The Case Against Seed Oils

What do WD-40, Uline spray, and vegetable oil have in common?

They were created to lubricate machines.

Yup, “vegetable” oils (more accurately called seed oils), are the health-wreckers that have been hiding in plain sight for the last 120 years. Since coming onto the scene, oils like canola, soybean, or sunflower oil have completely taken over in cooking and commercial food service. Ever since then, our bodies have been completely overloaded with them — and during that same time, rates of chronic disease have only gone up† (1). 

Here’s what’s really going on with industrial seed oils, and why they should all be on our radar.

🧪 First, What Are Seed Oils?

Seed oils come from—you guessed it—seeds. That includes:

1. Canola (from rapeseed)

   
   

2. Soybean

   
   

3. Corn

   
   

4. Sunflower

   
   

5. Safflower

   
   

6. Grapeseed

To get oil from seeds, you can’t just press them like you can with olives or coconuts. Instead, they have to go through heavy-duty processing that involves heat, chemicals, and even bleach to make them look and smell “clean.” This process strips away most of the natural nutrients and antioxidants the seeds may have had in their original state (2).

So what’s left?

👉 An oil that’s been ultra-processed and has very little nutritional value. Over time, consuming a lot of this kind of oil can keep your body in a state of chronic inflammation† (we don’t just mean pain — learn more about inflammation here).

Here's how they can disrupt your health from the inside out:

1. They promote chronic inflammation†

Omega-6 and omega-3 fatty acids are both essential, but they need to be in balance. Ideally, your intake should be around a 1:1 or 2:1 ratio. When eating whole foods from nature, this ratio isn’t hard to achieve — omega-6s are found naturally in things like walnuts, pumpkin seeds, brown rice, and oats.

But since the rise of industrial seed oils (which are basically concentrated omega-6), the average Westerner now consumes them at a 20:1 ratio or higher (3). Without enough omega-3s to offset them, this skewed balance leads to chronic inflammation†, which has been linked to:

1. Heart disease†

   
   

2. Diabetes†

   
   

3. Obesity†

   
   

4. Joint pain and fatigue†

To reiterate, the problem isn’t that omega-6s exist — it’s that modern diets are recklessly overdosed with them, and that’s a direct result of the extreme spike in poor-quality, industrially-processed seed oils. There’s absolutely no reason to be turning to them when we already have so much omega-6 from much cleaner sources in nature.

2. They disrupt cellular function and hormone balance†

Every cell in your body is surrounded by a membrane made of fat. The types of fat you eat help determine how that membrane functions.

Too much omega-6 in the membrane makes it rigid and prone to oxidation, which disrupts:

1. Cell communication

   
   

2. Nutrient absorption

   
   

3. Recovery and regeneration

   
   

4. Hormone production (including testosterone†), since hormones are also made from fats

   
   

Omega-3s, on the other hand, keep membranes fluid and healthy, supporting everything from brain function to metabolism and muscle growth.

3. They create free radicals which damage your cells

Seed oils are high in polyunsaturated fatty acids (PUFAs), which are unstable and break down easily when exposed to heat, light, or air. This breakdown creates free radicals, which are harmful molecules that can damage your cells†, kind of like tiny wrecking balls in your body. Over time, too many free radicals lead to something called oxidative stress†, which is tied to aging, inflammation, and disease† (4).

Cooking with seed oils, especially at high heat, is problematic for this exact reason — you’re releasing all those free radicals into your food and body. And yet it’s the most common way to consume them. Olive oil, especially extra virgin, contains antioxidants like polyphenols and vitamin E, which help protect it from oxidative damage.

4. They fuel inflammatory pathways†

Excess omega-6 is metabolized differently. While the body uses omega-3s to heal and lower inflammation, omega-6s are primarily used to increase inflammation. 

But omega-6 and omega-3 compete for the same enzymatic pathways. So when omega-6 is dominant, inflammation runs wild and omega-3’s protective effects are blocked (5).

Mainstream health advice often downplays this point, saying the conversion rate of omega-6 into inflammatory molecules is low. However, even slightly elevated levels can contribute to chronic low-grade inflammation, especially in those who already suffer from some sort of chronic disease (5).

