There are a few reasons that you should generally limit the amount of oils you consume.
One of those reasons is that most oils have a terrible omega fat ratio. A poor ratio of these key unsaturated fats can lead to inflammation, which can increase the risk of several health conditions.
We’re going to look at the specific omega 3 to 6 fat ratios of just about all plant-based oils here.
Table of Contents
Omega 3 to 6 Fat Ratio of Oils Table
All data in the table below comes from the USDA’s food database per 100 grams of each oil.
The fats don’t add up to 100 grams, even though oil is basically 100% fat in most cases, because these oils contain other types of fats as well (i.e. saturated, monounsaturated).
|Omega 3 (g)||Omega 6 (g)||Omega 3:6 ratio|
|Hemp Seed Oil||16.6||60||0.2767|
In general, you want to aim for an omega 3 to 6 fat ratio of .25 or above.
Only 3 of those oils meet that minimum threshold. In some cases, like olive oil, there aren’t that many omega fats in total, so the poor ratio isn’t that big of a deal.
However, you wouldn’t want to be eating sesame or grapeseed oil in large quantities.
The Ideal Ratio of Omega Fats in Oils
While the effects of omega fats on our health is complex, the easiest way to look at what sort of intake you should aim for is to base it on historical consumption.
The graph below shows the relative levels of omega 3 and 6 fats in human diets over a large time span (source). You can see that people historically had a diet with an omega 3 to 6 fat ratio of about 0.5 to 1.
The drastic worsening of the ratio and amount (of omega 6) recently isn’t due to people eating more seeds and nuts, it’s due to adding large amounts of oil while cooking almost everything.
It’s tough to balance out a large amount of omega 6 fats unless you regularly take an omega 3 fat supplement.
In practical terms, most people should look to limit their consumption of oils, and instead look to get omega 3 fats from seeds and fish (diet permitting).
Other Factors That Affect How Healthy An Oil Is
There are other aspects of oil that can affect your health, either negatively or positively.
One of the biggest aspects is how refined an oil is.
Oils are refined to remove impurities and free-fatty acids, which removes most of the nutritional benefit, but increases the shelf life and smoke point.
Refining oils also leads to a more consistent color and lighter odor, which can be desirable for manufacturers.
It’s typically best to consume unrefined oil when not cooking it, however, unrefined oil isn’t always great for cooking.
Smoke Points of Oils
The main data we looked at above beg the question:
Should you only eat flaxseed oil?
While flaxseed oil is a great idea for raw foods, it’s a terrible cooking oil.
Unrefined oils generally have low smoke points. When an oil is heated above its smoke point, it begins to break down and form harmful compounds. These aren’t fully understood still, but even breathing in the fumes are linked to certain cancers.
And obviously the oil can catch on fire as well (pro tip: smother grease fires with a lid, do not throw water on them.
Wikipedia has a great table of oil smoking points. I’ve reproduced part of it below for convenience:
|Oil||Quality||Smoke Point (C)||Smoke Point (F)|
|Avocado oil||Refined||270 °C||520 °F|
|Canola oil (Rapeseed)||220–230 °C||428–446 °F|
|Canola oil (Rapeseed)||Expeller press||190–232 °C||375–450 °F|
|Canola oil (Rapeseed)||Refined||204 °C||400 °F|
|Canola oil (Rapeseed)||Unrefined||107 °C||225 °F|
|Coconut oil||Refined, dry||204 °C||400 °F|
|Coconut oil||Unrefined, dry expeller pressed, virgin||177 °C||350 °F|
|Corn oil||230–238 °C||446–460 °F|
|Corn oil||Unrefined||178 °C||352 °F|
|Flaxseed oil||Unrefined||107 °C||225 °F|
|Grape seed oil||216 °C||421 °F|
|Olive oil||Refined||199–243 °C||390–470 °F|
|Olive oil||Virgin||210 °C||410 °F|
|Olive oil||Extra virgin, low acidity, high quality||207 °C||405 °F|
|Olive oil||Extra virgin||190 °C||374 °F|
|Olive oil||Extra virgin||160 °C||320 °F|
|Palm oil||Fractionated||235 °C||455 °F|
|Peanut oil||Refined||232 °C||450 °F|
|Peanut oil||227–229 °C||441–445 °F|
|Peanut oil||Unrefined||160 °C||320 °F|
|Sesame oil||Unrefined||177 °C||350 °F|
|Sesame oil||Semirefined||232 °C||450 °F|
|Soybean oil||234 °C||453 °F|
|Sunflower oil||Neutralized, dewaxed, bleached & deodorized||252–254 °C||486–489 °F|
|Sunflower oil||Semirefined||232 °C||450 °F|
|Sunflower oil||227 °C||441 °F|
|Sunflower oil||Unrefined, first cold-pressed, raw||107 °C||225 °F|
There are a few things of note:
- Unrefined oils have significantly lower smoke points, making most of them unsuitable for anything other than low-heat cooking.
- Extra virgin olive oil is minimally refined and has a reasonably high smoke point, so it’s a pretty good option for frying (not high temperature deep frying though).
- Flaxseed oil has a smoke point of just over 100 Celsius, which is basically the temperature of a frying pan at low heat. In other words, it’s not a good idea to cook with flaxseed oil, despite its great omega 3 to 6 fat ratio.
- Refined avocado or sunflower oil for higher temperature deep frying or high temperature searing.