Nutrition and supplementation in older people

Older people make up the fastest growing sector in society. Many people in this age group are fit and active, while others are frail and require care, but overall, this group has fairly specific nutritional needs.

The National Diet and Nutrition Survey: People aged 65 years and older¹ – carried out by the Food Standards Agency and the Department of Health – showed that older people in the UK are generally “adequately” nourished. However, on further investigation, the results show a mixed pattern of nutritional status with 3 per cent of men and 6 per cent of women living in the community showing signs of malnutrition (ie having a body mass index of less than 20).

Physiological changes associated with ageing

As people age, they naturally go through a series of physiological changes that have an impact on their nutritional requirements. These include:

Decreasing lean body mass – Lean body mass (muscles, organs, and skeletal tissue) and muscle cell metabolic activity decrease naturally with age; as the amount of body protein decreases, body fat increases. Changes in tasting ability – As people age, saliva production is reduced, and taste buds decrease in size and number. Older adults become more sensitive to bitter or sour flavours and less so to sweet and salty flavours. Bone mass reduction ? for every decade after the age of 40 there is a reduction of 3 to 5 per cent in bone mass, and this is accompanied by an increased risk of bone fractures. Reduction in gastro-intestinal motility – this contributes to constipation, which is exacerbated by a reduced level of general exercise. Nutrient absorption may also be reduced, and the stomach may produce less hydrochloric acid to aid in digestion. This in turn reduces the absorption of vitamin B12. Reduction in the ability to concentrate urine ? this can lead to increased thirst.

Common nutritional problems of older adults

Poor nutrition among older people may be due to a variety of factors, including a reduction in the variety and amount of food eaten. Non-dietary factors may include digestive disorders, depression, disease, drugs, illness and pain.

Reduced nutrient intake is a common problem, with depression, loneliness, and a sedentary lifestyle all potential causes of reduced appetite. A mentally impaired person may forget to eat, lose interest in food, or be unable to shop for and prepare their meals. Others may not be able to afford good, nutritious food due to income constraints, while others may have problems swallowing.

Nutritional requirements

The requirement for energy declines with increasing age, particularly if physical activity is restricted. However, requirements for protein, vitamins and minerals remain the same, and in some cases increase, so it is essential that older people eat a diet that supplies them with a rich supply of nutrients.

Energy needs decrease with age as lean body mass falls and overall activity levels are reduced. There is an estimated reduction of 10 per cent in calorie requirement between the ages of 51 and 75, with an additional drop of 10-15 per cent reduction after the age of 75, depending on individual activity.

Protein needs increase when the body is stressed by injury, infection, surgery, or illness, all of which become more likely with increasing age. For a person aged over 50, protein should make up 12 to 14 per cent of total calorie intake.

A small amount of fat is necessary for life and it plays a key role in the transportation of fat-soluble vitamins (A, D, K, E). However, to help prevent cardiovascular disease, older people should continue to restrict their intake of saturated fat in particular, unless they are frail, have suffered weight loss, or have a very small appetite. For a person aged over 50 the proportion of calories coming from fat should be no more than 30 per cent; no more than l0 per cent of the calories should come from saturated fat.

The minimum recommended daily carbohydrate intake is 50-100 g. At least 50 per cent of total calories intake should come from complex carbohydrate sources.

Many elderly people suffer from constipation and bowel problems, and this is mainly due to inactivity and reduced gut motility. Consumption of cereal foods, fruit and vegetables should therefore be encouraged, but excessive amounts of very high fibre foods may interfere will the absorption of certain nutrients. It is recommended that the daily fibre intake be 20-30 g. Many elderly people have high sugar intakes, but if the rest of the diet is healthy, this is not an issue.

Vitamins and minerals

Although older adults need fewer total calories, they have an increased need for certain vitamins and minerals as follows:

Vitamin D – a deficiency can lead to bone softening and distortion; the Department of Health (DoH) recommends that older people consider a vitamin D supplement of 10 g per day to aid calcium absorbtion². B vitamins – intakes may be low in older people due to poor appetite and poor diet. The consumption of foods rich in B12, such as lean red meat and chicken, should be encouraged. Chromium – The need for chromium increases, and the consumption of foods such as brewer?s yeast and whole grain is recommended. Zinc – The need for zinc, which plays a key role in maintaining the body?s immune system and wound healing response, increases in older people. Iron – Poor iron absorption, blood loss, and the use of certain drugs – together with a poor dietary intake – make iron-deficiency anaemia a common problem in older people. Absorption of iron can be maximised by consuming foods rich in vitamin C at the same time. Calcium – Loss of calcium from bones begins at around the age of 30 and accelerates considerably in later years, so older people have an increased need for calcium to help reduce the risk of bone fracture.

Where vitamin, mineral and nutrient needs cannot be met through diet alone, supplementation should be considered.

The National Diet and Nutrition Survey?s research into supplement use among the over-65s living in the community shows that 12 per cent of men and 13 per cent of women use multivitamins, and 15 and 12 per cent respectively use single vitamins. The proportion of men and women in this population using multivitamins and minerals is 12 and 15 per cent; the proportion using minerals alone 63 and 64 per cent respectively.

These supplements make a valuable contribution to the overall vitamin and mineral status of older people, with, for example, men getting 7 per cent of their vitamin A (retinol equivalents) from supplements, and women10 per cent. The percentage of intake taken in supplements rises to 10 and 13 per cent respectively for retinol. There is wider variance between the sexes when it comes to thiamine, with men taking 4 per cent of their intake from supplements against women?s 31 per cent, with riboflavin (4 versus 19 per cent), vitamin B6 (3 vs 22 per cent), and vitamin E (11 vs 35 per cent), among others.

However, caution must be exercised with regards to supplementation in older people. Those taking prescribed medications should check with their Doctor before starting supplementation with vitamins or minerals to ensure there will be no interactions.

References

1. Finch, S. Doyle, W, Lowe, C. Bates, CJ. Prentice, A. Smithers, G. Clarke, PC.(1998) National Diet and Nutrition Survey: people aged 65 years and over. Volume 1: Report of the Diet and Nutrition Survey. London TSO.

2 Committee on Medical Aspects of Food Policy. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. DH RHSS 41.

For further information on supplementation, visit www.hsis.org