Are Some Omega-3 Fish Oil Supplements Better Than Others?

Written by Dr. Steve Chaney on . Posted in current health articles, Omega-3 Fish Oil Supplements

Author: Dr. Stephen Chaney

truth about omega-3 fish oil supplementThe ethyl ester form of omega-3 fatty acids from fish oil has been the industry standard for high purity omega-3 fish oil supplements for many years. It is very stable, easily purified, and well absorbed by the body. What’s not to like?

If you believe some recent advertisements, there is a lot not to like about the ethyl ester form of omega-3s. These ads each claim that their particular form of omega-3s is more natural, better absorbed, and more efficiently incorporated into cell membranes, or some combination of those features. They each cite clinical studies “proving” that their products are superior. These advertisements seem so plausible and so compelling.

However, most of these advertisements come from relatively new companies that are trying to make a name for themselves in a very profitable and competitive product niche. Are the advertisements true, or is it all just smoke and mirrors? Most of these advertisements rate at least one Pinocchio.

However, it is almost impossible to tell you why I consider these advertisements omega-3 fish oil supplements to be misleading without getting a little “techie”, so let’s start with some basic definitions. I call this section “Omega-3s 101.”

 

Omega-3s 101

 

Let’s start with some basic definitions:

  • Free fatty acids (FFA) are long chain hydrocarbons with a single acid group at the end. They are only slightly water soluble. They are important intermediates in metabolism, but they are almost always combined with something else in the body.
  • Saturated fatty acids contain no double bonds, monounsaturated fatty acids contain one double bond, and polyunsaturated fatty acids contain multiple double bonds. The number of double bonds primarily affects whether they are liquids (polyunsaturated) or solids (saturated) at room temperature.
  • omega-3 fatty acidsThere are two classes of polyunsaturated fatty acids that are essential because the body cannot make them. Those with a double bond 3 carbons from the end are called omega-3s(If you think about the Greek alphabet, omega is at the end). Those with a double bond 6 carbons from the end are called omega-6s.
  • When 3 fatty acids are combined with a single molecule of glycerol they form very water insoluble compounds commonly referred to as fats or triglycerides. The proper chemical name is triacylglycerol, which is abbreviated TAG.
  • If one of the fatty acids on the glycerol chain is replaced by a compound containing phosphate and other charged residues, the resulting complex is called a phospholipid (PL). Because these compounds have a hydrocarbon surface that is attracted to fats and a highly charged surface that is attracted to water, they are good at emulsifying fats and are an important part of membrane structure. One phospholipid that is a major component of membranes is called phosphatidylcholine (PC), also known as lecithin.

Next, let’s look at how omega-3 fatty acids are metabolized:

  • The omega-3s in fish oil are primarily in the form of triglycerides, with small amounts of phospholipids. The omega-3s in most omega-3 supplements are in the form of ethyl esters for the reasons stated above.
  • Before the omega-3s leave the intestine they are hydrolyzed to free fatty acids.
  • In the cells that line the intestine the omega-3s are reconverted back into triglycerides and phospholipids and incorporated into special lipid-protein complexes for transport through the blood.
  • Once these lipid-protein complexes reach our cells, their contents are delivered to the cell where they can be stored as fat (TAG), used for energy (FFA), or incorporated into membranes (PL). It is primarily the omega-3s incorporated in cellular membranes that are thought to be responsible for the beneficial effects of omega-3s.

Finally, we should ask how one measures the bioavailability of the various forms of omega-3s:

While there are some nuances that I did not cover, the basic mechanisms of absorption and metabolism of omega-3s are remarkably similar regardless of whether they start out in the ethyl ester, triglyceride, phospholipid, or free fatty acid form. The questions then become, how does one test how efficiently the various forms are utilized by the body and how much do these individual test actually tell us?

  • When we look at what happens in the bloodstream, we need to be aware that we are looking at a combination of two effects – how rapidly the substance enters the bloodstream and how rapidly it leaves from the bloodstream. There are three important parameters we can measure when looking at delivery of omega-3s to the bloodstream:
    • The maximum concentration achieved (Cmax)
    • How rapidly that maximum concentration was achieved (Tmax)
    • The total amount in the bloodstream over time (AUC)
  • When you look at some of the ads touting specialized forms of omega-3s, they are usually based on studies looking at either the maximum levels of omega-3s in the bloodstream (Cmax) or how rapidly those maximum levels were achieved (Tmax). (One suspects the ads may have selectively featured whichever parameter made their product look best). However, the parameter that really matters is the total concentration of omega-3s achieved over time (AUC).
  • Finally, the most important question is how much of the omega-3 is actually incorporated into cellular membranes. Once again, there is more than one parameter that can be measured.
  • One can measure the level of omega-3s found in cellular membranes in a short term study (a few hours) or in a long term study following many weeks of supplementation.
  • The short term studies only measure the rate of incorporation. The long term studies measure the steady state levels attained over time, which is a much more relevant measure.
  • Once again, the ads touting specialized products are usually based on short term studies which are really measuring an initial rate of incorporation of omega-3s into cellular membranes, not on long term studies that measure the steady state level of omega-3s achieved over time.

