America’s Most Popular Vegetable Oil May Be Bad For Your Brain




By Joy Stephenson-Laws, JD, Founder


Many of us eat foods and buy products without really knowing what’s in them. Or, if we know what’s in them, we are often not aware of the potential consequences of consuming the  ingredients. 

Take, for example, soybean oil. 

Soybean oil is the most popular and widely consumed edible oil in the United States.

Processed soybeans are the world's largest source of animal protein feed and the second largest source of vegetable oil. The United States is the world's leading soybean producer and the second-leading exporter. Soybeans comprise about 90 percent of U.S. oilseed production, while other oilseeds—including peanuts, sunflower seed, canola, and flax—make up the remainder,” according to the United States Department of Agriculture (USDA).

This vegetable oil, which may be a misleading name because we usually associate vegetables with good health, appears to not be very good for us.

One study from 2015 found evidence which suggested that mice who were fed a high soybean oil diet “...showed increased weight gain, larger fat deposits, a fatty liver with signs of injury, diabetes and insulin resistance, all of which are part of the Metabolic Syndrome,” compared to mice who were given a high coconut oil diet. 

Soybean oil is used to fry fast foods and is found in many ultra-processed foods such as cookies, crackers and sweets. You may also find soybean oil in grocery items like bagels, frozen pizza, mayonnaise, salad dressings and more. It is used as a food preservative. It’s essentially everywhere you look and everywhere you can’t see it. There are plenty of restaurants that use soybean oil as their cooking and frying oil.

“If there's one message I want people to take away, it's this: reduce consumption of soybean oil," said one of the lead authors of an even more recent study on mice and soybean oil, referenced in this report discussing the study.

This study found evidence suggesting that consuming soybean oil could also have a negative effect on the brain and influence neurological conditions such as autism, Alzheimer’s, anxiety and depression.

The researchers compared mice that were fed three different diets that were high in fat: 

  • Soybean oil.
  • Soybean oil (changed to be low in linoleic acid, which is an essential fatty acid. It is a polyunsaturated fat (a type of good fat that has been associated with lowering the risk of coronary heart disease)).
  • Coconut oil.

The researchers discovered that mice who were fed diets with both regular soybean oil or soybean oil modified to be low in linoleic acid experienced “pronounced effects of the oil on the hypothalamus, where a number of critical processes take place.”

The hypothalamus is a small but critical area of the brain that produces hormones that control:

“The team determined a number of genes in mice fed soybean oil were not functioning correctly. One such gene produces the ‘love’ hormone, oxytocin. In soybean oil-fed mice, levels of oxytocin in the hypothalamus went down,” according to the study report.

This explains why consuming soybean oil may play a role in the development of depression.

Most disturbing of all, the research team discovered about 100 (yes, 100!) other genes were also impacted by consuming the soybean oil diets. (Mice fed the coconut oil diet experienced very few changes in hypothalamic genes).

“They believe this discovery could have ramifications not just for energy metabolism, but also for proper brain function and diseases such as autism or Parkinson's disease.”

The results of this study are not definitive proof that consuming soybean oil causes neurological diseases in humans. More research is needed and next steps are to determine which chemicals exactly in soybean oil may be doing the damage. Regardless, it’s enough motivation for me to certainly inquire more about what is in the foods I am eating when I am outside of my home.

It is important to note that this study is not suggesting that soy products as a whole are harmful. So things like edamame and soy milk appear to be fine.

How can we be proactive?

  • Opt for olive oil. Speak up at restaurants and ask if they use soybean oil. See if you can request olive oil.
  • Avoid the two “Big Fs.” Fast food and fried food (which are usually cooked and fried in soybean oil). These foods are nutrient-void and not good for us anyways. They increase the risk of diseases such as cancer, heart disease, hypertension and more. No, I would not like fries with that! (Make your own delicious sweet potato fries at home). 
  • Be a smarter shopper. Avoid buying processed, packaged foods. Stick to the produce aisle, fresh seafood and meat section and bulk items like oats and beans. If it comes in a package, there is a high chance that it contains soybean oil. This oil is used as a preservative to increase the shelf life of packaged foods. This is why fresh is always best! If you must buy something packaged, read the ingredient labels. If vegetable oil is one of them, it is probably soybean oil. See what packaged items you can let go of in your household. For example, stop buying bottled salad dressing. Make your own at home with olive oil, balsamic vinegar, lemon, garlic, herbs and any other natural ingredients. 

It may take a bit of extra work and discipline to let go of some of your favorite foods that contain soybean oil, but may be worth it. If we want to live long, healthy and happy lives, we have to understand that this will only be achieved if we fuel our bodies with needed nutrients and avoid foods that may cause inflammation and damage to our genes.


Enjoy your healthy life!


The pH professional health care team includes recognized experts from a variety of health care and related disciplines, including physicians, attorneys, nutritionists, nurses and certified fitness instructors. This team also includes the members of the pH Medical Advisory Board, which constantly monitors all pH programs, products and services. To learn more about the pH Medical Advisory Board, click here.


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