Eat Fish to Cut Depression?
WebMD News Archive
April 9, 2001 -- If an apple a day keeps the doctor away, could
a serving of salmon keep the psychiatrist at bay? According to a Finnish study,
Researchers in Finland have found that people who eat more fish
are less likely to have symptoms of depression. Many fish contain high levels
of omega-3 polyunsaturated fatty acids -- one in particular, docosahexaenoic
acid, or DHA, is necessary for optimal brain function.
But while the result of this study, written by Antti Tanskanen
and colleagues and published in this month's issue of Psychiatric
Services, supports findings from previous studies linking low DHA levels
with depression, the researchers say their study can't prove a cause-and-effect
relationship and that large-scale trials are needed before dietary
recommendations to increase fish consumption among psychiatric patients, or
even the general population, can be made.
"They are making a connection, but it is hard to say how
strong a connection it is," Barbara Rasco, PhD, JD, tells WebMD. Rasco, an
associate professor in the department of Food Science and Human Nutrition at
Washington State University in Pullman, reviewed the study for WebMD.
The researchers asked more than 3,000 Finnish adults whether
they experienced depressive symptoms. They also were asked various questions
about their lifestyles, such as marital status, employment status, smoking
habits, alcohol and coffee intake, and education level, in addition to how much
fish they consumed.
The researchers found that the likelihood of having mild to
severe depression was 31% higher among infrequent fish consumers, who ate fish
twice a month or less, than in people who ate fish once a week or more. The
connection between depressive symptoms and fish consumption was particularly
strong among women.
"I wouldn't be surprised that omega-3 fatty acids would
play a role in mental health because of their important role in nervous system
function and [biological] importance in our diet overall," Rasco says.
"But," she says, "frequent fish consumers tend to
have a healthier lifestyle and better diet overall ... a lower-fat diet,
reduced caffeine and alcohol intake, less smoking, more physical activity. ...
And I think people who tend to have that kind of lifestyle tend to be happier
people overall; they feel better, and that tends to make them happier." She
notes that the study doesn't do a terrific job of teasing out the effects of
fish consumption from the other lifestyle factors.