EVIDENCE FOR OMEGA 3 FATS LESS CONCLUSIVE THAN WE THOUGHT, SAY EXPERTS


http://bmj.bmjjournals.com/content/vol332/issue7543/press_release.shtml

1) EVIDENCE FOR OMEGA 3 FATS LESS CONCLUSIVE THAN WE THOUGHT, SAY EXPERTS
Online First
(Risks and benefits of omega 3 fats for mortality, cardiovascular
disease, and cancer: systematic review)
http://bmj.bmjjournals.com/cgi/rapidpdf/bmj.38755.366331.2F

Online First
(Editorial: Oliy fish and omega 3 fat supplements)
http://bmj.bmjjournals.com/cgi/rapidpdf/bmj.38798.680185.47

A study published online by the BMJ today doesn't find evidence of a
clear benefit of omega 3 fats on health.
These findings do not rule out an important effect of omega 3 fats, but
suggest that the evidence should be reviewed regularly, say the
researchers.
Consumption of long chain omega 3 fatty acids, found in oily fish and
fish oils, and a shorter chain omega 3, found in some plant oils, is
thought to protect against heart disease. UK guidelines encourage the
general public to eat more oily fish, and higher amounts are advised
after a heart attack.
Researchers analysed 89 studies (48 randomised controlled trials and 41
cohort studies) to assess the health effects of long and short chain
omega 3 fats on total mortality, cardiovascular events, cancer, and
strokes.
Each study involved a treatment group and a control group and
investigated the effect of omega 3 intake on health for at least six
months. Differences in study quality were taken into account to identify
and minimise bias.
Pooling the results showed no strong evidence that omega 3 fats have an
effect on total mortality or combined cardiovascular events. The few
studies at low risk of bias were more consistent, but they also showed
no effect of omega 3 on total mortality or cardiovascular events.
When data on long chain omega 3 fats were analysed separately, total
mortality and cardiovascular events were not reduced. No study showed
increased risk of cancer or stroke with higher intake of omega 3, but
there were too few events to rule out important effects.
Other recent reviews of omega 3 trials found that omega 3 fats decrease
mortality, but the publication of a large contradictory trial has
changed the overall picture. The authors cannot say exactly why the
results of this trial differ from the other large studies in this field.
They therefore conclude that it is not clear whether long chain or short
chain omega 3 fats (together or separately) reduce or increase total
mortality, cardiovascular events, cancer, or strokes.
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.
Contacts:
Paper: Lee Hooper, Lecturer, School of Medicine, Health Policy and
Practice, University of East Anglia, Norwich, UK
Email: l.hooper@xxxxxxxxx
Editorial: Eric Brunner, Reader in Epidemiology and Public Health, Royal
Free and University College London Medical School, London, UK
Email: e.brunner@xxxxxxxxx

--
Located In S Jersey USA Zone 5 Shade
This article is posted under fair use rules in accordance with
Title 17 U.S.C. Section 107, and is strictly for the educational
and informative purposes. This material is distributed without profit.
Vision Problems? Look at http://www.ocutech.com/ ~us$1500
.

Relevant Pages