Gastrointestinal malabsorption

What are the symptoms of gastrointestinal malabsorption?

There may be no symptoms if the malabsorption is mild and has not continued for very long. More severe or persistent malabsorption may lead to:

Tiredness (fatigue)

This is because of a lack of energy as you are not absorbing nutrients and essential vitamins and minerals from food.

Weight loss

If you can't absorb enough energy (calories) from your food then this will cause you to lose weight (and may cause poor growth in children).

Persistent (chronic) diarrhoea

This is a common symptom of persistent malabsorption.

Pale, bulky and smelly stools (steatorrhoea)

This is because there is excessive fat in the stools and they become pale, bulky and very smelly. Fatty stools float and are difficult to flush away. They often leave a greasy rim around the pan.

Intestinal malabsorption may also cause:

• Iron deficiency and iron-deficiency anaemia.

• Folate deficiency.

• Vitamin B12 deficiency.

• Abnormal bleeding, caused by low vitamin K.

• Vitamin D deficiency including rickets and osteomalacia.

• Oedema, which occurs because of insufficient protein and calories absorbed into the body.

There may also be other symptoms due to the particular underlying condition that is causing the malabsorption.

The most common causes in the UK are coeliac disease, Crohn's disease and chronic pancreatitis. However, the malabsorption of simple carbohydrates affects about 1 in 4 people in Europe. Some diseases associated with malabsorption are found more often in some families - for example, coeliac disease, Crohn's disease, cystic fibrosis and lactose intolerance.

The causes of gastrointestinal malabsorption include:

Problems with absorbing food from the gut (bowel) into your body

• Coeliac disease - a long-term disease that mostly affects the small intestine.

• Lactose intolerance.

• Cow's milk protein allergy.

• Soya milk intolerance.

• Fructose intolerance.

• Infection - for example, intestinal tuberculosis, traveller's diarrhoea.

• Immune deficiency - for example, HIV infection.

• Pancreatic insufficiency - for example, cystic fibrosis, chronic pancreatitis, pancreatic cancer.

• Bile salts and acid malabsorption.

Structural causes

Malabsorption may be cause by loss of part of the bowel that is essential to absorb the broken down (digested) food into the body - for example:

• Removal of the stomach or part of the bowel after a stomach or bowel operation.

• Crohn's disease.

Causes outside the bowel

Examples include:

• An overactive thyroid gland (hyperthyroidism).

• Eating disorders: anorexia nervosa, bulimia nervosa.

Initial tests will include blood tests and stool tests. Further tests may include an abdominal ultrasound scan, barium studies and a computerised tomography (CT) scan or a magnetic resonance imaging (MRI) scan. Any further tests will depend on the likely underlying cause of the intestinal malabsorption.

The treatment will mainly depend on the underlying cause of the malabsorption. However, treatment will also be needed to increase the amount of essential nutrients in the body, including carbohydrates, proteins, fats, minerals and fat-soluble vitamins (nutritional support).