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. Some reasons why this might occur are listed below.

Medical conditions

Medical conditions that can contribute 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
  • a health condition that makes swallowing painful or difficult (known as dysphagia)
  • persistent diarrhoea
  • persistent vomiting
  • taking many different types of medication at the same time – there are more than 250 types of medicine known to disrupt the body’s ability to absorb and then break down nutrients
  • your body has an increased demand for energy, for example if it is 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
  • an eating disorder, such as anorexia nervosa

Physical factors

Physical factors can 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 factors that can contribute to malnutrition include:

  • living alone and being socially isolated
  • 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 either:

  • 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.

Malnutrition due to inadequate food intake in this country is rare, although it may occur if a child is neglected or living in poverty.

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

Malnutrition in children

Malnutrition due to lack of food is uncommon in the UK, although it can occur if a child is being neglected or abused.

If you are concerned that a child may be at risk of neglect or abuse, call the NSPCC child protection helpline on 0808 800 5000.

Page last reviewed: 04/02/2013

Next review due: 04/02/2015