Omega-3 and Heart Disease Risk

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

Why Is There So Much Confusion About Omega-3 and Heart Disease Risk?

Author: Dr. Stephen Chaney

 

omega-3 heart diseaseConcerning omega-3 and heart disease, the pendulum keeps swinging. In the 1990’s several strong clinical studies showed that omega-3s reduced heart disease risk. In fact, a major clinical study in Italy, (Lancet 354: 447 – 455, 1999 , Circulation 105 : 1897 – 1903, 2002 ), found omega-3s to be just as effective as statin drugs for preventing heart attacks, but without any of the side effects of statins.

At that time, everyone was talking about the benefits of omega-3s in reducing heart disease risk. The American Heart Association recommended an intake of 500-1,000 mg/day of omega-3s for heart health. Some experts were recommending even more if you were at high risk of heart disease.

In the 2000’s the pendulum swung in the other direction. Several clinical studies found no benefit of omega-3s in reducing heart disease risk. Suddenly, experts were telling us that omega-3s were overrated. They were a waste of money. The American Heart Association kept their omega-3 recommendations for heart health, but put more emphasis on omega-3s for people with elevated triglycerides (where the benefits of omega-3s are non-controversial).

Suddenly regarding omega-3 and heart disease, the pendulum is swinging back again. A recent meta-analysis (Alexander et al, Mayo Clinic Proceedings, 92: 15-29, 2017) reported that omega-3s do appear to be beneficial at reducing heart disease risk. An editorial accompanying that article (O’Keefe et al, Mayo Clinic Proceedings, 92: 1-3, 2017) called the meta-analysis “the most comprehensive of its kind to date…” Those experts went on to say “…omega-3-fatty acid intake of at least 1 gram of EPA + DHA per day, either from seafood or supplementation (as recommended by the American Heart Association) continues to be a reasonable strategy.”

This was followed by publication of three clinical studies that came to essentially the same conclusion (Kieber et al, Atherosclerosis, 252: 175-181, 2016 ; Sala-Vila et al, Journal of the American Heart Association, In Press ; and Greene et al, American Journal of Cardiology, 117: 340-346, 2016 ).

Why is there so much confusion about omega-3 and heart disease? Let’s start by reviewing the recently published meta-analysis.

 

Do Omega-3s Lower Heart Disease Risk?

omega-3 lowers heart disease riskThis study (Alexander et al, Mayo Clinic Proceedings, 92: 15-29, 2017) combined the data from 18 randomized controlled trials with 93,000 patients and 16 prospective cohort studies with 732,000 patients. This was the largest meta-analysis on omega-3s and heart health performed to date. The results were as follows:

  • The combined data from the randomized controlled studies showed that omega-3 supplementation resulted in a non-significant 6% reduction in heart disease risk. This is similar to other recently published studies (more about that later).
  • However, when the investigators looked at high risk populations within the randomized controlled studies, the results were strikingly different.
    • In patients with elevated triglycerides, omega-3 supplementation caused a significant 16% reduction in heart disease risk.
    • In patients with elevated LDL cholesterol, omega-3 supplementation caused a significant 18% reduction in heart disease risk.
  • In addition, the combined data from the prospective cohort studies showed that omega-3 supplementation resulted in a significant 18% decrease in heart disease risk.

The authors concluded “[Our] results indicate that EPA + DHA may be associated with reducing heart disease risk, with greater benefits observed among higher-risk populations…”

 

Why Is There So Much Confusion About Omega-3s and Heart Disease Risk?

confusionThere are several major clinical studies in progress looking at the effect of omega-3s on heart health. Some experts predict that the confusion will be cleared up once they are published. I predict they will only add to the confusion. Let me explain why.

You’ve heard the old saying “Garbage in – garbage out.”  Proper design of clinical studies is essential. If a study is poorly designed, it provides incorrect information. When you analyze the previous clinical studies carefully, you find that many of them are flawed. Their results are, therefore, incorrect. My fear is that many of the ongoing clinical studies will contain the same flaws and will provide the same incorrect information.

Let’s look at the flaws, and why they provide incorrect information.

