For people who are conscientious about their diets, it will come as no surprise that some foods can increase their risk of cancer.
There are a lot of lists out there, some dubious, some more certain. As is the case for most of what you see online or get from the daily news, you need to read between the lines and think for yourself.
For some perspective, nutritional guidelines developed by the American Cancer Society (ACS) are a good place to start.
“Because people are interested in the relationship that specific foods, nutrients, or lifestyle factors have to specific cancers, research on health behaviors and cancer risk is often reported on the news,” the ACS says. “No one study, however, provides the last word on any subject, and single news reports may put too much emphasis on what appear to be contradictory or conflicting results.”
The ACS adds, however, there is enough evidence to point the finger at certain foods and beverages. Alcohol, for instance, raises the risk of several types of cancer, no doubt about it.
Studies have linked eating large amounts of processed meat to colorectal and stomach cancers. One prominent theory connects the risk to nitrites, which are added to lunchmeats and other meat products to preserve color and prevent bacterial growth.
Research also suggests that the way we prepare meats may increase our risk of cancer. That includes frying, broiling, and grilling, which form chemicals at high heat that may increase cancer risk.
The ACS says that, while there is no convincing evidence residues of pesticides and herbicides on fruits and vegetables increase the risk of cancer, it’s better to be safe and thoroughly wash produce before eating it.
“Studies in other countries link diets that contain large amounts of foods preserved by salting and pickling with an increased risk of stomach, nasopharyngeal, and throat cancer,” according to the ACS. “No evidence suggests that moderate levels of salt used in cooking or in flavoring foods affect cancer risk.”
Sugar increases calorie intake without providing any of the nutrients that reduce cancer risk. By promoting obesity and elevating insulin levels, high sugar intake may indirectly increase cancer risk.
There are high levels of salt and sugar in many of the foods we grab off of supermarket shelves. Read nutrition labels, and keep your intake of salt and sugar to at least moderate levels.
You’ve probably noticed that many foods are now marketed as being trans-fat free. Some of that is just silly – because some foods never had them to begin with. But, trans fats, whose potential risk lie in the hydrogenation that keeps them solid at room temperature, raise blood cholesterol levels. Their connection to cancer risk has not been determined, but the ACS nonetheless advises you to avoid foods that contain them.
Diets high in red meat have been linked to colon cancer. Dieticians suggest eating no more than 18 ounces of red meat per week.
A study by the American Institute for Cancer Research (AICR) to mark World Cancer Day suggests that, for Americans at least, it’s not about lists of foods you can blame for an increase in cancer risk, but about educating yourself on what science says we can do to definitely reduce cancer risk.
The AICR Cancer Risk Awareness Survey, conducted periodically since 2001, focused on the fact that Americans tend to miss the forest for all the trees. The trinity of moving more, weighing less, and eating better in general would prevent a third of the most common cancers in the U.S. Add protection from the sun, and that figure jumps to nearly half of cancers in the U.S.
"Instead of focusing on factors that you can't always control, we want Americans to learn more about the factors that you can and do control, every day," Alice Bender, the organization's associate director of nutrition programs, said in a statement.
Bender added that Americans focus too much on studies of individual risk factors, such as certain foods, but don’t see the overall scientific consensus. “When it comes to cancer, there are no guarantees,” she said. “But the science on lowering cancer risk has never been clearer.”
Cancer Research UK adds: “Very few specific foods or drinks have been convincingly shown to increase or reduce the risk of cancer. This is because our diets include many different foods, and those foods consist of many different nutrients and chemicals that could affect the risk of cancer. It is very difficult to design studies that can accurately look at the effect of a single food item.”
Still, if you want to ruminate, there’s plenty to choose from that can serve as food for thought. For the doozer of all food-based cancer risk lists, go here.
Once you get to the bottom of the list, you’ll note that it’s tied to a for-profit “detoxification” program, a book, and a lengthy disclaimer, obviously written by a lawyer, that takes the author off the hook for everything he just said. So take it with a grain of salt. But not too much. Of course.
The best advice of all may be the oldest advice of all: moderation in all things.
March 02, 2015
Christopher Nystuen, MD, MBA