Saturated fat impedes «good» cholesterol activity
NEW YORK – A study shows that eating one meal high in saturated fat can impair the ability of high-density lipoproteins (HDLs), the “good” cholesterol, to ward off inflammation of the blood vessels, which is thought to be a key event in vascular disease. It can also impair the ability of blood vessels to react normally to stress.
By contrast, consumption of a meal high in polyunsaturated fat “does not perturb these measures of vascular health,” Dr. David S. Celermajer from The Heart Research Institute in Sydney, Australia told Reuters Health.
The findings highlight new ways in which different dietary fatty acids may influence key processes in the development of arthrosclerosis, Dr. Celermajer and colleagues note in the Journal of the American College of Cardiology.
They tested the effect of consuming a single high-fat meal, differing in fatty acid composition, on the ability of HDLs to inhibit molecules associated with inflammation in large and small blood vessels.
On two separate occasions, 14 adult volunteers ate a meal with 75 percent polyunsaturated fat and an identical meal, except it contained 89.6 percent saturated fat.
They found that HDL collected six hours after the saturated fat meal was less effective in blocking expression of molecules associated with inflammation than HDL collected six hours after the polyunsaturated meal.
What’s more, HDL collected six hours after the polyunsaturated meal was more effective in inhibiting inflammation-related molecules than HDL collected during a period of fasting.
“Consuming a polyunsaturated fat enhanced, and a saturated fat meal reduced, the anti-inflammatory properties of HDL,” Celermajer and colleagues point out.
He acknowledged his team was “a little surprised” by the study results.
“Most everyone concentrates on the amount of ‘good’ cholesterol. This study shows that its quality may be very important too, in determining its protective ability,” he explained.
“Most people also measure cholesterol and its fractions with people fasting — but it seems that its quality after a meal (and most of us spend a lot of time in the post-absorptive state) may be important to consider too,” Celermajer added.