Flaw #1: Omega-3 supplementation will only be beneficial for people who are omega-3 deficient. The authors of the Mayo Clinic Proceedings editorial provided a useful analogy. They said: “Vitamin C bestows dramatic and lifesaving benefits to persons with scurvy, but is no better than placebo for persons who are replete with vitamin C.”

That means a well-designed study should measure omega-3 levels in red blood cells both prior to and at the end of the clinical study. The data analysis should focus on those individuals who started the study with low omega-3 status and whose omega-3 status improved by the end of the study. Unfortunately, few of the previously published studies have done that, and I am not confident that the ongoing studies have incorporated that into their experimental design.

Flaw #2: Omega-3 supplementation will be of most benefit for those people who are at highest risk for heart disease. This has been a recurrent pattern in the literature. Many of the clinical studies focusing on high-risk individuals have shown a beneficial effect of omega-3 supplementation on heart disease risk. Most of the studies focusing on the general population (most of which are of low risk for heart disease) have failed to show a benefit of omega-3 supplementation. The current meta-analysis is no exception. When they looked at the general population, there was a non-significant reduction in heart disease risk. However, when they looked at high-risk populations the beneficial effect of omega-3s was highly significant.

I can’t predict how the ongoing studies will analyze their data. If they focus on high-risk groups they are more likely to report a beneficial effect of omega-3s on heart health. If they only report on the results with the general population, they are likely to conclude that omega-3s are ineffective.

I do need to make an important distinction here. The inability to demonstrate a beneficial effect of omega-3 supplementation in the general population does not mean that there is no effect. It turns out to be incredibly difficult to demonstrate a beneficial effect of any intervention, including statins , in a healthy, low-risk population. Because of that, we may never know for sure about the relationship between omega-3 and heart disease. Do omega-3s reduce heart disease risk for the young and healthy. At the end of the day, you will need to make your own decision about whether omega-3s make sense to you.

omega-3 supplementationFlaw #3: Heart medications mask the beneficial effects of omega-3 supplementation. When the public hears about the results of a randomized controlled study they assume that the placebo group received no treatment and the omega-3 group was only receiving omega-3s. That is not how it works.  Medical ethics guidelines require that the placebo group receive the standard of care treatment – namely whatever drugs are considered appropriate for that population group.

That means that it has become very difficult to demonstrate that high-risk populations benefit from omega-3 supplementation. Back in the 90s, the standard of care for high risk patients was only one or two drugs. In those days, many studies were reporting beneficial effects of omega-3 supplementation in high risk populations. However, for the past 5-10 years the standard of care for high risk patients is 4-5 medications.

These are medications that reduce cholesterol levels, lower triglyceride levels, lower blood pressure, reduce inflammation, and reduce clotting time. In other words, the drugs mimic all the beneficial effects of omega-3s. (The only difference is that the drugs come with side-effects. The omega-3s don’t.) It is no coincidence that many of the recent studies have come up empty-handed.

The current studies are asking a fundamentally different question. In the 90s, clinical studies asked whether omega-3s reduced heart disease risk in high-risk patients. Today’s clinical studies are asking whether omega-3s provide any additional benefits for patients who are already taking multiple drugs. Personally, I think my readers are more interested in the first question than the second.

Once again, the current meta-analysis is perfectly consistent with this interpretation. The high-risk groups who clearly benefited from omega-3 supplementation were not ones with pre-existing heart disease or who had previously had a heart attack. They were the ones with elevated LDL cholesterol or triglycerides. They were patients who were, either not taking drugs for those risk factors, or patients for whom the drugs were ineffective.

Because subjects in future studies will be taking multiple medications, I predict that even those ongoing studies focusing on high-risk populations will come up empty-handed.

Now you understand why I started this section by saying that I predict many of the ongoing studies will provide incorrect results. I predict that you will see more headlines proclaiming that omega-3s don’t work. However, you won’t be swayed by those headlines because you now know the truth about the flaws in the clinical studies behind the headlines!

What Does This Mean For You?

omega-3 fish oilThe most recent meta-analysis and a careful evaluation of previous studies make two things clear:

  • If you are at high risk of heart disease, omega-3 supplementation is likely to reduce your risk.

We can divide risk factors for heart disease into those we know about, and those we don’t.

