The number over-60s admitted to hospital with malnutrition has more than trebled in the UK over the last decade, a charity has warned.
Those diagnosed with the condition at hospital jumped from 1,405 in 2007-2008 to 4,988 in 2017-2018, according to Age UK.
But the vast majority of cases are thought to go unnoticed. Age UK said more than 1 million of the the 12.2 million older people living in the UK were either malnourished or at risk of malnutrition.
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Malnutrition can place a strain on the health service as it is two to three times more expensive to treat someone who is underweight than someone of a healthy weight, the charity added.
The cost of the condition to health and social care services is expected to hit £13bn next year.
Age UK urged families to check if elderly relatives were struggling to eat enough to keep themselves healthy this Christmas.
Causes of malnutrition can vary from having difficulty with the physicality of eating such as cutting up food, or difficulty chewing and swallowing because of a dental condition.
The charity said younger relatives could help by organising trips to the dentist or GP, offering full-fat milk, yoghurt and cheese rather than skimmed alternatives, and making soft foods such as scrambled eggs.
It also recommended helping the elderly pick out foods in packaging that are easy to open and regular snack foods.
If eyesight is a problem, Age UK said switching to blue crockery made it easier for people to see what they were eating.
Poverty in old age is also a risk. The English Longitudinal Study of Ageing found 360,000 people aged 50 to 64 and 29,000 people aged 65 to 74 had to skip or cut meals because of a lack of money.
Dianne Jeffrey, head of Age UK’s malnutrition task force, said poverty, the inability to shop, eat or drink at home without help, loneliness and isolation, and poor physical and mental health were all risk factors.
She added: “However, whether you are slim or even if you are seemingly overweight, you can still be malnourished and a couple of days of not eating can have serious physical effects for older people.
“This is why we are appealing to everyone to look out for tell-tale signs at Christmas time that might mean an older person is not eating enough or needs help to plan, shop for, or cook meals.”
Additional reporting by Press Association