Food poisoning as a cause of irritable bowel syndrome

A US health organisation last week released a report warning that foodborne illnesses often have long-term consequences, especially in children, including the development of chronic illnesses such as irritable bowel syndrome.

The Center for Foodborne Illness Research & Prevention (CFI) report reviews what is currently known about the long-term health outcomes associated with five key foodborne pathogens. It also points out how under-reporting, inadequate follow-up and a lack of research make it difficult to assess the impact that foodborne illness is having.

"Foodborne illness is a serious public health issue in the 21st century", says Dr. Tanya Roberts, Chair of CFI's Board of Directors and an author of the report. "But the vast majority of these illnesses are never reported to public health agencies, leaving us with many unanswered questions about the impact that foodborne illness is having on different populations, particularly young children and the elderly."

The CFI's report, The Long-Term Health Outcomes of Selected Foodborne Pathogens, therefore calls for a new approach to foodborne illness research and surveillance.

Most people tend to assume that food poisoning results in gastroenteritis with symptoms of abdominal cramping, nausea/vomiting, diarrhoea and other very unpleasant symptoms but that it is an acute illness with no lasting effects. Unfortunately this is often not the case. The report also provides expert reviews about some of the long-term health outcomes of the five foodborne pathogens focused upon. Besides irritable bowel syndrome (IBS) these outcomes include hypertension, diabetes, kidney failure and mental retardation.

The full report gives detailed overviews of each of the five foodborne pathogens but the one most associated with IBS is E. Coli O157:H7 of which the report says:

Disproportionately affecting children under 19, E. Coli can taint ground beef and other meats, green leafy vegetables, unpasteurized (or raw) milk and cheeses made from such milk. About 15% of children infected with E. coli O157:H7 develop hemolytic uremic syndrome, which can lead to kidney failure, chronic kidney problems, diabetes, high blood pressure, gallstones, irritable bowel syndrome, narrowed gastro-intestinal passages and neurological problems -- including seizures -- that can take as long four years to resolve.

Children are disproportionately affected for a number of reasons. They are physically smaller so it takes a smaller dose of a harmful bacteria to cause illness. They are also less equipped to deal with pathogens once they have been ingested since they produce smaller quantities of stomach acid which usually kills most foodborne bacteria and their immune systems are less mature and less equipped to deal with infections.

Food poisoning is well known to increase the risk of a person subsequently developing IBS and in fact has its own name - Post-Infectious Irritable Bowel Syndrome (PI-IBS). Research indicates that a bout of food poisoning (bacterial gastroenteritis) makes an individual 12 times more likely to develop symptoms of IBS within the same year. The most common form of IBS following infection is diarrhoea prredimonant IBS (IBS-D). It is thought infection with foodborne pathogens alters the funcvtion of the gut nervous system, making it more sensitive, while also causing a shift in the immune system that results in increased amounts of inflammatory chemicals. Disturbances in the gut microflora may also play a role.

In line with the CFI report the American Academy of Pediatrics is urging public health officials, physicians and researchers to do a better job of understanding and stopping outbreaks of food poisoning and has also provided the following guidelines to help the public avoid food poisoning, therefore reducing the risk of both acute and chronic illness.

• Cook meat thoroughly.
• Clean work surfaces, cutting boards and bowls thoroughly after using them on uncooked meats or eggs to prevent contamination of other foods.
• Wash produce before consuming it.
• When buying milk and juice, make sure they're pasteurized, and make sure that products made from milk are made with pasteurized milk.
• Report any food-borne illness to a local health department.

With both health authorities and the public being more aware of issues surrounding foodborne illness perhaps the incidence of serious long-term consequences can be avoided.

Source: Center for Foodborne Illness Research and Prevention