in this review.
3.11 Older people are at increased risk of dehydration for a number of reasons including increased losses through skin as a result of skin becoming thinner, diminished ability of the kidneys to concentrate urine and a less sensitive thirst mechanism (Hodak, 2005). The consequences of dehydration are many and varied and most of these consequences impact on dietary intake and nutritional status.
3.12 The effects of dehydration in older people which may impact on deterioration in nutritional status include: increased risk of pressure sores, unpleasant taste in the mouth, drowsiness, confusion, constipation, and increased risk of urinary tract infections. It is therefore essential that fluid intake is considered when managing the nutritional status of older people. The FSA (2009a) currently recommend that all adults should have a fluid intake of 6-8 glasses per day 8.
( http://www.eatwell.gov.uk/healthydiet/nutritionessentials/drinks/drinkingenough/ accessed 23.1.09).
3.13 It is therefore recommended that older people are advised to drink a minimum of 6 glasses of fluid every day. This can be from a variety of sources but they also recommend that drinks with a high sugar content or caffeine content (e.g. tea and coffee) should not be drunk in excessive amounts.
Key findings
- In the main the nutritional requirements of older people are the same as for the rest of the adult population.
- Guidance on the types and proportions of foods people should eat are based on the Food Standards Agency "Eatwell Plate".
- Energy requirements are lower in older people but micronutrient requirements are unchanged therefore the nutrient density of the diet in older people is of prime importance to ensure that deficiencies do not develop (i.e. the diet should contain adequate nutrients in a smaller amount of energy).
- As older people are at increased risk of developing cardiovascular disease it may be prudent to consider the total amount of fat and the type of fat provided in interventions. In particular substituting saturated fat i.e. animal type fat with unsaturated fats i.e. vegetable type fat should be considered.
- Older people have a relatively higher intake of protein per kg lean body mass compared to younger adults. As there is some evidence that excessive protein intakes are associated with health risks excessively high intakes should be discouraged.
- Due to the increased risk of dehydration in older people fluid intakes should be considered as part of intervention strategies. Alongside this the increased risk of constipation in older people means that adequate fibre and fluid should be encouraged.
People aged over 65 years should take a vitamin D supplement to enable them to meet the requirement of 10µg vitamin D daily and thus optimise their vitamin D status.