We’ve made three updates to the Omega-3s Part 2—Research page.
First, a 2019 randomized controlled trial challenged the idea that EPA is commonly created from DHA (1). Study participants ingested DHA with labeled carbon and researchers did not find the labeled carbon in the participants’ EPA. They concluded that the increase in EPA levels after DHA ingestion is not from retroconversion, but rather from “slowed metabolism and/or accumulation of plasma EPA.”
Second, a 2020 meta-analysis of six cohort studies found no correlation between eating fish and a reduced risk of cardiovascular disease or mortality (2). This further strengthens our conclusion that plant eaters do not need to supplement with EPA and DHA to match the EPA and DHA intakes of fish eaters for the purpose of cardiovascular health. In fact, vegetarians tend to have a significantly reduced risk of heart disease already.
Third, a 2019 systematic review and meta-analysis of 13 randomized controlled trials concluded that marine-derived omega-3 supplementation is associated with a reduced risk of heart disease (3). The following points are important to consider:
- The meta-analysis is, for the most part, using pharmacological doses of omega-3 and therefore isn’t pertinent to diet.
- Such doses appear to work in regards to reducing triglycerides; if you’re a vegan with high triglycerides, you may consider talking to your doctor about pharmacological doses of omega-3s, for which there are vegan versions.
- Fish-eaters are thought to achieve health benefits from about 250 mg EPA and DHA per day and this can easily be obtained through supplementation, though we don’t think there is enough evidence to suggest vegans who do not supplement are at an increased risk of CVD.
These studies do not change our omega-3 recommendations.
1. Metherel AH, Irfan M, Klingel SL, Mutch DM, Bazinet RP. Compound-specific isotope analysis reveals no retroconversion of DHA to EPA but substantial conversion of EPA to DHA following supplementation: a randomized control trial. Am J Clin Nutr. 2019 Oct 1;110(4):823-831.
2. Zhong VW, Van Horn L, Greenland P, Carnethon MR, Ning H, Wilkins JT, Lloyd-Jones DM, Allen NB. Associations of Processed Meat, Unprocessed Red Meat, Poultry, or Fish Intake With Incident Cardiovascular Disease and All-Cause Mortality. JAMA Intern Med. 2020 Feb 3. doi: 10.1001/jamainternmed.2019.6969. [Epub ahead of print]
3. Hu Y, Hu F, Manson JE. Marine Omega-3 Supplementation and Cardiovascular Disease: An Updated Meta-Analysis of 13 Randomized Controlled Trials Involving 127 477 Participants. J Am Heart Assoc. 2019 Oct;8(19):e013543.