Vitamin d and fish oil fail to prevent depression in massive trial
NCT ID NCT01696435
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study tested whether taking daily vitamin D or fish oil supplements could prevent depression in over 18,000 adults without significant mood issues at the start. Participants were followed for about 5 years. The results showed that neither supplement reduced the risk of developing depression or improved mood scores compared to a placebo.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- vitamin D3 (2000 IU daily) and omega-3 fatty acids (fish oil, 1 gram daily)
- What this could lead to
- If effective, these common supplements could offer a simple, low-cost way to help prevent depression in the general population.
- What could go wrong
- This large, completed trial found no significant reduction in depression risk or improvement in mood scores with either supplement compared to placebo.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
-
Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
-
18,353 people
The number who actually took part.
- Start date
-
Jul 2010
- Finished
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Mar 2025
- Lead sponsor
-
Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
-
50 years and older
- Sex
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Anyone
- Healthy volunteers
-
Accepted
You do not need to have the condition being studied to take part.
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Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Participants in VITAL (NCT 01169259) who meet the following criteria are eligible to participate in this ancillary study. These are the criteria specific for testing of the primary aims in the VITAL-DEP ancillary study: * no current significant depressive symptoms * no core major depressive disorder symptoms for a period of two or more weeks in the past two years * no history of alcohol and/or substance abuse disorder active in the past 12 months, schizophrenia or other primary psychotic disorder, bipolar disorder, post-traumatic stress disorder or obsessive-compulsive disorder * no current psychotherapy or current use of psychotropics (including non-prescription agents for the treatment of mood disorders), except for limited use of mild sedatives/hypnotics * no history of major neurologic disorder or delirium episode in the past 12 months * no history of clinical (i.e., overt and not sub-clinical) hypothyroidism diagnosis
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
-
Brigham and Women's Hospital
Boston, Massachusetts, 02215, United States
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