Vegetable Oils May Cause Fatigue, Migraines and Dementia


When heart disease and heart attacks created a growing concern in the 1950s, most Americans tried to get healthier by swapping out their butter, cream and saturated fats for vegetable oils. But medical experts now suggest that may have been a serious mistake.

Credit: Mike Mozart/Flickr, CC BY 2.0

Research shows that eating vegetable oils can cause plaque buildup in the brain that can lead to fatigue, migraines and even dementia. This plaque buildup is a known precursor to serious neurodegenerative diseases, and while other oils carry this trait, vegetable oil is the type with which it’s most prevalent.

Vegetable oil causes oxidative stress, which damages brain membranes and results in plaque building up on the brain,” Dr. Catherine Shanahan, author of the new book Deep Nutrition: Why Your Genes Need Traditional Food (Flatiron Books), told MailOnline. ”We’ve seen in research with Alzheimer’s patients that doctors will biopsy part of the brain and see that plaque has built up.”

Why Vegetable Oils Are Dangerous

Credit:, CC BY-SA 2.0

Shanahan believes the problem stems from when vegetable oils — such as canola, palm and corn — are heated to high temperatures for cooking. Many of them are unstable and release dangerous compounds that break down into toxic aldehyde, which has been linked to cancer risk and other health conditions.

A study found that cooking vegetable oil for 20 minutes released 20 times the amount of aldehyde that is branded safe by the World Health Organization. Another report found that heating palm oil at 400 degrees Fahrenheit or higher triggered the oil to release toxins. Research shows that vegetable oils are also linked to heart disease and antioxidant depletion. These fats also strip the body of antioxidants because they oxidize easily and cause inflammation and mutation in cells.

Related: Report Claims Palm Oil Ingredient in Nutella Causes Tumors

The way vegetable oils are processed before they hit store shelves is also an issue. They, too, are stripped of antioxidants, which can affect the balance of free radicals in the oil. Free radicals in the body can promote disease.

Here is Dr. Shanahan discussing the issue on KCAL 9 News:

How Vegetable Oil Affects The Brain

While vegetable oils can cause damage to the body overall, this new research is specifically concerned about its effects on the brain. Vegetable oils are often promoted as a healthy choice because they do contain monounsaturated fats and Omega-3 fatty acids. But a separate study found that because vegetable oils are so rich in Omega-3 fatty acids once ingested, this in turn drains the amount of Omega-3 fatty acids in the brain.

“If you eat too much corn oil or sunflower oil, the brain is absorbing too much Omega-6, and that effectively forces out Omega-3,” said Professor John Stein, Oxford University’s Emeritus Professor of Neuroscience. “I believe the lack of Omega-3 is a powerful contributory factor to such problems as increasing mental health issues and other problems such as dyslexia.”

In this cerebral autopsy specimen of a patient with Alzheimer’s, several amyloid plaque formations are seen. Credit: Jensflorian/Wikimedia Commons, CC BY-SA 3.0

According to Shanahan, regular consumption of vegetable oil can cause short-term side effects like lethargy and difficulty concentrating.

Oxidative stress disrupts the function of the brain, so the cells cannot do their normal housekeeping,” continues Shanahan, a former nutritionist to Kobe Bryant and current Director of the Los Angeles Lakers’ basketball team nutrition program. This cell disruption leads to a buildup of plaque in the brain.

People who make vegetable oil a regular part of their diet may experience brain fog and fatigue. “The No. 1 symptom someone would feel is migraines,” says Shanahan. “[People] don’t realize how poorly they were thinking until they’re off this stuff.”

Plant-Based Oils Are Best for Diet

Plant, fat-based oils like olive, coconut, avocado and peanut are the best ones to use for cooking. Tests conducted that heat up those oils found that they naturally produce less aldehydes; the oil that produced the least amount was coconut. Some health experts say even butter or lard is okay, but it’s still important to use them in moderation.

Mount Sinai Hospital Diabetes Program Manager and registered dietician Maria Elena Rodriguez warns that some plant-based oils — namely coconut oil and butter — are high in saturated fats. So using these as a full-blown replacement isn’t always the healthiest choice especially depending upon your specific health circumstance.

Related: These Herbs and Vegetables May Prevent Breast Cancer From Spreading

“Saturated fat is shown to have a higher risk of plaque, heart disease, diabetes and inflammation,” Rodriguez told the New York Post.

But Shanahan sticks by the research she assembled for her book. She believes that with heart-healthy, plant-based oil choices available there’s no need to endanger your health when doing something as natural as cooking at home.

I would say when you’re doing your own cooking to choose oils that have a flavor, like coconut or peanut, and then make sure that it’s unrefined,” she says.  “Why not go with a healthier, tastier fat?”