17 Decemberr, 2004
Are Saturated Fats Heart Healthy?
Study Shows Possible Benefits for Older Women at High Risk for
By Salynn Boyles
WebMD Medical News Reviewed By Brunilda Nazario, MD
on Wednesday, December 08, 2004
Dec. 8, 2004 -- For decades we've been told that eating saturated
fat is bad for our hearts, but new research shows that the opposite
just might be true for those at risk for heart disease.
In a study involving older women with heart disease, women who
ate the most saturated fat had the least atherosclerosis disease
progression in coronary arteries over a three-year period.
While the findings may seem to turn the food pyramid on its head,
researcher Dariush Mozaffarian, MD, of the Harvard School of Public
Health in Boston, says more study is needed to understand its
public health implications.
"This is not really what we would have expected to find
based on studies in men, but postmenopausal women are not men,"
Mozaffarian tells WebMD. "This finding may be unique to this
population, but we just don't know."
Fats and Carbs Revisited
Saturated fats from the diet are the major determinate of "bad"
LDL cholesterol. Diets high in saturated fats, such as those found
in animal meat, cheese, milk, and baked goods can increase blood
levels of LDL. The American Heart association has recommended
limiting the amount of saturated fats in the diet to less that
7% as of part of a heart healthy diet.
The study involved 235 older women who were followed for three
years. All the women had some plaque buildup when they enrolled
in the trial, and X-ray imaging (angiogram) was used to compare
arterial plaque progression at entry with that at the end of the
The women completed a detailed questionnaire asking about the
foods they ate, and the findings took into account other risk
factors for heart disease, such as age and smoking habits.
On average, fats made up about 25% of the women's diets. In addition
to having less plaque buildup, women who ate the most saturated
fat had a better balance of good to bad cholesterol -- which protects
against heart disease.
Replacing saturated fats with other types of fats, such as monounsaturated
fats found in plant sources, did not appear to influence disease
progression, but replacing fats with highly refined carbohydrates
did. Higher carbohydrate intake was associated with more disease
The findings are published in the November issue of the American
Journal of Clinical Nutrition.
"This is consistent with the evidence that eating refined,
fiber-poor carbohydrates increases heart disease risk," Mozaffarian
"The American Paradox"
In addition to being postmenopausal, 75% of the women in the
study were overweight, one in four had diabetes and most had evidence
of metabolic syndrome -- a combination of risk factors that increases
the risk of heart disease and type 2 diabetes. Nutrition researcher
Robert H. Knopp, MD, says it is increasingly clear that people
with these heart disease risk factors do not process fats and
carbohydrates in the same way that healthier people do.
In an editorial accompanying the study, Knopp wrote of an apparent
"American paradox" suggesting that a high-fat diet may
be more protective against heart disease for this specific, high-risk
population than one that is low in fat.
"This is counterintuitive to say the least, and so the first
instinct is to dismiss it out of hand as an accident," he
tells WebMD. "But what intrigues me is that there are clues
that there might be some truth to this."
Knopp dismisses the idea that saturated fats may be uniquely
protective, however. He adds that there is a huge body of evidence
showing a high saturated-fat diet to be a risk factor for heart
"We now know that not all fats are bad," he says. "And
we may have to change our thinking again with regard to saturated
fats, at least when we talk about people with metabolic syndrome.
And there is reason to believe that this association is even stronger
in women than in men."