Where is the best evidence for fish oil in human nutrition?

Here are 10 health conditions, rated from 1 – 10 (1 = the best), each followed by a brief explanation of the strength of evidence


1. Heart disease
o Hundreds of clinical research trials involving thousands of people have shown consistent benefit of fish oil omega-3s for heart disease, for both prevention and intervention.

2. Healthy babies
o DHA, one of the fats in fish oil, is required for normal development of the brain, eyes, immune and nervous systems in infants. Mom’s diet is the source of this nutrient.

3. Joint/arthritis pain
o Fish oil is known to reduce inflammation, and several human clinical trials report that fish oil reduces arthritic pain and stiffness. Because of how fish oil works, people generally need to take at least 3 grams of EPA and DHA for 6-8 weeks before they get the benefits. It’s worth the wait, because the side effects are additional benefits.

4. Mental health: depression
o As the amount of omega-3 in our diet goes down, the incidence of depression goes up; this has been measured around the world. Double blind, placebo-controlled research shows that when depressed people take EPA and DHA from fish oil they get better.

5. Mental health: attention deficits
o Research indicates that children with attention deficits have lower blood levels of omega-3 compared to other children. Omega-3s are dietary essential fats, which means children and adults have to eat them to get them. Giving fish oil supplements to children has been shown to improve focus, attention and support learning.

6. Healthy immune function
o EPA and DHA are involved with supporting immune function in a myriad of ways, via genetic influence, biological response, etc. Research indicates that regular consumption of fish oil promotes healthy immune functioning in chronic (e.g. allergies) and more acute conditions.

7. Diabetes (type 2)
o Fish oil supports nerve conduction, healthy vision, good circulation, heart health and cognitive function; these are all important benefits for people with diabetes.

8. Postpartum depression
o Pilot research trials indicate that fish oil supplements may reduce postpartum depression. Considering that the baby relies on (and can deplete) mom for omega-3, plus the role that fish oil has been shown to play in helping depression, there is good reason to think the evidence will strengthen for fish oil as a safe, efficacious alternative.

9. Mental health: cognition, clear thinking with age
o Population studies suggest that people who have consumed fish over their lifetime have better cognition and clearer thinking as they age. Research is also indicating that those with a genetic risk for dementia may benefit from fish oil supplementation.

10. Dry eye syndrome
o Omega-3 consumption is associated with less dry eye syndrome in population studies. DHA, found in fish oil, is a specific, selected fat stored in the human eye. We can look to research to clarify this sighting in the future.