Is Omega-3 Uptake Gender Specific?

Written by Dr. Steve Chaney on . Posted in current health articles, Nutritiion, Supplements and Health

Do We Need To Reexamine Everything We Thought We Knew About Omega-3s?

Author: Dr. Stephen Chaney

is omega-3 uptake gender specific

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:

  1. 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.
  1. Omega-3s lower triglycerides and reduce inflammation, two important risk factors for heart disease.
  1. 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?omega-3

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:

  1. It was a very small study. Obviously, this study needs to be repeated with a much larger cohort of men and women.
  1. 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.
  1. 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

  1. 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.”
  1. 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.
  1. 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.

Trackback from your site.

Comments (3)

  • kathleen sibbel

    |

    this was very interesting, I find that the more Omegaguard I take the better I feel, less aches and pains (arthritis) still, my Dr. wants to put me on statin drugs, tried them once for about 3wks. and stopped, Told him I would rather die of a stroke than be in the pain those things caused in me.
    Being Diabetic I have to go in regularly for blood work, and it always seems to be a battle. And I am always told I take too much Vita E. I just reply: better to have too much than an amputation (not in my vocabulary and better not be in his) Am anxious to show him the Dr. letter for the new Blood Pressure supplement Shaklee has introduced.
    Thanks for all your articles. so good and informative.

    Reply

  • Sheri Duncan

    |

    That is interesting but only looks at one source of omega 3’s. I’d be interested in one that looks at Flax Seed oil with omega 3,6 & 9 which is what I take. not fair, I’m a subscriber & would like those freebies too. Do you already make them available to us? I don’t check my e-mails often. Thanks Sheri

    Reply

    • Dr. Steve Chaney

      |

      Dear Sherri,
      I usually emphasize sources of long chain omega-3 fatty acids because those are the ones most likely to be missing from the American diet. Most naturally occurring oils contain a mixture of omega-3, omega-6 and omega-9 fatty acids. Vegetable oils other than flaxseed and canola are the best source of omega-6 fatty acids, but also have omega-3 and omega-9. Olive and peanut oil are the best sources of omega-9, but also have omega-3 and omega-6. Flaxseed and canola oil are the best source of omega-3, but also have omega-6 and omega-9.
      Flaxseed oil is not magical, but it is a very healthy oil. What you should know is that vegetable oils such as flaxseed and canola contain short chain omega-3 fatty acids and the efficiency of conversion of those to the beneficial long chain fatty acids is around 10%. That means that you need about 25 grams of flaxseed oil to get the same health benefits that you would experience with 2 or 3 grams of fish oil. That’s OK if you are using a tablespoon or two of flaxseed oil as a salad dressing, but don’t count on much benefit from a flaxseed oil supplement.
      As for the free offers you missed, they were indeed contained in the emails you didn’t read, but I can give you links for each offer. For “Three Things Every Diet Must Do” eBook, click on:
      https://www.healthtipsfromtheprofessor.com/go/thank-you-three-things/
      For the “Myths of the Naysayers” eBook, click on:
      https://www.healthtipsfromtheprofessor.com/go/thank-you-new/
      Dr. Chaney

      Reply

Leave a comment

Recent Videos From Dr. Steve Chaney

READ THE ARTICLE
READ THE ARTICLE

Latest Article

A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney

 

low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?

 

How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.

 

Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.

 

What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]

 

low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line

 

  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

For more details read the article above.

 

 

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.

UA-43257393-1