  • Risk factors we know about include previously diagnosed heart disease or heart attack, genetic predisposition, age, elevated LDL cholesterol levels, high triglycerides, high blood pressure, inflammation, obesity, metabolic syndrome and diabetes.
  • Unfortunately, there are also risk factors we don’t know about. For too many Americans the first sign of heart disease is sudden death – sometimes just after receiving a clean bill of health from their doctor.
  • If you are not getting enough omega-3s in your diet, omega-3 supplementation is likely to reduce your heart disease risk.

If you are young and healthy, the unfortunate truth is that we may never completely understand the relationship between omega-3 and heart disease. We may not know whether omega-3 supplementation reduces your risk of heart disease. However, I think the overall evidence is strong enough that you should consider adding omega-3s to your diet.

In short, I agree with the authors of the Mayo Clinic Proceedings editorial and the American Heart Association that omega-3-fatty acid intake of at least 1 gram of EPA + DHA per day, either from seafood or supplementation, is a prudent strategy for reducing heart disease risk.

 

The Bottom Line

  • There has been a lot of confusion about the role of omega-3s in reducing heart disease risk.
  • In the 90s, several clinical studies reported that omega-3 supplementation reduced heart disease risk. Most experts, including the American Heart Association, were recommending that most Americans would benefit from adding 500-1,000 mg of omega-3s to their daily diet.
  • In recent years, several clinical studies have reported that omega-3 supplementation has no effect on heart disease risk. [There were some important flaws in those studies, which I discuss in the article above]. Experts started saying that omega-3s were overrated. They were a waste of money.
  • The largest meta-analysis ever undertaken in this area of research has recently reported that omega-3 supplementation decreases risk of heart disease in high-risk population groups. Three subsequent clinical studies have come to essentially the same conclusion.
  • Other studies suggest that omega-3 supplementation is also likely to reduce heart disease risk in individuals with poor omega-3 status, and most Americans have poor omega-3 status.
  • We may never know whether omega-3 supplementation reduces heart disease risk if you are young and healthy. Simply put, not enough young & healthy people develop heart disease within the time-frame of a clinical study for the results to be statistically significant. For this group, the old saying about “An ounce of prevention…” just makes sense.
  • I agree with those experts who recommend at least 1,000 mg/day of omega-3s as a prudent strategy for reducing heart disease risk.
  • There are several major clinical trials in progress studying the efficacy of omega-3s for reducing heart disease risk. Some experts predict that the confusion will be cleared up once they are published. I predict they will only add to the confusion. I predict that many of those studies will show no benefit of omega-3 supplementation, and you will see more headlines proclaiming that omega-3s play no role in heart health. If you have read the article above, you won’t be swayed by those headlines because you will know the truth about the flaws in the studies behind the headlines.

 

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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Is Coconut Oil Bad For You?

Posted July 25, 2017 by Dr. Steve Chaney

Nutty About Coconut Oil

Author: Dr. Stephen Chaney

is coconut oil bad for youCoconut oil is the latest miracle food. Bloggers and talk show hosts are telling us how healthy it is. We are being told to cook with it, spread it on our toast, and put it in our smoothies. We are told to be creative. The more coconut oil you can get in your diet, the better.  But, is coconut oil bad for you?

The hype is working. 72% of the American public believes coconut oil is healthy. This is why the recent American Heart Association (AHA) Presidential Advisory on saturated fats has proven so controversial.

Interestingly, most of the AHA advisory was about the linkage between saturated fats from meat & dairy and heart disease risk. Only one paragraph of the 24-page report was devoted to coconut oil, but the AHA recommendation to avoid coconut oil generated the lion’s share of headlines.

What Did The AHA Presidential Advisory Say?

The AHA advisory concluded that saturated fats from meat and dairy foods increased the risk of heart disease. This conclusion was based on randomized clinical trials in which the diet was carefully controlled for a period of at least two years. More importantly, the conclusion was not based on LDL cholesterol, particle size, HDL cholesterol, inflammation or any other potential marker of heart disease risk. It was based on actual cardiovascular outcomes – heart attacks, strokes, deaths due to heart disease.

