If you’ve ever glanced at the ingredient list on a bag of chips, a salad dressing bottle, or a loaf of bread, chances are you’ve seen names like “canola oil” or “soybean oil.” These might sound harmless—hey, they’re from vegetables, right
But according to Dr. Catherine Shanahan, a board-certified family physician and biochemist, these oils are silently damaging our health on a massive scale.
In her groundbreaking work, including Deep Nutrition and countless podcast appearances, Dr. Shanahan identifies a group of eight seed oils she calls the “Hateful Eight.” These industrial oils, she argues, are not only unnatural but toxic—driving inflammation, accelerating aging, and increasing the risk of chronic disease.
In this post, we’ll explore:
- What the Hateful Eight oils are
- Why their industrial processing makes them harmful
- How these oils affect your body at a cellular level
- The long-term health risks they contribute to
- What fats and oils you should be consuming instead
This Article Goes Beyond Microgreens
Much of this article isn’t about microgreens.
However, it is MORE IMPORTANT THAN WHAT MICROGREENS CAN DO FOR US!
There is a section on how all of this fits in with microgreens, and it has to do with the salad dressings you pour on your salads containing microgreens.
Hopefully, you are using a healthier salad dressing and not a store-bought variety. If you are using off-the-shelf prepared salad dressings, please read this article, as well as watch the video or listen to the podcast, to understand the warning, which will more than likely improve your health.
I have a section of this article dedicated to microgreens and salad dressings. Again, please watch the video or listen to the podcast embedded within this article. Dr. Shanahan explains it very well.
Let’s dive in.
FREE Home Microgreens Grow course that teaches you the basics of growing microgreens in your home! There are 12 video lessons (over 120 minutes), downloads, and more written information and tips!
- This Article Goes Beyond Microgreens
- From Seed to Shelf: The Industrial Process Behind Seed Oils
- The Omega Imbalance: Why These Oils Are Inflammatory
- Cellular Chaos: How Seed Oils Damage Your Body
- The Health Fallout: What the Science Says
- But Aren’t Some of These Oils “High Oleic” and Supposedly Healthier?
- Podcast on Hateful Eight Oils
- Here’s how that happens:
- What to Use Instead: Healthy Fats That Nourish, Not Harm
- How to Ditch the Hateful Eight in Real Life
- Buy Products that Use These Oils Instead:
- A Return to Ancestral Health
- Final Thoughts: You Are What You Eat
Meet the Hateful Eight – The Most Harmful Oils in Your Diet
According to Dr. Shanahan, the “Hateful Eight” seed oils to avoid are:
- Corn oil
- Canola oil
- Cottonseed oil
- Soybean oil
- Sunflower oil
- Safflower oil
- Rice bran oil
- Grapeseed oil
These oils dominate processed foods, restaurant fryers, and even “healthy” packaged snacks. But what makes these common ingredients so damaging?
From Seed to Shelf: The Industrial Process Behind Seed Oils
Despite being called “vegetable oils,” the Hateful Eight don’t come from vegetables—they come from seeds. And unlike olive oil, which can be cold-pressed directly from olives, extracting oil from these tiny seeds requires a high-tech, high-heat process.
Here’s how it works:
- High-heat extraction
Seeds are heated to extreme temperatures to extract the oil. This creates oxidized byproducts and begins breaking down fragile fats. - Solvent extraction
A chemical solvent—usually hexane, a petroleum byproduct—is used to strip remaining oil from the seed mash. - Refining, bleaching, and deodorizing (RBD)
The extracted oil smells and looks unappealing. So it’s chemically refined, bleached to remove color, and deodorized to mask the rancid smell.
The result? A bland, shelf-stable oil that’s cheap to produce—and highly inflammatory to your body.
The Omega Imbalance: Why These Oils Are Inflammatory
The Hateful Eight oils are extremely high in omega-6 polyunsaturated fatty acids (PUFAs), especially linoleic acid.
While omega-6 fats are essential in small amounts, most Americans consume 15-20 times more omega-6 than omega-3—a ratio that’s wildly out of balance with what our bodies evolved to handle.
This imbalance leads to:
- Chronic inflammation
- Oxidative stress
- Damaged cell membranes
- Increased risk of metabolic syndrome, obesity, and heart disease
In fact, Dr. Shanahan and others argue that inflammatory seed oils are more damaging to heart health than saturated fats ever were.
Cellular Chaos: How Seed Oils Damage Your Body
To understand how damaging these oils are, you need to understand what they do at the cellular level.
1. They alter your fat stores
Your body stores fat for energy, but what kind of fat? If you consume large amounts of seed oils, your body fat becomes rich in linoleic acid, which is unstable and oxidizes easily.
This leads to increased inflammation every time your body burns fat (during fasting, sleep, or exercise).
2. They damage mitochondria
PUFAs break down into harmful byproducts like 4-HNE (4-hydroxynonenal), which damage mitochondrial DNA—the power plants of your cells. Damaged mitochondria = less energy, slower metabolism, and increased disease risk.
3. They promote insulin resistance
Inflammation and mitochondrial dysfunction impair insulin signaling, making it harder for your body to manage blood sugar. Over time, this contributes to type 2 diabetes and obesity.
4. They increase mental health risks
New research shows that inflammation plays a role in depression, anxiety, and cognitive decline. Seed oils may quietly worsen mood disorders by contributing to chronic, low-grade inflammation in the brain.
The Health Fallout: What the Science Says
Here are just a few of the growing list of chronic conditions linked to overconsumption of omega-6 seed oils:
✅ Obesity
Studies have found a correlation between linoleic acid intake and rising obesity rates—not just from calories, but from how these oils alter metabolic function.
