Feeling
depressed? Ask not what your parents did or didn’t
do when you were a child. Ask yourself what you had
for dinner last night, and the night before, and the
night before that.
For half a dozen
years now, the evidence has been growing that
omega-3 fatty acids, the kind found in fatty fish
like salmon, sardines and tuna, can help prevent and
treat depression.
Rich in EPA (eicosapentaenoic
acid) and DHA (docosahexaenoic acid), these are
among the “good” oils that have long been known to
reduce the risk of heart attacks and strokes. They
are also the oils that, in recent decades, in tandem
with rising depression rates, Americans have not
been getting enough of.
The case for
linking low omega-3 levels to depression is strong,
though not yet a slam-dunk. But there is little risk
–and significant benefit - to following the
American Heart Association recommendation to eat
fish at least twice a week and, if you already have
heart disease, taking at least 1 gram a day of
supplements containing EPA and DHA. Unlike omega-6
fatty acids (from corn and safflower oils), which
most of us overindulge in, omega-3s combat
auto-immune diseases like rheumatoid arthritis ,
reduce cardiac arrhythmias and are crucial to the
development of the spinal cord, brain and retina in
infants and to healthy brain functioning in adults
as well.
The latest
evidence for the role of omega-3 fatty acids and
depression came several weeks ago last month, when
researchers from McLean Hospital in Belmont,
reported that omega-3 fatty acids, plus uridine,
another substance found commonly in food, prevented
depression in rats just as well as antidepressant
drugs. The effect of uridine was immediate, said
Bill [cq] Carlezon [cq], director of the behavioral
genetics lab at McLean. It took 30 days for omega-3
to kick in. But combining the two made omega-3
effective three times faster.
“There is
something to this story,” said Dr. Andrew Leuchter [cq],
vice chair of psychiatry at the Neuropsychiatric
Institute at UCLA. “I have seen enough patients who
treat themselves with omega-3 fatty acids to think
these substances may have, at least in some
individuals, potent effects on mood.”
No one knows
exactly why omega-3s might protect against
depression, but theories abound. One is that
depression may, in part, be an inflammatory problem,
which omega-3s can damp down, said Dr. Andrew Stoll,
[cq], director of psychopharmacology at McLean.
Another is that the oils keep cell membranes more
fluid, making it easier for receptors to respond to
neurotransmitters like serotonin, which is often
deficient in depression. Another is that omega-3s
may boost levels of serotonin.
Whatever the
underlying mechanism, “the epidemiological evidence
is huge,” Stoll said, that omega-3s can protect
against depression.
Overall, major
depression is 60 times more prevalent in countries
where little fish is eaten, said Dr. Joseph R.
Hibbeln [cq], senior clinical investigator at the
National Institute on Alcohol Abuse and Alcoholism.
In 1998,
Hibbeln and others showed that high fish-eating
countries like Japan and Taiwan have very low rates
of depression, while low fish-eating countries like
Germany and the United States have high rates. “When
you compare rates of depression across populations,
there is a consistent finding of strikingly lower
rates of major depression, bipolar depression,
seasonal affective disorder and postpartum
depression in countries where people eat more
seafood.”
A 2002
double-blind, placebo-controlled study of 20 people
in Israel, for instance, showed that adding EPA to
standard antidepressants significantly decreased
depression after three weeks. A 2002 Scottish study
of 60 people came to similar conclusions when
patients added a 1-gram daily supplement of EPA to
their standard treatment. (Interestingly, higher
doses did not work as well.) A 2002 Taiwanese study
of 28 people using both EPA and DHA also found
significant improvement in depression scores,
compared to placebo.
But not all
studies support this. A New Zealand team studied 77
mildly depressed people and randomly assigned them
to add 8 grams a day of fish oil or a placebo (olive
oil) to standard antidepressant therapy. Mood
improved in both groups.
A Finnish study
that asked nearly 30,000 men to recall their fish
oil consumption over the years also found no link
between omega-3 fatty acids and depression or
suicide, although studies based on recall are
notoriously inaccurate. And a double-blind,
placebo-controlled study of 35 people at Baylor
College of Medicine in Houston found no improvement
in depression when they gave patients only DHA, not
EPA.
In the plus
column, bi-polar depression, too, also known as
manic-depression, also seems to be helped by omega-3
fatty acids. A study comparing 10 countries showed
that higher fish consumption correlated with lower
rates of bi-polar disorder. A 1999 study by Stoll of
McLean showed that giving fish oil supplements to
people with bi-polar disorder reduced episodes of
depression and mania.
Omega-3 fatty
acids also appear to reduce hostility and homicide.
Several studies have found that low intake of fish
and omega-3s correlates with higher rates of
hostility, which is often associated with depression
in males. A 36-country study showed lower rates of
homicide in countries where people ate more fish.
And postpartum
depression also appears linked to omega-3 levels. A
study of women in 23 countries showed that women who
ate less seafood and had lower rates of DHA in their
breast milk were more likely to suffer postpartum
depression. Pilot studies by Dr. Marlene Freeman [cq],
director of the Women’s Mental Health Program at the
University of Arizona, suggest taking DHA and EPA
can reduce post-partum depression by 50 percent.
(Many pregnant
women and nursing mothers, added Freeman, have been
frightened about eating any kind of fish because of
government warnings of particularly high mercury
levels in a few species, king mackerel, shark,
swordfish and tilefish. The Center for Science in
the Public Interest, a nutrition advocacy group,
says that sardines and salmon contain little
mercury; women of reproductive age should probably
limit their consumption of canned tuna to one can of
white or two cans of light per week.)
Even borderline
personality disorder, characterized by volatile
interpersonal relationships and impulsivity, seems
to respond to omega-3 treatment. Yet another McLean
study of 30 patients found that EPA, without any
other medication, improved symptoms of borderline
personality.
That’s more
than enough evidence for me. Given the longstanding
overall health benefits of omega-3 fatty acids and
the newly-emerging psychiatric benefits, the
conclusion is a no-brainer. Eat fish three times a
week. And if you hate fish (as I do), take at least
one gram a day of a supplement with EPA and DHA.
Judy Foreman’s column appears every other week. Past
columns are available on
www.myhealthsense.com
