Tag Archive for: atrial fibrillation

Fish Oil: Reserve Judgment

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Let’s put the fish oil study from Tuesday in perspective. The most important thing is that observational studies such as these cannot demonstrate cause and effect. That’s not just a way to weasel out of making definitive statements; it’s because while fish oil supplements are associated in some way with atrial fibrillation in people who have no diagnosed heart disease, it may be something else that people who take fish oil supplements do that’s actually the culprit. Remember the hazard ratio (HR) was only 13%. What were the remaining 87% doing that was different?

The Problems

As I see it, these were the problems with this research paper.

Just as in the multivitamin study, researchers collected a whole host of dietary data and didn’t use much of it; they adjusted for those who ate oily and un-oily fish, but that was it. Fruit intake, vegetable intake, fiber intake, and a whole lot more dietary factors that have been shown to limit the development of cardiovascular disease were not considered. That may have impacted the HR.

The major problem was that they didn’t report the rate of AFib in those who did not take fish oil supplements. How can you not? What happens to those who do not take fish oil supplements could have provided comparison groups, which seems like a better analysis to conduct. No explanation. They just chose not to do it.

The final critique is that this study was conceived and executed by statisticians and epidemiologists. There were no nutrition experts on the team reported in the paper. I don’t know how that’s possible. If you’re considering a nutritional intervention, such as taking a fish oil supplement, there has to be someone who understands nutrition to consider other factors. It can’t be all statistics without thoughtful guidance.

The Big Question

How? How would fish oil supplements cause the development of AFib?

Research has shown that eating oily fish does not appear to cause AFib. Why would fish oil? The researchers cited a couple of possibilities having to do with an impact on channels that control electrical pathways but overall, no one has given any explanation.

This was not the first study that has examined fish oil supplements in large studies and found some relationship with AFib; there are also several that show no relationship at all. In this case, we have to reserve judgment because we can’t prove things either way.

The Bottom Line

What should you do? First, eat the healthiest diet you can and exercise regularly, because lifestyle is more important than supplements. Second, if you have already been diagnosed with CVD as I have—a stent more than 20 years ago—taking fish oil may be beneficial. If you’re under 60, it seems taking fish oil isn’t an issue and there’s no reason to stop. If you’re older than 60, should you begin to take fish oil supplements? It’s a matter of choice. I have to reserve judgment for now.

Next Tuesday is our primary election day in Michigan, and I’m taking the day off—I’m an election worker—but you’ll still get a Memo that goes into questions on this fish oil issue. There’s more to consider and I’ll let you know what those issues are.

What are you prepared to do today?

        Dr. Chet

Reference: BMJMED 2024;3:e000451.doi:10.1136/ bmjmed-2022-000451

Fish Oil and Atrial Fibrillation

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Researchers recently published an observational study on over 415,000 subjects in the UK Biobank database who took a fish oil supplement. During a follow-up period of almost 12 years, they statistically demonstrated a 13% increased hazard ratio (a measure over time of how often a particular event happens in one group compared to another group) in the development of atrial fibrillation in subjects. Atrial fibrillation is a type of arrhythmia, or abnormal heartbeat, that can result in extremely fast and irregular beats from the upper chambers of the heart. In those subjcts, there was a 5% increased risk of stroke.

The resultant impact was an attack on dietary supplements for being too easily available, leading to overconsumption, and questionable because of the lack of purity in dietary supplements. The Medscape Cardiology online section put out a video by a reputable researcher explaining who should take fish oil supplements. But if they’re so bad, why would she recommend them at all?

The other part of the results showed that if someone already had cardiovascular disease (CVD), the hazard ratio of developing major cardiac events was reduced if they took fish oil supplements. That’s why the expert made the video, taking the good and trying to make sense of it. Still, it gave the appearance of being a pitch for a pharmaceutical solution.

That’s the set-up for this week’s Memos. I’ll give you at least one of the questions you might have: Yes, this study tested only supplement use (and dietary intake) upon entrance to the study and nothing the rest of the 11.9 years, just like the multivitamin study from last week. But there’s so much more that I’ll cover on Saturday about the problems with this study. Just so you know, I’m still taking my fish oil supplements.

What are you prepared to do today?

