( ely) reduce or increase total mortality...)Evidence for omega 3 fats less conclusive than we thought, say experts

UK guidelines advising people to eat more oily fish should continue at present but the evidence should be reviewed regularly, say the authors. However, it is probably not appropriate to recommend a high intake of omega 3 fats for people who have angina but have not had a heart attack.

To understand the effects of omega 3 fats on health, we need more high quality randomised controlled trials of long duration that also report the associated harms, they conclude.

We are faced with a paradox, says Eric Brunner in an accompanying editorial. Health recommendations advise increased consumption of oily fish and fish oils. However, industrial fishing has depleted the world's fish stocks by some 90% since 1950, and rising fish prices reduce affordability particularly for people with low incomes.

Global production trends suggest that, although fish farming is expanding rapidly, we probably do not have a sustainable supply of long chain omega 3 fats, he warns.