The Fats That Feed Tumors

She followed the rules. And they failed her.

Clara never smoked. She drank green juice, counted her steps, and skipped the cheese plate at girls’ night. She swapped butter for a canola-based spread and traded her cast iron skillet for a nonstick pan—because that’s what the experts said was healthy.

She didn’t eat fried food. She read labels. Her salads were dressed in vinaigrettes touted as “heart healthy.”

But at 39, Clara was diagnosed with triple-negative breast cancer—one of the most aggressive forms of the disease.

How could someone so disciplined… get so sick?

A new study from Weill Cornell Medicine may have an answer. And the culprit isn’t what you’ve been warned about—it’s what you’ve likely been told to eat more of.

The Omega Equation: What You Need to Know About Essential Fats

Fats are the cornerstone of a healthy diet. And their composition and balance in your diet matters deeply.

There are two major classes of polyunsaturated fats:

• Omega-3 fatty acids (from wild fish, pastured meats, as well as flaxseed and chia in smaller amounts) are anti-inflammatory, supporting brain health, hormone production, and cellular resilience.
• Omega-6 fatty acids (from soybean, corn, safflower, sunflower, and grapeseed oils) are pro-inflammatory when consumed in excess.

Both are essential. But today, the typical Western diet contains up to 20x more omega-6s than omega-3s—a radical departure from our ancestral 1:1 ratio.^[1]

And now we know that this imbalance may do far more than disrupt inflammation—it may aggressively fuel cancer.

New Study Links Omega-6 to Aggressive Breast Cancer Growth

A groundbreaking 2025 study from Weill Cornell Medicine, published in Science, uncovered a striking connection between omega-6 fatty acids and the progression of triple-negative breast cancer (TNBC).^[2]

The researchers discovered that linoleic acid—the most common omega-6 in the modern diet—binds to a protein called FABP5, which is found in high amounts in TNBC cells. Once bound, this fat-protein duo activates mTORC1, a metabolic pathway that drives aggressive tumor growth.^[2]

“This helps explain why linoleic acid—a staple in Western diets—might accelerate cancer progression,” says Dr. John Blenis, senior author of the study.

Why This Study Matters So Much

Unlike most nutritional studies that merely suggest associations, this research goes a step further:

It demonstrates a direct link between linoleic acid—a common omega-6 fat found in seed oils—and tumor growth in triple-negative breast cancer (TNBC).

Researchers found that linoleic acid binds to a protein called FABP5, which is highly expressed in TNBC cells. This activates mTORC1, a key driver of cell growth and metabolism—essentially pouring fuel on the tumor’s fire.

It’s not just a theory. It’s a biochemical chain reaction.

And it flips decades of dietary advice on its head: The very oils we were told to eat instead of saturated fat… may be promoting one of the most aggressive cancers in women.

Where Is Linoleic Acid Hiding?

Linoleic acid is found in many commonly used oils:

• Soybean oil (51% linoleic acid)
• Corn oil (58%)
• Safflower oil (74%)
• Sunflower oil (65%)
• Grapeseed oil (up to 78%)

It also appears in conventionally-raised pork and poultry, processed snacks, salad dressings, and of course, fast food.

In fact, it’s estimated that linoleic acid now makes up roughly 10% of total calories in the average American diet—well above ancestral levels of ~2%.^[3]

Personalized Nutrition for Cancer Prevention

The researchers suggest that individuals with high levels of FABP5 in their tumors may benefit from personalized dietary recommendations, specifically a reduced linoleic acid intake.^[2]

This is a paradigm shift.

For decades, we were told to fear saturated fat and embrace “vegetable” oils.

But now, science is revealing what many ancestral health advocates have long believed: Native, ancestral fats are what our bodies are designed to consume for health and vitality!

Action Steps: Restore Your Ancestral Omega Balance

Here’s how to protect yourself:

Ditch the seed oils: Eliminate soybean, corn, safflower, sunflower, grapeseed, and canola oils from your pantry.

Use stable fats for cooking:

• Best: Grass-fed tallow, butter and ghee, pastured lard, coconut oil
• Better: Extra virgin olive oil (low-heat), avocado oil (moderate heat)

Eat more omega-3s:

• Wild salmon, sardines, mackerel
• Pastured eggs and grass-fed meats
• Chia, flax, and walnuts

Prioritize whole, unprocessed foods: Avoid ultra-processed items containing hidden seed oils.

Know your genes: Testing for fatty acid metabolism and FABP5 expression may help guide future dietary strategies.

Low Linoleic Meal Ideas

Want to reduce your linoleic acid intake while still enjoying deeply nourishing, flavorful meals? Here are a few low-LA favorites that support hormone balance, reduce inflammation, and may even help protect against chronic disease:

1. Crispy Skin Salmon with Roasted Cauliflower & Ghee

• Wild-caught salmon pan-seared in grass-fed ghee
• Roasted cauliflower tossed in tallow and turmeric
• Garnished with lemon zest and fresh dill

Why it works: Rich in anti-inflammatory omega-3s and CLA, with zero seed oils in sight.

2. Grass-Fed Ribeye with Sautéed Mushrooms & Garlic Spinach

• Pan-seared ribeye in tallow or butter
• Sautéed cremini mushrooms in ghee
• Garlic spinach finished with a drizzle of EVOO (off heat)

Why it works: High in fat-soluble nutrients, immune-modulating butyrate, and zero linoleic overload.

3. Egg Yolks & Avocado Bowl

• 2–3 pastured egg yolks (soft boiled or poached)
• Sliced avocado, microgreens, and pink salt
• Olive oil drizzle with apple cider vinegar splash

Why it works: A satisfying, omega-3-rich breakfast with none of the typical seed oil baggage.

4. Chicken Thighs in Coconut Milk with Cilantro & Lime

• Bone-in, skin-on chicken thighs braised in coconut milk
• Simmered with fresh ginger, garlic, and lemongrass
• Served with a side of riced cauliflower sautéed in ghee

Why it works: Replaces processed fats with stable, antimicrobial coconut oil and digestion-supportive spices.

5. Zucchini Noodles with Lamb Meatballs & Olive Oil Pesto

• Grass-fed lamb meatballs baked in lard
• Zoodles topped with homemade pesto (olive oil, walnuts, basil)
• Optional goat cheese crumble

Why it works: A seed-oil-free Italian comfort meal full of collagen, minerals, and real flavor.

Food Is Information

The foods we eat speak a molecular language to our genes.

For women like Clara—and for all of us—it’s time to rediscover the ancestral fats that have nourished human health for millennia.

Because not all fats are created equal, and some may be feeding more than your cells.

Good fats fuel your body and brain, support hormone balance, and help absorb essential vitamins. From avocados to grass-fed meats, these healthy fats are key to lasting energy and vibrant health. Visit our Discover Blog for more insightful articles today!

References

1. Simopoulos, A. P. (2002). “The importance of the ratio of omega-6/omega-3 essential fatty acids.” Biomedicine & Pharmacotherapy, 56(8), 365–379. https://doi.org/10.1016/S0753-3322(02)00253-6
2. Ganeshan, K., et al. (2025). “Linoleic Acid Promotes the Growth of Triple-Negative Breast Cancer via FABP5–mTORC1 Activation.” Science, April 2025. https://news.weill.cornell.edu/news/2025/04/omega-6-fatty-acid-promotes-the-growth-of-an-aggressive-type-of-breast-cancer
3. Ramsden, C. E., et al. (2010). “Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: Evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis.” BMJ, 346, e8707. https://doi.org/10.1136/bmj.e8707