Low-Fat Diet May Not Cut Cancer Risk
Study Fails to Show Lower Risk in Women of Breast Cancer and Heart Disease
WebMD News Archive
Reason for Optimism? continued...
Women in the low-fat group had a 9% lower risk of breast cancer than women
who made no dietary changes, which is not a significant reduction. But Nabel
and other experts say there is reason for optimism in the findings.
And reductions in risk were greatest among women who had cut their overall
fat intake and saturated fat intake the most. The researchers say longer
follow-up may show a clearer difference.
"It is best to say at this point that we have evidence of some
relationship between breast cancer risk and (dietary) fat content," says
the study's principal researcher, Ross Prentice, PhD. "But we should
probably leave it at that."
Good Fats and Bad
U.S. Dietary guidelines recommend that between 20% and 35% of daily calories
come from fat, with saturated fat accounting for less than 10% of daily
calories. The guidelines call for limiting saturated fats and trans fats in
favor of unsaturated fats, such as those found in fish, nuts, and certain
The WHI study did not make the distinction between so-called "good
fats" and "bad fats," however, and the researchers say this may
have influenced the findings.
There has been a shift in thinking about the role of dietary fat in disease
since the trial was designed in the early 1990s. The emphasis now is on
reducing saturated fats and trans fats in the diet, rather than reducing
overall fat consumption.
The link between cardiovascular disease and diets high in saturated fat has
been well established.
"This study shows that just reducing total fat intake does not go far
enough to have an impact on heart disease risk," says Jacque Rossouw, MD,
adding that women who are following diets low in saturated and trans fats
should be encouraged to continue doing so.
"We have a pretty clear signal that women who are still eating [high-fat
diets] would be well advised to reduce their fat intake," he says.