Do Omega-3s Reduce Heart Disease Risk

Written by Dr. Steve Chaney on . Posted in Omega-3s and Heart Disease

Omega-3 Confusion

Author: Dr. Stephen Chaney

 

do omega 3s reduce heart disease risk confusionDo omega-3s reduce heart disease risk?

Perhaps there is nothing more controversial in nutrition today than omega-3 fatty acids and heart disease risk. It is so confusing. One day you are told they reduce heart disease risk. The next day you are told they are worthless.

The controversy around omega-3s and heart disease risk is part of the larger controversy around supplementation. It is omega-3 supplements that are controversial, not omega-3-rich fish. Of course, that completely ignores the fact that many omega-3-rich fish are contaminated with PCBs and/or heavy metals.

Why is omega-3 supplementation so controversial? The problem is that proponents of omega-3 supplementation often seize on a single study as “proof” that everyone should supplement with omega-3s.  Opponents of omega-3 supplementation take the opposite approach. They pick studies showing that not everyone benefits from omega-3 supplementation as “proof” that nobody benefits. As usual, the truth is in between.

I have a section in my book, “Slaying The Food Myths,”  called “None of Us Are Average.” In that section I point out that clinical studies report the average results of everyone in the study, but nobody in the study was average.

For example, let’s say the study reported that (on average) there was no heart health benefit from omega-3 supplementation. That is what makes the headlines. That is what opponents of omega-3 supplementation cite as “proof” omega-3 supplementation doesn’t work.

However, some of the people in the study may have benefited from omega-3 supplementation, while others did not. Thus, the important question is not “Does everyone benefit from omega-3 supplementation?” It is “Who benefits from omega-3 supplementation?” and “Why do the results vary so much from study to study?”

Omega-3 Confusion

do omega 3s reduce heart disease risk rolesI have a chapter in my book called “What Role Does Supplementation Play?” which helps put this omega-3 controversy into perspective. I created the graphic on the left to answer the question “Who needs supplementation?”

The concept is simple. Poor diet, increased need, genetic predisposition, and pre-existing disease all increase the likelihood that supplementation will be beneficial. However, the benefit will be most obvious in the center of the diagram where two or more of these factors overlap.

Let’s take this concept and apply it to studies of omega-3 fatty acids and heart disease risk.  In particular, let’s use this concept to understand what I call “omega-3 confusion” – why some studies give negative results and others give positive results:

Poor Diet: Again, the concept is simple. You are most likely to see a benefit of omega-3 supplementation when the dietary intake of omega-3 fatty acids is low. Put another way, if the subjects in a study are already getting plenty of omega-3s from their diet, supplementing with omega-3s is unlikely to provide any benefit.

Until recently, dietary surveys were the standard method for assessing dietary omega-3 intake. However, dietary surveys can be inaccurate. The best of recent studies, measure the omega-3 levels in cellular membranes. The omega-3 levels at the beginning of the study reflect your diet. The omega-3 levels at the end of the study reflect how effective supplementation was at improving your omega-3 status. In short, this is the gold standard for omega-3 clinical studies. Subjects can lie about how many omega-3-rich foods they eat and whether they take their supplements, but the omega-3 levels in their cell membranes reveal the truth.

When you read the methods section, it turns out that most negative studies did not ask how much omega-3s their subjects were getting from their diet. Almost none of the negative studies measured omega-3 levels in cell membranes.

Increased Need: In terms of heart disease, we can think increased need as the presence of risk factors for heart disease such as:

  • Age
  • Obesity
  • Inactivity
  • Elevated cholesterol or triglycerides
  • Dietary factors like saturated fats and/or sugar and refined carbohydrates
  • Smoking

What does this mean in terms of clinical studies?

  • Studies in which most of the subjects have a poor diet, are over 65, and have multiple risk factors for heart disease are more likely to show a beneficial effect of omega-3s on heart disease risk.
  • Studies in which most of the subjects are young and healthy are unlikely to show a measurable benefit of omega-3s on heart disease risk. You would need to follow this population group 20, 30, or 40 years to demonstrate a benefit.

Genetic Predisposition: There is a lot we don’t know about genetic predisposition for heart disease. The only exception is family history. If you do omega 3s reduce heart disease risk geneticshave a family history of early heart disease, you can be pretty certain you are at high risk for heart disease. As you might suspect:

  • Studies focused on populations with genetic predisposition to heart disease are more likely to show a benefit of omega-3 supplementation.
  • Studies that just look at the general population without consideration of genetic predisposition to heart disease are less likely to show a benefit of omega-3 supplementation.

