Show 1420: The Cooking Oil Controversy Spotlights Cancer

This week, we are rummaging through the controversy of cooking oil. For decades, we have heard that we should use vegetable oils rather than butter, lard or other fats (maybe even olive oil). Corn, soy, sunflower or carthame seeds are rich in polyunsaturated fatty acids. Therefore, people who consumed them can have lower cholesterol levels than those who mainly use saturated fats. But could there be a drawback? We hear scientists who have found these seed oils can be linked to certain cancers.

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Controversy of cooking oil:

The more we learn from fats, the more it seems that focusing on a single aspect can be too simplistic. In the 1990s, health experts told Americans to avoid fat. When it has become clear that low -fat diets did not necessarily make everyone healthy, we received the message that we had to stand with polyunsaturated fatty acids (AGPI) like those of corn oil or canola. However, there are different types of PUFA. Chemists classify them like omega-3 fatty acids, omega-6 and omega-9. Only omega-3 and omega-6 are considered essential fatty acids.

Current cooking oils have a preponderance of omega-6 fatty acids. Consequently, the omega-6 ratio to omega-3 in our blood went from a pre-industrial average of around 4: 1 to our current reports of 20: 1 (Missouri medicineSep-Oct. 2021). This could have biological consequences.

Food fat and cancer:

Dr. William Aronson asked how different types of food fat affect the progression of prostate cancer. Laboratory studies show that a diet rich in corn oil accelerates the growth of cancer tumors of the human prostate established under the skin of the mice. It inspired him and his colleagues to conduct a randomized controlled trial (Journal of Clinical OncologyDecember 13, 2024).

Fish oil compared to prostate cancer:

For their test, they recruited 100 men diagnosed with prostate cancer which opted for active surveillance rather than immediate surgery or radiotherapy. They allocated these volunteers to different regimes for a year. A group followed their usual diet and has not taken fish oil. The researchers asked the other group to avoid omega-6 fats in their diet, increasing the amount of fish rich in omega-3 and taking supplements of fish oil. The minimization of omega-6 fat meant staying away from fried food, cooking oils, bottled vinegots and mayonnaise. At the end of the year, there was a significant difference in an important biomarker of prostate cancer called Ki-67.

Does controversy of the cooking oil extend to other cancers?

We spoke with Dr. Timothy Yeatman of his research on colorectal tumors. His research was published in IntestineA leading newspaper for gastroenterologists (December 20, 2024). He and his colleagues used a technique called lipidomic for their analysis. They found that the lipid profile of tumors and their micro-environments is pro-inflammatory. They seem to be lacking in resolution mediators (“resolvins”) which should normally accompany healing. The balance was disrupted.

Dr. Yeatman suspects that part of this disruption can be due to changes in the microbiome which constitutes a large part of the immediate environment for colorectal tumors. He suggests that an in-depth use of seeds rich in pro-inflammatory omega-6 fatty acids can contribute to imbalance. You can find soy oil, for example, in many foods where you might not expect it, such as breads, cakes, cookies, crackers, fries and even houmous. Cooking at home allows people to avoid seed oils, but it takes time, skills and resources that are not available for everyone.

Can we solve the controversy of the cooking oil?

None of the studies we discuss during this episode are final. Scientists need more research to be able to make solid recommendations based on evidence. However, our two guests suggest that we do not need to wait until the last word to reduce the inflammatory potential of our diet. Reading the labels carefully is a good first step to avoid some of the seed oils that provide excess omega-6 fats and gravitate more to omega-3 fats.