Browse evidence-based analysis of health-related claims and assertions
Oil made from tuna scraps has just as much of the healthy omega-3 fats as expensive cod liver oil.
Quantitative
Turning fish waste into oil and cleaning it with chemicals makes it cleaner and safer to use, without losing the healthy fats.
Descriptive
How well the clay soaks up bad stuff matters more than how acidic it is when cleaning palm oil.
If the raw palm oil is of low quality, it creates more harmful chemicals when heated during refining.
Using a lot of phosphoric acid to clean the oil and then a special clay removes almost all of another harmful chemical in the final product.
A special type of clay used to clean oil works better at removing harmful chemicals if it can trap more stuff, not because it’s more acidic.
Using water to clean raw palm oil before refining can cut down one harmful chemical by about half.
Scientists can estimate how long it takes for half of the healthy compounds in olive oil to break down when it’s heated at different temperatures.
Scientists can calculate exactly how fast the healthy parts of olive oil break down when heated at different temperatures, using a mathematical model.
The amount of heat energy needed to break down the healthy compounds in olive oil doesn’t change much, no matter how hot you heat it (within the range tested).
When you heat olive oil really hot, the healthy compounds called polyphenols break down faster the longer and hotter it gets.
When you heat olive oil, it gets more gunk in it — and the hotter you go, the more gunk forms. Some oils (like Armonia) get way gunkier than others (like Manzanilla).
When olive oil gets super hot, the main antioxidant (alpha-tocopherol) disappears completely, but other minor antioxidants (beta and gamma) stick around a bit longer — and some oils protect them better than others.
When you fry with olive oil at very high heat, the healthy unsaturated fats break down faster than the saturated ones — especially in oils that started with lots of unsaturated fats.
When olive oil gets really hot, it starts forming sticky, gummy molecules — and some types (like Armonia) make way more of them than others (like Picual).
Some types of olive oil — especially Cornicabra and Picual — hold up better when heated than others like Arbequina, meaning they break down less and make less gunk when frying.
When you heat olive oil really hot (200°C), it loses all its protective antioxidants and turns into more gunk than when heated at a lower temperature (170°C).
Both avocado oil and olive oil can be reused many times for frying before they break down enough to be considered unsafe by health standards.
Avocado oil breaks down a bit faster than olive oil when reused for frying — it hits the safety limit after 10 uses, while olive oil lasts until 13 uses.
Heating flaxseeds before pressing them and pressing them twice makes more oil that lasts longer — because the heat helps release natural antioxidants that work together to protect the oil.
When you add both vitamin E and plant sterols to flaxseed oil together, they work better than either one alone to keep the oil from going rancid — this combo could help make healthier oils that last longer.
Plant sterols — natural compounds in flaxseed — help keep the oil from going bad by stopping the chain reaction that causes rancidity and calming down unstable molecules in the oil.
Mechanistic
Adding too much of one type of vitamin E (α-tocopherol) to flaxseed oil can make it go bad faster when it's cool, but helps protect it when it's warm — because another type of vitamin E (γ-tocopherol) lasts longer and keeps working.
In flaxseed oil, a natural compound called γ-tocopherol stops oil from going bad by mopping up harmful molecules, and other natural compounds in the oil help keep γ-tocopherol working longer.