29/01/2026
The internet: "Seed oils are poison."
Also the internet: "Here's zero evidence."
So I looked at the actual science. Here's what I found:
An umbrella review of 48 systematic reviews and meta-analyses (Voon et al., 2023) examined real-food oils used in cooking.
Not capsules.
Not isolated compounds. Actual cooking oils.
The review covered:
- Seed oils: soybean, sunflower, safflower, canola, flaxseed, sesame, peanut, rice bran
- Plus: olive (virgin and refined), palm, palm olein, coconut
And here's what the data actually shows:
Not all seed oils are the same.
Seed oils high in polyunsaturated fats (PUFAs, especially linoleic acid) generally improved lipid profiles.
Oils high in saturated fats (coconut, some palm oils) pushed LDL higher, though HDL rose too.
Virgin olive oil, richer in polyphenols, showed extra benefits for lipids and oxidative stress versus refined olive oil.
Inflammation markers? Thinner data, lower certainty.
But flaxseed and sesame oils showed small reductions in blood pressure.
Olive and sesame oils showed modest improvements in HbA1c and fasting glucose.
Canola, peanut, coconut, and palm oils? No strong effects on blood sugar.
The review emphasizes context matters:
- How you use the oils (home cooking vs deep frying)
- Overall diet quality (fiber, fruits, veg, whole grains, protein)
- Total energy intake
Replacing saturated fats with unsaturated oils tends to improve cholesterol.
Neutral to modest benefits for blood pressure and blood sugar.
No clear harm for cardiovascular events.
There's no strong clinical evidence that seed oils cause disease via inflammation or oxidation in a normal diet.
Overall health effects are driven more by total diet quality and energy balance than by avoiding seed oils alone.
So stop blaming the oil.
Start looking at the plate.