Mice, however, rarely suffer though the precise reasons are unknown. Jeffrey S. Clark and colleagues, writing in The Journal of Physiology, have come up with some answers.

Kidney stones are crystalline deposits of various chemicals that should normally be excreted in the urine, particularly oxalate. Common in food, it is usually disposed of by the gut into the faeces by exchanging it for chloride. If there is little chloride available, in a low-salt diet for example, oxalate may be retained by the intestine to eventually be excreted by the kidneys, where the stones may form.

Mice, unlike men, do not spontaneously develop kidney stones, making it difficult to set up an animal model of this common disease. Now, some reasons for this difference between mice and men may have emerged.

The researchers showed that the human form of the protein responsible for secreting oxalate into the faeces requires a lot more chloride for efficient oxalate transport than the same structure in mice. Worse still, a variant form of the protein found in some people has even further reduced ability to export oxalate. Mice, it seems, are far more efficient at disposing of oxalate than we are.

Uncovering the molecular mechanisms of oxalate removal should help to develop improved treatments to prevent or even reverse the formation of kidney stones in humans, and paves the way for a mouse model of the disease to aid kidney stone research.

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According to the United States Department of Agriculture, Americans were eating an average of 36 ounces of red meat every week in 2006, Scroggs said. Scroggs recommends serving about three ounces (about the size of a deck of cards) of cooked red meat at meals. If you follow this recommended serving size, you can include red meat in as many as six meals of your weekly diet.

AICR also recommends eating very little processed meat (meat preserved by smoking, curing, salting or adding chemical preservatives), such as ham, bacon, hot dogs, sausages, pastrami and salami. Every ounce and a half of processed meat eaten a day is thought to increase a person's risks of developing colorectal cancer by 21 percent.

It's a good idea to avoid eating processed meats as much as possible, Scroggs said. Save that hot dog for special occasions, such as a family cookout or the ballpark.

Colorectal cancer is the third most common cancer found in men and women in this country. The American Cancer Society estimates almost 150,000 new cases of colorectal cancer in the United States for 2008. Colorectal cancer is the second leading cause of cancer death among Americans but is considered a highly preventable disease.

For more information on colorectal cancer prevention strategies, visit mdanderson/cancerawareness.

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