Dear Dr. SerVaas: I have heard that nitrates in processed meats could be linked to cancer. What are processed meats?

Dear Reader: Processed meats include ham, bacon, pastrami, bologna, corned beef, dried beef, pickle loaf, sausages, hot dogs, and other lunchmeats. Sixty-five to 70 percent of all pork products in the United States are processed.

Meatpackers add nitrates to processed, smoked, or cured meats to keep them from spoiling. Nitrates, however, break down to form nitrosamines, known to cause cancer in animals and perhaps in human beings. To counteract that problem, packers then add vitamin C to the meat to delay the formation of nitrosamines. But vitamin C isn't as stable as nitrosamines, even in the best of conditions.

Early results of a major new study show that eating about two ounces of processed meat daily could increase the risk of colorectal cancer by 50 percent. If your family enjoys ham casseroles, chipped beef on toast, beans and franks, and other processed meat recipes, consider adding one-half teaspoon of vitamin C crystals per six servings of these dishes.

Vitamin C crystals are less expensive to purchase than capsules and can be easily mixed with fruit juice or water. Bronson Laboratories advertises 1,000 mg vitamin C capsules for about eight cents each; 1,000 mg of crystalline C (from the same company) costs about four cents.