Do We Need To Reexamine Everything We Thought We Knew About Omega-3s?
Author: Dr. Stephen Chaney
Some of you may remember the book from a few years ago titled “Men are from Mars, Women are from Venus”. The book proposed that men and women communicate differently (Who would have guessed?), and understanding that fact would help husbands and wives communicate with each other more effectively. I know that some people complained that it was an overly simplistic viewpoint, but I know it sure helped me communicate more effectively with my wife.
I came across a very interesting article recently that suggested the omega-3 fatty acid EPA might be metabolized and utilized differently by men and women. You might say that the statement “Men are from Mars, Women are from Venus” applies to omega-3 utilization as well.
The Science Behind the Study
Now that I’ve captured your interest, perhaps I should fill in a few details. We have known for years that the long chain omega-3 fatty acids EPA and DHA appear to be beneficial at reducing the risk of heart disease. There are several mechanisms for that protective effect:
- Omega-3s reduce the stickiness of platelets so that platelet aggregation, a fancy name for blood clotting, occurs less readily. Of course, we want our blood to clot when we cut ourselves, but we don’t want it to clot inside our arteries, because that is the very process that can lead to heart attacks and stroke.
- Omega-3s lower triglycerides and reduce inflammation, two important risk factors for heart disease.
- Omega-3s help keep the walls of our blood vessels elastic, which enhances blood flow and reduces the risk of hypertension.
However, for any of those things to occur, the omega-3 fatty acids must first be incorporated into our cell membranes. Thus, it is not just how much omega-3s we get in our diet that is important. We need to know how many of those omega-3s are actually incorporated into our membranes.
What if the efficiency of omega-3 uptake into cellular membranes were different for men and women? That would change everything. It would affect the design of omega-3 clinical studies. It would affect omega-3 dietary recommendations for men and women. The implications of gender-specific uptake of omega-3s would be far reaching.
Is Omega-3 Uptake Gender Specific?
The authors of this week’s study (Pipingas et al., Nutrients, 6, 1956-1970, 2014) hypothesized that efficiency of omega-3 uptake might differ in men and women. They enrolled 160 participants in the study (47% male and 53& female) with an average age of 59 years. The study excluded anybody with pre-existing diabetes or heart disease and anybody who was significantly overweight. The study also excluded anyone taking drugs that might mask the effects of the omega-3 fatty acids and anybody who had previously consumed fish oil supplements or more than two servings of seafood per week.
This was a complex study. In this review I will focus only on the portion of the study relevant to the gender specificity of omega-3 uptake. For that portion of the study, both male and female participants were divided into three groups. The first group received 3 gm of fish oil (240 mg EPA and 240 mg DHA); the second group received 6 gm of fish oil (480 mg EPA and 480 mg of DHA); and the third group received sunflower seed oil as a placebo. The study lasted 16 weeks, and the incorporation of omega-3 fatty acids into red blood cell membranes was measured at the beginning of the study and at the end of 16 weeks.
When they looked at men and women combined, they found:
- A dose specific increase in EPA incorporation into red cell membranes compared to placebo. That simply means the amount of EPA that ended up in the red blood cell membrane was greater when the participants consumed 6 gm of fish oil than when they consumed 3 gm of fish oil.
- Very little incorporation of DHA into red blood cell membranes was seen at either dose. This was not unexpected. Previous studies have shown that EPA is preferentially incorporated into red cell membranes. Other tissues, such a neural tissue, preferentially incorporate DHA into their membranes.
When they looked at men and women separately, they found:
- The efficiency of EPA incorporation into red cell membranes compared to placebo was greater for women than for men. In women increased EPA uptake into red cell membranes was seen with both 3 gm and 6 gm of fish oil. Whereas, with men increased EPA incorporation into red cell membranes was only seen at with 6 gm of fish oil.
What Is The Significance Of These Observations?
The authors concluded “This is an important area for future research because dietary recommendations around long chain omega-3 polyunsaturated fatty acid intake may need to be gender specific.”
However, there are a number of weaknesses of this study:
- It was a very small study. Obviously, this study needs to be repeated with a much larger cohort of men and women.
- This study was just looking at incorporation of omega-3s into red cell membranes. We don’t yet know whether the specificity of omega-3 uptake will be the same for other tissues. Nor do we know whether there will be gender specificity in the biological effects of omega-3s.
- Most importantly, not all previous studies have reported the same gender specificity in omega-3 uptake seen in this study.
So what does this mean for you? Should men be getting more omega-3 fatty acids in their diet than women, as the authors suggested? That is an intriguing idea, but based on the weaknesses I described above, I think it’s premature to make this kind of recommendation until these results have been confirmed by larger studies.
The Bottom Line
- A recent study has suggested that women may be more efficient at incorporating the omega-3 fatty acids EPA into their cellular membranes than men. The authors of the study concluded that “…dietary recommendations around long chain omega-3 polyunsaturated fatty acid intake may need to be gender specific.”
- However, the study has a number of weaknesses:
- It was a very small study. Obviously, it needs to be repeated with a much larger cohort of men and women.
- This study was just looking at incorporation of omega-3s into red cell membranes. We don’t yet know whether the specificity of omega-3 uptake will be the same for other tissues. Nor do we know whether there will be gender specificity in the biological effects of omega-3s.
- Most importantly, not all previous studies have reported the same gender specificity in omega-3 uptake seen in this study.
- The idea that men and women may differ in their needs for omega-3 fatty acids is intriguing, but based on the weaknesses described above, it is premature to make this kind of recommendation until the results of the current study have been confirmed by larger studies.
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.