The American Heart Association suggests that Americans increase their consumption of fish high in omega-3 fatty acids to reduce the risk of cardiovascular disease. However, it specifically states:
- Enjoy fish baked or grilled, not fried.
- Choose low-sodium, low-fat seasonings such as spices, herbs, lemon juice and other flavorings in cooking and at the table.
While it is clear that there is a correlation between frying fish and negative health outcomes, it is not clear why. Some sources suggest that the omega-3 fatty acids degrade when fried, while others suggest that the types of fish typically used in frying are not high in these fats. It may simply be that the omega-3s in fish can't compensate for the negative effect of the added fat and salt in deep frying.
The Mayo Clinic includes a page on healthy cooking techniques: it lists almost every way under the sun to cook food - except frying.