Red meat and colon cancer

The next time you order a Dagwood on rye, ask them to hold the salami and switch from rye to whole wheat. Also, think twice before ordering bacon, cured ham, pastrami, corned beef or hot dogs.

Preliminary results from a massive study indicate that eating preserved or processed meat boosts the risk of colorectal cancer by 50 percent. The study, presented at the European Conference on Nutrition and Cancer, also reestablished the protective reputation of fiber, noting that a diet rich in fruits, vegetables and whole grains can reduce the risk of colorectal cancer by 40 percent.

Recent American analyses that detected little or no benefit from eating fiber were criticized by the Europeans as narrow and imprecise. "These findings put fiber firmly back on the menu as an important part of a healthy diet," says Gordon McVie, M.D., director general of the Cancer Research Campaign.

Surprisingly, the report found no clear connection between cancer risk and fresh beef, lamb, pork or veal. (Most previous investigations linking bowel cancer with meat intake have not distinguished between fresh and processed meat.) Still, an ancillary lab study at the Human Nutrition Unit at Cambridge University found that people who eat diet rich in red meat have higher levels of potentially cancerous compounds in the lining of the colon, compared to people who get their protein from chicken, fish, dairy or soy products. Investigators found a direct link between the cancerous compounds and dietary levels of heam, an iron-rich part of the blood that is higher in red meat than in white, and higher still in processed meat.

But researchers also say it's too early for a final verdict on the possible dangers of red meat, especially when different cuts of meat and different preparation methods may affect cancer risk. For example, cooking red meats, poultry and fish at very high temperatures results in foods being coated with heterocyclic amines, which can cause cancerous tumors in animals (see "10-Second Tip," below).

The European investigation is the largest study of diet and cancer ever undertaken, involving more than 400,000 people from nine countries. It is being coordinated by the International Agency for Research on Cancer, a branch of the World Health Organization.