In theory, taking an omega-3, or fish oil, supplement makes a lot of sense.  But this article from the New Yorker casts doubt on whether they’re worth it.  Maybe just eat fish!  I’ve written about omega 3 supplementation here.

The problem is that most of the evidence, particularly the trial evidence, just doesn’t support it at all,” she said.

Omega-3 fatty acids are vital for brain health: They are used to build brain cells, keeping the cell walls flexible and enabling the neurons to sprout new connections and communicate with other cells. Numerous studies have shown that people with higher levels of omega-3s in their blood have better cognition and healthier looking brains, as well as a lower risk of developing dementia. In contrast, people with Alzheimer’s disease have been shown to have lower omega-3 levels.

But there’s a catch: The vast majority of clinical trials have found that taking omega-3 supplements offers virtually no benefit for cognition or dementia symptoms.

Omega-3 Supplements and Brain Health: Key Takeaways

• The paradox: Omega-3 fatty acids are essential for brain health, yet clinical trials consistently show that omega-3 supplements do not improve cognition or prevent dementia in most people.
• A recent clinical trial specifically targeted people most likely to benefit:
  • Older adults with low fish intake.
  • Many carried genes increasing Alzheimer’s risk.
  • Researchers confirmed that supplements raised omega-3 levels in the brain.
  • Despite this, there was no improvement in cognition or brain structure compared with placebo.
• Hypothesis #1: Most people already get enough omega-3s.
  • The brain requires relatively little DHA each day.
  • The body can convert plant-derived ALA (from nuts and seeds) into DHA.
  • High blood omega-3 levels may simply reflect an overall healthier lifestyle rather than being the direct cause of better brain health.
• Hypothesis #2: Metabolism matters more than intake.
  • Some people, especially those genetically predisposed to Alzheimer’s, may break down omega-3s more rapidly.
  • A healthy gut microbiome and diets rich in plants, fiber, and fermented foods may help the brain retain and utilize omega-3s more effectively.
  • In other words, fish alone isn’t enough—the accompanying healthy diet matters.
• Hypothesis #3: Timing may be critical.
  • Most trials last only a few years.
  • The benefits of omega-3s may require decades of consistent intake, primarily through food rather than supplements.

Bottom Line

• Current evidence does not support taking omega-3 supplements solely to improve cognition or prevent dementia.
• The strongest evidence favors regular consumption of omega-3-rich foods (especially fish) as part of an overall healthy dietary pattern, rather than relying on supplements as a shortcut.
• This reinforces a broader principle in nutrition: whole dietary patterns appear to matter far more than isolated nutrients in pill form.