Malnutrition (undernutrition)
This is not only about hunger or poverty, although it is about those too. Far more often a person is eating and still getting less than the body needs…
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This is not only about hunger or poverty, although it is about those too. Far more often a person is eating and still getting less than the body needs: appetite has gone with an illness, chewing hurts, the bowel has stopped absorbing. The body responds by breaking down its own muscle, and from there it goes round in a circle — weakness, less moving about, less appetite still. Caught early, this is put right by changing what is eaten; caught late, what has to be treated are the consequences, from fractures after a fall to wounds that will not close.
How it shows itself in adults
The most reliable sign is weight that falls on its own, with no diet and no intention of slimming. A loss of roughly five to ten per cent of body weight over three to six months is considered significant. Often the person does not notice it, but does notice the indirect things: the belt does up two holes further along, the ring slips off the finger, the denture has become loose, a familiar shirt hangs off the shoulders.
Then come the signs that are easy to blame on age: constant weakness, feeling cold even in a warm room, difficulty getting out of a chair without pushing up, unsteadiness and falls. Wounds take weeks to heal and colds follow one another. Attention and mood suffer as well: apathy goes with undernutrition just as regularly as weakness does.
Individual deficiencies have their own signals: pallor and breathlessness when iron is short, a sore smooth tongue, cracks at the corners of the mouth, tingling in the hands and feet, bleeding gums, poor vision in dim light, brittle nails and thinning hair.
Undernutrition at a normal or high weight
Being thin is not a requirement. Someone of ordinary or even large build can be undernourished, and those cases are found last, because neither they nor anyone around them suspects it.
This happens for two reasons. The first: the diet supplies enough calories but is poor in protein, iron, vitamin B12, folate and vitamin D. Living on bread, sweet tea and biscuits is the classic example, with a full stomach and no building material. The second: body weight is kept up by fat and fluid while muscle is lost. Checking this is easier than it sounds: if at the same weight it has become hard to rise from a chair without using the hands, to carry the shopping or to open a jar, the problem is loss of muscle.
A separate trap is the state after stomach or bowel surgery, strict self-imposed diets, and a monotonous diet with no animal foods: here deficiencies appear on what looks like a normal intake.
What to look for in a child
In children what matters is not weight in itself but growth and the gains over time. It is worrying when weight gain stops and then height slows down; on the chart this shows as a move onto lower lines, so it is worth bringing the child's record of measurements to the appointment.
Behaviour changes too: the child becomes listless, irritable or, on the contrary, unusually quiet, tires sooner at play and loses interest in what used to be enjoyed, and in toddlers new skills come more slowly. In teenagers undernutrition is most often bound up with an eating disorder, and that needs a separate, careful conversation without blame.
Do not put off a visit if the child refuses whole groups of foods, if eating brings pain, posseting, coughing or choking, if the stools have become bulky, greasy and foul smelling, since that is how conditions in which food is not absorbed show themselves, or if the weight gain stopped after solids were introduced or after a bout of gastroenteritis.
Illnesses and medicines that lead to it
The commonest cause is not lack of food but illness. Some take the appetite away: cancer, severe heart and lung failure, disease of the liver and kidneys, chronic infection. Others prevent food being taken up: coeliac disease, Crohn's disease and ulcerative colitis, pancreatic insufficiency, the after-effects of bowel surgery. Others raise the demand: extensive burns, serious injuries, recovery from major operations, an overactive thyroid.
A large group of its own are the swallowing disorders that follow a stroke and accompany neurological disease, and also dementia, in which a person forgets to eat or does not recognise food. Depression and anxiety reduce appetite, eating disorders lead to undernutrition by the most direct route, and dependence on alcohol is doubly dangerous: the calories are there, the vitamins and protein are not.
Medicines play their part: nausea, a dry mouth, altered taste and early fullness can all be side effects, and some drugs taken long term reduce the absorption of vitamin B12 and iron. Nothing should be stopped on your own initiative, but going through the whole list with a doctor is worth doing.
Causes that are talked about less
A healthy person living alone can become undernourished with no illness involved at all, and those causes are the easiest to put right.
The first is teeth. Bad teeth, missing back teeth and a poorly fitting denture quietly shift the diet towards soft, low-protein food, so here the dentist matters as much as the doctor.
The second is difficulty with shopping and cooking: painful joints, breathlessness, tremor, weakness after an illness, not being able to carry the bags or stand at the stove. The third is loneliness and bereavement: after the death of a partner people often stop cooking and eat whatever is to hand. Appetite is noticeably better in company, and shared meals work as well as supplements. To this add limited money, no habit or skill in cooking, and the demands of caring for an ill relative, when one's own meals come last.
