Malnutrition (undernutrition) is caused by a lack of nutrients, either as a result of a poor diet or problems absorbing nutrients from food.
Certain things can increase your risk of becoming malnourished.
Some health conditions that can lead to malnutrition include:
You can also become malnourished if your body needs an increased amount of energy – for example, if you're healing after surgery or a serious injury such as a burn, or if you have involuntary movements such as a tremor.
Some types of medicine may also increase your risk of developing malnutrition.
Some medicines have unpleasant side effects, such as making you feel sick, losing your appetite, or having diarrhoea, which could mean you eat less or do not absorb as many nutrients from food.
The following factors can also contribute to malnutrition:
In the UK, malnutrition in children is often caused by long-term health conditions that:
Some children may become malnourished because of an eating disorder or a behavioural or psychological condition that means they avoid or refuse food.
Malnutrition caused by a poor diet is rare in the UK, but it can happen if a child is neglected, living in poverty or being abused.