        Dr. Chet

Reference: BMJMED 2024;3:e000451.doi:10.1136/ bmjmed-2022-000451

Aging Stressor: The Cardiovascular System

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The next three Memos before Christmas will identify the three major stressors of aging as I see them and the general solution to them. The first stressor of aging is the changes to the cardiovascular system (CV). Cells wear out in all systems at all ages, but there are some that stop replacing and repairing themselves in the CV. A few examples:

  • The sino-atrial node is the pacemaker of the heart. As we get older, some of the specialized nerve cells of this area are not replaced. That can cause abnormal heart rhythms such as atrial fibrillation.
  • The arteries can become less pliable, called arteriosclerosis, which can cause an increase in blood pressure. (Atherosclerosis, the buildup of plaque in arteries, can be considered a special type of arteriosclerosis and can happen at any age depending on genetics and lifestyle.)
  • The heart muscle can get damaged and be replaced with scar tissue. That automatically weakens the heart, which pumps less blood (called the ejection fraction) and reduces fitness levels.

The solution? CV exercise, also called aerobic exercise: walking, riding an exercise bike, swimming or water aerobics, or pulling a sleigh (just checking to make sure you’re reading.) It doesn’t matter which mode you choose as long as you move your body for 30 to 45 minutes per day most days of the week. You can’t reverse every effect of aging on the CV and other systems, but nothing impacts every system of the body like exercise does. Aging with a vengeance requires aerobic exercise within the limitations you currently have, and the younger you start, the more successful you’ll be.

What are you prepared to do today?

        Dr. Chet

Omega-3s and A-Fib: More Analysis Required

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I hope that you took the time to review the paper on atrial fibrillation as well as the research letter on omega-3s and atrial fibrillation. If you haven’t, especially the primer on A-fib, please do it. It’s a serious condition that requires attention if you have it; in most cases, fixing it is surprisingly simple.

The research letter included five studies. I decided to look at each of those research papers individually to see how each trial was conducted, especially on the populations used in those experiments. Here’s what I found.

The Subjects

The subjects in the studies had several characteristics in common. First, they were, on average, in their mid 60s and older. Second, they had already had a myocardial infarction (heart attack) or were at high risk for cardiovascular disease due to factors such as obesity, hypertension, elevated triglycerides, and others. Third, most were taking multiple medications.

They definitely were not healthy and free of disease. The potential for a cardiac event increases if you’ve already had a cardiac event. On top of that, in the trials that used prescription fish oils, the attempt was to lower triglycerides in those patients who were taking a maximal dose of statins. There may be some interaction that hasn’t been identified yet between very high doses of omega-3s, equal to or greater than four grams, and statin medications or other pharmaceuticals the patients were taking to control blood pressure, heart rate, etc.

In short, this does not apply to everyone. In fact, in the concluding statement of the research letter, the researchers state that physicians should be cautious when prescribing high-dose omega-3s in patients with high triglycerides and an increased risk of cardiovascular disease.

Additional Analyses

As I alluded to in the prior paragraphs, I think the analysis should include factors such as exercise, diet, and especially prescription medications. It may be that the number of subjects might not be able to be broken down by statin intake, beta blocker intake, or ace inhibitors, but I think that it should at least be examined to see if there’s any trend.

Also, the data could be separated into those people who’ve had a heart attack and those that haven’t, even though they may have significant risk factors for cardiovascular disease. After a heart attack, there may be morphological changes such as damage to nerve conduction or the buildup of scar tissue that could impact how omega-3s impact the heart itself.

Are all of these possible? I would think it would be with over 150,000 subjects from all the studies included in the meta-analysis.

Two More Things

I still have not found a single nutritionist involved in any of this research. When you look at prior studies that seemed to benefit heart rhythms, it’s DHA omega-3, not EPA, which is the factor related to better heart rhythms.

Take a look at the map that’s in the primer on atrial fibrillation. It applies to those on Medicare who are 65 and older, but there’s an amazing and obvious trend. I’m even going to give it a name; I’ll tell you that next Tuesday. The only clue that I’ll give you is to think maps and what they’re typically used for.

