Ultra-Processed Foods and Risk for Obesity and Cancers


Two studies in the current British Medical Journal give us more reasons to cut back on ultra-processed foods:

• One study followed more than 200,000 U.S. men and women for up to 28 years and found that eating almost any type of ultra-processed food was associated with increased risk for colorectal cancer in men, but not in women (BMJ, August 31, 2022;378:e070688). Men were at significantly higher risk for colon cancer if they ate a lot of meat and sugar-sweetened beverages. Ultra-processed foods were also associated with increased risk for weight gain. Fermented dairy products such as yogurt and kefir were associated with reduced risk for colon cancer, probably because they contain healthful bacteria that turn soluble fiber into short chain fatty acids (SCFAs) when they reach your colon. However, you have to eat soluble fiber and fermented food products regularly to keep the healthful bacteria in your colon. Whole unground grains were also associated with reduced risk, probably because most are not broken down until they reach the colon.

• The second study followed more than 22,000 Italian men and women for 12 years and found that eating ultra-processed foods, meat and sugar-added foods, each markedly increased risk for premature death mostly from heart attacks and cancers (BMJ, Aug 31, 2022;378:e068921).

Many other studies associate ultra-processed foods with heart attacks, cancers, obesity, and premature death (BMJ, May 29, 2019;365:l1451; Cancer Sci, Jan 2022;113(1):277-286; Gastroenterology, 2017 Dec;153(6):1517-1530)).

What Are Ultra-Processed Foods?
The NHANES study (J of the Am Heart Assoc, Jun 23, 2021;0:e020254) defines ultra-processed foods as “Formulations of several ingredients which, besides salt, sugar, oils, and fats, include flavors, colors, sweeteners, emulsifiers and other additives used to imitate sensorial qualities of unprocessed or minimally processed foods, or to disguise undesirable qualities of the final product.”

Ultra-processed foods make up almost 70 percent of the calories in the foods that children and teens eat (JAMA, 2021;326(6):519-530). Ultra-processed foods include ready-to-eat packaged foods and prepackaged foods; meats such as hot dogs, sausages, bacon, hamburgers, ham, salami and corned beef; fried foods such as French fries and potato chips; sugared and artificially flavored sodas; sugar-added foods such as cookies, cakes, candies, doughnuts and ice cream; and most other foods that come in a package with a long list of ingredients. See Ultra-Processed Foods

How Ultra-Processed Foods may Increase Colorectal Cancer Risk
Researchers at Harvard Medical School found that a western-style diet loaded with ultra-processed foods increases growth of specific gut bacteria called “polyketide synthase E. Coli” that produce a chemical called colibactin, which causes DNA mutations that can turn normal colon cells into cancer cells (Gastroenterology, June 23, 2022). Many studies have previously shown that ultra-processed foods in the typical western diet can cause inflammation, an overactive immune system that is associated with increased risk for colon cancer (Gastroenterology, Jun 2017;152(8):1944-1953).

My Recommendations
When you go to buy groceries, start at the fresh fruit and vegetable department and then pick up lots of whole grains, beans, seeds and nuts. Then go to the checkout counter. Exposure is a far more important factor in what you eat than your willpower. Multiple studies show that most people will eat any foods that they have in their house, and increased access to healthy foods corresponds with healthier dietary practices (Am J Prev Med, 2009;36(1):74-81).