In a prior email, I discussed the three simplest nutrition tips that you had probably ever seen.
One of those tips was to eat real food. And in the category of stuff to not eat, I mentioned a few industrially refined oils including canola, corn, safflower, and soybean oil.
Whether you had previously read that tip or are just now seeing this info for the first time, you might have some questions. Namely:
- Aren’t those all vegetable oils?
- Why aren’t they considered real food?
- What makes them unhealthy?
To answer those questions, I’ll turn to a section early in Dr. Georgia Ede’s book, Change Your Diet, Change Your Mind, in which she discusses the perils of processed foods, including refined vegetable oils.
(For reference, Dr. Ede is a Harvard-trained psychiatrist who subsequently went on to study nutrition after arriving at the intersection of a challenge and an observation: The challenge was a host of “perplexing new [health-related] symptoms” experienced in her early forties. The observation was that her practice and the practices of many colleagues and mentors were filling up with pharmaceutical-consuming patients who weren’t getting any better.)
She begins this section of the book by stating that vegetable oils have traditionally been promoted as good for us but also that they’ve come under recent scrutiny for their potential role in declining mental and physical health.
The primary concern is a certain aspect of their chemical makeup, which I’ll summarize shortly.
But, first, let’s cover a related highlight: the rather unsavory refining process required to produce such oils.
For comparison, there are two categories of unrefined fats: The first category includes those that occur naturally in plants or animals (e.g. ribeye steak, avocado, walnut). The second category includes those that are extracted using simple and traditional processing methods like cooking (e.g. tallow, lard), churning (e.g. butter), or cold-pressing (e.g. olive oil). Even though this second category undergoes some processing, it’s still considered unrefined because the resulting chemical structure remains largely unchanged.
Alternatively, “vegetable” oils (which come from nuts, seeds, or legumes) require significantly more (unappealing) processing and result in a relatively odorless substance with a bland taste and long shelf-life.
Here’s the detail that Ede provides:
How to Make Soybean Oil in Thirteen Easy Steps (Don’t Try This at Home)
Remove seed hulls, flatten beans into flakes, then pass through an industrial feedscrew extruder to compress the flakes and destroy their cellular integrity.
(Before proceeding to the next step, decrease the atmospheric pressure in the room to reduce the risk that flammable gases will escape and explode.) Next, add hexane [an explosive, petroleum-based solvent], and let the mixture percolate. Place mixture in a desolventizer and heat to 212 degrees Fahrenheit until most of the hexane has evaporated, then let cool. Air dry, then pour into a steam stripper to further concentrate the oil. To prevent unsavory deposits from forming during shipping, degum your hot oil with water and set the extracted gums aside. (Important! Do not discard, as these gums can later be sold to your fellow processed food manufacturers as soy lecithin.)
To neutralize your oil, mix with sodium hydroxide (lye) and place in a centrifuge to remove the soap that naturally forms as a by-product. Add a natural bleaching agent such as clay, then filter to remove any soapy residues, pigments, waxes, and rancid fatty acids. To complete the refining process, place in a vacuum deodorizer and heat to at least 356 degrees Fahrenheit. Let cool, pour into bottles, and label “heart-healthy, plant-based vegetable oil.”
Mmm, yummy. Or not!
In any case, that brings us back to the chemical structure and the primary issue with veggie oils: a high concentration of linoleic acid.
Dr. Ede points out two causes for concern:
As an omega-6 fatty acid, linoleic acid produces inflammation in the body. That fact isn’t a concern in and of itself because inflammation is a normal part of body functioning.
However, research suggests that our pre-Industrial Revolution diets contained roughly equal portions of omega-6 to omega-3 fatty acids or ever-so-slightly more omega-6s, whereas our typical modern diets often contain at least twenty times more omega-6s than omega-3s. Omega-3s produce anti-inflammatory responses in the body, and chronic inflammation has been linked to numerous diseases including autoimmune disorders, cardiovascular disease, arthritis, and dementia (to name just a few).
So the primary cause for concern is the mismatch in favor of inflammation.
The second cause for concern revolves around the brain’s use of linoleic acid. Under normal conditions, our brains preferentially burn glucose (sugar) or ketones (fatty acid fragments that have been partially “pre-digested” by the liver).
However, when higher amounts of linoleic acid are present, our brains seem to use the excess for energy instead of converting it to other more useful molecules.
The potential problem here is that “burning fatty acids generates many more oxygen radicals, which increases oxidative stress inside the brain”. Some researchers have speculated that could be a contributing factor in the development of some mental health problems, including dementia.
Ultimately, Dr. Ede makes three other relevant points:
- Small quantities of linoleic acid exist in many whole foods, and there are reasons to believe that we’ve evolved to (safely) consume it in those quantities.
- Vegetable oils (and, subsequently, linoleic acid) are ubiquitous in processed foods today. Some sources suggest that soybean oil alone constitutes up to 8% of the calories consumed in the standard American diet.
- More research needs to be done, but what we currently know is potentially concerning.
And she closes the section by saying: “If you share this concern, you have nothing to lose (and potentially a great deal to gain) by removing these industrially refined oils from your diet.”
Putting it into practice
As mentioned above, “vegetable” oils come from nuts, seeds, and legumes. This includes:
- Grape seed
- Walnut
- Corn
- Cottonseed
- Soybean
- Sesame
- Peanut
- Canola (rapeseed)
- Sunflower
- Safflower
(As a related aside, this is the order from a graph in the book which shows the relative concentrations of linoleic acid, from most to least.)
Technically, coconut oil also falls into this category. However, its concentration of linoleic acid is on par with butter and tallow (i.e. very low). And virgin coconut oil is expeller-pressed instead of processed like the other vegetable oils (see soybean oil “recipe” above).
So this week, consider ridding your kitchen not only of the pure oils listed above (other than virgin coconut oil) but also of any packaged foods that contain them. (Salad dressing and crackers are among the worst offenders, in my observation.)
Then replace them with animal fats (e.g. butter, tallow, lard) or fruit oils (e.g. olive, avocado).
It’s a simple change that could have significant health impacts in both the short and long terms.