Week of August 13, 2012
Contact: Alice Bender, (202) 328-7744
Karen Collins, MS, RD, CDN
American Institute for Cancer Research
Q: I know sausage and other processed meats are linked with colon cancer risk. Is it true that they’re linked with risk of diabetes, too?
A: Yes, several large population studies now link greater consumption of processed meats with increased risk of type 2 diabetes. Processed meats are those that are salted, cured or smoked or contain preservatives (such as nitrite- or nitrate-based products). Common examples of processed meat in the United States are bacon, sausage, hot dogs, processed canned meats, ham and packaged lunchmeats. Scientists have identified several potential mechanisms that could explain the convincing link between processed meats and greater risk of colorectal cancer. Risk of type 2 diabetes increases with overweight, so processed meats’ high content of fat (and therefore calories) could explain part of the link to diabetes risk. However, even after adjusting for weight and some other aspects of eating habits, people who consume the most processed meat show at least 45 to 60 percent greater risk of developing type 2 diabetes. Researchers hypothesize that nitrite-based preservatives form nitrosamine compounds within our gut increase cancer risk, and these nitrosamines also damage the cells of the pancreas responsible for producing insulin. Another potential explanation for the diabetes link involves formation during meat processing of compounds called advanced glycation endproducts (AGEs) that seem to increase low-grade inflammation and oxidative stress and both of these conditions promote a metabolic environment that can lead to type 2 diabetes.
Q: I've heard that intense cycling can elevate PSA levels. If that’s true, does that mean cycling puts prostate health at risk?
A: Men, particularly those with a history of prostate issues, may be concerned about rumors that bicycle riding elevates blood levels of prostate-specific antigen (PSA), a marker for prostate cancer. It’s true that rigorous cycling, bicycle saddle pressure, and active pelvic muscles squeezing the prostate gland, may cause a temporary increase in PSA levels in some men, but this is not something all men should expect from cycling. When it does occur, it does not mean cycling is putting prostate health at risk; it is simply a factor that doctors need to consider when they interpret PSA test results. The prostate specific antigen (PSA) test measures blood levels of PSA, a protein made by the prostate. The higher a man’s PSA level, the more likely it is that prostate cancer is present. However, PSA may also be elevated in non-cancerous conditions, such as infection, prostatitis and benign prostatic enlargement (known as BPH). Like cycling, prostate manipulation during manual exams or medical procedures and recent ejaculation may have a similar temporary effect. The National Cancer Institute advises men, especially those over the age of 50, or with a history of prostate cancer or elevated PSA, to discuss rising PSA levels with their physician, and to make sure their doctor is aware of potential influences such as high-intensity cycling on their PSA test results. Bicycling, whether indoors or outdoors, is an excellent and enjoyable form of exercise. For men who cycle more than three hours a week on extended rides, more common bicycle saddle-related pressure problems, such as numbness, can often be avoided by adjustments in seat height, tilt, padding and width, as well as padded cycling shorts.
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