[extropy-chat] Failure of low-fat diet

[BillK]

On 2/21/06, "Hal Finney" wrote:
> We probably all saw the study that came out a couple of weeks ago
> from the Woman's Health Initiative, which showed that a low-fat diet
> failed to offer protection from cancer or heart disease.  This was
> a major blow to the conventional wisdom on this issue and there have
> been a number of excuses and explanations offered to try to explain the
> results.  (At about the same time, a different study found that calcium
> supplementation failed to prevent osteoporosis, further contradicting
> what public health officials have been saying for years.)
>

This article seems to be pop-sci journalism at work.

Try:
<http://www.nelm.nhs.uk/Record%20Viewing/viewRecord.aspx?id=560359>
and
<http://news.bbc.co.uk/2/hi/health/4690230.stm>

Researchers running the Women's Health Initiative study of
post-menopausal health asked more than 19,500 women aged 50 to 79 to
reduce their total fat consumption and eat more fruit and vegetables.
The women were then monitored over eight years during the 1990s, and
compared with another group of 29,300 women whose diet was unchanged.
---------------------------

Ifs and buts.......

Various study flaws have been highlighted, both by the investigators
and by health professionals in the UK (See BBC news report), for
example:

• The dietary intervention did not include advice that is now given -
there was no restriction on salt intake, intakes of polyunsaturated
fat, vegetables and fruits, and fibre were lower than now recommended,
plus there was no focus on consumption of fish (the difference between
'good' and 'bad' fats was not known at the time of trial initiation)

• The difference in the percentage of energy from fat between the
women in the intervention group and women in the comparison group was
only about 70% of the design goal

• A large proportion of study participants were overweight or obese
(hence at an increased risk of heart disease).
----------------------------

>From the BBC report:

The American researchers say that they are not disheartened by the results.
They said the difference between "good" and "bad" fats was not
recognised when the study started, so women were only told to reduce
fat consumption - rather than to reduce levels of trans-fats, which
are classed as bad, while fats in nuts, fish and vegetable oils are
said to have health benefits.

But Judy O'Sullivan, a cardiac nurse at the British Heart Foundation,
said: "Numerous studies have confirmed there are huge heart benefits
from maintaining a healthy lifestyle which involves a balanced diet
and regular physical activity.

"It is easy to identify a number of important reasons why this study
did not agree with previous research.
"It didn't reflect current advice for good heart health, such as salt
reduction, increasing intake of good fats such as those in oily fish,
and increasing exercise.
"Additionally, most of the women in the study were overweight or
obese, which increases your risk of developing diabetes - another risk
factor for heart disease."

Dr Emma Knight, science information manager at Cancer Research UK,
said: "People should continue to eat a healthy balanced diet, with
lots of fruit and veg.
"At present, the only diet-related factors that definitely increase
breast cancer risk are obesity and alcohol.
"Bowel cancer risk can be increased by a diet high in red and
processed meat, but is lowered by eating a high-fibre diet."



BillK