WHI Low Fat Study

[Guest guest]

We've kicked the WHI study in the shins a little bit here. It

deserves a high, harder kick. While most of the mainstream press

swallowed the story whole, here are a couple of opinions from better

informed journalists:

http://www.nutraingredients.com/news/ng.asp?n=65778-low-fat-cvd

and

http://www.businessweek.com/magazine/content/06_08/b3972070.htm

Both Text versions below:

Nutraingredients--

The Cost of Bad Research

13/02/2006 - The science has spoken. Low-fat diets don't work:

Forget the carrots and broccoli sprouts, I can now have my cake and

eat it, and put extra cream on top.

Ask the average person in the street if a low-fat diet is good for

them they would instinctively say `yes'. Ask them why and they'll

almost certainly tell you it's better for your heart, and protects

against other diseases they may not even be able to name.

But now, if you believe the headlines, there's no benefit in low-

fat. If it didn't reduce the risk of certain cancers and heart

disease for 25,000 women in a medical trial, what are the chances of

it helping others?

Published in the hugely respected Journal of the American Medical

Association, the Women's Health Initiative (WHI) Dietary

Modification Trial involved 48,835 post-menopausal women, eight

years of follow-up and cost a staggering $415 million dollars of

taxpayers' money.

Scientists from such esteemed institutions as Harvard Medical

School, UCLA, Ohio State, Brown and Northwestern Universities

carried out the research.

The end results created headlines that declared a low-fat, fruit-`n'-

veg-rich diet does not change your risk of colorectal or breast

cancer of cardiovascular disease (CVD).

The trial set out to compare women eating a normal diet with women

eating a diet low in fat and high in fruit, vegetables and whole

grains.

Nice idea, so what went wrong?

The design of the study was flawed from the start, which is

undoubtedly why there was opposition when the study was first

proposed. Leading nutritional and medical researchers said it wasn't

worth doing, while the National Institute of Health initially

rejected calls for funding.

Strategic lobbying and then a run through congress eventually got

the necessary approval and the WHI was off.

The diet aimed to cut down fat intake for the intervention group to

less than 20 per cent, eat five servings of fruit and veg, and six

portions of grains per day. The studies claim they succeeded in

reducing fat intake by 8.2 g, but by year six the average fat intake

was still 29 per cent. The normal diet group was eating 35 per cent

fat.

The intake of vegetables and fruit did go up as well, but only by

about one serving per day.

The researchers themselves admit that very few of the women in the

intervention group actually met the targets.

Excuse me for being so bold, but does this not mean that $415

million were spent on an intervention study that didn't really

intervene?

Does this not immediately put a massive question mark on any claims?

Apparently, no – at least if you believe the headlines. Many

national and local newspapers have picked up on these reports and

run with stories taking the conclusions to the consumer.

The San Francisco Chronicle ran with, " OK, so don't hold the fries " ;

the UK's Independent chose, " Modern nutrition: Forget all you ever

knew about diets " ; CBS News said, " Study: Low-Fat Diets Big Letdown. "

The limitations with this study, of which there are several, do not

mean however that it was completely useless: It has given us some

big clues as to how not to do studies.

Being overweight or obese is a known contributor to diseases such as

CVD. Between the test and control groups, the number of overweight

or obese women was about the same: 36 per cent of women were

overweight and a further 38 per cent were clinically obese.

The researchers claim that weight loss was never a target of the

study. I feel the need to ask the question, " Why not? "

With such a body of evidence linking obesity to diseases such as

diabetes, CVD and breast cancer, and with over 70 per cent of

volunteers with a `weight issue' surely weight loss should have been

a crucial target.

And what about regular exercise? No mention.

Reducing the size of portions? Not a target.

In future, trials should distinguish the type of fat to reduce.

Knowledge has expanded to clarify good and bad fats. Effort should

be made to reduce trans fatty acids and saturated fat, while omega-3

fatty acids should be increased, for example.

In terms of CVD, no effort was made to reduce salt intake, increase

potassium intake, or use the DASH (Dietary Approach to Stop

Hypertension) diet. No wonder there was a null result.

And this study was only about post-menopausal women. Maybe this diet

could have worked for other groups.

Some experts have rightly spoken out against the studies,

encouraging the public to stick with five portions of fruit and

vegetables a day and stressing that people take care about fat

intake. But are consumers now questioning such advice?

