Eating fish is good for the heart, but watch how it's cooked.
Eating fish is good for the heart, but watch how it’s cooked.
Eat more fish, but make sure that you don’t fry or steam it is the conclusion from two separate studies published recently by researchers in Europe and the US.
Researchers at the University of Vienna, Austria, studied the effect that cooking method has on the nutritional content of salmon 1. Cholesterol oxidation products formed in cholesterol-rich food during cooking are known to be harmful to health, being linked with cancer and thickening of the arterial walls. Karl-Heinz Wagner and colleagues found that all cooking methods increased oxidation product levels in fish but, surprisingly, steaming fish increased levels most of all - by 1000 per cent.
However, eating fish remains a healthy option, reports Dariush Mozaffarian, researcher at the Channing laboratory, Brigham and Women’s Hospital, Boston, US. Mozaffarian found that eating grilled or baked fish - but not fried - just once a week was associated with a lower risk of developing atrial fibrillation (AF), the most common form of heart rhythm disturbance 2. Mozaffarian and colleagues analysed data from nearly 5000 participants over the age of 65 for a period of 12 years. This study is the first to try to evaluate the effects of dietary fish intake on common arrhythmia although prior studies have indicated that oily fish intake reduces the risk of sudden death and ventricular fibrillation.
AF is a condition that affects five per cent of the UK population aged over 65. The study showed that eating up to four portions of oily fish - tuna, salmon and fresh-water trout - a week lowers the risk of developing AF by nearly a third with even lower risks associated for people eating five or more portions. Mozaffarian is careful to note, however, that ’this observed relationship does not prove causality and may be related to other factors associated with both fish intake and risk of AF.’
1. I Elmadfa et al, J. Agric. Food Chem., 2004, 52, 5290
2. D Mozaffarian et al, Circulation, 2004, 110, 368