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Keywords:

  • nutrition;
  • elderly;
  • developing countries;
  • vulnerability

The vital roles played by older people in maintaining the structure and healthy functioning of developing country societies cannot be understated. As well as being the repositories of cultural and religious heritage, knowledge and experience, older people are involved in, among other things, income generation, childcare, care of the sick (especially among communities living with HIV), and housework. In rural communities older people are often the only remaining population group working the land, as younger village members migrate to urban areas looking for paid work. To support these assertions, a recent analysis of historical data collected in rural Gambia highlighted the crucial role of older people in childcare, by demonstrating significantly improved nutritional status and survival among those children who had a living maternal grandmother (Sear et al. 2000).

Developing country populations are currently undergoing rapid and unprecedented changes in their age structure resulting in considerable population ageing. While the percentage of the total population under 15 years will drop from its current level of 33% to 22% in 2050, the percentage aged over 60 years will more than double from 8% to 19% over the same time. Similarly the percentage of very old people (over 80 years) will increase nearly fivefold by 2050 to more than 3% of the total population in developing countries (equivalent to 270 million people). The increase in the proportion of over 60s in developing countries is 1.5 times faster than that projected in developed countries, and by 2050, 80% of all over 60s will be living in developing countries (United Nations 2001).

This population ageing is a consequence of demographic transition and particularly the marked fall in fertility rates over the past 30 years. The total fertility rate in developing countries halved between 1965–70 and 2000–2005 falling from 6.0 to 2.9. As a result of this change, children and young people have come to represent a smaller proportion of the population, while older people, the survivors of large birth cohorts, account for greater proportions. This trend has been amplified by marked falls in mortality and increased life expectancy. These changes in the level of mortality have been accompanied by a transformation in both the cause and age structure of death.

Patterns of disease and causes of mortality have shifted from a high prevalence of infectious disease (diarrhoea and pneumonia) and malnutrition (characterized by stunting), towards an increasing prevalence of nutrition-related chronic disease and obesity. The increase in many of these diseases is related directly to reduced mortality and increased survival to older ages, and also to changes in behaviour that lead to increased risk for nutrition-related chronic diseases. The coexistence within populations of both under- and over-nutrition, the so-called double burden of disease, is also becoming increasingly widespread. Therefore, as a direct consequence of the rapid demographic and epidemiological transition, developing countries are facing an enormous increase in the number of people with age-associated physical and mental disabilities and dependencies. This is increasing the demands on national health budgets and other resources, and is a matter of considerable immediate and future concern.

The importance of good nutrition among older people for the maintenance of health has long been advocated, and in collaboration with Tufts University, the WHO has recently published helpful guidelines on the nutritional needs of older people (http://www.who.int/nut/publications.htmolder). However, the reality is, that for a variety of functional, physiological, psychological and social reasons older people are nutritionally vulnerable (Kohrs et al. 1989; Ismail & Manandhar 1999), and frequently consume diets that are poor in both quality and quantity. This vulnerability has resulted in macronutrient and micronutrient undernutrition among older people in developed but especially in developing country settings.

The public health consequences of undernutrition and poor micronutrient status in older people are considerable. There is accumulating evidence that low body mass in old age is associated with increased risk of morbidity and mortality. However, as a consequence of the relationship between energy and micronutrient sufficiency in diets, older people with long-term low energy intake may also be consuming micronutrients at considerably below the required levels. Furthermore, it is important to note that dietary micronutrient deficiencies among older people may currently be underestimated, as requirements may well be greater than previously thought (Richard & Roussel 1999).

Independent of body weight, there is growing evidence that subclinical micronutrient deficiencies in older people are associated with declines in immune function (High 1999) and cognitive ability (Duthie et al. 2002). To support these associations, several intervention studies suggest that dietary supplementation with micronutrients may be able to significantly delay the progression of morbidities such as bone fractures (Chapuy et al. 1992), mental deterioration (Sano et al. 1997) and loss of immune function (Chandra 1992; Meydani et al. 1997). This opens the very real possibility that micronutrient supplementation in older people may play a crucial role in preventing death and disability, and promote successful ageing.

For obvious demographic, epidemiological and political reasons, most research on nutritional status among older people has, to date, been carried out in developed country settings. For example, a recent review of longitudinal research on the effect of ageing on height, found studies on 19 separate populations. However, none of the studies was from a developing country, or indeed from a non-Caucasian group (Sorkin et al. 1999). Unfortunately, the results of studies on developed country populations may not be directly transferable to developing countries as the older people in these countries are ‘old’ at a chronologically younger age, and are also likely to have reached their old age after a lifetime of poor health and suboptimal nutrition.

Some research on nutritional status in older people from developing countries has recently become available, such as the work of Karen Charlton in South Africa, and the fruits of the HelpAge International collaboration with the Public Health Nutrition Unit at the London School of Hygiene and Tropical Medicine among older people in India, Tanzania and Malawi. However, the relatively small amount of data among these populations is a great hindrance to the development of public health policies aimed at improving the nutrition and health of these vulnerable groups.

While there is still much to learn about which interventions will have a positive benefit for older people in developing countries, some governments have already implemented relevant policies. These include a non-contributory pension scheme for women over 60 years and men over 65 years in South Africa, and a cash-transfer programme aimed at improving the food budget of poor older people in Mexico. Evaluations of these programmes are ongoing; however, it appears that the benefits of the interventions may often extend far beyond the original target population. For example, in South Africa, the pension income is widely redistributed both within and across households. Interestingly, while pension-sharing decreases the direct monetary value of the intervention to the older person, it provides a simple means through which older people can increase their status and (self-)respect within South African society (Sagner & Mtati 1999).

Direct food interventions are also being attempted such as that recently launched by the Government of Chile which distributes a powdered instant puree mixture to all individuals over 70 years registered at primary health clinics. Beneficiaries of the programme receive 2 kg of the mixture every month, which provides 400 kcal/100 g as well as a large array of micronutrients. The recommended serving size of this supplement supplies 50% of the daily micronutrient requirements and 15–20% of the daily energy requirements of older people. This programme has been designed in the hope that it will have a significant impact on the nutritional status, health and quality of life of older people in Chile, and thereby positively impact on the link between rapid population ageing and the subsequent health profile of the country.

While the actions of governments aimed at improving the nutritional status and quality of life of older people should be heartily applauded, they are often brave steps taken in relative data vacuums. There is obviously a great need for much more research to assess the nutritional status of older people in developing countries, and to investigate the effectiveness of nutrition and health interventions among these vulnerable groups. The challenge is great, but inaction will affect us all.

References

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  2. References
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Authors Alan D. Dangour and Suraiya J. Ismail, Public Health Nutrition Unit, Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, 49-51 Bedford Square, London WC1B 3DP, UK. E-mail: alan.dangour@lshtm.ac.uk