Omega-3 has different forms - alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA is in plant foods. But DHA is what we need for our brain.

  • But how do you know how much DHA and EPA you really need?
  • Can you get all your DHA and EPA on a plant-based diet?
  • And why do some people need more DHA and EPA than others?

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DHA and EPA: Should You Supplement?

You need to make sure you’re getting enough of the right type of omega-3 for weight management, brain health, exercise recovery and mood regulation.

But the advice online is confusing and contradictory. Even official guidelines are unclear (1,2).

Some say you can get all your omega-3 from the ALA in seeds (like chia and flax) and convert it to DHA ourselves. (We know can convert some but how much is debatable.)

Others say you need to supplement algal oil for the DHA if you’re on a plant-based diet because we can’t convert enough ALA to DHA.

Did you know that algal oil is the best choice for any diet type? This is because of the higher levels of mercury in the brain of those who eat fish (3).

How Much DHA and EPA Do You Really Need?

The truth is there’s no one-size-fits-all. You’ll need a different amount of omega-3 than another person.

For example, you may be more able to manage your weight with a particular balance of fat in your diet.

Or you might not be able to transport enough DHA to your brain on a ‘normal’ dose.

These three genes are crucial to working out how much DHA you need.

FADS1

FADS1 is the enzyme converting ALA to DHA and EPA.

The ‘slow’ variation in the FADS1 gene means you may not be able to convert much ALA to DHA. If you have this gene you might need to supplement algal oil every day to get enough DHA (4,5).

But there are other genes you should consider when figuring out how much DHA and EPA you need.

APOE

APOE is an important gene which codes a protein for transporting DHA to your brain (6-8).

Your brain is mostly fat and DHA is very important to make the cell walls of your brain cells so your neurons function properly. So transporting DHA in and around your brain is critical to its function.

Variations in APOE associated with reduced transport of DHA are significantly associated with dementia and Alzheimer’s disease risk (9,10). The risk variant is called APOE4.

Actually around a third of the population have this allele. But studies into supplementing DHA for Alzhiemer’s have been inconclusive - until now.

The ‘usual’ recommended intake of DHA and EPA for adults is 250 mg per day (11). But a study in 2020 found more than 2 g DHA every day might be needed to get enough DHA to the brain in people with a common variation in the gene APOE (12).

HTR1A

HTR1A is the gene encoding for a type of serotonin receptor in our brain (13). The receptor binds to the neurotransmitter serotonin to regulate our mood, sleeping patterns and appetite among other things (14).

But some people have a variation in the HTR1A gene resulting in reduced serotonin receptor function. So it doesn’t bind to serotonin as well leading to reduced effects and an increased risk of depression (15-17).

DHA has been shown to increase serotonin synthesis and improve serotonin receptor binding (18,19). So the people with this particular genetic variation may benefit from the mood-enhancing properties of supplementing extra DHA.

Conclusion: Should You Supplement DHA and EPA?

Whether you’re on a plant-based diet or not for most people the answer is ‘YES’. But how much depends on genetic factors. Getting the balance right may be important for your long-term brain health and mood - which can impact other things like your sleep and appetite regulation

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  1. https://www.efsa.europa.eu/en/efsajournal/pub/2815
  2. https://www.efsa.europa.eu/en/efsajournal/pub/1461
  3. https://pubmed.ncbi.nlm.nih.gov/26836731/
  4. https://academic.oup.com/HTTPHandlers/Sigma/LoginHandler.ashx?error=login_required&state=7e1f1124-de5f-4916-b39b-5789ad11a2a4redirecturl%3Dhttpszazjzjacademiczwoupzwcomzjmbezjarticlezj33zj7zj1726zj2578764
  5. https://pubmed.ncbi.nlm.nih.gov/2638395/
  6. https://pubmed.ncbi.nlm.nih.gov/30465491/
  7. https://pubmed.ncbi.nlm.nih.gov/26836731/
  8. https://pubmed.ncbi.nlm.nih.gov/30550413/
  9. https://pubmed.ncbi.nlm.nih.gov/30550413/
  10. https://pubmed.ncbi.nlm.nih.gov/23801662/
  11. https://www.efsa.europa.eu/en/efsajournal/pub/1461
  12. https://pubmed.ncbi.nlm.nih.gov/32690472/
  13. https://www.ncbi.nlm.nih.gov/gene/3350
  14. https://pubmed.ncbi.nlm.nih.gov/15777190/
  15. https://pubmed.ncbi.nlm.nih.gov/31228794/
  16. https://pubmed.ncbi.nlm.nih.gov/30664620/
  17. https://pubmed.ncbi.nlm.nih.gov/31120232/
  18. https://pubmed.ncbi.nlm.nih.gov/30530735/
  19. https://pubmed.ncbi.nlm.nih.gov/25713056/