Red meat linked to one type of colon cancer

Women who eat more red meat appear more likely to develop cancer in the lower part of the colon, but not in the upper part of the colon near the small intestine, new research reports.

These findings reinforce the theory that the two types of colon cancer are distinct entities, and should be considered separately, the authors write in the International Journal of Cancer.

And for meat-lovers, lead author Dr. Susanna C. Larsson of the Karolinska Institutet in Stockholm, Sweden recommends eating red or processed meats "sparingly" to reduce cancer risk.

"Replacing red meat with a combination of fish, poultry, and legumes may be recommended, and it may also reduce the risk of coronary heart disease and possibly other chronic diseases," she told Reuters Health.

This is not the first study to associate eating red meat with colon cancer. In one previous report, researchers found that people who consistently ate the most red meat and processed meats had a 50-percent higher rate of colorectal cancer than those who ate the least amounts of red or processed meat.

Larsson explained that red meat contains iron, along with substances from the cooking and processing of red meat, which researchers have shown may increase the risk of colon cancer.

Recent research has also suggested that cancer that originates in the upper part of the colon - called proximal colon cancer - may have different causes and characteristics than cancer that begins in the lower part of the colon, near the rectum, called distal colon cancer.

During the current study, Larsson and her colleagues reviewed information collected from 61,433 women over an average of 14 years, noting who developed proximal and distal colon cancers, and their eating habits.

The investigators found that women who ate more red meat were more likely to develop distal - but not proximal - colon cancer. Specifically, the risk of distal colon cancer increased by 70 percent for every additional 100 grams of red meat per day women ate.

Overall, women who ate the most red meat were more than twice as likely to develop distal colon cancer than women who ate the least amount of red meat.

Eating fish had no clear influence on colon cancer risk, although eating chicken appeared to reduce the risk slightly.

Larsson explained that different types and amounts of bacteria are present in the distal and proximal colons, which may help explain why different regions respond differently to red meat.

Moreover, the distal colon contains less water than the proximal colon, which means that any potentially "harmful compounds" will be more concentrated in the lower part of the colon, which may increase cancer risk, she added.

SOURCE: International Journal of Cancer, February 20, 2005.