 

Are Some Omega-3 Fish Oil Supplements Better Than Others?

omega-3 fish oil supplementThere has been a lot of confusion in the literature about whether the form of omega-3 supplements matters. Various studies have been published supporting the superiority of one form or another of omega-3s. Most of these studies have been supported by manufacturers who have a particular form of omega-3s they want to sell, and, as I mentioned above, the parameters tested seem to have been selected to make their supplement look good.  So, are some omega-3 fish oil supplements better than others?

 

Finally, someone has designed a comprehensive study to clear up all the confusion and provide answers that can be trusted (West et al, British Journal of Nutrition, 116: 788-797, 2016). Interestingly, this research was supported by a pharmaceutical company (Vifor Pharma) that does not appear to sell an omega-3 product currently. Perhaps they simply wanted to find out what worked best before designing their own product. What a novel concept!

The authors tested 4 different forms of omega-3 fish oil supplements:

  • Unmodified fish oil containing the omega-3s primarily in triglyceride form (uTAG).
  • An omega-3 supplement in which the omega-3s in the fish oil had been hydrolyzed to free fatty acids (FFA).
  • An omega-3 supplement in which the omega-3s in the fish oil had been hydrolyzed to free fatty acids and converted back to triglycerides (TAG)
  • An omega-3 supplement in which the omega-3s in the fish oil had been hydrolyzed to free fatty acids and converted to ethyl esters (EE)

All 4 supplements contained 1.1 grams of EPA and 0.37 grams of DHA.

The authors conducted two studies:

  • One was a cross-over study where healthy men consumed each of the supplements in random order on different days with 14 days between tests. Blood samples were collected over the next 6 hours and levels of EPA and DHA in the blood and cellular membranes was determined.
  • The other was a long term study in which a randomized group of healthy men and women consumed one of the supplements for 12-weeks and incorporation of the EPA and DHA into cellular membranes was measured.

The results were pretty clear cut:

  • In the short term study there were no significant differences between the various supplements in the rate of uptake, maximum concentration achieved, or the total concentration over time when uptake of omega-3s into plasma triglycerides and phospholipids was measured.
  • The ethyl ester form was less efficiently incorporated into plasma free fatty acids than the other forms as reported in some previous studies, but this is perhaps the least important parameter measured, and there was large variability from subject to subject.
  • In the long term study, no significant differences were seen between the various supplements in omega-3 incorporation into cellular membranes.

The authors concluded: “Together, these findings show that in healthy individuals neither the lipid structure nor the overall fatty acid composition of supplements influence their bioavailability during dietary supplementation, despite the apparent lower postprandial availability [in short term studies] of EPA + DHA ethyl esters compared with triglycerides or free fatty acids.”

What Do These Studies Mean For You?

You can forget all those ads hyping the newest, greatest form of omega-3 fish oil supplements. Objective research has shown there is not a dimes worth of difference between the various forms of omega-3 supplements.

A far more important question is the purity of the omega-3 supplement you are using. Purity of omega-3 supplements is a huge issue. You need to remember that the EPA + DHA supplements you purchase come from polluted fish. Unfortunately, many manufacturers have inadequate purification and quality control standards. In other words, neither you nor they know whether their omega-3 products are pure. You need to make sure that the omega-3 supplement you purchase is made by a manufacturer with stringent quality control standards.

Sustainability is also an issue, so you should choose manufacturers who source their omega-3s in a sustainable manner. There are two comments I will make about sustainability so you won’t be misled.

  • Krill oil is marketed as a more sustainable source of omega-3s. Krill reserves are quite large, but they are not infinite. Krill is also the very foundation of the food chain that supports a large percentage of our ocean’s fish. We need to be very cautious about depleting our krill reserves.
  • Omega-3s derived from algae are also marketed as a more sustainable source of omega-3s. Algae-derived omega-3s have purity issues of their own, but may become an important source of omega-3s once those issues have been resolved.

 

The Bottom Line

  • The ethyl ester form of omega-3 fatty acids from fish oil has been the industry standard for high purity fish oil supplements for many years. It is very stable, easily purified, and well absorbed by the body.
  • However, in recent years, some manufacturers have been claiming that their omega-3 fish oil supplements were better utilized by the body because their supplements contained the omega-3s in triglyceride or free fatty acid forms.
  • Unfortunately, the clinical studies supporting those claims have been supported by the manufacturers making the products. There is reason to suspect that the data has been “cherry picked” to support the conclusions that support the manufacturer’s claims.
  • Finally, an independent and comprehensive study has compared the various forms of omega-3 fatty acids. It found that neither the lipid structure nor the overall fatty acid composition of omega-3 supplements influenced their bioavailability during long term dietary supplementation.
  • A far more important question is the purity of the omega-3 supplement you are using. Purity of omega-3 supplements is a huge issue. You need to remember that the EPA + DHA supplements you purchase come from polluted fish. Unfortunately, many manufacturers have inadequate purification and quality control standards. In other words, neither you nor they know whether their omega-3 products are pure. You need to make sure that the omega-3 supplement you purchase is made by a manufacturer with stringent quality control standards.

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Comments (1)

  • Peggy Shearin

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    very, very interesting..

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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.

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