It looked like a golden roasted chicken drumstick. The smell wafting up from the plate in front of a dozen hungry senior citizens was of chicken too. When they dug in with their knives and forks, it even tasted loosely like one.
Except that it was not chicken at all. What this group of elderly nursing home residents in Germany were tucking into was puree, printed into the shape of a drumstick. Each “chicken leg” – actually formed from vegetable paste shaped by a 3D printer and given a more pleasurable texture than ordinary puree – was tweaked to match the nutritional needs of the individual elderly diners.
The group, who first ate this “not-chicken” meal in taste tests five years ago, were the participants of an innovative food project in Europe, named “Performance”, which explored whether 3D printed food could be delivered to elderly people with problems swallowing food, also known as dysphagia.
For many people with chewing and swallowing issues eating a chicken drumstick would normally be difficult. Currently, however, most foods created for elderly people with this problem tend to be unappetising and boring, which can often lead to them not getting the nutrition they need. But a number of research teams are now developing solutions that might allow older people to still enjoy a nutritious, varied and interesting diet in a format which is easy to eat.
To create their “chicken” dish, Biozoon, the company leading the 3D-printing project, first mixed fresh broccoli, cauliflower and potato puree with a variety of vitamins, calcium, carbohydrate and protein according to the needs of each diner. This mixture was then put into a 3D food printer, where it was mixed with a gelling agent to help the mixture solidify when printed into any shape they desired. The printed food was then frozen, to be reheated for serving.
The project proved to be a success in terms of improving the appetite of those taking part, says Biozoon chief executive Matthias Kück. During the trial participants gained an average of 1.7kg (3.7lb) and over half of the respondents gave thumbs up to the texture of the 3D printed food.
Their efforts are more important than you might think. More of us than ever before can expect to live to a ripe old age. By 2050, one in six people in the world will be over age 65, while one in four people living in Europe and Northern America could be aged 65 or over, according to figures released by the United Nations in 2019. The number of people aged 80 or over is estimated to triple from 143 million in 2019 to 426 million in 2050. And there could be as many as 3.7 million people over the age of 100 by 2050.
With this “silver tsunami” set to hit nearly every country, creative food solutions are needed to ensure they get the healthy diets they need.
Older people tend to experience more issues preventing them from eating the right diet. Dental problems as well as trouble swallowing can make eating difficult, while those with neurodegenerative conditions also struggle to get the right balance of food, according to a 2018 study in Hong Kong. One in three Chinese people aged 60 years and above have chewing difficulties, the study says.
In Belgium alone, a study in 2009 found that over 70% of adults aged between 75 and 85 were identified with swallowing difficulties. Ageing also tends to blunt the sense of taste and smell due to a declining number of odour receptors in the nose.
These issues in turn have a significant impact on nutritional status. When coupled with other factors such as lower levels of exercise and the side effects of medication, many older people can suffer from malnutrition or obesity. Food consumption among the elderly can decline by as much as 25% in people aged 70 years and older while the proportion of malnourished adults in nursing homes, for example, can be as high as 60%.
“Malnutrition is more frequent in the elderly that do exercise regularly, develop depressive disorders and have poor health,” says Mariane Lutz, a professor of human nutrition at the University of Valparaiso in Chile.
Obesity is also becoming more prevalent among the elderly. Almost a fifth of people over the age of 50 in Europe were obese in 2015 while roughly 30% of people over the age of 60 in the US are classified as obese.
A major part of the problem is that as we age we tend to change our diet, either through choice or because we are forced to. But the World Health Organization says although changes to the diet can alter the risk of disease through out a person’s life, it has a greater impact in older people. Reductions in saturated fat and salt intake, for example, can reduce blood pressure and cholesterol concentrations, as well as the burden of cardiovascular disease.
An ideal diet for the elderly should be rich in proteins, vitamins – especially B complex and D which can increase bone and muscle strength – along with minerals, long-chain omega-three fatty acids and fibre, according to Lutz. An adequate supply of calcium can also help preserve bone and muscle mass, while they also require a high amount of energy derived from dietary protein, according to recent research conducted by Lutz.
“A diet that includes plenty of plant-based foods – vegetables, legumes, cereals, nuts, seeds and fruits – is also a good source of phytochemicals (compounds that form part of a plant’s chemical defense system) that exert many beneficial effects, avoiding the need to use commercial dietary supplements,” she added.
Fish and shellfish products are also highly recommended for better protein intake, Lutz adds.
But in a strong body of research on the nutritional needs of the elderly, one European study found that one in five adults and people aged 64 or above don’t get enough vitamin D, folic acid, calcium, selenium and iodine.
So, how do you get older people to eat more food that is nutritionally right for them?
Serving them the same food you would serve younger adults is not the right approach, says Tanja Sobko, a food scientist at the University of Hong Kong.
“The elderly eat much slower and a lot less, so the nutritional value of the food should be much higher,” she says.
Pureed food has been a common solution, but the texture and appearance can often be off-putting. Many experts argue how food is represented is also important. Foods that are sticky and adhesive also require more effort for the elderly to eat.