✅ Heart Disease
Though once promoted as “heart-healthy,” seed oils can oxidize LDL particles (the so-called “bad” cholesterol), making them more likely to cause arterial plaque.
✅ Cancer
Oxidized linoleic acid metabolites may play a role in promoting tumor growth, especially in breast and colon cancers.
✅ Liver Disease
Non-alcoholic fatty liver disease (NAFLD) has risen sharply alongside seed oil consumption. Research suggests a direct link between linoleic acid and liver fat accumulation.
✅ Alzheimer’s and Cognitive Decline
Your brain is 60% fat. Feeding it unstable fats like PUFAs may impair neuron function and increase beta-amyloid buildup, a hallmark of Alzheimer’s.
But Aren’t Some of These Oils “High Oleic” and Supposedly Healthier?
Some food manufacturers now use “high-oleic” versions of sunflower or safflower oil. These contain more monounsaturated fat (like olive oil) and less linoleic acid.
While better than standard versions, these oils are still:
- Highly processed
- Often genetically modified
- Typically used in ultra-processed foods
They’re a lesser evil, but still not ideal.
Podcast on Hateful Eight Oils
Salad Sabotage: How Seed Oils Undermine the Benefits of Microgreens
Microgreens—tiny, nutrient-dense shoots of vegetables like broccoli, kale, arugula, and radish—are often hailed as superfoods.
Rich in antioxidants, phytonutrients, vitamins C, E, and K, and anti-inflammatory compounds, they can offer concentrated health benefits in every bite. Including microgreens in your salads is a smart move for anyone looking to reduce inflammation and support cellular health.
But here’s the catch: if you dress that salad with a vinaigrette made from soybean, canola, or sunflower oil, you’re essentially cancelling out many of those benefits.
Here’s how that happens:
- Pro-Inflammatory Overload: Microgreens fight inflammation, but seed oils fuel it through their high linoleic acid content. You’re introducing conflicting biological signals in the same meal.
- Nutrient Absorption Disruption: Healthy fats help your body absorb fat-soluble vitamins (A, D, E, and K). However, industrial seed oils are oxidized and unstable, and their byproducts may actually interfere with nutrient utilization, especially if your gut or liver is already compromised.
- Lipid Peroxidation: When seed oils oxidize (either during processing or in your body), they form toxic aldehydes like 4-HNE, which can damage DNA and mitochondrial membranes, undoing the protective antioxidant effects of the microgreens.
- Misleading Health Halos: Many store-bought “healthy” dressings contain organic greens and herbs, but are still made with inflammatory oils like expeller-pressed canola. Don’t be fooled by the label—check the ingredient list!
Better Choice:
Pair your microgreens with healthy fats like extra virgin olive oil, avocado oil, or cold-pressed flaxseed oil. These support vitamin absorption and amplify the anti-inflammatory effects of greens rather than suppressing them.
What to Use Instead: Healthy Fats That Nourish, Not Harm
Dr. Shanahan recommends returning to traditional, minimally processed fats that humans have consumed for centuries.
Here are the best alternatives:
1. Extra Virgin Olive Oil
- High in monounsaturated fats
- Rich in polyphenols (antioxidants)
- Cold-pressed and low-heat processed
- Great for salad dressings or low-heat cooking
2. Avocado Oil
- Similar fatty acid profile to olive oil
- High smoke point, good for sautéing
- Look for cold-pressed, unrefined versions
3. Grass-Fed Butter or Ghee
- Contains fat-soluble vitamins (A, D, E, K2)
- Ghee (clarified butter) is great for high-heat cooking
- Rich in butyrate, a short-chain fatty acid that supports gut health
4. Coconut Oil
- High in medium-chain triglycerides (MCTs)
- Antimicrobial and heat-stable
- Great for baking or sautéing
5. Animal Fats (Tallow, Lard)
- Traditional fats have been used for millennia
- High in saturated fat (heat stable)
- Best from pastured, organic animals
6. Omega-3-Rich Fats (Fish, Flaxseed, Chia)
- Help restore balance to your omega-6:omega-3 ratio
- Support brain and heart health
- Prioritize whole food sources over supplements
How to Ditch the Hateful Eight in Real Life
Removing seed oils from your diet isn’t just about what you cook at home—it’s also about avoiding hidden sources.
Check these common foods for seed oils:
- Salad dressings
- Packaged snacks and chips
- Granola bars
- Fast food
- Restaurant fryers
- Mayonnaise
- Vegan butter and margarine
- Plant-based meat substitutes
Look for these red flags on ingredient labels:
- “Vegetable oil”
- “Expeller-pressed” (still often refined)
- “Blended oils” (which usually include soy or canola)
Buy Products that Use These Oils Instead:
- Salad dressings made with olive oil or avocado oil
- Snacks cooked in coconut oil or animal fats
- DIY condiments with real-food ingredients
A Return to Ancestral Health
Dr. Shanahan’s recommendations stem from what she calls the “Four Pillars of Human Nutrition”—principles drawn from traditional diets around the world. One key pillar is consuming healthy, stable fats from real foods.
Ironically, the fats we’ve been told to avoid—like butter, lard, and coconut oil—are often far safer than the industrial seed oils that now dominate our food system.
To learn more about Dr. Cate Shanahan, visit her website.
Final Thoughts: You Are What You Eat
It’s not just a cliché—your body is literally built from the fats you consume. Your cell membranes, brain tissue, hormones, and even gene expression are influenced by your dietary fat choices.
By eliminating the Hateful Eight from your life and embracing real, whole-food fats, you can:
- Reduce inflammation
- Improve energy and metabolism
- Support mental clarity
- Reduce your risk of chronic disease
It may take time to detox from decades of poor oil advice, but your body will thank you, one cell at a time.
