Low-Fat Diets Don't Protect Postmenopausal Women

[Guest guest]

TUESDAY, Feb. 7 (HealthDay News) -- A large U.S. government study has

found that a diet low in fat but high in vegetables, grains and fruits

does not reduce the risk of breast cancer, colorectal cancer or

cardiovascular disease in postmenopausal women.

The results, the latest from the Women's Health Initiative (WHI), are

not likely to be the last word on the subject, however.

" The issue isn't over, " said Dr. Jacques E. Rossouw, WHI project

officer at the National Heart, Lung, and Blood Institute. " We plan to

follow these women for another five years because it's quite possible

that a benefit for both breast cancer and colorectal cancer will

emerge over time. This is not going to go away. "

Added Dr. Thun, vice president of epidemiology and

surveillance research at the American Cancer Society: " This is by far

the most definitive study showing exactly what it showed -- that a

concerted effort to reduce fat intake to 20 percent of total energy

over an eight-year period did not reduce the incidence of breast or

colorectal cancer in these women. But it's unlikely to end the debate

completely. "

Previous evidence has suggested that low-fat diets might protect

against cancer and heart disease, but no other studies have been this

large or this well-designed.

The WHI is a mammoth, 15-year study designed to identify the most

common causes of death, disability and poor quality of life in

postmenopausal women.

The findings, which appear in three separate papers in the Feb. 8

issue of the Journal of the American Medical Association, involved

almost 50,000 postmenopausal women. The women were randomly chosen to

follow either a diet with reduced fat (20 percent of total calories)

and increased amounts of vegetables and fruits (five or more servings

per day) and grains (six or more servings per day), or to a control

group that was not asked to change diet. The participants were

followed for just over eight years.

The women in the low-fat part of the study had a 9 percent lower risk

of breast cancer than women in the control group, but the difference

was not statistically significant. Women who started out with a higher

fat intake did have a significant reduction in their risk, however,

indicating that such a diet might indeed confer a benefit.

The low-fat diet did not reduce the risk for colorectal cancer. Here,

however, there was a reduction in the incidence of polyps, a precursor

to this type of cancer, leaving open the tantalizing possibility that

some benefit may appear later on. " It's possible that with longer-term

adherence to such a diet, a benefit might emerge, " Rossouw said.

Finally, the low-fat diet did not appreciably reduce the risk of

coronary heart disease, stroke or cardiovascular disease. It achieved

only modest effects on risk factors for cardiovascular disease, such

as triglyceride levels. LDL ( " bad " ) cholesterol levels and diastolic

blood pressure were significantly reduced.

It's possible that a diet lower in particular types of fat might show

a benefit. " Reducing total fat didn't make any difference to heart

disease, but women who chose to reduce their saturated fat or chose to

reduce trans fat more within their total fat had a significant

reduction, " Rossouw said. " With heart disease, it's very clear that

total fat isn't enough. We've got to focus on specific types of fat. "

Researchers were also interested to note that high intake of

carbohydrates did not increase body weight. Rather, it tended to

maintain it.

Dr. G. Nabel, director of the National Heart, Lung, and

Blood Institute, said at a press briefing Tuesday: " We really think

these findings are good news. This study was the most comprehensive

study of this kind and the findings are very consistent with current

U.S. dietary recommendations about following a diet low in saturated

and trans fats and cholesterol, keeping fat calories to about 20 to 35

percent of total calories.

" Its always important when interpreting findings from any study that a

woman consult with her physician and we encourage women to do that, "

she said.

Cardiologists were cautious about the findings.

" We have to be very careful. The last thing I want is someone to go

out eating a high-fat, high-calorie diet, " said Dr. Nieca Goldberg,

chief of women's cardiac care at Lenox Hill Hospital in New York City

and a spokeswoman for the American Heart Association. " It's a

combination of things that lowers cardiovascular risk. It's no one

diet, no one exercise, no one pill. " Goldberg is also author of The

Women's Healthy Heart Program.

" It would be easy to misinterpret the results of this study, " Dr.

H. Eckel, president of the heart association, added in a

prepared statement. " Reducing the risk of cardiovascular disease is

about following an integrated lifestyle program, rather than

concentrating solely on dietary composition. "

There were other cautionary notes. It's not clear if starting a

low-fat diet earlier in life might have conferred a greater reduction

in risk. All of the women in the study were postmenopausal when they

changed their eating habits.

Despite the somewhat surprising findings, there are still things that

experts know can make a difference.

Ways to reduce the risk of breast cancer include maintaining a healthy

body weight, avoiding weight gain in adulthood, getting regular

physical activity, limiting the consumption of alcoholic beverages and

avoiding postmenopausal hormones, Thun said.

As for heart disease, " we have to avoid extremes, " Goldberg said.

" Really, it's about a balance, how we exercise and how we eat and

balance the stress level as well. We need to keep it real. Nobody

wants to hear it. We all want the quick fix. Now's the time to say we

really need to be balanced about this. "

Rossouw said: " The cancer-prevention findings aren't strong enough to

say that most women should now go to a low-fat diet, but women already

on such a diet can certainly choose to continue, because over time a

benefit might emerge. Women who are currently eating a high-fat diet

should seriously consider cutting it down. And, for heart disease,

reducing total fat isn't enough. You've got to reduce the bad fat and

do all the other things you need to do to improve your risk of heart

disease. "

Ninety percent of the women in the study will be followed for an

additional five years, and more examination will be done on the

existing data, leaving open the possibility that more specific dietary

components might be shown to have an effect on health, experts said.

" We can do a lot more analysis on this data set to systematically

investigate these nutrients and their effect on their endpoints, " said

Barbara , of the Medstar Research Institute and

University in Washington, D.C., and one of the WHI investigators.

http://www.forbes.com/lifestyle/health/feeds/hscout/2006/02/07/hscout530883.html

[Guest guest]

Once again, the devil in in the details..

This is the same " issue " that has come up in many of these studies..

Here are the numbers..(pre - post)

Percent fat 38 - 25%

Saturated Fat 12 - 8%

Poly 7.8 - 5.2

Fiber 15.4 - 18.1

Whole grains 4.7 - 5.1

Vegetables 3.6 -5.1

So, the intervention diet was 25% fat, 8% saturated fat, 18 grams of

fiber. There was little change in the amount of whole grains and

vegetables (~10 total) and the poly went down also.

How does that compare to a healthy low fat diet with ~15% fat, < 4%

Saturated and > 45 grams of fiber and 15 or more servings of whole

grains, fruits and veggies?

Regards

Jeff

[Guest guest]

Once again, the devil in in the details..

This is the same " issue " that has come up in many of these studies..

Here are the numbers..(pre - post)

Percent fat 38 - 25%

Saturated Fat 12 - 8%

Poly 7.8 - 5.2

Fiber 15.4 - 18.1

Whole grains 4.7 - 5.1

Vegetables 3.6 -5.1

So, the intervention diet was 25% fat, 8% saturated fat, 18 grams of

fiber. There was little change in the amount of whole grains and

vegetables (~10 total) and the poly went down also.

How does that compare to a healthy low fat diet with ~15% fat, < 4%

Saturated and > 45 grams of fiber and 15 or more servings of whole

grains, fruits and veggies?

Regards

Jeff