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March 7, 2006
“If all you read is the bottom line of these studies, you can make a lot of incorrect assumptions,” says Rock, who teaches nutrition to doctors. “That's what happens with a lot of these studies. And that only causes confusion and frustration with the general public, who aren't sure what to believe.”
In many clinical health studies, the devil's in the details. Unfortunately, those details don't always make it into the 6 o'clock news sound bites.
In search of a sexy spin or caught in tight time or space restrictions, the media sometimes report on these studies without explaining the protocols, methods and other important factors that could alter the way the public views the results. While studies are reported in their entirety in medical journals, some of which are available online and at public and university libraries, most people don't bother with, or can't decipher, these publications.
“Study results can't be crunched into headlines and summary statements. It leaves out too many details that are crucial to interpreting what was actually done and how it relates to our current (health) recommendations,” says Rock.
In the low-fat diet study, researchers weren't putting any focus on fruits and vegetables, which have a more potent effect on breast and colon cancer, Rock says. They also weren't looking at the type of fat consumed, which is extremely important in cardiovascular disease.
“It was a clinical trial and they wanted to simplify it and concentrate on just one dietary factor,” she says. “That dietary factor (total fat) turned out not to be crucial (for these diseases) over this particular time frame.”
The $415 million federally funded study was part of the Women's Health Initiative, the massive study that a few years ago showed hormone treatment after menopause conferred more risks than benefits (and now has us confused with the latest findings that hormone therapy may not be dangerous for the hearts of younger women).
The low-fat diet study involved nearly 49,000 women ages 50 to 79 who were followed for eight years. In the end, those assigned to a low-fat diet had the same rates of breast cancer, colon cancer, heart attacks and strokes as those who ate whatever they pleased, reports said.
But Rock says the problem isn't that people are eating too much total fat. It's that we're eating too much bad fat – saturated and trans fats.
“Nutritionists don't even recommend a low-fat diet,” Rock says. “For (reducing the risk of) heart disease, it's better to eat a higher amount of fat, as long as they're healthier fats – mono and unsaturated fats, that have a cholesterol-lowering effect.”
The study failed to make that distinction.
One of the biggest omissions of the study, according to Rock, was that the women participants were not getting a lot of fresh fruits and vegetables, only about five servings a day, “only a bare minimum,” she says.
The U.S. Department of Agriculture's new food pyramid says people should be eating five to nine servings (4 ounces is a serving) of nutrient dense (vitamin-rich broccoli instead of watery iceberg lettuce) fruits and vegetables every day.
“More fruits and vegetables, lots of plant foods and whole grains, that's what's associated with a lower risk of heart disease and a lower risk of stroke and many cancers,” Rock says. “But, that's not what they studied.”
Rock's bottom line: “People shouldn't jump to conclusions based on any single study, no matter how impressive it may sound,” she cautions. “As science moves forward, we integrate new information as it comes out, and that's what drives the general recommendations that are made over time. If you hear something contrary to what you've always heard or believed, wait a bit (to react) until it all comes together and guidelines are produced.”
Find this article at:
http://www.signonsandiego.com/news/health/20060307-9999-lz1c07bigpix.html
© Copyright 2006 Union-Tribune Publishing Co.
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