I have reviewed the AHA report in a previous issue of “Health Tips From the Professor,” Are Saturated Fats Bad For You, and have concluded their statement that saturated fats from meat and dairy increase the risk of heart disease was based on solid evidence. We can now say definitively that those saturated fats should be minimized in our diets.

 

Is Coconut Oil Bad For You?

 

coconut oil bad for heartIn contrast to the saturated fats in meat and dairy, there have been no studies looking at the effect of coconut oil on cardiovascular outcomes. Instead, the authors of the AHA report relied on studies measuring the effect of coconut oil on LDL cholesterol levels. There have been 7 controlled trials in which coconut oil was compared with monounsaturated or polyunsaturated oils.

  • Coconut oil raised LDL cholesterol in all 7 studies.
  • The increase in LDL cholesterol in these studies was identical to that seen with butter, beef fat, or palm oil.

This evidence makes it probable that coconut oil increases the risk of heart disease. However, LDL is not a perfect predictor of heart disease risk. The only way to definitively prove that coconut oil increases the risk of heart disease would be to conduct clinical studies in which:

  • Coconut oil was substituted for other fats in the diet.
  • All other dietary components were kept the same.
  • The study lasted at least 2 years.
  • Adherence to the “coconut oil diet” was monitored.
  • Cardiovascular outcomes were measured (heart attack, stroke, death from heart disease).

In short, one would need the same type of study that supports the AHA warning about saturated fats from meats and dairy. In the absence of this kind of study, there is no “smoking gun.” We cannot definitively say that coconut oil increases the risk of heart disease.

Is Coconut Oil Healthy?

coconut oil healthyDoes that mean all those people who have been claiming coconut oil is a health food are right? Probably not. At the very least, their health claims are grossly overstated.

Let’s start with the obvious. In the absence of any long-term studies on the effect of coconut oil on cardiovascular outcomes, nobody can claim that coconut oil is heart healthy. It might be, but it might also be just as bad for you as the saturated fats from meat and dairy. It’s effect on LDL cholesterol suggests it might increase your risk of heart disease, but we simply do not know for certain.

I taught human metabolism to medical students for 40 years. I was also a research scientist who published in peer reviewed journals. When I look at the health claims for coconut oil on the internet, I am dismayed. Many of the claims are complete nonsense. Others sound plausible, but are based on an incomplete understanding of human metabolism. None of them would pass peer review, but, of course, there is no peer review on the internet.

In addition, some of the claims have been “cherry picked” from the literature. For example, claims that coconut oil increases metabolic rate or aids weight loss are based on short-term studies and ignore long-term studies showing those effects disappear over time.

Let me review some of the more plausible-sounding claims for coconut oil.

  • Coconut oil increases HDL levels, which is heart healthy. The effects of HDL cholesterol are complex. Elevated HDL levels are not always heart protective.

For example, a few years ago a pharmaceutical company developed a drug that raised HDL levels. They thought they had a blockbuster drug. You didn’t need to exercise. You didn’t need to lose weight. You would just pop their pill and your HDL levels would go up. There was only one problem. When they did the clinical studies, their drug had absolutely no effect on heart disease risk. It turns out it is exercise and weight loss that reduce heart disease risk, not the increase in HDL associated with exercise and weight loss.

The implications are profound. Just because something increases HDL levels does not mean it will reduce cardiovascular risk. You have to actually measure cardiovascular risk before claiming something is heart healthy. That has not been done for coconut oil, so no one can claim it is heart healthy.

