30th July 2023

Causes of malnutrition

The causes can be divided into the following subcategories.

Reduced dietary intake and inadequate diet

This, in turn, can be due to a variety of reasons, including:

• Reduced appetite as a consequence of malignancy, chronic nausea, and other systemic illnesses
• Eating disorders, e.g. anorexia nervosa
• Oropharyngeal and upper GI disorders causing difficulty with intake and swallowing, e.g. oesophageal strictures, chronic candidiasis, severe acid reflux
• Dementia – leads to reduced appetite and unintentional self-neglect (i.e. forgetting or being unable to cook)
• Social factors – poor diet, neglect or self-neglect, alcoholism, substance misuse, food poverty
  • The biggest cause in children of malnutrition

Malabsorption

It can be the primary pathology for a variety of diseases or occur as a consequence.

• Inflammatory bowel disease – especially Crohn’s disease
• Coeliac disease
• Cystic fibrosis
• Chronic pancreatic insufficiency
• Chronic diarrhoeal illnesses – e.g. tropical sprue, giardiasis
• Short gut syndrome
• Whipple’s disease
• Lactose intolerance (and other food intolerances)
• Biliary disease

Excessive losses

Generally in the context of severe burns, these patients have specific nutrient requirements and losses, which often leads to malnutrition if not appropriately addressed.

Increased energy expenditure

Chronic systemic illnesses may lead to increased energy demands, which, if not met by increased dietary intake, can lead to malnutrition. This is often exacerbated by the co-existence of reduced appetite.

Examples include:

• Malignancy
• Chronic infectious diseases – e.g. tuberculosis
• HIV/AIDS
• Cystic fibrosis