Dec. 11, 2003 -- Modern refrigeration is justifiably heralded as one of the most significant health advances of the 20th century, but French researchers say it may also be the cause of one malady -- the mysterious bowel disorder known as Crohn's disease.
It is just a theory, but they say the evidence points to food refrigeration as the catalyst for a dramatic increase in Crohn's cases. It is known that genetic predisposition plays a role in Crohn's disease, and environmental factors such as smoking and diet have also been implicated. But while theories abound, no single cause has been identified.
"Cold Chain Hypothesis"
In a paper published Dec. 13 in the journal The Lancet, widely respected Crohn's researcher Jean-Pierre Hugot, MD, and colleagues from Paris' Hospital Robert Debre point out that the arrival of mechanical refrigeration in kitchens throughout the industrialized world paralleled the rise in diagnosed cases of Crohn's disease.
They implicate specific bacteria that thrive at low temperatures as the potential cause of Crohn's disease in genetically susceptible people, and they dub this theory the "cold chain hypothesis."
"The cold chain hypothesis suggests that psychotropic bacteria such as Yersinia and Listeria-- commonly found in beef, pork, chicken, sausages, hamburgers, cheese, and lettuce -- contribute to the disease," Hugot noted in a news release.
Toothpaste and Corn Flakes
Crohn's expert David Sachar, MD, says it is widely believed that environmental changes during the 20th century have played a role in the rising prevalence of the disorder. He tells WebMD that the observation has led to some provocative, but hard to prove, hypotheses, such as those linking Crohn's disease to such components of modern life as toothpaste and corn flakes.
Sachar says Hugot and colleagues make a good case for their theory that food refrigeration is the environmental catalyst researchers have been looking for, and adds that there is no group of researchers with better credentials to make such a claim.
The director emeritus of the gastroenterology department at New York's Mount Sinai School of Medicine, Sachar says while it is clear the researchers are "in the right church," it is not clear that they are "in the right pew."
"Their suggestion that the modern industrialized environment has introduced new bacteria into the food supply is not in itself novel," he says.
"What is novel is their argument that it is refrigeration in particular that has promoted the emergence of causative bacteria in food. This is certainly a proposal worthy of serious consideration, but it may be no more plausible than parallel hypotheses linking the development of pathologic lesions to ingested small particles -- whether from food additives or packaging or cooking utensils or, for that matter, even from toothpaste."
If the hypothesis is proven, investigators say it could have implications for future Crohn's disease research. But nobody is suggesting that Crohn's patients should, or even could, avoid foods that have been refrigerated.
"(Refrigeration) has produced many benefits for western societies, including the prevention of enteric infections, allowing more people access to a well-balanced diet," Hugot and colleagues wrote. "These advantages clearly outweigh the putative risks discussed here."