When to see a doctor
Make an appointment if weight is falling by itself, if appetite has been absent for more than a couple of weeks, if weakness and frequent infections have appeared, or if you notice this in an elderly relative or in a child. Weight loss together with blood in the stool or in the sputum, night sweats, a long-standing cough, difficulty swallowing or persistent pain calls for investigation without delay: a tumour or a chronic infection can lie behind it.
Call an ambulance (in European countries, on the single number 112) if:
- the person has been unable to eat or drink for more than a day and is drowsy, confused or cannot be woken;
- there are signs of severe dehydration: a dry tongue, no urine for many hours, a fast weak pulse, dizziness on trying to stand;
- choking occurred while eating, with coughing and going blue, or food has gone into the airway;
- a child is listless and unresponsive, refuses to drink and has had a dry nappy for many hours;
- seizures, disturbance of the heart rhythm or sudden muscle weakness appear in someone who has recently started eating heavily after a long period of going without.
In every other case an ambulance is not what is needed, but an appointment with a doctor within a few days.
How it is assessed
The start is simple: weight and height are measured and the body mass index worked out, but what counts is comparing the weight with what it was and finding out over what period it changed. The doctor will ask what the person actually eats in a day, rather than what they think they ought to eat, and will ask about teeth, swallowing, bowels, mood and about who does the shopping and the cooking. It helps to bring a note of recent weights and a list of medicines.
Muscle is assessed as well: the circumference of the upper arm, the strength of the grip, the ability to get out of a chair without using the arms. Short screening scores are used to work out who needs a dietitian.
Blood tests answer two questions: what is lacking and why. The usual set includes a full blood count, iron and ferritin, vitamin B12 and folate, vitamin D, calcium, glucose, liver, kidney and thyroid tests, markers of inflammation and coeliac serology. Depending on the suspicion, stool tests, endoscopy, imaging and a swallowing assessment are added. With continuing unexplained weight loss the investigation goes on rather than everything being put down to nerves.
What helps with eating
First rule: food first, supplements afterwards. The point is not to eat a greater volume, which is impossible with a poor appetite, but to make every spoonful count for more: oil, cream, grated cheese, milk powder or an egg yolk go into porridge and mashed dishes, and ground nuts into soups. Low-fat products and light versions have no place here.
Second rule: little and often. Five or six small meals are tolerated far better than three large ones, and each one is worth building around protein (meat, fish, egg, curd cheese, pulses), with calorie-rich snacks in between. Drinks are best left until after the meal, because fluid takes up room in the stomach; the drinks themselves, though, can be nourishing, such as milk, cocoa or milk-based shakes.
Things unconnected with the food itself help too: eating with company, a walk before the meal, arranging a grocery delivery, cooking in batches, getting the teeth sorted out, having the denture refitted. If chewing or swallowing is hard the texture is modified, but that is best worked out with a professional so that food does not end up in the airway. Weighing once a week, always at the same time, is enough.
When ordinary food is not enough
If eating cannot be put right, the doctor or dietitian adds ready-made nutritional preparations, drinks and powders high in protein and calories. They are taken between meals rather than instead of them. Vitamins and minerals are taken not "for the appetite" but for a proven deficiency, because some of them do harm in excess.
When eating by mouth is impossible or unsafe, because of severe swallowing difficulty, an obstruction or a long stay in intensive care, feeding is given by tube: a fine tube through the nose into the stomach, or through the abdominal wall if it is to be long term. If the bowel is not working, the nutrient solution is given into a vein. Such feeding is started in hospital and continued at home, and people live with it for years.
There is one important danger that few people know about. If, after a long period without food, feeding is restarted straight away and in quantity, the levels of phosphate, potassium and magnesium in the blood fall sharply within the first days, which threatens disturbances of heart rhythm, swelling and weakness of the breathing muscles. That is why in marked undernutrition feeding is built up slowly, with blood tests along the way and with vitamin B1 given. Nobody who has gone a long time without food should be fed up on somebody's own initiative.
Online consultation
A remote appointment works well for making the first sense of the problem. The doctor will ask how much weight has been lost and over what period, what has happened to appetite, teeth, swallowing and bowels, which medicines are being taken and who cooks at home. That conversation alone shows where to look for the cause, and the list of tests is drawn up so that nothing unnecessary is done and there is no second trip.
The follow-up work suits online contact just as well: going through the results, working out how to make familiar dishes more nourishing, setting a plan for putting weight back on and checking it against weights taken at home, deciding whether nutritional preparations are needed. It is particularly useful for relatives of an older person who can see that he "has stopped eating much" but have no idea where to begin. With signs of severe dehydration, choking while eating or confusion, though, there is no waiting for an online appointment: that needs urgent care.
This material is for information only and does not replace medical advice.
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