There is a beautiful book by Simon Carey Holt called Eating Heaven, in which Holt asserts that “eating is never just about the food – eating is the lubricant that makes so many other things possible”.

Everyone who is now in their later years has experienced food as so much more than nutrition. They’ve sat at family tables where the lives of relatives and friends were shared over meals. They were involved in celebrations big and small with food at the centre and probably also experienced the nurturing effect of food at times of sadness and loss.

Food as a lubricant is a great analogy. Food facilitates the flow of conversation and social interaction that helps support cognitive function, but it also ensures that all essential body systems run smoothly. It makes everything that’s needed to age successfully – repair and maintenance, immune function, cognition and physical ability – possible.

Keeping ageing bodies going

Body maintenance involves constant renewal of cells, immune function necessitates continuing manufacture of specialist proteins – and then there is what’s needed to keep your brain functioning and your body moving around. The need for some nutrients, especially protein, antioxidants and some vitamins and minerals, is elevated by the accumulation of years. Oxidative damage compounds over time, chronic inflammation and some medical conditions increase demands on the immune system, and the ability to maintain essential protein reserves in muscle is hampered.

Brain function and cognitive ability are hampered because, whilst the brain contributes only 2 per cent to body weight, it consumes 20 per cent of body energy, so its demands are significant. Its energy supply is almost exclusively glucose – sourced from carbohydrates in food (adequate only from good, regular meals) and very limited body carbohydrate reserves. But shortfalls in supply are common – more so in later age – and body fat is no help; it can’t be converted into glucose. However, protein can, so our muscle reserve of protein takes up the slack and that means loss of vital muscle, which gets more difficult to replace as time goes on.

It always amazes me that it’s been only quite recently that malnutrition has been widely recognised as such a major player in physical and mental decline in older people. The longer people live, the more critical appropriate nutritional strategies become for maintaining independence.

Health messages can be unhelpful for older people

Reduced appetite is one obvious contributor to malnutrition and it’s a common problem because there are so many factors involved: medications; changes in the way the stomach works; dental problems; altered levels of digestive enzymes and hormones; depression; constipation and many more. There is also a lifetime worth of food negatives (‘don’t eat too much of…’, ‘that’s bad for you’, ‘stop eating …’, etc.). These are intonations against gluttony and excess that attempt to achieve avoidance in younger adults but are counterproductive in later years. Unfortunately, they rarely work to suppress overconsumption in younger people but paradoxically seem to work in older people when they are no longer appropriate.

In fact, most health messages are intended for younger adults but are anything from counterproductive to dangerous for those in their later years. Messages such as lose weight and eat low fat can contribute to appetite decline and muscle loss in older adults and that needs to be avoided, not encouraged.

The importance of muscle

Maintaining a good muscle reserve is vital in later ages because it forms a supply of protein that your body accesses between meals and any time you don’t happen to be eating, in order to keep up cognitive and immune function and body organ maintenance, as well as repair of any damage from accident, illness or surgery.

In younger adulthood, any protein lost from muscle at these times is usually quickly replaced at your next meal. But as you get older not only is replacement increasingly inefficient, but also many, many people don’t eat enough protein to keep up supplies. That results in a gradual loss of muscle and weight that eventually hampers immunity, increasing the chance of illness and slowing down wound repair and recovery from skin tears, bruising and surgery. It also hampers organ maintenance, increases frailty, saps appetite and makes falling more likely.

Well before muscle loss is physically obvious it can be reducing an individual’s reserve for many years. Unfortunately, it’s far too common for a cycle of muscle loss and illness to develop amongst older people living in the community, increasingly affecting their independence and quality of life. In residential facilities where residents may have already suffered substantial muscle loss, the effects can be disastrous, as immunity plummets and organs are not able to be adequately maintained.

And that’s frequently exacerbated if people require hospitalisation. Inexplicably, in far too many hospitals now, food provision falls into housekeeping, competing for budget allocation with cleaning and maintenance, rather than being part of the medical focus of patient care, where it rightly belongs.

Food as medicine

It needs to be recognised that food is medicine. Food is what supports body repair and maintenance so that pharmacology, physiotherapy, surgery and many more facets of patient care at all levels can be effective. It makes life and – particularly in older age – independent living, possible.

Eating in older age, especially meals in aged-care facilities, needs to be nutrient packed to support the additional needs of ageing bodies. Protein foods need to be the centre of three meals a day to support muscles. It’s not enough to concentrate the protein into one meal, as is often the case. It doesn’t need to be large amounts; it just needs to be at the centre of breakfast, lunch and dinner. And to be most effective that should be combined with activity. Along with that, good nutrition requires antioxidant-rich foods to combat the escalating oxidative load ageing imposes and essential vitamin and minerals to release energy from food and allow body and brain systems to function efficiently.

Ngaire Hobbins is a dietitian specialising in geriatrics and author of the book Eat to Cheat Ageing. eattocheatageing.com.au