People who take fish oil capsules may not be getting the
heart-health benefits they desired, according to a pair of new research
reports.
Both studies found that the omega-3 fatty acids in fish oil
supplements do not provide any significant protection against heart disease,
when compared to other types of dietary fats.
"Looking at the 17 randomized clinical trials that we
combined, the majority of the trials -- especially the more recent and
large-scale ones -- showed consistently little or no significant effect on
reducing coronary heart disease events," said Dr. Rajiv Chowdhury, lead
author of a comprehensive review of nutrition research related to fats.
Of the range of fats studied, only trans fats showed a clear
negative effect on heart health, according to the review published in the March
18 Annals of Internal Medicine by Chowdhury, a cardiovascular epidemiologist at
the University of Cambridge, and colleagues.
Trans fats can still be found in processed foods -- look for
the words "hydrogenated" or "partially hydrogenated" in the
ingredient list.
Saturated fats, long considered a dietary no-no, appeared to
pose no additional risk for heart disease according to recent research,
Chowdhury said. They carried about the same cardiac risk as unsaturated fats,
omega-3 fatty acids and omega-6 fatty acids.
Saturated fats are solid at room temperature. They can be
found in butter, lard, cheese and cream, as well as the fatty white areas on
cuts of meat. By contrast, unsaturated fats are liquid at room temperature --
think of vegetable cooking oil or olive oil.
A second study also came to the same conclusion regarding
omega-3 fatty acids, via a different route. This study had been reviewing the
use of omega-3s for eye health, but researchers used their data to look at
whether the supplements also helped prevent heart disease.
That study found no reduction in heart attack, stroke or
heart failure among almost 1,100 people taking omega-3 supplements, compared to
similar numbers of people taking other supplements for eye health or just an
inactive placebo. It appeared online March 17 in JAMA Internal Medicine.
The meta-analysis performed by Chowdhury's team involved
data from 72 studies with more than 600,000 participants from 18 nations. The
team combined study findings to assess the heart health benefits of all types
of dietary fat -- saturated fat, unsaturated fat, and the omega-3 and omega-6
fatty acids.
Until now, doctors have said that saturated fats increase
"bad" LDL cholesterol, which can cause plaques to form in your
arteries and raise your risk of a heart attack or stroke.
At the same time, omega-3 fatty acids were said to improve
heart health because it increases your level of "good" HDL
cholesterol. Good cholesterol is believed to help the body rid itself of bad
cholesterol.
While this is still true, Chowdhury and his team found that
neither effect seemed to make much difference for overall cardiac risk.
"Saturated fats are not essentially the main problem
when it comes to risk of heart disease," Chowdhury said. "Also,
omega-3 or omega-6 fatty acids have no or little impact on reducing
cardiovascular disease outcomes."
The Council for Responsible Nutrition, a trade association
representing the dietary supplement industry, released a statement calling the
new report's viewpoint "potentially irresponsible" and accusing it of
causing "nutritional guidance whiplash" for consumers.
"There are thousands of studies and decades of
recommendations from government, academic, nutritional and medical
organizations and experts supporting the important heart health benefits associated
with diets high in polyunsaturated fats, low in saturated fats, and avoidance
of trans fats," Duffy MacKay, a naturopathic doctor and the council's
senior vice president of scientific and regulatory affairs, said in the
prepared statement.
MacKay added that dietary recommendations from the American
Heart Association and the federal government both emphasize the importance of
omega-3 fatty acids in a person's diet.
Omega-3 fatty acids do play an important role in good
nutrition, as do other unsaturated fats, study author Chowdhury noted.
"Omega-3 fatty acids are essential nutrients for
health," Chowdhury said. "We need omega-3 fatty acids for numerous
normal body functions, such as controlling blood clotting and building cell
membranes in the brain."
But people should focus on getting their omega-3 fatty acids
from food rather than through supplements, the researcher said.
Dr. Linda Van Horn, a professor of preventive medicine at
Northwestern University Feinberg School of Medicine and a member of the
nutrition committee of the American Heart Association (AHA), agreed.
"There is continuing data to support eating fish on a
regular basis for heart health and other health benefits like [mental]
function," Van Horn said. "There's no question that eating fish
provides tremendous value in reducing risk for cardiovascular disease, but the
use of a supplement -- whether it's a fish oil or any other nutrient -- really
needs to be handled carefully."
People should keep their overall fat intake low because fats
contain twice the calories of proteins or carbohydrates, according to federal
guidelines.
Van Horn said the AHA's nutrition committee will review
these new findings at its next meeting.
"I don't think we take any of these kind of findings
lightly, nor would we recommend the benefit of a supplement ever over a
heart-healthy diet," she said, noting that the new review is "further
elaborating on nutrient data that weren't even available five or 10 years
ago."
And, she added, "While there's a tendency for the
American public to throw up their hands, the better way to interpret this is,
'How wonderful we have additional data and can look at these questions that
previously went unanswered.'"
For his part, MacKay said the new studies will not alter the
tips he provides his patients.
"If you want to play an active role in staying heart
healthy, the best advice remains the same: Eat a healthy diet rich in
polyunsaturated fats such as omega-3s, add omega-3 supplements if you're not
eating enough fatty fish, and exercise regularly," MacKay said.
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