We've long heard that trans fats are bad for the heart. Now a new study from Japan suggests they may be bad for your brain, too.
It followed more than 1,600 people over the age of 60 for 10 years.
"People having higher levels of trans fat in their blood, increases your risk of onset of dementia - whether it's from Alzheimer's disease as a cause of dementia - or other kinds of dementia as well," says Dr. Jagan Pillai, a neurologist at the Cleveland Clinic.
The researchers say sweet pastries drove up trans fats the most, followed by margarine, candies, croissants, ice cream, and rice cakes.
Although trans fats were banned in the US last year, some food makers got extensions.
And scientists say the small amounts in foods labelled "zero trans fats" can add up quickly.
Study: Trans fats in diet tied to memory loss, dementia