Surprising Facts About Cooking Oils

Surprising Facts About Cooking Oils

Around 1907, a German scientist contacted Procter & Gamble to tell them he had invented a way to turn liquid fat into a solid and suggested it would transform their soap products. But when the company’s scientists found they could turn cottonseed oil into a creamy, lard-like substance, they decided to forget soap! They saw it as a perfect replacement for animal fats used for cooking—and so did America. The company sold 2.6 million pounds of what it branded as Crisco in 1912, and 60 million pounds four years later.

Although this vegetable fat was marketed as the healthier way to cook, it was 50 percent trans fats, which are hydrogenated fats commonly used in processed and fast foods. Current studies show trans fats are heart-stopping: For every two percent increase in consumption of trans fat, the risk of heart disease increases by 23 percent! Studies also implicates that trans fats have adverse effects on the brain and nervous system and can even cause an increased risk of depression and dementia.

Nonetheless, for 100 years, all vegetable oils were touted as the solution to Americans’ health problems. Instead we have grown more obese, more likely to have diabetes and dementia and more depressed.

The truth? Not all vegetable oils are created equal—not by a long shot. And now, to add to the confusion, there’s a study suggesting that canola oil—the current darling of the processed food industry and home cooks—may help lay the foundation for the development of Alzheimer’s disease (AD). There’s much to dispute in those scary headlines about the study in Scientific Reports. The researchers themselves are more cautious, saying, “Taken together, our findings do not support a beneficial effect of chronic canola oil consumption on two important aspects of AD pathophysiology, which includes memory impairments as well as synaptic integrity. While more studies are needed, our data do not justify the current trend aimed at replacing olive oil with canola oil.” So, it’s basically just a study that says to stick with olive oil when cooking at home.

Furthermore, the study was done on mice that are engineered to develop markers of AD and it found only one indicator that may be significant: While mice choosing a direction at a fork in the road tend to alternate in their selection from time to time, 20 percent of the canola-eating rodents in the study didn’t alternate as often as expected. So does that mean humans who eat canola oil will be cognitively impaired? Doubtful.

Your health and vegetable oils
A vegetable oil is healthy or not healthy depending on how it’s processed, what it contains and how it’s used.

  • Processing is often done using a solvent (typically the toxin hexane) to separate the oil from the seed. However, expeller pressed oils use mechanical not chemical means. The cold pressed method is also mechanical, but the oil is kept cooler during extraction. There’s little health difference between expeller and cold pressed.
  • Some oils contain a boatload of saturated fat and should be avoided. One tablespoon of palm oil has 7 grams of sat fat; 1 tablespoon of palm kernel oil—11 grams; coconut oil—12 grams. Others are rich in polyunsaturated and monounsaturated fats, which if not eaten in excess are heart-healthy and help to reduce inflammation. Your best bet—opt for omega-3-rich oils like extra virgin olive oil (EVOO) and oil in avocados and nuts. EVOO helps lower lousy LDL cholesterol and contains beta carotene and vitamins A, E, D and K.
  • Some oils, especially light/refined olive, almond, avocado and sunflower oils, are perfect for searing and browning at higher temperatures—they have a high smoke point, so you avoid producing toxic fumes and unhealthy byproducts. Canola, grapeseed and peanut oils have a medium high smoke point; use for baking, stir frying and oven cooking. Some are good for use at room temp: flaxseed, wheat germ, walnut and EVOO.

Medically reviewed in October 2019.

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