Key Topics Covered
Considering the fear-mongering and negativity around seed oils and the attention these oils have received online, we thought it was only fitting to dive into the topic of seed oils and whether they are bad for consumption.
Defining Seed Oils
- Seed oils are oils that are extracted from the seeds of various plants.
- Common examples include canola oil, sunflower oil, soybean oil, and safflower oil.
- These oils are typically high in polyunsaturated fatty acids, such as omega-6 fatty acids.
Processed vs Unprocessed
- Much of the negativity is in relation to the processing aspect, in that seed oils are quote unquote “highly processed”
- Some people will also argue the omega 6 vs omega 3 thing which would be relevant regardless of how processed they are and we will touch more on that as well.
- But going back to the processing, it’s worth noting that it’s possible to produce seed oils in a relatively low processed fashion, just like extra-virgin olive oil
- The reason why it’s not as common to do it that way is because it has downsides that would make it harder to sell, such as being less cost effective as well as differences to appearance, texture and smell.
Aidan Topic 3: How are they normally made?
- Moving on to how these oils are made since this is the big thing you see people commenting on.
There are different methods, but we will simplify it down to one, largely based on canola oil.
And we will lay out 2 versions of this. The first one is slightly more fear monger-y, but worth hearing for context. The second is a bit more balanced.
Fear Monger Version:
- Seeds are gathered
- They are then heated to extract oil. This reduces the vitamin and antioxidant content. It also oxidises a lot of the fatty acids.
- A solvent such as hexane is then added to help degum the oil and separate it to extract more. Hexane is a known neurotoxin.
- And other chemicals such as sodium hydroxide are often added to continue the processing.
- The seed oils are also deodorised to reduce the off putting smell. This also masks if it is rancid.
- The oil is then bleached to make it more appealing to consumers.
So when you actually put it like that, it doesn’t sound great. Which is why it seems to easy to make a case against consuming seed oils.
Balanced Version:
Technically all of those things are true. But let’s go one step further.
- Seeds are gathered.
- The heating process does reduce the antioxidant and vitamin content. The fatty acid oxidation depends on the duration and temperature of the heating, as well the antioxidant content.
- A solvent such as hexane is added. When you see how it’s made you can also see that this significantly increases how much oil is extracted, which obviously reduces cost of production.
- Any of the chemicals that are added are removed later in the process. The final amounts are trace amounts at maximum and are considered safe by regulatory agencies. I can see why people would be concerned though.
- The deodorising process is typically done without chemicals, although it does involve high heat again.
- The oil being bleached is typically done with components such as absorbent clays and activated charcoals. These are removed at the end. I’ve seen criticisms mention the use of chlorines, but that doesn’t actually seem common.
The balanced perspective is good to be aware of. But regardless of how you look at it, you can see why this leaves people a bit concerned vs the alternative of just pressing at a lower temperature of ~40 degrees without chemicals.
Omega 6 vs Omega 3
- We’ve previously talked about this in our omega 3 series back in episodes 94 and 95.
- We will treat it seriously and discuss it if you haven’t heard our thoughts though, since it is very relevant here.
- There’s an argument that the ideal ratio of omega 6 vs omega 3 is 1:1, but people typically consume a ratio somewhere between 5:1 and 20:1.
- The argument that the ideal omega 6 to omega 3 ratio should be 1:1 stems from the idea that our ancestors ate a diet with this ratio, so it must be ideal for human health.
- This is rooted in evolutionary thinking, suggesting that because early human diets had a balanced intake, we should aim to replicate it.
- However, while there’s logic behind this—”our bodies evolved to function on certain nutrient profiles”—it’s essential to note that modern evidence might paint a different picture of what is actually optimal
- It would be smarter to focus on the abundance of evidence we have in relation to nutrition and human health right now.
- There IS abundant evidence about the health benefits of omega 3 fatty acids in supporting heart health, reducing inflammation, and improving brain function.
- At the same time, omega 6 is also essential for overall health, contributing to growth and development, brain function, and metabolic regulation.
- Foods like nuts and seeds are high in omega 6 but we see a positive correlation between those who eat more nuts and seeds and long term health outcomes
- So instead of aiming for an exact ratio, focusing on adequate intake of both fatty acids is more realistic and backed by evidence.
- The emphasis should be on consuming more omega 3 (which is often deficient in modern diets) rather than strictly limiting omega 6.
- Focusing on the ratio without considering total consumption can be misleading. For example, if someone consumes high amounts of both omega 6 and omega 3, their ratio might stay the same, but their total intake of each is vastly different compared to someone who consumes low amounts of both. The impact on health can vary greatly based on total intake, not just the ratio. For instance, consuming higher amounts of omega 3 can benefit heart health, regardless of how much omega 6 you’re consuming. This is why context matters more than a fixed number.
Obesity Was Rare Before Seed Oils Were Introduced Into the Food Supply
- Have you seen those photos from the 50s where everybody on the beach was lean, and then there is a caption saying how “this was taken before the influx of seed oils?”
- I don’t even know if this is worth addressing…
- Many things have changed since then.
- There’s a big decrease in activity, particularly in relation to everyday tasks related to work and home life.
- There’s an increase in calorie intake. We have more access than ever to hyper-palatable food + food marketing has improved too.
- From another angle, seed oils reportedly make up 7-8% of the calories in the American diet (which I assume isn’t TOO different from Australia).
- Obviously reducing seed oils would result in a reduction in calorie intake for many reasons.
Any Positives?
- If consumed in moderation, in a minimally processed form, there can be some arguments here.
- For example, the Vitamin E content (if not destroyed by processing) is an antioxidant that can provide health benefits
- Flaxseed oil is particularly high in omega 3. This form of omega 3 (ALA) is not as easily converted as the omega 3 in fish, but it’s still beneficial. Flaxseed oil in particular is consistently associated with health benefits when consumed in small amounts.
- There is also the argument that, If somebody were to otherwise have a low omega 6 intake, there are benefits of adding it in. It is still quite literally an essential fat.
- Plus replacing saturated fats with polyunsaturated fats is consistently linked with reductions in LDL cholesterol and cardiovascular disease. This isn’t necessarily a controversial take since the research is consistent on this.
- So it’s not like a we should be lumping omega 6 in with saturated fats which are commonly referred to as “bad fats.”
Consensus / Interpretation
- All the benefits of seed oils can be gotten in other ways e.g. even if you needed omega 6, there are many other sources
- In many cases, seed oils are highly processed, low in micronutrients and high calories.
- They are also often found in products that fit that description e.g. cakes, biscuits, fast food etc
- That doesn’t sound like something that is typically a good thing.
- Talking about each point individually can make it seem like it’s a really negative topic.
- But the other thing worth addressing is that legitimately a large amount of the criticism is overblown.
- Although it doesn’t make sense to go out of your way to ADD them to your diet outside of rare exceptions, food flexibility is very valuable too.
- Small amounts of these things really aren’t a big deal.
- If they currently made up 7-8% (or more) of your own diet, I’d wager you would see improved health outcomes if you replaced a lot of that with minimally processed, nutrient dense foods.
- But I also wouldn’t stress about having a small portion of your intake including them either.
Relevant Blogs/Research
Relevant Studies:
Polyunsaturated fatty acids for the primary and secondary prevention of cardiovascular disease
Relevant Blog Posts:
Why You Should Eat More Omega-3 | Ideal Nutrition
Everything You Need To Know About Omega-3 On A Vegan Diet
Are Seed Oils Bad for You? | Ideal Nutrition
Relevant Podcasts: