Diet and Cancer

Over the past 50 years, deaths from heart disease, stroke and infectious diseases have decreased significantly, but the same cannot be said of cancer.

By Mark Anthony, Ph.D.

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Unlike meat, fish is not generally associated with the “Western Dietary Pattern” that includes low intake of fruits and vegetables, and high consumption of desserts and fried foods. This could account for some of the differences in cancer risk between the two groups.

Another factor is the presence of omega-3 fatty acids. Fish, especially the wild, deep-ocean varieties, are high in omega-3s.

“Cold-water fatty fish, such as wild salmon, sardines, albacore tuna and sablefish are among the very best sources of omega-3s,” says Randy Hartnell, president of Vital Choice Seafood (, Anacortes, Wash. Omega-3 fatty acids are powerful anti-inflammatory agents, but their effect on cancer is unclear.

High meat consumption was also linked to gastric cancer, but the risk was greatest if the subjects also were infected with Helicobacter pylori, a bacterium responsible for most cases of ulcers and chronic gastritis. H. pylori can weaken the protective lining of the stomach and small intestine, allowing corrosive digestive acids and enzymes to irritate the sensitive gut lining.

In 1994, the World Health Organization’s International Agency for Research on Cancer declared H. pylori a "definite carcinogen": Half of the world’s population may be infected with H. pylori, which thrives in crowded, unsanitary conditions. Yet many persons have the organism in the gut without any ill effects. Also, in the study meat eaters were more likely to be former smokers, and tended to eat less fruits and vegetables – both confounding risk factors.

The Whole Diet

Many healthy foods and food components are associated with a reduced risk of cancer, and while it’s tempting to read a study and declare that green tea, soy, blueberries, tomatoes or any one food or food fraction prevents cancer, we’d be missing the point: It’s the whole diet.

It also is clear that lowering our risk of cancer requires pursuing total health. “Manufacturers of nutrient-rich foods and beverages need to meet consumers’ taste, packaging and branding expectations,” says Seth Goldman, co-founder of Honest Tea (, Bethesda, Md. “If our products don’t taste great and look great or are not easy to understand, consumers will pass us by. They have too many choices, and processed food folks have already set the bar quite high.”

State Your Claim

The difficulty in pinning down the relationship between diet and cancer drives the highly stringent FDA guidelines regarding health claims on food labels. The FDA requires “convincing evidence” that a particular food or food ingredient is associated with a decreased risk of cancer before any claims to that effect can be made on the label.

For example, omega-3 fatty acids are essential to health and are known anti-inflammatory agents. Some studies link them to a lowered risk of cancer, too. However, the evidence is not sufficiently convincing to claim this – or even imply it – on a food label.

The FDA allows only a general statement regarding fats and cancer; “Development of cancer depends on many factors. A diet low in total fat may reduce the risk of some cancers,” is considered a responsible claim.

Claims regarding fiber-containing fruits, vegetables, and whole grains are similarly restricted. The food must be low in fat; a good source of dietary fiber (without fortification) and the type of fiber may not be specified. “Low-fat diets rich in fiber-containing grain products, fruits, and vegetables may reduce the risk of some types of cancer, a disease associated with many factors,” is a model claim permitted by the FDA.

This conservative approach protects consumers and manufactures. But it also makes it tricky to promote foods with added nutraceuticals as helping to prevent cancer. For more information on FDA claims, visit

For more on cancer and nutrition, visit You’ll find more than 100 articles, products and papers.

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