Biozoon’s Kück agrees that mashed food is not visually appealing and may play a role in the loss of appetite that many older people experience. In their project at the German nursing home, his team used red colouring to make the 3D printed food more stimulating.
The colour of the food can enhance its visual appeal and warm colours work best, says Lutz.
“Foods should be appealing in their representation, and a good combination of colours is fundamental,” she says. “Colour is a very important intrinsic sensory cue that drives our sensory and hedonic expectations towards the food to be consumed, by making predictions and judgements about their taste and flavour.”
Biozoon are not the only ones to have tested concept of 3D food printing to cater for the old. Sweden’s research institute Rise, based in Gothenburg, is also testing 3D-printed food in elderly care homes. The project spans three locations – Halmstad and Helsingborg, and a company that offers catering to hospitals.
“In Sweden, we recreate the purees into shape-stable products that can be cut, or picked up by hand, and are smooth and easy enough to swallow,” says Evelina Höglund, the project organiser. “It aims to make the meal looks more appealing and you can eat it with a knife and a fork.”
The team use food purees of broccoli, chicken and bread to give a protein boost to their elderly diners. The printed food is then baked in the oven before being served to the participants.
“We want the food for dysphagia to look just like normal food, so they know what they are eating,” says Höglund. “Achieving the same goal by hand is too time-consuming in a commercial kitchen. That’s why we want to 3D print it.”
In Asia, a university in Singapore has attempted to recreate some of the country’s most popular foods and signature dishes as a sensory solution for older people. The joint project between Singapore Polytechnic’s Food Innovation and Resource Centre and SIT-Massey University used 3D printing to create a version of chicken rice for older people that was fortified with calcium, chicken and broccoli puree. The result was a ginger-yellow coloured drumstick, surrounded by white and green puree meticulously printed to resemble rice and broccoli. The team also created 3D printed durians – a large and hugely popular fruit in Asia – with reduced sugar, and a chilli crab dish intended to resemble the original in taste and texture.
“We conducted consumer insight gathering in the initial phase of our research, to understand the needs of the silver-agers; specifically, foods that they love but restricted in consumption due to health concerns,” says Evelyn Ong, production innovation manager at Singapore Polytechnic’s Food Innovation and Resource Centre.
But despite the excitement around projects like those in Germany, Singapore and Sweden, 3D food printing is still relatively early in development and some way from a viable commercial product.
Biozoon’s Kück says they encountered difficulties ensuring the printed food had the same quality when using cauliflower puree, as printers perform differently in varying room temperatures, and it took too long to print all the meals. When feeding residents in a large nursing home, that could be a problem.
The project has instead led to another company that is focused on 3D printing of chocolates instead.
That’s nearly the only area where 3D food printing is finding success, according to Jeffrey Lipton, a mechanical engineer at the University of Washington focusing on soft robotics and 3D printing. The biggest hurdle facing the technology is its ability to produce foods on large scale and at speed. The number of edible materials that can be printed are also limited.
“Not every food should or can be put into a 3D fabrication process,” he says. “For that, we need to interface with robotic cooking technology more broadly.”
Fortunately there are other ways to improve the food for the senior generation.
One study found that it can be as easy as adding monosodium glutamate, a flavour enhancer commonly-used in canned and processed food, to elderly people’s food to increase their salivary flow and improve their appetite. Other artificial flavourings including roast beef, bacon, cheese, fruits are also said to be able to increase the elderly person’s food intake.
Manipulating food textures has also been found to be effective in helping the elderly with eating difficulties. Making foods softer, moister and in smaller portions can all help with this. The Irish Agricultural Development Agency, for example, has been experimenting with adding rice protein and lentil flour to beef patties in order to improve their texture.
But sometimes simply getting to the food itself can be a challenge for the elderly. Operating a tin opener or twisting open a jar with arthritis, for example, can leave many older people unable to eat a wide range of food. There are attempts, however, to develop innovative food packaging tailor-made for older age groups .
These include paper wrappers that can be easily torn but keep the food fresh. Others include orbit lids on jars, which have a separate outer ring that can be loosened more easily than a traditional lid. Vacuum skin packaging technology also allows food to be cooked, transported, reheated and served in one single package.
“Food label texts should be reader-friendly, well distinguished from the background and use short texts,” adds Lutz.
In Australia, government agencies and non-governmental organisations provide a rating on packaging accessibility, showing how easily products can be opened by older people. Their research showed more than 80% of elderly patients in hospitals in New South Wales experienced difficulties or unable to open food packaging items.
Other tricks can also make a difference. In Sweden, some nursing homes bake cinnamon buns before mealtimes so the elderly can connect the smell with positive emotions.
“It is a strong tradition in Swedish homes to bake cinnamon rolls – we do this for children and when we sell our houses,” says Sobko. “It brings back the good memories for the old people. It is difficult for them to feel hungry, but the pleasant smell can stimulate it. Coupled with milk, that is their childhood memory.”