  • Coconut oil consists of medium chain triglycerides, which are absorbed more readily than other fats. That is true, but it is of interest to you only if you suffer from a fat malabsorption disease. Otherwise, it is of little importance to you.
  • Medium chain triglycerides are preferentially transported to the liver, where the fats in coconut oil are converted to energy or released as ketones rather than being stored as fat. This is partially true, but it is misleading for two reasons.
    • First, the fat in coconut oil actually has three possible fates in the liver. Some of it will be converted to energy, but only enough to meet the immediate energy needs of the liver. If carbohydrate is limiting, the excess will be converted to ketones and exported to other tissues as an energy source. If carbohydrate is plentiful, the excess will be converted to long chain saturated fats identical to those found in meat and dairy and exported to other tissues for storage.
    • Secondly, nobody has repealed the laws of thermodynamics. If the fat in coconut oil is being preferentially used as an energy source by the liver and being exported as ketones to other tissues as an energy source, you need to ask what happens to the calories from the other components in your diet. If you are eating a typical American diet, the carbohydrate that would have been used for energy will be converted to fat and stored. If you are eating a low carbohydrate diet, the other fats that would have been used for energy will simply be stored. Simply put, if you are preferentially using the calories from coconut oil for energy, the calories from the other foods in your diet don’t just evaporate. They are stored as fat.
  • Coconut oil increases metabolic rate, which will help you lose weight. When you look at the studies, this is only a temporary effect. This is due to a phenomenon called metabolic adaptation that is often seen when one makes a dramatic shift in diet composition. Initially, you may see an increase in metabolic rate and weight loss. After a few weeks, the body adapts to the new diet,and your metabolic rate returns to normal.
  • Coconut oil is metabolized to ketones which have many beneficial effects. There is some truth to this claim. As I discussed in my analysis of the keto diet,  ketones have some real benefits, but not nearly as many as proponents claim. Furthermore, the amount of ketones produced by coconut oil will depend on the availability of carbohydrate. Much of the coconut oil in the context of a very low carbohydrate diet will likely be converted to ketones. Coconut oil spread on a piece of bread or used in baking is more likely going to be converted to fat.

I could go on, but you get the point. The hype about the benefits of coconut oil sounds good, but is misleading. There may be some benefits, but in the absence of long-term studies we have no convincing evidence that coconut oil is good for us.

What Does This Mean For You?

coconut oil bad or goodWhen you started reading this article, you were probably hoping that I would settle the coconut oil controversy. Perhaps you were hoping that I would tell you the American Heart Association was right, and you should avoid coconut oil completely. More likely you were hoping I would tell you the coconut oil proponents were right and you could continue looking for more ways to incorporate coconut oil into your diet. As usual, the truth is somewhere in between.

Coconut oil may increase our heart disease risk, but the evidence is not definitive. We cannot say with certainty that coconut oil is bad for us. On the other hand, most of the hype about the benefits of coconut oil is inaccurate or misleading. We have no well-designed, long-term studies on health outcomes from coconut oil use. We cannot say with certainty that coconut oil is good for us.

I recommend moderation. Small amounts of coconut oil are probably alright. If you have a particular recipe for which coconut oil gives the perfect flavor, go ahead and use it. Just don’t add it to everything you eat.

Finally, there are other oils we know to be healthy that you can use in place of coconut oil. If you are looking for monounsaturated oils, olive oil and avocado oil are your best bets. Olive oil can be used in salads and low temperature cooking. Avocado oil is better for high temperature cooking. Also, less frequently mentioned, safflower and sunflower oils are also good sources of monounsaturated fats.

If you are looking for a mixture of monounsaturated and polyunsaturated fats, safflower oil, canola oil and peanut oil are your best bets. Peanut oil is also good for high temperature cooking.

Corn oil and soybean oil are your best sources of omega-6 polyunsaturated fats, while flaxseed oil is your best vegetable source of omega-3 polyunsaturated fats.

 

The Bottom Line

 

  • Coconut oil is the latest diet fad. It is highly promoted by the popular press, and 72% of Americans think it is healthy, even though it is a saturated fat.
  • The American Heart Association (AHA) has recently advised against the use of coconut oil because it likely increases the risk of heart disease and “has no offsetting beneficial effects.”  Because this statement is controversial, I have carefully analyzed the pros and cons of coconut oil use.
  • Coconut oil may increase our heart disease risk, but the evidence presented by the American Heart Association is not definitive. We cannot say with certainty that coconut oil is bad for us.
  • On the other hand, most of the hype about the benefits of coconut oil is inaccurate or misleading. We have no well-designed, long-term studies on health outcomes from coconut oil use. We cannot say with certainty that coconut oil is good for us.
  • I recommend moderation. Small amounts of coconut oil are probably alright. If you have a particular recipe for which coconut oil gives the perfect flavor, go ahead and use it. Just don’t add it to everything you eat.
  • For details of my analysis and suggestions for healthy fats you can substitute for coconut oil, 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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