New study links too much seed oil to colon cancer surge in young people

Popular cooking oils used in ultra-processed Western diets may be causing a surge in colon cancer cases, a new US government-led study has shown.

Unhealthy seed oils like sunflower, grapeseed, canola, and corn could trigger chronic inflammation in the body, the groundbreaking research found.

Until now evidence linking cooking oil to colon cancer has been inconclusive.

But the recent American study identified seed oils as the possible contributing factor when they examined tumours from more than 80 people with colon cancer, aged between 30 and 85.

The tumours showed increased levels of bioactive lipids, which are small oily molecules produced when the body metabolises seed oils, compared to healthier fats, according to the study published in the Gut journal.

As well as increasing inflammation, bioactive lipids hinder the body’s natural healing process and foster tumour growth.

Oils rich in omega-3 fatty acids, found in avocados and olives, are a healthier alternative, the researchers said.

Renowned physician-scientist Dr. Timothy Yeatman said the findings stressed an urgent need to reevaluate parts of the Western diet, including added sugars, saturated fats, ultra-processed foods, chemicals and inflammatory seed oils.

“It is well known that patients with unhealthy diets have increased inflammation in their bodies,” said Dr. Yeatman, who is also an associate centre director for Translational Research and Innovation at the TGH Cancer Institute.

“We now see this inflammation in the colon tumours themselves, and cancer is like a chronic wound that won’t heal - if your body is living off of daily ultra-processed foods, its ability to heal that wound decreases due to the inflammation and suppression of the immune system that ultimately allows the cancer to grow.”

But top US health institutions have clarified that consuming moderate amounts of seed oils as part of a balanced diet has not been shown to cause cancer.

Seed oils list

It is important to note that seed oils themselves are not unhealthy when consumed in moderation, like most foods, the experts say. They pose the greatest health risk in a diet high in ultraprocessed foods.

These are some of the most common seed oils, according to Cleveland Clinic:

- Canola oil, also known as rapeseed oil
- Corn oil
- Cottonseed oil
- Grapeseed oil
- Sesame oil
- Soybean oil
- Sunflower oil
- Safflower oil
- Rice bran oil
- Peanut oil

Healthiest cooking oils

Yes, cooking oil can be part of a healthy diet, the experts say, and many of the most common types of cooking oils have health benefits

When cooking with oil, try to choose one with less saturated fat, that's unrefined and from nontropical fruits, vegetables nuts or seeds, TODAY.com previously reported.

Here are some of the healthiest cooking oils when consumed in moderation:

- Olive oil
- Avocado
- Canola
- Corn
- Peanut
- Safflower
- Soybean
- Grapeseed
- Sunflower