Doctors Warn: These 6 Cooking Oils Should Be Limited, as Excessive Consumption May Increase Can.cer Risk

Cooking oil is a staple ingredient in nearly every kitchen. Whether frying, stir-frying, roasting, or preparing salads, most people use cooking oils every day without giving much thought to their long-term health effects.

However, some health experts are raising concerns about the excessive consumption of certain oils, particularly those high in Omega-6 fatty acids.

According to Dr. Liao Zhiying, a radiation oncology specialist in Taiwan, some commonly used cooking oils may contribute to inflammation and potentially increase the risk of certain cancers when consumed in large amounts over long periods.

While cooking oils are essential for health, experts emphasize that choosing the right types—and maintaining a healthy balance of fatty acids—is key.

Experts say cooking oils are an important part of a balanced diet, but the type and quantity consumed matter.

Why Cooking Oils Matter

Cooking oils provide essential fatty acids that play important roles in:

• Cell function
• Hormone production
• Brain health
• Energy metabolism
• Absorption of vitamins A, D, E, and K

Among the most important fatty acids are:

Omega-3

Known for its anti-inflammatory properties and potential benefits for heart and brain health.

Omega-6

An essential fatty acid that supports normal body functions but may contribute to inflammation when consumed in excessive amounts relative to Omega-3.

Omega-9

A monounsaturated fat commonly found in olive oil and avocado oil that is generally associated with heart-healthy dietary patterns.

Experts emphasize that balance—not elimination—is the goal.

The Concern About Excess Omega-6

According to Dr. Liao, modern diets often contain significantly more Omega-6 than Omega-3.

He cited research suggesting that excessive Omega-6 intake may promote inflammatory pathways in the body.

Some laboratory and animal studies have explored links between high Omega-6 consumption and biological mechanisms involved in the growth of certain cancer cells, including breast, prostate, colorectal, and liver cancer.

However, experts note that cancer is a complex disease influenced by many factors, including genetics, lifestyle, body weight, smoking, alcohol use, and overall dietary patterns.

No single cooking oil directly causes cancer on its own.

Nutrition experts generally recommend increasing sources of Omega-3 while maintaining a healthier balance between Omega-3 and Omega-6 intake.

Recommended Oils for Everyday Use

Oils Rich in Omega-3

These oils are often praised for their anti-inflammatory properties:

• Flaxseed oil
• Perilla oil
• Canola oil

Oils Rich in Omega-9

These oils are commonly recommended for regular cooking:

• Olive oil
• Avocado oil
• Tea seed oil

For high-temperature cooking, avocado oil and tea seed oil are often considered suitable due to their stability.

Moderate Consumption

Experts suggest rice bran oil can also be used in moderation as part of a varied diet.

6 Oils Experts Suggest Limiting

According to Dr. Liao, the following oils are relatively high in Omega-6 and should be consumed in moderation rather than as primary daily cooking oils:

1. Soybean Oil

Widely used in processed foods and commercial cooking.

2. Peanut Oil

Commonly used for frying and high-heat cooking.

3. Corn Oil

Contains substantial amounts of Omega-6 fatty acids.

4. Sunflower Oil

Popular for its neutral flavor but relatively high in Omega-6.

5. Grapeseed Oil

Often marketed as healthy but contains significant Omega-6 levels.

6. Pumpkin Seed Oil

Nutritious in some contexts but also rich in Omega-6.

Health professionals encourage focusing on overall dietary quality rather than relying on any single food or ingredient.

What About Animal Fats and Coconut Oil?

Dr. Liao also advised limiting:

• Pork fat (lard)
• Coconut oil

Because these fats contain relatively high levels of saturated fat, excessive consumption may contribute to cardiovascular and metabolic health concerns.

As with all dietary fats, moderation remains important.

The Bigger Picture

Nutrition experts stress that no cooking oil should be viewed as entirely good or entirely bad.

Health outcomes depend on:

• Overall diet quality
• Portion sizes
• Physical activity
• Smoking status
• Alcohol consumption
• Body weight
• Family history

Using a variety of healthy oils, increasing Omega-3 intake, and consuming plenty of fruits, vegetables, whole grains, and lean proteins may have a far greater impact on long-term health than focusing on a single ingredient.

The Bottom Line

Cooking oils are an essential part of daily nutrition, but experts say balance matters.

While oils high in Omega-6 fatty acids are not inherently harmful, excessive consumption over long periods may contribute to inflammation and potentially increase health risks.

Doctors recommend prioritizing oils rich in Omega-3 and Omega-9, such as olive oil, avocado oil, flaxseed oil, and canola oil, while limiting overreliance on soybean, peanut, corn, sunflower, grapeseed, and pumpkin seed oils.

A balanced diet—not a single "super oil"—remains the foundation of good health.