Why fish is good and fast food still bad for heart
Tuesday August 25th, 2009
British scientists have a fresh explanation for why eating fish oil may help prevent heart disease, it was announced today.
Eating oily fish has been linked to improved heart health for some time.
It was thought that fish oil simply substituted healthy fats for unhealthy ones.
But the latest research suggests a more complex explanation - linked to the ability of fish oils to control the immune system.
The researchers from Birmingham University, UK, say that omega-3 oils found in fish can prevent white blood cells from crossing the walls of blood vessels.
This may help prevent immune system reactions which cause inflammation of the walls and blockages to the circulation.
The finding, reported in PLoS Biology, was welcomed by the British Heart Foundation, which helped fund the research.
Professor Jeremy Pearson, of the BHF, said the findings were "unexpected".
He said: "We believe that untangling the processes by which normally-protective white blood cells can cause inflammatory damage in our arteries will lead to new ways to protect the heart and circulation.
"This research sheds light on how fatty acids found in fish oils can have beneficial effects on heart and circulation health. Unexpectedly, they appear to be able to block the migration of white blood cells across the walls of small blood vessels, a crucial step in causing inflammation."
Meanwhile researchers in Hong Kong, China, are highlighting the dangers of a form of cholesterol called oxycholesterol.
It is an oxidised cholesterol present in some fried and processed food, particularly fast food. When cholesterol is oxidised, under some food processing conditions, it creates "cholesterol oxidation products".
So far, more than 30 cholesterol oxidation products have been identified. They have been linked with cell toxicity, genetic mutation, and increased risk of cancer.
Experts led by Dr Zhen-Yu Chen of Chinese University of Hong Kong, believe the effect of dietary cholesterol oxidation products on blood cholesterol is "unfortunately ignored and there is very limited information about its effect on atherosclerosis risk".
The team carried out a study to investigate these effects using hamsters. They found that oxidised cholesterol raised total cholesterol in the blood serum by 22 per cent, compared with 12 per cent for non-oxidised cholesterol.
Results were presented at the National Meeting of the American Chemical Society, held in Washington, DC, USA.
Dr Chen said: "Total cholesterol, low-density lipoprotein cholesterol, and the heart-healthy high-density lipoprotein cholesterol are still important health issues, but the public should recognise that oxycholesterol is also important and cannot be ignored."
S Tull et al. Omega-3 fatty acids and Inflammation: novel interactions reveal a new step in neutrophil recruitment. Plos Biology 25 August 2009
Chen, Z. Y. et al. Oxidized cholesterol is more hypercholesterolemic and atherogenic than nonoxidized cholesterol in hamsters. Paper AGFD 237, presented on Thursday, August 20, during the General Papers symposium.
Tags: Asia | Diet & Food | Heart Health | UK News
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