Disease: Diseases like diabetes and high blood pressure increase heart disease risk. And, of course, pre-existing heart disease, especially a recent heart attack, dramatically increase the risk of a subsequent heart attack or stroke. Studies focusing on subjects with diabetes have been inconsistent. However, studies focusing on patients with pre-existing heart disease are more clear-cut:

  • Studies focused on populations with pre-existing heart disease and/or a recent heart attack are more likely to show a benefit of omega-3 supplementation.
  • Studies that just look at the general population without consideration of genetic predisposition to heart disease are less likely to show a benefit of omega-3 supplementation.

Interestingly, the situation is very similar with statin drugs. As I reported in a recent issue  of “Health Tips From the Professor” on cholesterol lowering drugs, studies done with patients who had recently had a heart attack show a clear benefit of statin drugs, while studies with the general population show little or no benefit of statin drugs.

One More Factor: There is one more confounding factor that is somewhat unique to the omega-3-heart disease studies and, therefore, not included in the figure at the beginning of this section. Ethical considerations dictate that the placebo group in a double-blind, placebo controlled clinical study receive the “standard of care” for that disease. In the case of heart disease, the standard of care is 4-5 drugs which provide most of the same benefits as omega-3 fatty acids (although with many more side effects).

Thus, these studies are no longer asking whether omega-3s reduce heart disease risk. They are asking whether omega-3s have any additional benefits for heart disease patients already on 4-5 drugs. I have discussed this in more detail in a previous issue of “Health Tips From the Professor” on omega-3 and heart disease.

do omega 3s reduce heart disease risk conflicting studiesWhy Are Omega-3 Studies Conflicting? In summary, the likelihood that clinical studies show a beneficial effect of omega-3 fatty acids on heart disease risk is highly dependent on study design and the population group included in the study. Many of the studies currently in the scientific literature are flawed in one way or another. Once you understand that, it is obvious why there are so many conflicting studies in the literature.

Unfortunately, meta-analyses that combine data from many studies are no better than the individual studies they include in the analysis. It is the old “Garbage in – garbage out” principle.

What Does An Ideal Study Look Like? In my opinion, an ideal study to evaluate the effect of omega-3s on heart disease risk should (at minimum):

  • Determine omega-3 levels in cellular membranes as a measure of omega-3 status (dietary intake of omega-3s plus their utilization by the body). The percentage of omega-3 fatty acids in cell membranes is referred to as Omega-3 Index. Based on previous studies (W.S. Harris et al, Atherosclerosis, 262: 51-54, 2017, most experts consider an Omega-3 Index of 4% to be low and an Omega-3 Index of 8% to be optimal.
  • Focus on a population group at high risk for heart disease or include enough subjects in the study so that you can determine the effect of omega-3s on high risk subgroups.
  • Measure cardiovascular outcomes (heart attack, stroke, cardiovascular deaths, etc.).
  • Perform the study long enough so that you can accumulate a significant number of cardiovascular events.
  • Include enough subjects for a statistically significant conclusion.

 

Do Omega-3s Reduce Heart Disease Risk?

do omega 3s reduce heart disease riskMost of you have probably heard of the Framingham Heart Study. It was started in 1941 with a large group of residents of Framingham Massachusetts and surrounding areas. The data from this study over the years has shaped much of what we know about cardiovascular risk factors. The original participants have passed on, but the study has continued with their offspring, now in their 60s.

A recent study (W. H. Harris et al, Journal of Clinical Lipidology, doi: 10.1016/j.jacl.2018.02.010 ) with 2500 subjects in the Offspring Cohort of the Framingham Heart Study incorporates many of characteristics of a good omega-3 clinical study.

  • The average age of the subjects was 66. While none of the subjects enrolled in the study had been diagnosed with heart disease at the time the study began, this is a high-risk population. At this age a significant percentage of them would be expected to develop heart disease over the next few years.
  • The subjects did have other risk factors for heart disease. 13% of them had diabetes, 44% had high blood pressure, and 40% of them were on cholesterol medication. However, those risk factors were corrected for in the data analysis, so they did not influence the results.
  • The Omega-3 Index was measured in their red blood cell membranes at the beginning of the study.
  • The study was long enough (7.3 years) for cardiovascular disease to develop.

