High levels of saturated fat in the blood may promote damaging inflammation, potentially increasing the risk of heart disease and cancer, new research has shown.
The findings reinforce warnings about eating too much food laden with saturated fat, such as cakes, biscuits, fatty meat and dairy products.
Scientists studying mice found that high levels of saturated fat kick-starts a process that involves white blood cells called monocytes migrating from the blood into tissues and organs.
They believe the migrating cells may exacerbate ongoing or underlying inflammation, raising the risk of tissue damage.
Inflammation, marked by an influx of immune cells to an injury site, is a destructive immune response that has got out of hand.
It is closely linked to heart disease and stroke, and recent evidence indicates that it plays a key role in the growth and spread of cancer.
Kevin Woollard, from Imperial College London, who led the Wellcome Trust-funded research published in the journal Cell Reports, said: “The mice we studied were treated with a drug that caused them to accumulate extremely high levels of fat in their blood.
“Although it is unusual, humans do sometimes have measurements approaching those levels, either from an inherited condition, or through eating fatty foods.
“Modern lifestyles seem to go hand-in-hand with high levels of fat in the blood.
“This fat comes from the food and drink that we consume; for example, you’d be surprised how much saturated fat a latte contains, and some people drink several through the course of the day.
“We think that maintaining a relatively high concentration of saturated fats for example by constantly snacking on cakes, biscuits, and pastries could be causing monocytes to migrate out of the blood and into surrounding tissues.”
The scientists are still investigating what effect the migrating monocytes might be having and plan to study groups of patients with inflammatory diseases.
They point out that people with certain immune disorders affecting monocytes, such as lupus, sometimes have unexpectedly high levels of saturated fats in their blood and are also more prone to early heart attacks and strokes.
A key discovery was that the migrating monocytes were all one specific type.
“It’s really exciting to see that the monocytes that migrate into tissues are all of one type and that means we actually may be able to develop drugs that change this behaviour,” Woollard said.