Is the oil you are consuming safe?
What exactly are dangerous oils? And which oils can you use with confidence?
Note: The process of making vegetable oil can vary by region. Although chemical solvents are eventually removed, so they are not a major concern, the use of high temperatures during processing is a common practice worldwide and carries potential risks.
Just like in skincare, oils contribute significantly to health. However, things with many benefits often come with strict usage guidelines or drawbacks.
Some oils can even be harmful rather than healthy.
Whether in health or beauty, it ultimately comes down to oils. But what exactly are these oils? How can you identify them?”
Let’s take a look at dangerous oils. One of them is ‘vegetable oil.’
The primary raw materials for salad oil include nine types: safflower, grape, soybean, sunflower, corn, cottonseed, rapeseed, sesame, and rice.
Any of these may be used to make vegetable oil, and sometimes they are mixed.
You might think, ‘Oh, it’s just vegetable, so it’s fine, right?’
However, to turn these vegetable into vegetable oil, they go through many processes, such as bleaching, dewaxing, and deodorizing.
During these processes, chemical solvents are used to forcibly extract the oils from the plants.
These chemical solvents are derived from petroleum. While petroleum is an essential resource for maintaining our modern way of life, it has its downsides depending on how it is used.
Consuming petroleum can have many disadvantages.
To make oil that is odorless, clear, and visually appealing, it is heated at high temperatures using these solvents.
Vegetable oils are very delicate and sensitive to heat.
When subjected to high temperatures, components that are normally beneficial to health can transform into a toxin known as ‘hydroxynonenal.’ This means that because vegetable oil is made using chemical solvents and further heated at high temperatures, it may look clean and odorless, but it is very likely to contain toxins.
Moreover, since it’s used for cooking, it gets heated again. While the amount of toxins may vary, they are almost certain to be present, even in small quantities.
“So, what is this hydroxynonenal?”
Vegetable oils contain omega-6 fatty acids, including linoleic acid.
Linoleic acid is an essential fatty acid that the human body cannot synthesize and is beneficial on its own.
In the past, linoleic acid was less common in Japanese diets, so it was definitely a good addition.
However, nowadays, linoleic acid is present in many modern foods, such as fried foods, meats, and Western cuisine.
This includes eating out, as vegetable oil is inexpensive and thus commonly used by budget-friendly restaurants.
On the other hand, specialty tempura restaurants change their oil every 1-2 hours.
While this might seem wasteful, it’s necessary to ensure that they provide tasty and healthy dishes, so it’s not actually wasteful.
Furthermore, snack foods, fast food, and cakes often use vegetable oil.
Many recipe books recommend using vegetable oil, although there are substitutes available.
The excessive intake of linoleic acid can be problematic.
While omega-6 fatty acids are essential, too much can be harmful.
When linoleic acid is heated to around 200°C, it transforms into hydroxynonenal.
This compound causes oxidation in the brain, which can have significant negative effects on nerve cells.
It can lead to conditions like dementia, loss of motivation, and even diabetes and depression in children.
Additionally, it can weaken cell membranes, trigger inflammation, and cause nerve cell death or interfere with nutrient absorption, making it easier for viruses and bacteria to enter the body.
This can increase the likelihood of developing allergies and result in persistent fatigue.
Trans fats are also a concern!
Trans fats are artificially created fatty acids found in products like margarine.
Once ingested, they cannot be broken down by the body and accumulate over time.
Trans fats can cause cell oxidation and may lead to conditions such as diabetes and allergies.
So, how can you minimize the intake of dangerous oils?
First, avoid using vegetable oil. Ideally, you should switch to other types of oil, but price can be an issue, and even though olive oil is a good option, it might not always be affordable.
One approach is to use less oil in cooking.
There are many cooking methods and tools that do not require oil. For instance, microwaves are surprisingly effective.
Steaming or boiling vegetables can lead to the loss of vitamins along with the water, making these methods less ideal. However, microwaving can retain more of the vitamins and is quite efficient. Plus, it’s convenient and helps cook food evenly without burning.
Below is a ranking of oils by their linoleic acid content.
Please use this as a reference. Note that the composition may vary by product, so consider this as a general guideline.
- Safflower Oil: 73% (Recently, there are high oleic types with lower linoleic acid, around 12%. However, there’s no need to focus too much on oleic acid.)
- Evening Primrose Oil: 72%
- Grape Seed Oil: 71.3%
- Sunflower Oil: 57.6%
- Cottonseed Oil: 56.7%
- Corn Oil: 54.1%
- Wheat Germ Oil: 53.5%
- Soybean Oil: 52.2%
- Pumpkin Seed Oil: 51.8%
- Hemp Seed Oil: 47%
- Pine Nut Oil: 45.5%
- Sesame Oil: 43.9%
- Carya Oil: 41.9%
- Borage Oil: 38%
- Rice Bran Oil: 34.3%
- Argan Oil: 33.2%
- Peanut Oil: 36.7%
- Green Nut Virgin Oil: 30%
- Almond Oil: 24%
- Canola Oil: 19%
- Avocado Oil: 12%
- Tea Oil: 10.5%”
The daily recommended intake of linoleic acid is around 9 grams.
For example, in high-linoleic safflower oil, approximately 11 grams of linoleic acid are contained in 15 grams of oil.
15 grams is roughly equivalent to one tablespoon, or about 15 cc.
Next, avoid products that contain dangerous oils. These include:
- Coffee creamers
- Whipped cream
- Ice milk
- Lactose ice cream
- Margarine
- Fat spreads (often labeled as ‘soft’ or ‘〇〇 soft’)
- Shortening
And so on. When shopping at the supermarket, try to check ingredient labels as much as possible.
While margarine and fat spreads might seem like harmless options, they can actually be quite problematic. Butter is a safer choice, so if you have to choose, go with butter.
(Of course, consuming too much butter is not ideal either.)
Recently, some claims have stated that vegetable oils are not harmful to the body.
However, there are still many people who experience heartburn, which might be a defensive reaction to toxins.
While some argue that heating is minimal and that hydroxynonenal evaporates and does not remain, the fact is that both restaurants and homes involve heating. Additionally, the imbalance between omega-6 and omega-3 fatty acids is a concern.
Even if vegetable oil were truly harmless, excessive consumption is not recommended.
The body has a limit on the total amount of oil intake, so whether it’s omega-3 or omega-6, oil is still oil.
Therefore, if you consume too much vegetable oil (even if it were completely harmless), there would be less room for omega-3s.
There are also theories suggesting that hydroxynonenal can form even without heating, so it’s advisable to limit omega-6 oils.
How do the ingredients in the oil work?
