Certain foods can interfere with your body’s fight against cancer cells, study says

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The food you eat can affect your body’s ability to fight colon cancer cells, according to a new study.

The potential culprit: an excess of certain omega-6 fatty acids—perhaps from ultra-processed foods in your diet—which can hinder the anti-inflammatory and tumor-fighting properties of another essential fatty acid, omega-3.

“There are mutations every day in the GI (gastrointestinal tract) and usually they are immediately cleared by the immune system using molecules or mediators from omega-3,” said Dr. Timothy Yeatman, senior co-author of the study published on Tuesday in the gut, the journal of the British Society of Gastroenterology.

“But if you have a body that’s been exposed for years to a chronic inflammatory environment created by an imbalance of omega-6s, the type commonly found in ultra-processed foods and junk foods, I think it’s easier for a mutation to take hold and harder for the body to fight it,” said Yeatman, a surgical oncologist and professor at the University of South Florida and Tampa General Hospital Cancer Institute.

A Western diet is often high in omega-6 fatty acids, experts say, because of widely available seed oils that are often used to fry fast food and make the ultra-processed foods that now make up about 70% of the US food supply. Linoleic acid, an omega-6 fatty acid found in corn, peanut, soybean, safflower and sunflower oils is most common omega-6 in the US food supply.

Many people have a significant imbalance between omega-6 and omega-3 in their bodies – a November 2015 survey found levels of linoleic acid have increased by 136% in the adipose tissue of Americans over the past half century.

“It’s a leap to say that omega-6s from ultra-processed foods are the cause. Americans are low in omega-3 fatty acids because they don’t like fatty fish like mackerel, herring and sardines, which are good sources,” says Dr .Bill Harris, professor of internal medicine at the University of South Dakota’s Sanford School of Medicine, who was not involved in the new research.

“Don’t blame the omega-6s, it’s not their fault — it’s the lack of omega-3 fatty acids that’s the problem,” said Harris, who is also president and founder of the nonprofit Fatty Acid Research Institute in Sioux Falls , South Dakota.

Both omega-3 and omega-6 polyunsaturated fatty acids are essential for human health. However, your body cannot make them on its own and must create both from the foods you eat.

Omega-3s – found in large amounts in fatty fish such as salmon as well as flax and chia seeds, pecans, walnuts and pine nuts – maintain your body’s cells, provide energy, maintain the immune system and reduce inflammation when at optimal levels (such as eg most, too much omega-3 can be harmful).

Omega-6 is also necessary to maintain good health. These molecules stimulate hair and skin growth, regulate metabolism, increase bone health and in some cases can even be anti-inflammatory.

However, Omega-6 can also be converted into molecules such as prostaglandins which signal the onset of inflammation—not a bad thing when your body is quickly trying to reject an invader or tumor, but devastating if left to simmer for long periods without resolution.

Colorectal cancer was traditionally a disease of the old, but not anymore. Colon and rectal cancer are on a deadly march among people as young as 20 years old, with diagnosed cases continuing to rise among those younger than 50 in the United States and around the world.

Millennials born between 1981 and 1996 have twice the risk of colon cancer compared to those born in 1950, according to a survey from February 2017. For younger men, this type of cancer is the most deadly; for younger women, colorectal cancer ranks third after breast and lung cancer National Cancer Institute informs on its website.

Experts aren’t entirely sure what’s behind the increased risk: Genetics play a role, but the disease appears in younger patients with no family history, gastroenterologist Dr. Robin Mendelsohn to CNN in an earlier interview.

Rising obesity may explain the increase, but some young patients are vegetarians and exercise fanatics, said Mendelsohn, co-director of the Center for Young Onset Colorectal and Gastrointestinal Cancers at Memorial Sloan Kettering Cancer Center in New York City.

However, more evidence links an unhealthy diet high in ultra-processed foods, red meat and processed meats such as ham, bacon, sausages, hot dogs and deli meats — as well as a lack of fresh fruits and vegetables — to early-onset colorectal cancer, according to the National Cancer Institute.

Resolves inflammation so the body can heal

In the new study, researchers used colon cancer tissue harvested from 80 patients in the United States and compared the tumor with normal colon tissue taken from the same patient.

The goal: to identify specialized pro-resolving mediators, produced by the body from omega-3 fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), during the resolution phase of acute inflammation.

These specialized pro-resolving mediators include resolvins, lipoxins, protectins, and maresins, which have potent anti-inflammatory effects that help inflamed tissue return to normal once the need for an inflammatory response is over.

“There are two components to healing from injury or infection,” Yeatman said. “First, the immune system fights the infection with inflammation, like fever, and then resolves that inflammation with specialized pro-resolving mediators created by derivatives of omega-3s.”

However, omega-3 mediators only come into play when the body is fighting inflammation and are therefore often difficult to detect during the onset of inflammation, said study co-author Dr. Ganesh Halade, associate professor of internal medicine at the University of South Florida. To overcome this obstacle, Halade said, he used a highly sensitive analytical technique to identify trace amounts of various omega-3 mediators in the cancer tumor samples while also measuring levels of omega-6.

“This is the first study that looks in a comprehensive way how the molecules from omega-3 and omega-6 behave in the cancer tumor and normal control tissue from the same patient,” Halade said.

“We found that the control tissue has a perfect balance of omega-6 and omega-3 molecules,” he said. “But we found a huge imbalance in the tumor microenvironment—omega-6 fats from ultra-processed foods made more proinflammatory molecules inside the cancer tumor but not in the control tissue.”

Bottom line: Without enough omega-3s available to help control the inflammatory response created by the body’s response to cancer, inflammation continues to rage, further damaging cell DNA and prolonging an environment conducive to cancer growth.

“The researchers are basically saying that there’s so much omega-6 around that it gives the cancer tumor a chance to just take off, and I think that’s probably correct,” said analytical chemist Tom Brenna, professor of pediatrics at Dell Medical School at the University of Texas at Austin, which was not involved in the new study.

“When linoleic acid is increased in the body, it decreases the amount of two omega-3s, EPA and DHA, in the body’s tissues,” Brenna said. “And Americans aren’t getting enough omega-3 as it is, so the implication of the study is that if a person has too much omega-6, they probably need to boost their omega-3 to counteract that impact.”

Try to get as many omega-3s from your diet as you can, experts say. The omega-3s EPA and DHA are found in fatty fish such as anchovies, salmon, mackerel, herring, sardines, sea bass, tuna and trout. Oysters and clams are also good sources, according to American Heart Association.

Eat two servings a week that are about 3 ounces or about ¾ cup of flaked fish, the AHA said. Some types of fish, typically larger species such as tuna, contain higher levels of mercury or other environmental pollutants, so be sure to vary the types of seafood you eat to reduce your risk.

Another important omega-3, alpha-linolenic acid, or ALA, is found in nuts and seeds such as walnuts, flaxseeds and chia seeds — with ground flaxseed and flaxseed oil providing the highest amounts, according to Harvard Medical School’s website. Try sprinkling ground flax or chia seeds on granola and yogurt, and eat small amounts of nuts throughout the day.

A good quality fish oil supplement can also help. There can be side effects from supplements, such as bad breath and sweat and headaches, as well as digestive problems such as heartburn, nausea or diarrhea, Harvard’s website stated.

Because omega-3s have anticoagulant effects, experts say it’s always best to check with your doctor before starting to take omega-3s (or any supplement). Suggested limit values ​​for different omega-3 fatty acids vary according to age and health conditions — another good reason to check with your doctor.