By Craig Weatherby
Sex may matter when it comes to benefits of the two major omega-3s in seafood.
Medical research has long ignored possible differences in the ways people of different gender and ethnicity respond to drugs and nutrients.
That's beginning to change, and nutrition-health researchers are paying more attention to gender gaps in the ways people absorb and benefit from omega-3 fatty acids.
Omega-3 EPA and DHA – which are found only in seafood and marine oils – serve distinct but overlapping functions in the body, and exert distinct but overlapping effects.
The results of a new trial and similar ones published recently suggest three things:
Each omega-3 fatty acid (EPA and DHA) offers gender-specific benefits.
These gender-specific benefits vary by body system (e.g., heart versus brain).
Both sexes benefit from getting ample amounts of omega-3 EPA and DHA ... though each fatty acid affects men and women somewhat differently.
Thus, the new findings oppose the trend toward customizing fish oil supplements to make them extra-rich in or the other omega-3 fatty acid.
That “magic bullet” approach is typical of drug companies seeking unique, patentable products … but it reduces the broader benefits obtainable only from the natural EPA/DHA balance found in whole fish and fish oil.
Omega-3s bring distinct benefits to each gender
Scientists from Australia's University of Newcastle have led the search for gender distinctions in the way dietary omega-3s benefit the body.
Three years ago, they found that men and women react differently to the two key omega-3s (EPA and DHA) in fish or krill oils when it comes to the “stickiness” of blood … see “Gender Gap in Omega-3 Benefit
Specifically, that 2010 clinical trial showed that EPA and DHA exerted different, gender-specific effects on the tendency for platelets in the blood clump together to form dangerous clots … called platelet aggregation.
They found that while the combination EPA and DHA both reduced platelet aggregation, there was a gender difference: EPA was significantly more effective in men, compared with DHA or placebo capsules.
DHA was significantly more effective in women, compared with EPA or placebo capsules.
The University of Newcastle team suggested that the observed differences could be caused by differing interactions between the two omega-3s and male and female sex hormones.
Gender differences detected in the two omega-3s' clot-prevention effects
Recently, the same Australian research group recruited 94 healthy men and women for a larger double-blind, randomized, placebo controlled trial (Phang M et al. 2013).
Participants were randomly assigned to receive one of three regimens for four weeks:
After one month, the men and women in both omega-3 supplemented groups showed reductions in platelet aggregation, compared with the placebo group.
Before considering gender differences, platelet aggregation dropped by 12 percent in the EPA group and by 15 percent in the DHA group.
But there were gender differences: as in the 2010 study, men benefited more from EPA, while women benefited more from DHA.
The authors put it this way: “With respect to thrombotic [clot-based cardiovascular] disease risk, men are more likely to benefit from supplementation with EPA, whereas women are more responsive to DHA.” (Phang M et al. 2013)
Over the course of the one-month study, DHA blood levels rose much more in the women (148 percent) than in the men (64 percent) … results that reflect those of a prior test tube study showing slower uptake of DHA into men's blood platelet cells.
Again, despite these gender-specific differences – which researchers should always look for – the Aussie team's findings do not undermine the idea that it's smart for both sexes to get ample amounts of both omega-3s.
Health authorities worldwide recommend getting 250 to 500mg of EPA+DHA every day … see our Omega-3 Facts & Sources
Phang M, Lincz LF, Garg ML. Eicosapentaenoic and docosahexaenoic Acid supplementations reduce platelet aggregation and hemostatic markers differentially in men and women. J Nutr. 2013 Apr;143(4):457-63. doi: 10.3945/jn.112.171249. Epub 2013 Feb 6.
Phang M, Sinclair AJ, Lincz LF, Garg ML. Gender-specific inhibition of platelet aggregation following omega-3 fatty acid supplementation. Nutr Metab Cardiovasc Dis. 2012 Feb;22(2):109-14. doi: 10.1016/j.numecd.2010.04.012. Epub 2010 Aug 12.