When they compared subjects with the highest Omega-3 Index (>6.8%) with those with the those with the lowest Omega-3 Index (<4.2%):

  • Death from all causes was reduced by 34%
  • Incident cardiovascular disease was reduced by 39% (Remember that none of the subjects had been diagnosed with heart disease at the beginning of the study. This terminology simply means that they received a new diagnosis of heart disease during the study.)
  • Cardiovascular events (primarily heart attacks) were reduced by 42%
  • Strokes were reduced by 55%.

There were two other interesting observations from the study:

  • There was no correlation between serum cholesterol levels and heart disease in this study.
  • The authors estimated that it would require an extra 1300 mg of omega-3s/day, either from a serving of salmon or from fish oil supplements, to bring the membrane Omega-3 Index from the lowest level in this study to an optimal level.

The authors cited three other recent studies performed in a similar manner that have come to essentially the same conclusion. These studies are not perfect. They are all association studies, so they do not prove cause and effect.

However, the authors concluded that Omega-3 Index should be measured routinely as a risk factor for heart disease and should be corrected if it is low.

 

The Bottom Line:

Perhaps there is nothing more controversial in nutrition today than omega-3 fatty acids and heart disease risk. It is so confusing. One day you are told they reduce heart disease risk. The next day you are told they are worthless.  I have discussed the reasons for the conflicting results and the resulting omega-3 confusion in the article above.

I shared a recent study that escapes many of the pitfalls of previous studies because it measures the Omega-3 Index of red blood cells as an indication of omega-3 status.

When the study compared subjects with the highest Omega-3 Index (>6.8%) with those with the those with the lowest Omega-3 Index (<4.2%):

  • Death from all causes was reduced by 34%
  • Incident cardiovascular disease was reduced by 39% (Remember that none of the subjects had been diagnosed with heart disease at the beginning of the study. This terminology simply means that they received a new diagnosis of heart disease during the study.)
  • Cardiovascular events (primarily heart attacks) were reduced by 42%
  • Strokes were reduced by 55%.

There were two other interesting observations from the study:

  • There was no correlation between serum cholesterol levels and heart disease in this study.
  • The authors estimated that it would require an extra 1300 mg of omega-3s/day, either from a serving of salmon or from fish oil supplements, to bring the membrane Omega-3 Index from the lowest level in this study to an optimal level.

The authors concluded that Omega-3 Index should be measured routinely as a risk factor for heart disease and should be corrected if it is low.

 

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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Comments (7)

  • EROCA

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    A share button would make it easier to show others.

    Reply

    • Dr. Steve Chaney

      |

      Dear Eroca,

      Good idea, but not sure how to make that happen. I will have to check with my IT guru.

      Dr. Chaney

      Reply

  • Joann Miley

    |

    This information really told the truth about omega 3’s and I totally feel that was the best explanation I have ever read.

    I sincerely thank you for your expertise and sharing this valuable information to us. I firmly believe the omega 3’s have been a benefit to me. Thank you, Keep up your excellent work.
    Joann Miley

    Reply

  • Joann Miley

    |

    thank you

    Reply

  • William Byrne

    |

    GREAT N/L information….all good stuff to keep us healthy and going. personally I love our “heart healthy” products…..especially now at almost 80, indeed I need a strong heart….one that can carry me through an intense match of tennis….one that can sustain my interest and need to exercise…or just a heart strong enough to take on the daily stresses of life in general. So yes…I LOVE THE OMEGAS as well as any Shaklee preparations related to HEART HEALTH.

    Reply

  • William Byrne

    |

    THE OMEGAS…WHY A LL THE CONTROVERSY??? ITS PROVEN ISN’T IT? INDEED QUALITY.. AND .HARVESTING OF THE CLEAN FISH ALL PLAY AN IMPORTANT ROLE IN RESULTS (OR NOT) WE RECEIVE FROM SUPPLEMENTING OUR DIET WITH FISH OIL. PERSONALLY I AM ALL FOR IT ESPECIALLY WHEN MY DOCTOR SAYS I AM IN GOOD SHAPE AND THAT I MAKE GOOD BLOOD. A LARGE PART, I BELIEVE, DUE TO CONSISTENCY BOTH WITH STRENGTH / AEROBIC EXERCISE AS WELL AS TAKING A GOOD QUALITY PURE OMEGA 3
    FOR MANY YEARS. RARELY MISSING MY OPPORTUNITY TO CONTINUE TO BUILD NEW HEART HEALTH. EVEN AT THE RIPE OLD AGE OF 79.

    Reply

    • Dr. Steve Chaney

      |

      Dear William,

      Yes. Omega-3s are part of the puzzle, but so is exercise and a good diet. Keep up the good work!

      Dr. Chaney

      Reply

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Latest Article

Does Protein Supplement Timing Matter?

