I have reviewed study and the extra Table describing the papers
included in the Hooper et al. review and I feel I must make some comments.
To me, the studies included seem to fall into at least three different
categories...
Firstly, some of the studies appear to have achieved only very modest
fat intake changes (ie. reduction of 3-5% total fat and 2-3% sat fat).
Secondly, some studies do not record dietary results achieved at all.
Thirdly, a few studies actually increased fat intake quite
substantially with additions of corn/olive oil supplements.
As noted in the article, follow-up times were indeed disapointingly
short... and this cannot be helped, but inclusion of studies with no
intake data and/or very modest or increased intake effects can be helped.
I would like to see the review analysed on the basis of achieved
dietary change. I suspect that including studies with missing intake
data, short follow-up times, and overall very modest diet effects all
conspire to attenuate the results. I am also of the belief that the
baseline fat intakes are, in general, far too high a starting point. At
the turn of the century in North America, the diets of affluent people
provided approximately 20% of calories in the form of fat...by todays
standards, these (formerly)average people would have a diet comparable to
the intervention group in your included study #27 with intakes of 18%
total/6% sat fat. A study by the way that did show a positive effect even
with only a 1.7 year follow-up.
Allan Sinclair, M.H.Sc.,
Manager of Health Services, Public Health
Lakeland Regional Health Authority,
Alberta, Canada.
Rapid Response:
Let's revisit fat intakes achieved...
I have reviewed study and the extra Table describing the papers
included in the Hooper et al. review and I feel I must make some comments.
To me, the studies included seem to fall into at least three different
categories...
Firstly, some of the studies appear to have achieved only very modest
fat intake changes (ie. reduction of 3-5% total fat and 2-3% sat fat).
Secondly, some studies do not record dietary results achieved at all.
Thirdly, a few studies actually increased fat intake quite
substantially with additions of corn/olive oil supplements.
As noted in the article, follow-up times were indeed disapointingly
short... and this cannot be helped, but inclusion of studies with no
intake data and/or very modest or increased intake effects can be helped.
I would like to see the review analysed on the basis of achieved
dietary change. I suspect that including studies with missing intake
data, short follow-up times, and overall very modest diet effects all
conspire to attenuate the results. I am also of the belief that the
baseline fat intakes are, in general, far too high a starting point. At
the turn of the century in North America, the diets of affluent people
provided approximately 20% of calories in the form of fat...by todays
standards, these (formerly)average people would have a diet comparable to
the intervention group in your included study #27 with intakes of 18%
total/6% sat fat. A study by the way that did show a positive effect even
with only a 1.7 year follow-up.
Allan Sinclair, M.H.Sc.,
Manager of Health Services,
Public Health
Lakeland Regional Health Authority,
Alberta, Canada.
Competing interests: No competing interests