Crohn's disease and milk

Scientists at St Georges hospital in London are claiming there is a link between Crohns disease - a debilitating digestive problem that affects more than 40,000 people in the UK - and drinking milk. Professor John Hermon-Taylor, a surgeon, and his team have reported finding minute traces of an organism known as myco-bacterium paratubercolosis in two thirds of the intestinal tissue removed from Crohns patients after surgery and although the National Dairy Council has disputed such claims on the basis of its own studies, the hospital researchers say they have also found the organism in supplies of whole, pasteurised milk.

Hermon-Taylor and his colleagues are suggesting mycobacterium, which causes Johnes disease in sheep and cattle (a condition similar to Crohns disease in humans), is being transferred through food and water systems and can sometimes survive the process of pasteurisation. The full results of the study will be published in September and these may be convincing enough for sufferers to be told, for the first time since the condition was originally diagnosed in 1932, that scientists have discovered a concrete cause.

Although public awareness of the condition is still limited, 3000 new cases are diagnosed every year. Crohns affects both men and women equally. The incidence has doubled in the past 20 years.

Crohns disease can affect any part of the digestive tract but is more commonly found in the small intestine where it causes inflammation, deep ulcers and scarring to the intestinal wall. The main symptoms - tiredness, urgent diarrhea and loss of weight - can be controlled by drugs but surgery is frequently necessary to remove the damaged or narrowed sections of the intestine. There is no known cause, and no known cure, for Crohns, although there is evidence of a genetic predisposition.

Sisters Sue Middleburgh 44, and Ruth Ardley, 40, have both suffered from Crohns disease since their teens. Middleburgh, a financial adviser who was first diagnosed at 16, remembers passing out from the crippling stomach pain but being told her symptoms were psychological "After one operation at the age of 24, I turned to acupuncture and for the past 12 years I have coped with the disease without further surgery, although there are times when it does get me down", she says.

Ardley a part time book-keeper and mother of two, says Crohns affects not only her life but her whole family. "Fortunately, I have an understanding husband but it is a difficult disease to live with. When you need the toilet you have to go straight away and people don't understand the urgency". The national association for Crohns and colitis (NACC) issues its 24500 members with a can't wait card, designed to facilitate quicker access to public lavatories in shops and also runs support groups across the country for sufferers. Richard Driscoll the NACC director is cautious about the new research linking Crohns with milk and says one problem is that no other research group has as yet been able to repeat the results reported by the group at St Georges hospital.

"Aside from the genetic aspect we believe there may be environmental factors that give rise to the disease. There must be something about our modern way of living that is causing an increase in sufferers" he says. "It may be there is more than one external agent that triggers the disease, but the sad fact for sufferers is that, once they have it, it is a lifelong condition for which there is no cure"

Researchers at the Royal Free hospital in London have suggested the measles virus may be linked to the disease. The hypothesis is that measles may cause lasting damage to the blood vessels lining the bowel wall, triggering the onset of Crohns in some people.However like the milk hypothesis, this research is in its infancy and, despite a suggestion that a measles vaccine given to children could lead to Crohns in later life, the consensus of medical opinion is that the benefits of the vaccine outweigh the unproven risks of a link with Crohns.

Driscoll emphasises that there is no link between Crohns and irritable bowel syndrome - one does not lead to the other and there is in fact, no tissue inflammation with the latter and no obvious sign of damage to the intestine.

Another problem facing Crohns sufferers is that it can take up to a year to rule out similar conditions and many are sent packing by their GP's who mistakenly believe the symptoms to be psychosomatic.

"The best way to describe the condition to non-sufferers is to tell them to think of the worst tummy bug they have ever had on holiday and then to try to imagine living that every day," Driscoll says.

"Sufferers never know how they will feel from one day to the next, which is debilitating enough and although Crohns is more common that multiple sclerosis and almost as prevalent as Parkinsons disease, people know very little about it"

LA Times

Monday, September 18, 2000 Home Edition Section: Health Page: S-1

Milk May Be the Carrier of Crohn's

Causes: Some argue that the bug that may cause the disease is found in dairy herds.

By: THOMAS H. MAUGH II TIMES MEDICAL WRITER

If, as some scientists are now convinced, Crohn's disease is caused by a microorganism, the question becomes: How is it transmitted?

The shocking answer, they say, is through that most sacrosanct of beverages--milk. The microorganism under suspicion, Mycobacterium avium subspecies paratuberculosis, or MAP, is common in U.S. dairy herds, activists argue, and it is not killed by conventional pasteurization. Transmission of MAP from infected cattle to humans through milk could explain much about the occurrence of Crohn's, including its geographical distribution and rising incidence. The purported spread of MAP through milk "constitutes a public health disaster of tragic proportions," said Dr. John Hermon-Taylor of St. George's Hospital Medical Center in London.

Both the U.S. dairy industry and the Food and Drug Administration argue vehemently that the U.S. milk supply is safe and that pasteurization is effective at removing any potential threats. But several large milk distributors in Britain have already changed their pasteurization procedures to make it more likely that the microorganism will be killed. The suspected links between MAP, milk and Crohn's have received a great deal of attention in that country, but none in the United States.

Some facts seem indisputable. MAP causes Johne's disease in cattle, a debilitating disorder whose symptoms are identical to those of Crohn's in humans. Large numbers of cattle in the United States are infected by the organism. According to a National Animal Health Monitoring System study conducted in 1996, 22% of U.S. dairy herds have infected cows. The cows secrete the mycobacterium in their milk. And there the two sides part company. The dairy industry argues that the link between MAP and Crohn's is unproved and that, even if there were a link, pasteurization kills the microorganism.

"It is the position of the Food and Drug Administration that the latest research shows conclusively that commerical pasteurization does indeed eliminate this hazard," Joseph Smucker, FDA's milk safety team leader, wrote to activists concerned about the risk.

But the activists have compiled a growing dossier of evidence. Dr. Walter Thayer of Rhode Island Hospital notes that Crohn's is not distributed evenly around the world, but is seen only in milk-drinking areas--Australia, southern Africa, Europe, the United States, Canada and New Zealand. It is rare in India, where they drink milk but boil it first.

Work by Hermon-Taylor and Dr. Irene Grant of Queen's University in Belfast, Ireland, has shown that DNA from MAP was present in about 20% of milk samples collected throughout the country. Living bacteria could be grown from many of the samples.

An as-yet-unpublished study by the Ministry of Agriculture in Britain found that researchers could grow MAP from at least 3% of samples of commercial pasteurized milk, Hermon-Taylor said. "It confirms, as sure as God made little green apples, that retail milk in Britain is a definite source of human exposure to these bugs," he added.

MAP is extremely difficult to kill, and commercial pasteurization--which involves heating milk to 161 degrees Fahrenheit for 15 seconds--is not sufficient, according to studies by Grant. Heating to higher temperatures--up to 194 degrees for the same period of time--is also not effective, she said, but increasing the pasteurization time to 25 seconds, even at 161 degrees, is.

Last year, several large milk distributors in Britain told their suppliers to increase pasteurization time, and that has been accomplished. Activists want to see the same steps taken here.

"There comes a point in time where consumer health takes precedence over commerical concerns," says Karen Meyer, president of the Paratuberculosis Awareness and Research Assn. "If a human pathogen is entering the food chain, that is a major concern. We need to ensure the protection of the public health."

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