Recent research surrounding cooking oils has raised concerns about their potential health risks, particularly over their potential link to cancer. A growing body of evidence is giving way to a reassessment of what is considered a “healthy” cooking oil. Several studies, including those examining oils in the context of prostate cancer, suggest that the type of oil used may be influencing cancer progression.
The Role of Cooking Oils in Diet
Cooking oils have been a staple in kitchens for ages, with different types available for different cooking methods. Some oils, like olive and avocado, are heralded for being heart-healthy choices, while seed oils (e.g., sunflower, corn, canola), are more common in a Western diet. Each oil contains a different amount of omega-3 and omega-6 fatty acids, which seem to play a role in cancer development. Research now links cooking oils cancer risks to the presence of certain fats and compounds found in oils after they are heated.
A study from UCLA looked at men in the early-stages of prostate cancer and focused on the effects of diet change with cancer progression. The study put the participants into two groups: one that followed a diet high in omega-3 fatty acids and low in omega-6, and another that maintained a standard Western diet of refined and pre-packaged foods. One year later, the group with the adjusted diet showed a 15% reduction in cancer markers, while the control group saw a 24% increase. These findings highlights how cooking oils that rich in omega-6 fats can contribute to cancer, especially in the context of prostate cancer.
Seed oils (canola, sunflower, and cottonseed) are commonly used and consumed in the Western diet. These oils are high in omega-6 fatty acids, and are linked to increased inflammation. Inflammation is also known to fuel cancer development by damaging tissues and hindering the body’s ability to fight tumors. The American Heart Association and other medical bodies maintain that seed oils are safe, but critics like Robert F. Kennedy Jr., have raised concerns about their role in contributing to cancer. A recent study from the University of South Florida further suggests that seed oils may also be linked to a rise in colon cancer cases in young adults.
When oils are heated to high temperatures, particularly for frying, they can release toxic compounds called aldehydes. Research from the University of the Basque Country has identified certain aldehydes, like 4-hydroxy-[E]-2nonenal, that are believed to contribute to various types of cancer. These aldehydes form when fatty acids – like the ones found in seed oils – degrade. This is especially prevalent in polyunsaturated oils such as sunflower oil. These harmful compounds then remain in the prepared food, increasing the potential risk of cancer. The study indicated that while olive oil makes less toxic aldehydes than sunflower oil, polyunsaturated fats in general are much more likely to produce the compounds under heat in general.
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Cooking Oils, Cancer, and Processed Foods
In perfect contrast to omega-6-rich oils, omega-3 fatty acids actually possess anti-inflammatory properties, which help to mitigate the risk of cancer. Research indicates that by increasing your omega-3 intake, vie fish or flaxseed oil, you can decrease cancer cell growth. The previously mentioned study done on men with prostate cancer showed a 15% reduction in tumor markers, suggesting that the right balance of omega-3 fats in cooking oils may help slow cancer progression. This finding suggests that modifying your dietary fat inake could serve as a tool in cancer management.
A study published in The BMJ took a look at the connection between ultra-processed foods and cancer risks. The study found that consistently consuming ultra-processed foods was associated with a higher risk of developing cancer, particularly breast cancer. Although the study did not definitively link processed foods to cancer, it most certainly calls us to properly consider what oils are used in packaged and processed foods.
While it is clear that certain oils are linked to cancer risks, it is important to remember all things in moderation – including our diets. The UCLA study on prostate cancer, for instance, stressed that while reducing omega-6 intake may help slow cancer progression, we should not eliminate these fats entirely. Incorporating omega-3 fatty acids via fish, nut, and seed intake, while moderating how much omega-6-rich oils we consume would be an effective strategy for cancer prevention.
The evidence linking cooking oils cancer is compelling and continues to grow. While the evidence is not yet definitive, it is becoming increasingly clear that the type of oil we consume plays a significant role in how cancer develops and progresses in our bodies. Be mindful of the oils used in your cooking; choose those rich in omega-3s, and limit ones high in omega-6 fats. More research is needed to fully understand how diet and cancer fully enmesh, we need to establish clear guidelines for reducing cancer risks with our dietary choices.
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