Evidence mounts for Crohn's-milk consumption connection

Americans, unlike the British, have largely distanced themselves from the hubbub over the supposed connection between milk and Crohn's disease, but that might all change as activists assemble increasing amounts of evidence reportedly indicating a link.

In the United Kingdom, concerns about the presence in milk of mycobacterium avium subspecies paratuberculosis (MAP), suspected of causing Crohn's, has prompted several major milk distributors to alter pasteurization methods to increase the likelihood MAP will be eliminated, according to a recently published Los Angeles Times article.

Reportedly on the rise, Crohn's is a chronic inflammatory disease capable of affecting any part of the gastrointestinal tract.

In February, British newspaper The Times reported that preliminary results from a study in which 1,000 pasteurized milk samples were analyzed showed that four out of 129 contain MAP (see related article).

The previous month, a British physician labeled the presence of MAP in unpasteurized milk a "public health disaster" and said government leaders should stop the sale of unpasteurized milk and boost current pasteurization procedures.

"The problems caused by MAP in the milk supply constitute a public health disaster of tragic proportions, for which a range of remedial measures are urgently needed and for which the government must take responsibility," John Hermon-Taylor, head, surgical department at St. George's Hospital, London, was quoted by Reuters at the time.

But Hermon-Taylor's point of view finds no support among the U.S. dairy industry or FDA, which say the U.S. milk supply is safe and that pasteurization is doing its job at keeping bugs out of the beverage. The U.S. dairy industry claims that a MAP-Crohn's connection isn't confirmed and if a link did exist, pasteurization eliminates the microbe, a position backed by FDA.

But while the jury still is out on whether MAP causes Crohn's in humans, it has been confirmed to give cattle Johne's disease, which shares the same symptoms as that of Crohn's in the human population, the Los Angeles Times report said.

A 1996 National Animal Health Monitoring System study indicates that 22% of U.S. dairy herds include MAP-infected cows, which secrete mycobacterium in their milk.

Activists say that despite FDA's and the U.S. dairy industry's assertions to the contrary, evidence points to a MAP-Crohn's link. Walter Thayer, a physician at Rhode Island Hospital, says that Crohn's only occurs in the world's milk-drinking regions, including Australia, New Zealand, Europe, the United States, Canada and southern Africa. Crohn's is rare in India, where milk is consumed after boiling.

Commercial pasteurization, which heats milk to 161 degrees Fahrenheit for 15 seconds, is ineffective in killing MAP, according to studies conducted by Irene Grant of Queen's University in Belfast, Ireland. Raising the heat to 194 degrees for the same duration also proved incapable of eliminating the bug. However, boosting pasteurization time to 25 seconds even at 161 degrees destroys the microbe.

Grant also worked with Hermon-Taylor on a study showing that MAP existed in roughly 20% of milk samples culled from throughout Ireland, with living bacteria capable of being grown from several samples.

Several British milk distributors last year instructed their producers to boost pasteurization duration. American activists, including the Paratuberculosis Awareness and Research Assn., want the same action to occur in the United States.

British authorities say that MAP might be responsible for the United Kingdom's 80,000 cases of Crohn's. The nation's Public Health Laboratory Service statistics indicate that since 1992 more than 420 individuals have suffered pasteurized milk-related food poisoning. Children often have been the victims, with one child having died and others treated for kidney damage.

Edited by Gerry Clark
Managing Editor, Dairy Network.com