Posted May 15, 2018 by Dr. Steve Chaney

How Do You Gain Muscle Mass & Lose Fat Mass?

Author: Dr. Stephen Chaney

 

protein supplement timingMost of what you read about protein supplements on the internet is wrong. That is because most published studies on protein supplements:

  • Are very small
  • Are not double blinded.
    • Both the subjects and the investigators knew who got the protein supplement.
  • Are done by individual companies with their product.
    • You have no idea which ingredients are in their product are responsible for the effects they report.
    • You have no idea how their product compares with other protein products.
    • There is no standardization with respect to the amount or type of protein or the addition of non-protein ingredients.

Because of these limitations there is a lot of misleading information on the benefits of protein supplements timing and maximal benefit. Let’s start by looking at why people use protein supplements. Let’s also look at what is generally accepted as true with respect to the best supplement timing.

There are 4 major reasons people consume protein supplements:

  • Enhance the muscle gain associated with resistance training: In this case, protein supplements are customarily consumed concurrently with the workout.
  • Preserve muscle and accelerate fat loss while on a weight loss diet: In this case, protein supplements are customarily consumed with meals or as meal replacements.
  • Provide a healthier protein source. In this case, protein supplements are customarily consumed with meals in place of meat protein.
  • Prevent muscle loss associated with aging or illness. There is no customary pattern associated with this use of protein supplements.

How good are the data supporting the customary timing of protein supplementation? The answer is: Not very good. The timing is based on a collection of weak studies which do not always agree with each other.

The current study  (J.L. Hudson et al, Nutrition Reviews, 76: 461-468, 2018 ) was designed to fill this void in our knowledge. It is a meta-analysis that compares all reasonably good studies that have looked at the effect of protein supplement timing on weight gain or loss, lean muscle mass gain, fat loss, and the ratio of lean muscle mass to fat mass.

How Was The Study Done?

The authors started by doing a literature search of all studies that met the following criteria:

  • The study was a randomized control trial with parallel design. This means that study contained a control group. It does not mean that the investigators or subjects were blinded with respect to which subjects used a protein supplement and which did not.
  • The subjects were engaged in resistance training.
  • The study lasted 6 weeks or longer.
  • Reliable methods were used to measure body composition (lean muscle mass and fat mass).
  • The subjects were healthy and at least 19 years old.
  • There was no restriction on the food the subjects consumed.

The authors started with 2074 published studies and ended up with 34 that met all their criteria. They then separated the studies into two groups – those in which the protein supplements were used with meals and those in which the protein supplements were used between meals.

Both groups were diverse.

  • Group 1 included subjects who consumed their protein supplement with their meal and those who consumed their protein supplement as a meal replacement.
  • Group 2 included subjects who consumed their protein supplement concurrent with exercise (usually immediately after exercise) and those who consumed their protein supplement at a fixed time of day not associated with exercise.

Does Protein Supplement Timing Matter?

 

protein supplement timing workoutsBecause the individual studies were very diverse in the way they were designed, the authors could not calculate a reliable estimate of how much lean muscle mass was increased or fat mass was decreased. Instead, they calculated the percentage of studies showing an increase in lean muscle mass or a decrease in fat mass.

When the authors compared protein supplements consumed with meals versus protein supplements consumed between meals:

  • Weight gain was observed in 56% of the studies of protein supplementation with meals compared to 72% of the studies of protein supplementation between meals. In other words, protein supplements consumed with meals were less likely to lead to weight gain than protein supplements consumed between meals.
  • An increase in lean muscle mass was observed in 94% of the studies of protein supplementation with meals compared to 90% of the studies of protein supplementation between meals. In other words, timing of protein supplementation did not matter with respect to increase in muscle mass.
  • A loss of fat mass was observed in 87% of the studies of protein supplementation with meals compared to 59% of the studies of protein supplementation between meals. In other words, protein supplements consumed with meals were more likely to lead to loss of fat mass.
  • An increase in the ratio of lean muscle mass to fat mass was observed in 100% of the studies of protein supplementation with meals compared to 87% of the studies of protein supplementation between meals. In short, protein supplements consumed with meals were slightly more likely to lead to an increase in the ratio of lean muscle mass to fat mass.

The following seem to suggest protein supplement timing matters:

The authors pointed out that their findings were consistent with previous studies showing that when protein supplements are consumed with a meal they displace some of the calories that otherwise would have been consumed. Simply put, people naturally compensate by eating less of other foods.

