Causes
Malnutrition (undernutrition) is caused by a lack of nutrients in your diet, either due to a poor diet or problems absorbing nutrients from food.
Certain things can increase a person's risk of becoming malnourished.
Health conditions
Some conditions that can lead to malnutrition include:
- long-term conditions that cause loss of appetite, feeling sick, vomiting and/or changes in bowel habit (such as diarrhoea) – these include cancer, liver disease and some lung conditions (such as chronic obstructive pulmonary disease)
- mental health conditions, such as depression or schizophrenia, which may affect your mood and desire to eat
- conditions that disrupt your ability to digest food or absorb nutrients, such as Crohn's disease or ulcerative colitis
- dementia, which can cause the person to neglect their wellbeing and forget to eat
- an eating disorder, such as anorexia
You can also become malnourished if your body needs an increased amount of energy – for example, if it's healing after surgery or a serious injury such as a burn, or if you have involuntary movements such as a tremor.
Medicines
Some types of medication may increase your risk of developing malnutrition.
Some medicines have unpleasant side effects – such as loss of appetite, diarrhoea or nausea – that could mean you eat less or don't absorb as many nutrients from your food.
Physical and social factors
The following factors can also contribute to malnutrition:
- teeth that are in a poor condition, or dentures that don't fit properly, which can make eating difficult or painful
- a physical disability or other impairment that makes it difficult to move around, cook or shop for food
- living alone and being socially isolated
- having limited knowledge about nutrition or cooking
- alcohol or drug dependency
- low income or poverty
Causes of malnutrition in children
In the UK, malnutrition in children is commonly caused by long-term health conditions that:
- cause lack of appetite
- disrupt digestion
- increase the body's demand for energy
Examples of these types of conditions include childhood cancers, congenital heart disease, cystic fibrosis and cerebral palsy.
Some children may become malnourished because of an eating disorder or a behavioural or psychological condition that means they avoid or refuse food.
Malnutrition as a result of a poor diet is rare in the UK, but may occur if a child is neglected, living in poverty or being abused. Call the NSPCC helpline on 0808 800 5000 if you're concerned about a child.
Page last reviewed: Mon Feb 2020 Next review due: Wed Feb 2020
