September 2009

Increased Intestinal Permeability - 'Leaky Gut'
30th September 2009

Increased Intestinal Permeability, 'Leaky Gut' , GAP Syndrome

Introduction

A well functioning gut, or gastro-intestinal tract, is essential for good health- our ability to digest and absorb the nutrients from the food we eat and maintain a strong immune system is directly linked to the health of this important organ. The gut is essentially a long tube which begins when we swallow food, continues down and through the stomach then small intestine and eventually to the large intestine and colon which manages the excretion of waste products.

The gut plays a key role in (i) breaking down food and absorbing vital nutrients and (ii) in supporting immune health by acting as a barrier to infections from bacteria, viruses or other pathogens. Problems with the integrity of the gut wall have been associated with many health conditions. Some of the common terms used to describe this increase in permeability include Hyper Permeability Syndrome , 'leaky gut' and GAP Syndrome. 

How the gut wall works

When healthy, the gut wall is made up of small cells packed together with very narrow spaces held together by ‘tight junctions’. Food which has already been digested is broken down into even smaller particles in the intestines. Then special carriers that are part of the cell carry nutrients across the cell where they pass into the blood and are then utilised to make energy and carry out all of the vital functions within the body. Meanwhile, any large pieces of food that have not been digested properly and any foreign invaders like bacteria or viruses are kept out of the body as they can not pass through the tight gaps between the cells. 

If the gut wall has been damaged for any reason it may become more permeable or ‘leaky’. This means that the special carriers that help the nutrients get into the body may no longer work and nutrients may not be absorbed properly. In addition, the gaps between the cells in the gut widen allowing large particles of undigested food or other pathogens such as bacteria to enter the body which can lead to multiple symptoms.

Factors which may contribute to an increase in intestinal permeability

  • chronic stress
  • frequent use of non-steroidal anti-inflammatory drugs such as ibuprofen, antibiotics or steroid medications
  • stomach or intestinal infections
  • food allergies or intolerances
  • alcohol, caffeine and other stimulants
  • candida or other pathogenic overgrowth
  • high consumption of convenience foods, high carbohydrate, high sugar diets
  • imbalances in the gut bacteria 
  • poor digestion  
  • chemotherapy
  • ageing itself

Testing for 'leaky gut'

There are a number of tests measuring intestinal permeability but each follow a similar principle : you are asked to drink a small amount of a solution containing sugars or a substance called Peg 400 and then collect urine in a sample container for a period. A small percentage of the sample is then sent directly to the lab using the provided kit. The test measures how many of these sugars pass out of the body in urine and give a measure of whether there is increased permeability in the gut membrane.

Why lab testing may be useful 

A test to measure intestinal permeability measures how well the gut is likely to be functioning in both absorbing food and preventing pathogens from entering the body. The results of such a test can directly inform where to focus the initial nutritional programme. There are many factors which may contribute to leaky gut syndrome and this test is often used alongside other tests which help pinpoint the causative factors for each individual.  ‘Leaky gut’ is not a permanent condition and a sound nutritional approach can help restore the gut and reduce symptoms. A test for intestinal permeability can also be useful when planning a pregnancy as a well functioning gut plays a key role in helping to nourish and protect a growing baby. 

References and Further Reading

  1. BESTED, A. C., SAUNDERS, P. R. & LOGAN, A. C. (2001) Chronic fatigue syndrome: neurological findings may be related to blood-brain barrier permeability. Medical Hypotheses, 57, 231-237.
  2. CAMPBELL-MCBRIDE, N. (2004) Gut and psychology syndrome : natural treatment for autism, dyspraxia, A.D.D., dyslexia, A.D.H.D., depression, schizophrenia, Cambridge, Medinform Publishing.
  3. LIPSKI, E. (2005) Digestive wellness, New York, N.Y. ; London, McGraw-Hill.
  4. LIU, Z., LI, N. & NEU, J. (2005) Tight junctions, leaky intestines, and pediatric diseases. Acta Paediatr, 94, 386-93.
  5. MACDONALD, T. T. & MONTELEONE, G. (2005) Immunity, Inflammation, and Allergy in the Gut. Science, 307, 1920-1925.
  6. MAES, M., COUCKE, F. & LEUNIS, J. C. (2007) Normalization of the increased translocation of endotoxin from gram negative enterobacteria (leaky gut) is accompanied by a remission of chronic fatigue syndrome. Neuro Endocrinol Lett, 28, 739-44.
  7. MEDDINGS, J. (2008) The significance of the gut barrier in disease. Gut, 57, 438-40.
  8. PICHE, T., BARBARA, G., AUBERT, P., BRULEY DES VARANNES, S., DAINESE, R., NANO, J. L., CREMON, C., STANGHELLINI, V., DE GIORGIO, R., GALMICHE, J. P. & NEUNLIST, M. (2009) Impaired intestinal barrier integrity in the colon of patients with irritable bowel syndrome: involvement of soluble mediators. Gut, 58, 196-201.
  9. SIGTHORSSON, G., TIBBLE, J., HAYLLAR, J., MENZIES, I., MACPHERSON, A., MOOTS, R., SCOTT, D., GUMPEL, M. J. & BJARNASON, I. (1998) Intestinal permeability and inflammation in patients on NSAIDs. Gut, 43, 506-11.
  10. WHITE, J. F. (2003) Intestinal Pathophysiology in Autism. Experimental Biology and Medicine, 228, 639-649.