The central issue remains the ratio of omega-6 to omega-3. If the omega-6 intake is very high and omega-3 intake is low, it can shift the balance toward more pro-inflammatory pathways, even if not all of it is getting converted into inflammatory molecules.

5. They release toxic byproducts during processing†

Unlike oils from olives or coconuts, you can’t just press a sunflower or soybean and get oil to come out. Seed oils have to go through intense chemical processing that involves:

1. High-heat extraction (damaging delicate fatty acids)

2. Chemical solvents like hexane (used to pull oil from seeds)

3. Refining, bleaching, and deodorizing (removing natural antioxidants & adding synthetic stabilizers to make them shelf-stable)

This process creates toxic byproducts, including:

1. Trans fats (sometimes even in "zero trans fat" products)

2. Oxidized lipids (linked to heart disease†)

3. Aldehydes (toxic compounds with carcinogenic properties)

   
   

By contrast, cold-pressed oils like extra virgin olive oil retain their natural antioxidants and don’t require all this chemical processing.

🥑 What Should You Use Instead?

You don’t need to eat dry salad or plain chicken breast to avoid seed oils. There are better fats out there that are easier on your body†, more natural, and actually good for you†.

Here are a few:

1. Olive oil: Great for salad dressings and light cooking, high in antioxidants

   
   

2. Avocado oil: Has a high smoke point, so it’s good for cooking

   
   

3. Coconut oil: Stable at high heat, great for baking or sautéing

   
   

4. Butter or ghee: Real fats like these have been used for centuries and contain vitamins like A, D, and K2

The Bottom Line

Seed oils have been marketed as “heart-healthy” by the AHA since the 1940s. Coincidentally, heart disease recently reached 100 years as the leading cause of death in the US. Just read this article and savor the irony — great work, AHA 👏

Seed oils are everywhere — chips, salad dressings, takeout food, even “healthy” granola bars. But when you start replacing them with real, whole-food fats, your body will feel the difference. Cutting out seed oils could just be the biggest step you take for your health this year.

† We are required to say that these statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Sources

1. Goodman, R., Posner, S., Huang, E., Parekh, A., & Koh, H. (2013). Defining and Measuring Chronic Conditions: Imperatives for Research, Policy, Program, and Practice. Preventing Chronic Disease, 10. https://doi.org/10.5888/pcd10.120239.

2. Kiczorowska, B., Samolińska, W., Andrejko, D., Kiczorowski, P., Antoszkiewicz, Z., Zając, M., Winiarska-Mieczan, A., & Bąkowski, M. (2019). Comparative analysis of selected bioactive components (fatty acids, tocopherols, xanthophyll, lycopene, phenols) and basic nutrients in raw and thermally processed camelina, sunflower, and flax seeds (Camelina sativa L. Crantz, Helianthus L., and Linum L.). Journal of Food Science and Technology, 56, 4296 - 4310. https://doi.org/10.1007/s13197-019-03899-z.

3. Patel, A., Desai, S., Mane, V., Enman, J., Rova, U., Christakopoulos, P., & Matsakas, L. (2022). Futuristic food fortification with a balanced ratio of dietary ω-3/ω-6 omega fatty acids for the prevention of lifestyle diseases. Trends in Food Science & Technology. https://doi.org/10.1016/j.tifs.2022.01.006.

4. Liguori, I., Russo, G., Curcio, F., Bulli, G., Aran, L., Della-Morte, D., Gargiulo, G., Testa, G., Cacciatore, F., Bonaduce, D., & Abete, P. (2018). Oxidative stress, aging, and diseases. Clinical Interventions in Aging, 13, 757 - 772. https://doi.org/10.2147/CIA.S158513.

5. DiNicolantonio JJ, O'Keefe J. The Importance of Maintaining a Low Omega-6/Omega-3 Ratio for Reducing the Risk of Autoimmune Diseases, Asthma, and Allergies. Mo Med. 2021 Sep-Oct;118(5):453-459. PMID: 34658440; PMCID: PMC8504498.