Researchers studied over 258,000 people in the UK to see if omega-3 fatty acids (healthy fats found in fish) could help protect against self-harm and suicidal thoughts. They measured the amount of omega-3 in people’s blood and compared it to their mental health records. The study found that people with higher levels of omega-3 fatty acids had lower rates of self-harm and suicidal thoughts. Those with the highest levels of certain omega-3s had about 33% lower chances of having a history of self-harm. While these results are promising, researchers emphasize this is one piece of the puzzle and more research is needed before making major dietary changes.

The Quick Take

  • What they studied: Whether people with higher amounts of omega-3 fatty acids in their blood have fewer thoughts of self-harm or suicidal feelings
  • Who participated: Over 258,000 adults from the UK Biobank study who had blood tests measuring their omega-3 levels and answered questions about their mental health
  • Key finding: People with the highest levels of omega-3 fatty acids had significantly lower rates of self-harm. For example, those with the most DHA (a type of omega-3) had 33% lower odds of having harmed themselves in the past
  • What it means for you: Eating more omega-3 rich foods like fish, walnuts, and flaxseeds may help protect mental health, but this study shows a connection, not proof that omega-3s directly prevent self-harm. Always talk to a doctor or mental health professional if you’re struggling with self-harm or suicidal thoughts

The Research Details

This was an observational study, meaning researchers looked at information that was already collected rather than running an experiment. They used data from the UK Biobank, a massive health database with information from hundreds of thousands of people. Researchers measured omega-3 levels in participants’ blood using a special technique called Nuclear Magnetic Resonance (NMR), which is like taking a detailed snapshot of the fats in your blood. They then looked at medical records and survey answers to see who had experienced self-harm or suicidal thoughts. The researchers adjusted their analysis for many other factors that could affect the results, like age, sex, diet, exercise, and other health conditions.

This approach is important because it uses real-world data from a very large group of people, which makes the findings more likely to apply to the general population. By measuring omega-3 levels directly in blood rather than just asking people what they eat, the researchers got more accurate information. The large sample size means the results are less likely to be due to chance alone.

This study has several strengths: it included a very large number of people (over 258,000), used objective blood measurements rather than just surveys, and adjusted for many other factors that could influence results. However, because it’s observational rather than experimental, we can’t be completely certain that omega-3s directly cause the protective effect—other unmeasured factors could be involved. The study also found stronger associations when using medical records compared to self-reported information, which suggests the medical record findings may be more reliable.

What the Results Show

The main finding was that higher omega-3 levels were connected to lower rates of self-harm and suicidal thoughts. Specifically, people with the highest levels of non-DHA omega-3s (a group that includes ALA, EPA, and DPA) had a 14% lower risk of passive suicidal ideation in the past year. People with the highest DHA levels had a 33% lower chance of having a history of self-harm. These associations were consistent across different types of omega-3 fatty acids, suggesting that multiple types of these healthy fats may be protective. The protective effect was stronger when researchers looked at medical records compared to when they relied on people’s self-reported answers, which suggests the medical record findings are likely more accurate.

The study also found that the protective associations held up even after accounting for many other factors like age, sex, smoking status, alcohol use, exercise, and other health conditions. This suggests that the connection between omega-3 and reduced self-harm wasn’t simply because healthier people in general had higher omega-3 levels. The dose-response pattern (meaning higher omega-3 levels showed stronger protective effects) also supports the idea that omega-3 itself may be playing a protective role.

Previous research has suggested that omega-3 fatty acids, especially EPA and DHA, may help with depression and other mental health conditions. This study adds to that evidence by specifically looking at self-harm and suicidal ideation in a very large population. The findings align with smaller studies suggesting omega-3s support brain health and mood regulation. However, this is one of the first large studies to examine this specific connection in such a large, diverse population.

This study shows a connection between omega-3 levels and self-harm, but it cannot prove that omega-3s directly prevent self-harm. People with higher omega-3 levels might differ in other ways not measured in the study. The study relied partly on self-reported information about self-harm, which may be underreported due to stigma or privacy concerns. The study was conducted in the UK, so results may not apply equally to all populations. Additionally, the study is observational, meaning we’re looking at patterns in existing data rather than randomly assigning people to take omega-3 supplements or not.

The Bottom Line

Based on this research, eating more omega-3 rich foods may be a helpful addition to overall mental health care. Good sources include fatty fish (salmon, mackerel, sardines), walnuts, flaxseeds, and chia seeds. However, this study should not replace professional mental health treatment. If you’re experiencing self-harm or suicidal thoughts, please reach out to a mental health professional, call a crisis line, or go to an emergency room. The evidence suggests omega-3s may play a supportive role, but they are not a substitute for professional help.

Anyone interested in supporting their mental health through diet should find this research relevant. It may be particularly interesting to people with depression, anxiety, or other mood concerns. However, people with bleeding disorders or those taking blood thinners should talk to their doctor before significantly increasing omega-3 intake. This research is not a substitute for professional mental health care for anyone experiencing self-harm or suicidal thoughts.

If you start eating more omega-3 rich foods, it may take several weeks to months to notice any mental health benefits. Brain health changes happen gradually. This is why it’s important to combine dietary changes with professional mental health support if you’re struggling.

Want to Apply This Research?

  • Track daily omega-3 food intake (servings of fish, nuts, seeds) and weekly mood/mental health check-ins using a simple 1-10 scale. This helps you notice patterns between diet and how you’re feeling over time.
  • Set a goal to include one omega-3 rich food daily—such as adding walnuts to breakfast, having fish for dinner twice a week, or sprinkling flaxseeds on yogurt. Start small and build the habit gradually.
  • Use the app to log omega-3 foods weekly and track mood trends monthly. Create reminders for omega-3 rich meals and set check-ins to reflect on overall mental wellness. Share patterns with your healthcare provider during regular visits.

This research shows an association between omega-3 levels and reduced self-harm, but does not prove omega-3s prevent self-harm. If you are experiencing thoughts of self-harm or suicide, please contact a mental health professional, crisis helpline, or emergency services immediately. This information is for educational purposes and should not replace professional medical or mental health advice. Always consult with your healthcare provider before making significant dietary changes, especially if you take medications or have health conditions. This study was observational and cannot establish direct cause-and-effect relationships.