Cholesterol itself is divided in two main forms. Low-density lipoprotein (LDL) is the bad cholesterol in the form of fatty deposits in arteries around the heart. While HDL is the good cholesterol, transports fat to the liver to be disposed of safely.
But in recent years, the medical officer had been puzzled by the fact that increased levels of HDL are not effectively cut the number of heart attacks.
In fact, one of the big drug companies do not get approval to launch a new drug to raise HDL levels, after the results showed that the increase in HDL have no benefit in reducing heart disease.
The latest study, by experts at Maastricht University in the Netherlands, shows that increases in HDL levels trigger a negative response of the immune system.
Starting from the rise in the number of inflammatory cells, called macrophages, which in turn damages the lining of blood vessels and effectively remove all of the major benefits of the good cholesterol, according to a report in the journal Cell Metabolism.
Researcher Dr Marjo Donners said, "A key message brought by our study is that the function of HDL is not as simple as you thought. So, you should still limit your intake."