Whether a study costs $1 or $415 million, care should be taken in

design, time should be taken to identify the key factors, and

methods improved to get maximum benefit from the data.

The public has a right to read about studies like the WHI, but only

if journalists take the time to describe the limitations. Many do

not, and this is where the problem is exaggerated.

There will undoubtedly be consumers who accept these studies, people

who are reluctant to change their diet or lifestyle, despite a

mountain of science saying the opposite. The true cost of this study

could well exceed the $415 million spent on it.

ls is the Food Science Reporter for

NutraIngredients.com and NutraIngredients-USA.com. He has a PhD in

Chemistry from Queen's University Belfast and has worked in research

in the Netherlands and France

Business Week --

Skip Your Veggies? Not So Fast

A new study questions low-fat diets. The real story is more

complicated

Here comes another wild ride on the roller coaster of health advice.

For years we have been told that eating less fat and munching on

more fruits and veggies can work magic, preventing everything from

heart disease to cancer. Now a study of 48,835 women, part of the

Women's Health Initiative, says that such " healthier " diets bring no

benefits.

The study was published by the respected Journal of the American

Medical Assn. (JAMA). But before you rush out for fast food, ask a

few simple questions. What did the study actually examine? Do its

data support such a sweeping conclusion? We often overreact to

studies that are more limited and uncertain than we realize. One

startling fact: Fully one-third of all dramatic new findings simply

don't hold up in later studies. Remember hormone replacement

therapy? Once presumed to cut heart disease risk, it was later found

to be dangerous -- and now doctors are questioning those supposed

risks.

Among other things, the new diet report shows how research dollars

can be won for questionable studies. In the early 1990s, when the

study was proposed, prominent researchers such as Harvard's Dr.

Walter Willett argued that it wasn't worth doing. Reviewers at the

National Institutes of Health turned it down for funding. But Dr.

Bernadine Healy, appointed as NIH director in 1991, lobbied

relentlessly for support for the suite of studies that make up the

Women's Health Initiative. " It was an end-run through Congress that

got it approved, " Willett recalls.

Based on its design, the trial had little chance of making major

advances in the science of nutrition. It set out to compare women

eating normal diets with women asked to eat less fat and more fruits

and vegetables. But the two groups' diets really didn't differ all

that much. Those with " healthier " diets cut calories from fat by

only 8.2% compared with the normal group and ate only 1.1 additional

servings of fruits and vegetables a day. That's too small a

difference to expect health benefits.

What's more, scientists now know that the type of fat we eat is

generally more important than the amount. Monounsaturated fats, such

as those in olive oil, or omega-3 fats found in fish are healthier

than saturated fat, as in butter or beef. Worst of all are so-called

trans fats, which are created by adding hydrogen to natural fat.

Trans fats are widely used in everything from margarine to cookies,

and have been linked with increased risks of heart disease. By

focusing just on total fat intake, the study missed a chance to

tease out the effects of these different types of fat. " It's really

important not to go away with the message that diets don't matter, "

says Willett.

There are larger lessons as well about how science works. The

detailed methods of a study are crucial, and their limitations are

often glossed over. When Dr. Woloshin of Dartmouth Medical

School looked at press releases trumpeting various scientific

articles, " we found that 77% failed to mention the study's

limitations, " he says. And up to half of all articles exaggerated

the actual benefit or risk being studied.

One common distortion is to present the effects of a treatment or

intervention in relative terms, such as saying that a particular

diet or drug cut the death rate in half. That sounds huge, but it

might mean that there was only one death per million people instead

of two, which is a reduction in actual risk that's too small to

matter. All this helps explain why science so often seems to be flip-

flopping. And there's no mystery about why results are often

exaggerated: Researchers, medical centers, and scientific journals

are all competing for funds and publicity, just like everyone else.

The truth is, science is often less definitive than people think.

Even when a study does find a clear benefit or danger, the results

may not be applicable to the real world, where people have more

complicated health issues and medicine isn't so black and white.

There's a long list of treatments and medical interventions, from

bypass operations to back surgery, where the benefits may not be as

great as once thought. What does this mean for diet? " We don't want

to be morbidly obese or too skinny, " says Dr. Nortin Hadler,

professor of medicine at the University of North Carolina at Chapel

Hill, " and it's pretty compelling that between those two extremes,

we can't measure many differences. " So try to stay fit, keep your

weight down, aim for a relatively healthy diet, and don't worry too

much about the latest headlines in the medical journals.

Mike