In contrast, the authors stated that previous studies have shown that when foods, especially liquid foods, are consumed as snacks (between meals), people are less likely to compensate by reducing the calories consumed in the next meal.

The others concluded: “Concurrently with resistance training, consuming protein supplements with meals, rather than between meals, may more effectively promote weight control and reduce fat mass without influencing improvements in lean [muscle] mass.”

What Are The Limitations Of The Study?

Meta-analyses such as this one, are only as good as the studies included in the meta-analysis. Unfortunately, most sports nutrition studies are very weak studies. Thus, this meta-analysis is a perfect example of the “Garbage In: Garbage Out (GI:GO)” phenomenon.

For example, let’s start by looking at what the term “protein supplement” meant.

  • Because the studies were done by individual companies with their product, the protein supplements in this meta-analysis:
    • Included whey, casein, soy, bovine colostrum, rice or combinations of protein sources.
    • Were isolates, concentrates, or hydrolysates.
    • Contained various additions like creatine, amino acids, and carbohydrate.
  • As I discuss in my book, Slaying the Food Myths, previous studies have shown that optimal protein and leucine levels are needed to maximize the increase in muscle mass and decrease in fat mass associated with resistance exercise. However, neither protein nor leucine levels were standardized in the protein supplements included in this meta-analysis.
  • Previous studies have shown that protein supplements that have little effect on blood sugar levels (have a low glycemic index) are more likely to curb appetite. However, glycemic index was not standardized for the protein supplements included in this meta-analysis.

protein supplement timing workout peopleIn short, the conclusions of this study might be true for some protein supplements, but not for others. We have no way of knowing.

We also need to consider the composition of the two groups.

  • Protein supplements used as meal replacements are more likely to decrease weight and fat mass than protein supplements consumed with meals. Yet, both were included in group 1.
  • Some studies suggest that protein supplements consumed concurrent with resistance exercise are more likely to increase muscle mass than protein supplements consumed another time of day. Yet, both are included in group 2. We also have no idea whether the meals with protein supplements in group 1 were consumed shortly after exercise or at an entirely different time of day.

This was the most glaring weakness of the study because it was completely avoidable. The authors could have grouped the studies into categories that made more sense.

In other words, there are multiple weaknesses that limit the predictive power of this study.

What Can We Learn From This Study?

Despite its many limitations, this study does remind us that protein supplements do have calories. This is of relatively little importance for people whose primary goal is to increase lean muscle mass.

However, most of us are using protein supplements to lose weight or to increase our lean mass to fat mass ratio. Simply put, we are either trying to lean out (shape up) or lose weight. And, we want to lose that weight primarily by getting rid of excess fat. For us, calories do matter. With that in mind:

  • If we are consuming a protein supplement immediately after exercise or between meals we probably should make a conscious effort to reduce our daily caloric intake elsewhere in our diet.
  • Alternatively, we could consume the protein supplement with a meal, but time the meal so it occurs shortly after exercise.

 

The Bottom Line:

 

A recent study looked at the optimal timing of protein supplements consumed by subjects who were engaged in resistance exercise. Specifically, the study compared protein supplements consumed with meals versus protein supplements consumed between meals on weight, lean muscle mass, fat mass, and the ratio of lean muscle mass to fat mass. The study reported:

  • Protein supplements consumed with meals were less likely to lead to weight gain than protein supplements consumed between meals.
  • Timing of protein supplementation did not matter with respect to increase in muscle mass.
  • Protein supplements consumed with meals were more likely to lead to loss of fat mass.
  • Protein supplements consumed with meals were slightly more likely to lead to an increase in the ratio of lean mass to fat mass.

The authors pointed out that their findings were consistent with previous studies showing that when a protein supplement was consumed with a meal it displaces some of the calories that would have been otherwise consumed. Simply put, people naturally compensate by eating less of other foods.

In contrast, the authors said that previous studies have shown that when foods, especially liquid foods, are consumed as snacks (between meals), people are less likely to compensate by reducing the calories consumed in the next meal.

As discussed in the article above, the study has major weaknesses. However, despite its many weaknesses, this study does remind us that protein supplements do have calories. This is of relatively little importance for people whose primary goal is to increase lean muscle mass.

However, for those of us who are using protein supplements to lose weight or to increase our lean mass to fat mass ratio, calories do matter.  With that in mind:

  • If we are consuming a protein supplement immediately after exercise or between meals we probably should make a conscious effort to reduce our daily caloric intake elsewhere in our diet.
  • Alternatively, we could consume the protein supplement with a meal, but time the meal so it occurs shortly after exercise.

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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