Eating a buttery pastry like a croissant every day can “silently” increase the risk of serious heart problems, a study has found.
Researchers at Oxford University monitored volunteers who ate a diet high in saturated fat including croissants, cakes and sausages.
Another group consumed healthier fats, such as salmon or nuts.
After 24 days, the group given food higher in fat were given an MRI scan and blood tests.
Neither group were found to have gained weight, but those on a diet higher in fats saw their cholesterol rise by 10 per cent on average.
There was also a 20 per cent rise in the amount of fat stored in the liver, which increases the risk of type 2 diabetes.
The group who ate healthier fats saw a drop of 10 per cent in their cholesterol during the same period.
Lead researcher Nikola Srnic, from Oxford University, said: “It’s the type of fat, not the amount of fat, that’s important.
“It is interesting how you can see such a change so quickly, within three weeks.
“For diets that were higher in saturated fat we asked people to increase consumption of butter, whole fat dairy products, cakes and pastries.
“The polyunsaturated fat diet is higher in fats from fish, certain vegetable oils and certain nuts and seeds.”
He added: “The results suggest that a diet high in saturated fat may negatively change cardiovascular disease risk factors even when a person does not gain weight.
“On the other hand, we saw protective effects if a person ate a diet high in polyunsaturated fat.”
Professor James Leiper, the associate medical director of the British Heart Foundation, said: “This study gives us evidence that saturated fat may silently start to pose a risk to heart health very quickly, without causing any changes to a person’s weight.
“The results the researchers saw in lab-grown heart cells will hopefully improve our understanding of how these changes happen.
“Longer studies with more participants are needed to confirm these findings and show whether these short-term changes increase people’s risk of serious heart problems in the long term.”