The Bottom Line

While interesting, the Research Letter on the update of omega-3s in relation to atrial fibrillation leaves more questions than answers. So far, it applies only to people over 65 with high triglycerides and other risk factors for cardiovascular disease. If you already take omega-3 fatty acids, there’s probably no reason to stop, but it’s a discussion you should have with your physician.

It’s also obvious that if you do have high triglycerides, you can work on changing that by changing your diet first. Reducing refined carbohydrates is the key; eating more vegetables helps as well.

It always comes back to this: eat better. Eat less. Move more.

What are you prepared to do today?

        Dr. Chet

References:
1. European Heart Journal – CVD Pharm. 2021 doi:10.1093/ehjcvp/pvab008
2. Curr Atheroscler Rep. 2020. https://doi.org/10.1007/s11883-020-00865-5
3. Atrial Fibrillation Primer. https://www.cdc.gov/heartdisease/atrial_fibrillation.htm

Research Update on Omega-3s and A-Fib

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A recent research letter to The European Heart Journal caught my attention. This was a continuing meta-analysis of data linking the use of omega-3 fatty acids to atrial fibrillation. The result of the original analysis in 2020 and the additional studies that were examined in the current meta-analysis led to the conclusion that there’s an increased risk of atrial fibrillation for those who take omega-3 fatty acids. That seemed surprising to me because prior research suggests that there’s a reduced risk of fibrillation in those that use omega-3 fatty acids.

To quote Vince Lombardi, “What the heck is going on around here!”

The concern by the research group seems to be focused on the current recommendations for high-dose prescription fish oil for elevated triglycerides. The problem is that the original meta-analysis that included 14 studies did not just use prescription fish oil; it used fish oil from dietary supplements as well. While the current update seemed to focus on the prescription omega-3s, it also used margarines enhanced with vegetarian-sourced omega-3s.

What are we supposed to do? Dig deeper. Do the results apply to everyone? No. Are there other potential problems with these studies? Yes, and I’ll cover those on Saturday. Until then, if you want a primer on atrial fibrillation, read the link in Reference 3; pay close attention to the map. You can also read the Research Letter by checking out reference 1; it’s open access.

What are you prepared to do today?

        Dr. Chet

References:
1. European Heart Journal – CVD Pharm. 2021 doi:10.1093/ehjcvp/pvab008
2. Curr Atheroscler Rep. 2020. https://doi.org/10.1007/s11883-020-00865-5
3. Atrial Fibrillation Primer. https://www.cdc.gov/heartdisease/atrial_fibrillation.htm

Interaction Between Food and Blood Thinners

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Blood thinners are the second most common medication that can interact with food and supplements. Blood thinners such as warfarin are used to prevent blood clots in people with atrial fibrillation, artificial heart valves, and deep vein thrombosis.

When a blood thinner is prescribed, people are given a list of foods and supplements to avoid. Top of the list is vitamin K and foods that contain vitamin K such as green leafy vegetables. Herbs such as garlic and ginkgo, supplements that contain vitamin E, coenzyme Q10, and omega-3 fatty acids are also discouraged because they may make the blood thinner. The goal is to optimize the international normalized ratio (INR), a measure of clotting ability. It isn’t that those types of patients have blood that coagulates more than normal; the theory is that keeping vitamin K from interfering with the blood thinner will reduce the probability of clots.

The problem: the recommendations are not supported by definitive research; it’s more a matter of playing it safe based on the theory of what the nutrients will do rather than actually based on science. In a recent review article, the authors concluded: “Restriction of dietary vitamin K intake does not seem to be a valid strategy to improve anticoagulation quality with vitamin K antagonists. It would be, perhaps, more relevant to maintain stable dietary habits, avoiding wide changes in the intake of vitamin K.” I absolutely agree.

What do you do? First, decide what diet you want to eat and supplements you want to take and stick to it. Second, work with your physician to adjust the blood thinner to get the dosage just right to keep your INR within range. Third, if you can’t get it normalized, there may be other factors as yet unknown that are affecting clotting. You’ll have to stick to the common recommendations, science-based or not.

Last chance to become an Insider and listen to tonight’s free conference call and get your health questions answered. You can learn more and join at this link.

What are you prepared to do today?

Dr. Chet

 

Reference: Medicine (Baltimore). 2016 Mar;95(10):e2895.