A new study, led by King's College London, has found that
omega-3 fatty acids reduce the rates of depression among patients
with high levels of inflammation.
Patients with increased inflammation have a greatly increased
risk of depression. The study involved patients who were receiving
medical treatment (interferon-alpha therapy) over six months for
chronic hepatitis C. Approximately 30 percent of patients receiving
this type of treatment become depressed, and it is a commonly-used
model of inflammation-induced depression.
Omega-3 fatty acids, more commonly known as fish oils, have a
long list of health benefits, including lowering the risk of heart
disease and reducing triglyceride levels. Omega-3s are of high
interest to the depression field, where several studies have
suggested benefits for depression and other psychiatric disorders.
The two main omega-3 fatty acids in fish oil supplements are EPA
(eicosapentaenoic acid) and DHA (docosahexaenoic acid).
In the study, 152 patients with hepatitis C were randomised to
receive two weeks of treatment with EPA, DHA or placebo. Following
the two-week treatment, the patients received a 24-week course of
interferon-alpha treatment and were evaluated repeatedly for
depression.
The researchers found that treatment with EPA, but not DHA or
placebo, decreased the incidence of interferon-alpha-induced
depression in patients being treated for hepatitis C. In addition,
both EPA and DHA delayed the onset of depression, and both
treatments were well tolerated, with no serious side effects.
Professor Carmine Pariante of the Institute of Psychiatry,
Psychology & Neuroscience (IoPPN) at King's, said: "It is now
established that increased inflammation plays a role in causing
depression in at least a subgroup of patients. Our study shows that
even a short course of a nutritional supplement containing one type
of omega-3 fatty acid (EPA) reduces the rates of new-onset
depression to 10 percent, as opposed to the rate of 30 percent we
usually see in this group."
EPA is produced naturally by the body and considered an
endogenous anti-inflammatory. Previous work, also led by Professor
Pariante, found that patients with low levels of endogenous EPA in
the blood were at higher risk of developing depression.
Professor Pariante added: "We believe that this nutritional
intervention restores the natural protective anti-inflammatory
capabilities of the body, and thus protects patients from new-onset
depression when inflammation occurs."
The paper, Omega-3 Fatty Acids in the Prevention of Interferon-Alpha-Induced
Depression: Results from a Randomized, Controlled Trial, is
published in Biological Psychiatry.