Diet soda tied to stroke risk, but reasons unclear
February 09, 2011
By MARILYNN MARCHIONE, AP Medical Writer
LOS ANGELES (AP) - It's far from definitive proof, but new research
raises concern about diet soda, finding higher risks for stroke and
heart attack among people who drink it everyday versus those who drink
no soda at all.
The beverage findings should be "a wakeup call to pay attention to diet
sodas," said Dr. Steven Greenberg. He is a Harvard Medical School
neurologist and vice chairman of the International Stroke Conference in
California, where the research was presented on Wednesday.
A simple solution, health experts say, is to drink water instead.
Doctors have no chemical or biological explanation for why diet soda may
be risky. It could be that people who drink lots of it also fail to
exercise, weigh more, drink more alcohol or have other risk factors like
high blood pressure and smoking. However, the researchers took these and
many other factors into account and didn't see a change in the trend.
"It's reasonable to have doubts, because we don't have a clear
mechanism. This needs to be viewed as a preliminary study," said lead
researcher Hannah Gardener of the University of Miami.
But for those trying to cut calories, "diet soft drinks may not be an
optimal substitute for sugar-sweetened beverages," she said.
The numbers come from the Northern Manhattan study, which enrolled about
2,500 adults over 40 in the New York area from 1993 to 2001 through
random phone calls. Half are Hispanic and one-fourth are black, making
it one of the few studies to look at these risks in minorities, who have
higher rates of stroke.
Participants filled out a standard survey about their diets at the start
of the study, and their health was tracked for nearly 10 years. In that
time there were 559 strokes or heart attacks, 338 of them fatal.
Daily diet soda drinkers (there were 116 in the study) had a 48 percent
higher risk of stroke or heart attack than people who drank no soda of
any kind (901 people, or 35 percent of total participants). That's after
taking into account rates of smoking, diabetes, waistline size and other
differences among the groups.
No significant differences in risk were seen among people who drank a
mix of diet and regular soda.
Earlier studies have tied diet and regular soda consumption to greater
risk of diabetes and a group of weight-related problems called the
metabolic syndrome.
Some diet soda critics have suggested it can promote a sweet tooth,
affecting behavior and how much of a person's diet comes from sugary
sources rather than healthier fruits, vegetables and grains.
These sorts of studies just observe groups of people and are not strong
enough evidence to prove risk.
"It's too preliminary to suggest any dietary advice," but other big
studies should look at this question, Gardener said.
Greenberg, of the stroke association, called it "a real-world" look at
possible risk.
Dr. Maureen Storey, senior vice president of science policy for the
American Beverage Association, said in a statement that there is no
evidence "that diet soda uniquely causes increased risk of vascular
events or stroke."
"The body of scientific evidence does show that diet soft drinks can be
a useful weight management tool, a position supported by the American
Dietetic Association. Thus, to suggest that they are harmful with no
credible evidence does a disservice to those trying to lose weight or
maintain a healthy weight."
The beverage group's statement also noted researchers didn't adjust
their results for family history of stroke. Gardener, the researcher,
said that's not "a substantial weakness."
The same federally funded study also looked at a more conventional
health risk - salt. It found higher risks for people eating more than
1,500 milligrams a day. That's the limit the American Heart Association
recommends, but last week's new dietary guidelines from the government
say it's OK to have a little more.
Researchers found that stroke risk rose 16 percent for every 500
milligrams of salt consumed each day. Those who took in 4,000 or more
milligrams of salt had more than 2.5 times greater risk of stroke
compared to those who limited themselves to 1,500 milligrams.
A teaspoon of salt contains about 2,300 milligrams of sodium. About
three-fourths of the salt we eat, though, comes from processed foods,
especially tomato sauce, soups, condiments, and canned foods.
___
Online:
Stroke conference:
www.strokeconference.org