Eating foods high in oxycholesterol increases blood cholesterol levels

A form of junk food cholesterol virtually unknown to the public may pose the biggest threat of heart disease, research suggests.

Oxycholesterol can be formed when foods such as burgers and steaks are fried or grilled, causing their fats to react with oxygen. Photo: PA

Scientists want to raise public awareness of oxycholesterol, which is mostly found in fried and processed food and take-aways.

Oxycholesterol can be formed when foods such as burgers and steaks are fried or grilled, causing their fats to react with oxygen.

Food manufacturers also introduce oxycholesterol to improve the texture, taste and stability of processed foods.

The new research indicates that eating foods high in the substance gives an extra boost to blood cholesterol levels and is more likely to damage arteries than ordinary cholesterol.

Most cholesterol health warnings involve low-density lipoprotein (LDL), or "bad" cholesterol, which helps form hard deposits in the arteries called atherosclerotic plaques.

In addition there is high-density lipoprotein (HDL), or "good" cholesterol, which is healthy for the heart.

Study leader Dr Zhen-Yu Chen, from the Chinese University of Hong Kong, said: "Total cholesterol, low-density lipoprotein cholesterol (LDL), and the heart-healthy high-density lipoprotein cholesterol (HDL) are still important health issues.

"But the public should recognise that oxycholesterol is also important and cannot be ignored. Our work demonstrated that oxycholesterol boosts total cholesterol levels and promotes atherosclerosis more than non-oxidised cholesterol."

Dr Chen's group measured the effects of a high oxycholesterol diet in hamsters.

The researchers found that the animals' blood cholesterol rose up to 22 per cent higher than when they were fed non-oxidised cholesterol.

Hamsters on an oxycholesterol diet also had more cholesterol deposited in the lining of their arteries.

Oxycholesterol reduced the elasticity of arteries, impairing their ability to expand and carry more blood when the need arose.

Healthily functioning arteries can reduce the risk of clots forming leading to a heart attack or stroke.

The findings were presented today at the American Chemical Society's annual meeting in Washington DC.

A healthy antioxidant-rich diet rich in fruits, vegetables, beans and certain herbs and spices can counter the effects, said Dr Chen.

Healthy alternatives to high oxycholesterol fast food included whole grains, fresh fruits, vegetables, seeds and nuts.

It is not yet known whether the popular cholesterol-lowering drugs, called statins, can reduce levels of oxycholesterol.

Previous research has not shown that oxycholesterol is any worse for health than LDL cholesterol.