Browse evidence-based analysis of health-related claims and assertions
Perilla oil makes a specific harmful chemical called HHE and ethyl furan when heated, and peanut oil makes more of another chemical called pentyl furan — because each oil has different fats.
Descriptive
When you heat different cooking oils really hot for a long time, they break down and make harmful chemicals, and the type of oil you use determines which chemicals are made.
When pork is heated up and simmered in a microwave-style oven, its fats break down quickly and create strong, oily smells.
Adding seasonings while cooking pork helps create more savory, meaty smells because they supply ingredients that react with heat to make those flavors.
Adding spices or seasonings while cooking pork in a microwave-style oven helps reduce some smelly, oily flavors that come from fats breaking down.
Heating turmeric in oil between 50°C and 70°C for 4 to 6 hours pulls out useful plant chemicals.
Turmeric in olive oil released the most β-carotene when heated at 70°C for 6 hours.
Turmeric in coconut oil released the most carotenoids when heated at 50°C for 5 hours.
The most plant chemicals came out of turmeric when it was heated in coconut oil at 70°C for 4 hours.
When you heat turmeric in coconut oil, more of the beneficial plant chemicals come out than when you heat it in olive oil.
Different types of palm oil respond differently to antioxidant additives — some work better in one kind than another.
When palm oil is heated to high temperatures, a type of unhealthy fat called trans fat (C18:1n9t) is formed and can be measured with specialized equipment.
When palm oil is heated to 130°C, it creates chemical compounds called aldehydes, which can be detected by their unique infrared signature.
Adding certain chemical preservatives like TBHQ or BHT helps palm oil stay fresh longer when it's stored hot.
When palm oil products are stored hot, they go bad faster, turning rancid and changing color more quickly.
People who take the highest dose of fish oil for six months end up with more oxidized fat in their red blood cells than those taking a low dose — even if they started with the same level of protection.
Fish oil can help protect your blood cells from damage at first, but if you take a lot for a long time, it ends up making them more fragile — and how much you take and how long you take it both matter.
After six months of high-dose fish oil, the protective antioxidant in red blood cells drops back down, and the cells become more easily damaged by oxidation — and the higher the dose, the worse it gets.
After one month of taking high-dose fish oil, your red blood cells temporarily get more of a protective antioxidant called alpha-tocopherol, which helps them resist damage from oxidation.
Taking fish oil supplements with EPA and DHA over time makes the membranes of your red blood cells more filled with these types of fats, making them more flexible but also more prone to damage from oxidation.
Trans fats from dairy and meat (vaccenic acid) don’t seem to make insulin resistance worse in overweight women, even when eaten at levels higher than typical industrial trans fats.
Correlational
In healthy young people, eating more trans fat for a month doesn’t make their insulin work worse than eating the same amount of butter or olive oil.
Japanese people living in the U.S. have similar levels of this unhealthy fat in their blood whether they have diabetes or not, suggesting that their overall diet might mask any link between trans fat and blood sugar problems.
Japanese people with diabetes have more of a certain unhealthy fat in their blood than those with normal or slightly elevated blood sugar, hinting that processed foods might play a role in their condition.