Causes of malnutrition 

Malnutrition is caused by a lack of nutrients in your diet. 

This is either due to an inadequate diet or problems absorbing nutrients from food.

Medical conditions

Medical conditions that can lead to malnutrition include:

  • a condition that causes a lack of appetite, such as cancer, liver disease, persistent pain or nausea
  • a mental health condition, such as depression or schizophrenia, which may affect your ability to look after yourself
  • a health condition that requires frequent hospital admissions
  • a health condition that disrupts your body’s ability to digest food or absorb nutrients, such as Crohn's disease or ulcerative colitis
  • dementia – people with dementia may be unable to communicate their needs when it comes to eating
  • dysphagia – a condition that makes swallowing difficult or painful 
  • persistent vomiting or diarrhoea 
  • an eating disorder, such as anorexia nervosa

Some types of medication may increase your risk of developing malnutrition. More than 250 types of medicine are known to disrupt the body’s ability to absorb and then break down nutrients.

You may also be at risk of becoming malnourished if your body has an increased demand for energy – for example, if it's trying to heal itself after major surgery, or a serious injury such as a burn, or if you experience involuntary movements, such as a tremor.

Physical factors

Physical factors can also contribute to malnutrition. For example:

  • if your teeth are in a poor condition, or if dentures don't fit properly, eating can be difficult or painful 
  • you may lose your appetite as a result of losing your sense of smell and taste
  • you may have a physical disability or other impairment that makes it difficult for you to cook or shop for food yourself 

Social factors

Social situations that can contribute to malnutrition include:

  • living alone and being socially isolated
  • having limited knowledge about nutrition or cooking
  • reduced mobility
  • alcohol or drug dependency
  • low income or poverty


In the UK, the most common causes of malnutrition in children are long-term health conditions that:

  • cause lack of appetite
  • disrupt the normal process of digestion
  • cause the body to have an increased demand for energy

Examples of these types of conditions include childhood cancers, congenital heart disease, cystic fibrosis and cerebral palsy.

In the UK, malnutrition as a result of inadequate food intake is rare, although it may occur if a child is neglected, living in poverty or being abused. If you're concerned that a child may be at risk of neglect or abuse, call the NSPCC child protection helpline on 0808 800 5000.

Sometimes, children become malnourished because they avoid eating due to issues with their body image.

Page last reviewed: 21/01/2015

Next review due: 21/01/2017