Yesterday Health Secretary, Jeremy Hunt drew attention to the plight of 800,000 elderly and lonely people in England who are “invisible” to those with busy lives. Citing research from the Campaign to End Loneliness, Mr Hunt said that television was the main form of company for some 5 million people – and this should be a source of “national shame”.

As a researcher in Social Epidemiology, I am particularly interested in the connection between people’s social relationships, or lack of contact with friends and family, and their diet – and the impact that combinations of these factors have on older people’s health.

In the next two decades there will be a 45% increase in the number of over-65s and a more than seven-fold increase in the number of people aged 100 or over. While life expectancy is rising, however, so too is the time spent living with chronic illness. Nutrition plays a key role in healthy ageing just as it does at earlier stages of life. In the UK, it is estimated that around 70,000 avoidable deaths are caused by diets that fall short of current guidelines on healthy eating.

Back in 1993 EPIC-Norfolk recruited around 25,000 people aged 40 to 80 to take part in a Europe-wide study of health. For 20 years it has been following their diet and other lifestyle factors in relation to the onset of chronic diseases such as cancer or diabetes. Previous research drawing on data gathered by the study has shown that individuals who consumed extra vegetables or vegetable-based items per week had a 13% lower risk of developing type 2 diabetes.

People’s diet is not fixed: it changes over time. Furthermore, the ability to eat healthily is influenced by a person’s social environment – including factors such as marriage, cohabitation, friendship and general social interaction. As people age, they are less likely to eat well – and when older people are living alone their diet often suffers.

As the Campaign to End Loneliness has quite rightly brought to the nation’s attention, isolation is a growing social phenomenon – and one that affects health as well as emotional well-being. According to research cited by the Campaign, loneliness has a negative health impact equivalent to smoking 15 cigarettes a day and is worse for us than well-known risk factors such as alcohol obesity and physical inactivity.

Around half of those people aged 75 or over now live alone. Not surprisingly, solitude has an impact on the health and eating patterns of this elderly population. Along with men and those who are socially isolated, those who live alone are the group eating a diet with least variety.

On a more optimistic note, these findings suggest that improving people’s social ties can have a positive impact on health. As one of the researchers contributing to this CEDAR study, I have been using data from EPIC-Norfolk to look at the combined influences of multiple social ties in relation to the daily variety of fruits and vegetables eaten, regardless of quantity.

Our research adds new evidence to the understanding of how a combination of factors in older people’s social lives come together to affect their diet – and, thus, their health. The results confirm, for instance, that the marital/relationship status of older people has a marked impact on the quality of their diet.

Compared with older adults in a partnership, those over-50s who were single ate 2.3 fewer vegetable products daily. Those who were widowed ate 1.1 fewer vegetable products daily. Moreover, widows and widowers living alone consumed 1.3 fewer vegetable products than married lone-dwellers. By contrast, widowers and widowers living with someone else ate the same number of different vegetable products each day as over-50s who were in a partnership and also sharing their living arrangement.

The picture to emerge from these figures is significant: it is not widowhood alone that puts people at risk of a lower quality of diet but, rather, the combination of widowhood and living alone.

In terms of implications for policy, our research points to the need for interventions that increase the availability of various social relationships which, among other benefits, encourage a healthy diet. Such interventions might range from the organisation of social activities to a consideration of accommodation for the elderly that is designed to support social interaction.

An important factor to take into account is that the over-50s are more likely than any other group in the population to experience changes in their social relationships – for example, due to marital break-down or bereavement. These are key moments for assessment and intervention. For example, around the time of widowhood, an assessment of risk of unhealthy eating needs to consider gender, living arrangements, and contact with friends as part and parcel of a major life adjustment.

As the Campaign to End Loneliness argues, and Jeremy Hunt has underlined, social isolation and initiatives to combat it should be right at the top of the health policy agenda.

Annalijn Conklin is a Gates Scholar and a PhD candidate in Medical Sciences at the MRC Epidemiology Unit. Her research focuses on the collective of social and economic factors influencing diet and obesity in British older women and men. Annalijn did her undergraduate degree in Biology and Philosophy at the University of Toronto, Canada, her first Master’s in Life Sciences at the University of Edinburgh, and her second Master’s in Public Health at Columbia University in New York.

For more information about this story contact Alex Buxton, Office of Communications, University of Cambridge, amb206@admin.cam.ac.uk 01223 761673