Relationship between protein deficiency and sarcobesity in older urban black Cape Town populations: a feasibility study of diet interventions

South Africa is a developing country with an ageing population and increasing prevalence of non-communicable diseases such as type II diabetes, high blood pressure, cardiovascular diseases, obesity etc. South Africa also suffers from a high burden of infectious diseases such as HIV/AIDS and tuberculosis. HIV medications prolong lifespan but HIV infection speeds up the ageing process to the extent that a typical 50-year-old HIV patient would be considered an old person in need of care. Thus many individuals in South Africa are physically 'older' than their biological age. In the elderly muscle becomes smaller and weaker leading to frailty and decreased quality of life. Older people in these communities are at an increases risk of ill health: HIV infection predisposes to the development of metabolic and cardiovascular disease and with ageing there is an increased prevalence of metabolic and cardiac diseases such as diabetes and heart disease. The elderly also suffer more from metabolic and cardiac diseases such as type 2 diabetes and heart disease.

A good diet can prevent both infectious disease and 'lifestyle' diseases like type 2 diabetes. Good nutrition, especially protein, is also essential to prevent muscle wasting in the elderly. We know that in South African townships people under 65 do not eat enough protein. This problem is likely to be worse in largely poor older black South Africans who most likely do not eat enough protein. This is due to relatively high costs of protein, typically from animals and diary products. As such, it is likely that ageing muscle decline and frailty will be accelerated in the elderly, resulting in decreased overall health, reduced mobility, increasing disease rates, economic demands on healthcare systems and premature death. Frailty and lifestyle diseases in older black South Africans could be reduced by a healthy diet, especially adequate protein.

As many older black Cape Town inhabitants have multiple health complications they are regularly attending community healthcare clinics. These clinics provide an opportunity for clinicians and other healthcare professionals to provide information on a healthier diet that includes higher levels of protein. However it's very difficult to give advice because we do not know what black older South Africans eat or can afford to eat. Complicating this many older South Africans also provide for their grandchildren and may compromise their own dietary needs to feed grandchildren. Thus, before offering advice to an ageing black urban Cape Town population (aged 65-80), we need to answer several preliminary research questions:

1) What is the feasibility and validity of assessing dietary intake in this population?
2) Are black older South Africans protein deficient?
3) Does a lower protein intake contribute to accelerated ageing and increased frailty and disease?
4) How much can black older individuals afford to spend on food for themselves?

To answer these questions we will employ 2 Xhosa speaking field workers and 1 research assistants to recruit 150 individuals aged 65-80 (male and female) in the Cape Town Township of Khayelitsha over 12 months. We will carry out repeated dietary recall measurements, to assess for reliability and validate against urine measurements that indicate the amount of protein eaten. We will also carry out laboratory based measurements at the University of Cape Town to assess muscle quality, frailty and risk of developing metabolic disease. Finally, we will use recently developed measurement tools to assess the food budget.

Effects of diet and food security is unexplored in older South Africans. It is anticipated that this study will produce extremely useful data to inform on health requirements, nutrition requirements and financial constraints for black older South Africans. These data will also be extremely valuable for larger scale studies to assess the health effectiveness of altering diet in this population.

Low and middle income countries (LMIC) are burdened with increasing non-communicable disease (NCD) against a background of high communicable disease (CD) prevalence. South Africa is no exception with a pre-existing background of e.g. HIV/AIDS and tuberculosis and increasing cardiometabolic disease. CD and NCD interact to increase the rate of ageing. The force of this effect is felt most by older people in South Africa and other LMIC. One contributor to loss of independence in old age is sarcopenia, the loss of muscle strength and mass that occurs in ageing. NCD and sarcopenia are considered diseases of ageing. It is well known that adequate nutrition can moderate both sarcopenia and NCD as well as protect against infection. Public health advice on proper nutrition could therefore make a large difference to health in LMIC just as such it did in developed nations in the early 20th century. To develop and disseminate advice policy makers need data on current dietary habits. We already know that 18-64 year old black South Africans are protein deficient. Older black South Africans are also likely protein deficient but the diet patterns and macronutrient intake of this population are unexplored. In this project, we will gather preliminary data on the dietary patterns and nutritional intake of older black South Africans. We will examine whether older black South Africans are protein deficient and how this relates to the prevalence of sarcopenia and both CD and NCD in this population. Finally, we will assess how economic restraints on nutrition might compromise the usefulness of nutritional advice for older black South Africans. Our aim is to generate data that can be used by individuals, communities and policy makers to provide nutritional advice which has a positive effect on the health and quality of life of older people in LMIC.

Who might benefit from this research?

This research will benefit the citizens of LMIC at three levels. Firstly, individuals can become more informed. It is our hope that at least some people will make a positive change in lifestyle through being part of the study. Secondly the communities we draw on, and therefore similar communities in other LMIC will be able to make use of the data. This will allow those communities to address problems they face which are caused or at least sharpened by inadequate nutrition. Third we hope to generate data that can be used by policymakers to inform policy and resource allocation in South Africa and other LMIC. The last point is particularly important given the evidence quoted above about the lack of governance in nutrition in many LMIC.

How might they benefit?

The most immediate beneficiaries from this work will be older black South Africans who take part in the study. These people will be in contact with project workers who have some knowledge about nutrition and participation in the study will likely lead to discussion with researchers involved. Some may even reflect on their current nutritional habits and aim to make changes for the better. Older people in other LMIC would benefit if dissemination of our data leads to positive change in those countries. Positive change is often driven at the community level. We hope the communities we include in the study will also benefit. Community leaders will be equipped with data they can use as evidence to lobby for change or to directly make positive changes for the community. These changes will in turn filter back down to individuals and, we hope, lead to improvements in health across the community not just in older people. Finally, policy makers will benefit from our study because they will have access to data that can be used to draw up policies to benefit the wider population. Our data will also serve as a baseline for monitoring the impact of executed policies. We also hope to provide a framework for the robust collection of nutrition data in LMIC. Thus, our findings are easily expandable to other LMIC where inadequate nutrition worsens the double burden of infectious and non-communicable disease e.g. India, Sri Lanka, Egypt. In short, our project and the data it generates will benefit older people, wider communities and policy makers in South Africa and these benefits are immediately transferrable to other LMIC.