Blog Comparison of Health Impacts: Seed Oils, Vegetable Oil, Olive Oil, and Butter

Comparison of Health Impacts: Seed Oils, Vegetable Oil, Olive Oil, and Butter

Comparison of Health Impacts: Seed Oils, Vegetable Oil, Olive Oil, and Butter

Are vegetable and seed oils “harmful”?!

From TikTok trends to bestselling publications, vegetable oils—commonly known as “seed oils”—are a hot topic these days.

To be fair, the discussion about the value of vegetable oils has been ongoing since they first appeared in the market.

Recently, however, with the rise of the carnivore diet, the backlash against vegetable oils has surged on social media. You may have seen posts labeling these cooking oils as “toxic sludge,” “motor oil,” “the hateful eight,” and “the leading cause of chronic illness that remains under the radar.”

The reasoning against vegetable oils goes like this…

Animal fats have been consumed by humans for millennia. In contrast, vegetable fats were created in the past century when profit-driven companies sought to promote inexpensive foods to unaware buyers.

Another perspective: Similar to margarine, vegetable oils were promoted as healthier substitutes for butter, yet, critics argue, these oils are more detrimental than butter, increasing your chances of obesity, anxiety, depression, ulcerative colitis, and other issues.

Conversely, some experts will assert that vegetable oils pose no harm, may even be beneficial to health—and are certainly superior to butter.

So, who is accurate?

Like many nutrition discussions, the truth is too complex to condense into a meme.

In this article, we’ll assist you in distinguishing science from pseudoscience so you can make educated choices about the oils you incorporate into your diet.

What are vegetable oils?

Often referred to as “seed oils,” vegetable oils originate, as you might expect, from the seeds of plants. The most commonly found types in a standard grocery store include:

  • Canola oil
  • Corn oil
  • Safflower oil
  • Sesame oil
  • Sunflower oil
  • Soybean oil
  • Grapeseed oil

By the way, if it seems like there are a number of oils absent from that list, it’s likely because those oils derive from non-seed plants (such as olive, avocado, palm, or coconut oil, which are all fruit-based and not considered vegetable or seed oils).

How are vegetable oils processed?

Non-vegetable oils—like olive and avocado oil—are extracted from naturally fatty foods. Indeed, olives are so rich in oil that you could theoretically produce your own olive oil at home. (Just search “how to make olive oil from scratch,” and you’ll find various videos demonstrating the process.)

This cannot be said for most vegetable oils, which predominantly originate from foods with relatively low fat content.

For instance: A cup of green olives has about 20 grams of fat,1 whereas a cup of corn only has 2 grams.2

Consequently, manufacturers must employ a complex multi-step process to extract this minimal amount of oil from these low-fat foods. These steps include:

  • Crushing: A machine applies high pressure to extract oil from the seeds.
  • Refining: The seeds are heated with a solvent, such as hexane, to extract additional oil.
  • Deodorizing: To achieve a neutral flavor and eliminate undesirable compounds, the extracted oil is heated at 400 F (204 C) for several hours.

Throughout this process, beneficial polyphenols and other stabilizing nutrients are diminished, and small amounts of unsaturated fats are converted into trans fatty acids (also known as partially hydrogenated fat).

(An interesting note: This transformation also occurs during deep frying. When vegetable oils are heated in a restaurant’s deep fryer for extended periods, the trans fat levels in the oil increase.)

Labeling these processed oils as “toxic” may be an overstatement. Nonetheless, nutrition scientists generally concur that individuals should steer clear of trans fats in their diet, and in 2018, the Food and Drug Administration prohibited manufacturers from incorporating trans fats into processed foods.3 4