Diet is a powerful tool to prevent and fight chronic disease. In regard to cancer, what we eat has the potential to modify our genes, either improving our health or leaving us susceptible to developing cancer.
Processed food consumption is at an all-time high, while intake of whole foods such as fruits and vegetables is less common. Approximately 60% of calories consumed by adults in the United States come from processed foods. Examples of processed foods include frozen dinners, pastries, boxed meals and hot dogs. Many foods are processed for convenience, to increase shelf life or to improve palatability (texture, taste and appearance). This is done using food additives, artificial flavorings, colors, sweeteners and preservatives.
Interestingly, a study led by researchers from the International Agency for Research on Cancer (IARC) found that for every 10% increase in consumption of processed foods, there is a 2% increase in overall cancer risk and a 19% increase in ovarian cancer risk. Causation was not identified, but other research has raised suspicions that food additives may be linked to hormone disruption and oxidative processes within the body.
The IARC has a classification system in which it reviews current research and categorizes substances that may cause cancer or be carcinogenic.
- Class 1 substances: Known to cause cancer in humans. Examples: smoking, alcohol intake.
- Class 2A substances: Probably cause cancer in humans. Examples: nitrates and nitrites (found in processed meats).
- Class 2B substances: Possibly cause cancer in humans. Examples: titanium dioxide (found in sauces, icings, candies, toothpaste and chewing gum).
You might be thinking that if these classifications are in place, why these additives are still present in foods. The Food and Drug Administration (FDA) maintains a list of more than 3,000 ingredients used in processed foods. The FDA requires that a food additive be proven safe for its intended use unless it is already “generally recognized as safe” by qualified experts with scientific training and experience or meets other exclusions outlined in Section 201(s) of the Federal Food, Drug, and Cosmetic Act.
Even though the FDA monitors food additives, it is still a good idea to limit intake of these ingredients to promote good health. In addition to potentially lowering cancer risk, reducing processed food intake can help promote a healthy weight and lower blood pressure and blood sugar.
Here are simple ways to be an informed shopper and limit processed foods:
- Follow a plant-based diet. Focus on eating whole fruits, vegetables, whole grains and high-quality animal proteins.
- Packaged fruits and vegetables are OK when fresh is not available.
- Look for foods labeled “no added salt” or “low sodium.” In general, try to limit sodium intake to 2,000 milligrams daily.
- Look for foods with no added sugars. Check the ingredient list, as sugar can have many different names (e.g., high-fructose corn syrup, dextrose, fructose, corn syrup, malt syrup, honey, sweeteners).
- Become aware of potentially harmful food additives. Cspinet.org is a helpful resource to learn more.
- Shop the outer perimeter of the grocery store rather than the aisles.
- Look for foods with short ingredient lists — the fewer the ingredients, the less processed the food.
- Enjoy the art of cooking. This allows you to better control ingredients (e.g., prepare a homemade pizza using ingredients in your pantry instead of buying frozen pizza).
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References:
- U.S. Food and Drug Administration. “Food Ingredients & Packaging.” Accessed April 6, 2026. https://www.fda.gov/food/food-ingredients-packaging.
- Bischoff NS, et al. Possible adverse effects of food additive E171 (titanium dioxide) related to particle-specific human toxicity, including the immune system. Int J Mol Sci. 2020 Dec. 28;22(1):207. doi:10.3390/ijms22010207.
- Chang K, et al. Ultra-processed food consumption, cancer risk and cancer mortality: A large-scale prospective analysis within the UK Biobank. EClinicalMedicine. 2023 Jan. 31;56:101840. doi:10.1016/j.eclinm.2023.101840.
- Martínez Steele E, et al. Ultra-processed foods and added sugars in the U.S. diet: Evidence from a nationally representative cross-sectional study. BMJ Open. 2016 Mar. 9;6(3):e009892. doi:10.1136/bmjopen-2015-009892.
- Smith MT, et al. Key characteristics of carcinogens as a basis for organizing data on mechanisms of carcinogenesis. Environ Health Perspect. 2016 June;124(6):713-21. doi:10.1289/ehp.1509912.
