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Study clarifies impact of diet on the
risk of gout
Meat and seafood associated with
greater risk, dairy products may be protective
BOSTON - March 10, 2004 - A new study has clarified the role
of diet in the risk of developing gout - the most common form of
inflammatory arthritis in men. By taking a comprehensive look at
a broad range of dietary factors, the report confirms the suspicion
that consumption of purine-rich meats and seafood increases the
risk of gout. It also determines that purine-rich vegetables and
overall protein intake do not raise risk. Appearing in the March
11 New England Journal of Medicine, the study also finds
that intake of dairy products, particularly low-fat, may be protective
against gout.
"The association of purine-rich foods with gout had long been
suspected but never proven," says Hyon Choi, MD, DrPH, of the
Massachusetts General Hospital (MGH) Rheumatology
Unit, the paper's lead author. "Any contribution of protein
intake to risk was uncertain, and this is the first evidence that
dairy products can be strongly protective." The report is part
of the Health
Professionals Follow-up Study, which is based at the Harvard
School of Public Health (HSPH).
A painful condition affecting more than 5 million adults in the
U.S., gout is caused by deposits of uric acid in connective tissue,
often in joints of the feet or ankles, that lead to inflammatory
arthritis. Symptoms include swelling, redness, stiffness, and severe
pain. Although attacks of gout can subside in a few days, repeated
attacks can cause permanent joint damage, and the disease often
results in substantial disability, occupational limitations and
frequent medical care. Treatment includes the pain-relieving drugs
called NSAIDs (non-steroidal anti-inflammatories) and for more serious
outbreaks, corticosteroid drugs like prednisone. Most patients with
gout eventually require long-term treatment with medications that
lower blood uric acid levels.
Because uric acid is formed by the breakdown of purines - compounds
found in all human tissues and in many foods - gout patients have
long been advised to avoid purine-rich foods. And since many animal
products are rich in purines, avoidance of animal proteins has also
been recommended. But the association of these foods with the risk
of gout was never confirmed by prospective studies.
Initiated in 1986, the Health Professionals Follow-up Study has
gathered information regarding the relationship between dietary
factors and several illnesses from more than 50,000 men employed
in the health professions. Every two years participants complete
questionnaires regarding their diseases and health-related topics
like smoking and exercise, and every four years the questionnaires
also collect comprehensive dietary information.
The current investigation began with 47,000 men who did not report
a history of gout at the study's outset. Participants who subsequently
reported developing gout were surveyed to verify that they met standard
criteria for the disorder, confirming a diagnosis of gout in 730
men by 1998. The researchers then analyzed dietary information that
all study participants provided in 1986, 1990 and 1994 to determine
how diet related to their risk for gout.
The study results confirmed that consumption of meat - particularly
beef, pork and lamb - significantly increases the risk of gout and
that consumption of all types of seafood tended to carry an even
higher risk. Notably, no increased risk was seen with consumption
of purine-rich vegetables - which include peas, beans, mushrooms,
cauliflower and spinach - or with overall protein intake. The study
actually found a potential protective effect from vegetable and
dairy proteins. The protective impact of dairy products had been
suggested by an earlier study finding that a dairy-free diet could
increase uric acid in the blood, and the current report confirmed
that increased consumption of low-fat dairy products significantly
reduced the risk of gout.
Choi notes that this study's results are probably most relevant
to individuals who have a history of gout or are at increased risk
because of family history or other factors. "Dietary manipulation
and behavioral modification to reduce risk of gout may have a much
more substantial impact than currently believed. Reducing red meat
consumption may be recommended because it also has been associated
with such problems as colon cancer and diabetes. At the same time,
healthy foods such as vegetables do not need to be restricted. Recommendations
for seafood or dairy intake should be individualized with a physician
or dietitian, taking into account their potential impact on any
other health issues," he explains. Choi is an instructor in
Medicine at Harvard Medical School.
While this study examined only men, in whom gout is more common,
the investigators strongly suspect that the results would also apply
to women. Future studies to investigate whether reducing meat and
seafood consumption or increasing low-fat dairy intake actually
prevents outbreaks in gout patients could be valuable, the researchers
say.
Choi's co-authors include senior author Gary Curhan, MD, ScD, of
HSPH and the Channing Laboratory at Brigham and Women's Hospital
(BWH), Karen Atkinson, MD, MPH, of the MGH Rheumatology Unit; and
Elizabeth Karlson, MD, and Walter Willett, MD, DrPH, of BWH and
HSPH. The study was supported by grants from the National Institutes
of Health and TAP Pharmaceuticals.
Media Contact: Sue
McGreevey, MGH Public Affairs
Physician Referral Service: 1-800-388-4644
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