There's so much conflicting information out there about nutrition and how it affects our health, especially when it comes to conditions like cancer. It's difficult to tell which foods you should take caution with and which you may want to eat more of.
When it comes to foods and complex diseases like cancer, there's no definitive evidence any food directly causes or prevents cancer. That said, there are some foods associated with a higher risk of certain cancers, while others have been tied to a lower risk.
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Below, we've untangled the evidence on four foods linked to cancer, and how worried you should actually be.
1. Processed Meat
You probably already know processed foods aren't the most nutritious, especially when it comes to meat. Dietitians and doctors have long debated which types of meat to keep in your diet — and then there are those who say to cut it out completely.
Here's the lowdown on red meat versus processed meat. Researchers did not find a link between unprocessed red meat and overall mortality (including cancer-related deaths), but they did find an association between overall mortality and processed meat in a January 2019 review in the European Journal of Epidemiology.
Previous studies have tied processed meat and cancer, and the current body of research suggests nitrite may be to blame. This compound, which is added during processing, was linked to a higher risk of developing colorectal cancer in a November 2019 review in Nutrients.
Processed meats and red meat are also often cooked with high heat, such as with grilling, which may produce cancer-causing compounds, according to the National Cancer Institute (NCI), so it's probably a good idea to limit the amount of processed meat in your diet.
Processed meats are foods like:
- Hot dogs
- Canned meat
- Deli meats
Examples of unprocessed red meat include:
- Fresh ground beef
- Lean beef tenderloin
Heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) are the chemicals you need to worry about when grilling, according to the NCI.
HCAs are produced in the meat over high temps and the PAHs are in the smoke that can bind to your food. It's important to note these chemicals can adhere to any meat, not just red or processed meat.
2. Added Sugar
There is some research linking high amounts of added sugar to cancer. For example, drinking sugar-sweetened beverages was tied to a higher overall risk of cancer in a July 2019 study in the BMJ.
Excess added sugar is related to weight gain and not just any weight gain: Specifically, it's associated with central adiposity or belly fat. Added sugar can lead to extra pounds around the midsection, and a larger waistline puts you at a higher risk for cancer, according to the MD Anderson Center.
That said, this doesn't necessarily mean added sugar definitely leads to cancer. Rather, it might contribute to other factors that increase your risk. Your best bet, then, is to stick with the current American Heart Association recommendations of no more than 6 teaspoons of added sugar per day for people assigned female at birth (AFAB) and no more than 9 teaspoons per day for people assigned male at birth (AMAB).
You probably don't need to cut back on the natural sugars found in fruit or dairy. Added sugars are those put in your food during processing.
Here are some popular foods with added sugar:
- Sugar-sweetened beverages (soda, juice)
- Takeout food
The recommendations on alcohol may leave you stumped on whether or not you should imbibe. While red wine has been tied to lower rates of certain heart disease risk factors, drinking a lot of alcohol is associated with multiple types of cancer, including head and neck, breast, esophageal, liver and colorectal cancers, per the NCI.
It may be particularly important to drink less (or abstain) if you're worried about or at a higher risk for breast cancer. Drinking more than one alcoholic drink (that's 12 ounces of beer, 5 ounces of wine or 1.5 ounces of liquor) has been associated with an increased risk of breast cancer, and the risk goes up even higher the more you drink, according to the University of Texas MD Anderson Center.
It's possible heavy drinking may interfere with the body's ability to absorb important antioxidants, such as vitamins A, C and D, according to the National Institute of Alcohol Abuse. People who drink a lot of alcohol may also be more likely to eat fewer fruits, vegetables and whole grains, which are associated with lower disease risk.
It's best to stick with the current recommendations of no more than two drinks per day for people AMAB and one for people AFAB. If you know you are at a higher risk for breast cancer, it's better to abstain altogether.
4. Red Dye 40
One of the most debated potential carcinogens is red dye 40, a dye used for food coloring. One of the components in red dye 40, p-Cresidine, is listed as reasonably anticipated to be a human carcinogen, based on the National Toxicology Program at the U.S. Department of Health and Human Services.
All of the studies on red dye 40 have been done in animals, and so far, no evidence concludes it causes cancer in people. No current studies link red dye 40 and cancer of any type. But some experts recommend, if you like to err on the side of caution, to start checking your ingredient lists.
You can find red dye 40 in many artificially red-colored foods, including some:
- Gelatin snacks
What About Artificial Sweeteners?
Your takeaway message is this: moderation. You've heard it a million times, maybe more, but it really is the final word on potentially cancer-causing foods. Small amounts of each of these foods are probably not going to hurt you, but having too much may increase your risk. Cancer is rarely caused by one thing alone, so take note of your eating and drinking habits and make changes if needed.
As long as you are filling your diet with nutrient-dense foods like fruits, vegetables, nuts, seeds, fish and healthy fats, then you probably have little to worry about. If you have concerns about your cancer risk, it's always best to talk to your doctor.
Correction: An earlier version of this story incorrectly listed the ounces of beer considered one alcoholic drink.
- European Journal of Epidemiology: "Red meat, processed meat, and other dietary protein sources and risk of overall and cause-specific mortality in The Netherlands Cohort Study"
- Nutrients: "A Review of the In Vivo Evidence Investigating the Role of Nitrite Exposure from Processed Meat Consumption in the Development of Colorectal Cancer"
- BMJ: "Sugary drink consumption and risk of cancer: results from NutriNet-Santé prospective cohort"
- PLoS One: "Sugar-sweetened beverages and colorectal cancer risk in the California Teachers Study"
- Harvard T.H. Chan School of Public Health: "Waist Size Matters"
- National Cancer Institute: "Alcohol and Cancer Risk"
- National Cancer Institute: Risk Factors Age Alcohol Cancer-Causing Substances Chronic Inflammation Common Cancer Myths and Misconceptions Diet Hormones Immunosuppression Infectious Agents Obesity Radiation Sunlight Tobacco Genetics Cancer Prevention Overview Research Chemicals in Meat Cooked at High Temperatures and Cancer Risk
- American Heart Association: "Added Sugars"
- MD Anderson Center: "Does Sugar Cause Cancer"
- Cancer Research and Treatment: "Light Alcohol Drinking and Risk of Cancer: A Meta-Analysis of Cohort Studies"
- FDA: The Declaration of Added Sugars on Honey, Maple Syrup, Other SingleIngredient Sugars and Syrups, and Certain Cranberry Products: Guidance for Industry
- National Institute of Alcohol Abuse: Alcohol and Nutrition
- University of Texas MD Anderson Center: Alcohol and Breast Cancer Risk