Diet for Atrial Arrhythmias: No Fibbing

Jeanette Brooks: Hi there and welcome to Medicine with a Fork, from the educational nonprofit Gaples Institute. Our mission is to advance the role of nutrition and lifestyle in medicine. I'm Jeanette Brooks, the Director of E-Learning Experience for the Gaples Institute, and with me today is our executive director, Dr Stephen Devries. He's a preventive cardiologist who is also a faculty member in the Department of Nutrition at the Harvard T.H. Chan School of Public Health. Steve, thanks for being with us today.

Stephen Devries, MD: Oh, great to be with you.

Brooks: So we're covering something today that physicians are seeing more of in recent years, and that is atrial fibrillation. And one of the things we want to drill down to is how a patient's diet can affect AFib. But first let's get the lay of the land here, Steve. Just how common is atrial fibrillation?

Devries: Well, it's actually the most common of all the sustained arrhythmias. And the prevalence continues to increase. Interestingly, the lifetime risk of atrial fibrillation is more than 20%. By 2030 it's estimated that atrial fibrillation will affect over 12 million individuals in the United States. So, it's quite a problem, and the problem is growing.

Brooks: And why the uptick? What's causing that prevalence to rise?

Devries: There's several reasons. First and foremost is the increased prevalence of overweight and obesity, and along with those problems come associated type 2 diabetes. In addition, there's more individuals than ever living with a wide range of chronic diseases. And these include cardiovascular, pulmonary, renal disease. And we know that atrial fibrillation is often the bottom of the funnel, that it is the end result of living with these multi-system diseases.

Brooks: Okay. So let's talk about that connection to diet. Atrial fibrillation isn't something that folks often associate with food, right? So it's intriguing to think about a patient's food choices having some influence here. Are there specific dietary patterns that are helpful for preventing AFib?

Devries: Absolutely. A recent study showed that individuals who were most adherent to a Mediterranean-style diet with a special callout for nuts, vegetables, and fruit—they had actually a one- third lower risk of atrial fibrillation compared to those who ate less healthfully.

It's interesting that analysis of the data from one of the landmark studies of the Mediterranean diet, which is PREDIMED—this was a study of the Mediterranean diet for primary prevention—identified extra-virgin olive oil as a prominent feature of the Mediterranean diet that was especially linked to lower rates of atrial fibrillation.

It's interesting to think about why that would be the case. And it's not really clear why those particular foods—fruits, vegetables, nuts, extra-virgin olive oil—were especially associated with reduced risk. But the one thing they have in common is that they're all dense in phytochemicals that have strong antioxidant and anti-inflammatory properties.

Another dietary issue is that there's an increased risk of atrial fibrillation related to intake of salt. And the mechanism of that isn't very clear, but very likely involves a blood-pressure-raising effect with especially high intake of salt.

Brooks: What about alcohol, Steve? We've all heard about “holiday heart.” Is there truly a connection between alcohol intake and atrial fibrillation?

Devries: Yes, and some individuals for sure can be especially sensitive to alcohol. Even a single drink can trigger arrhythmias. On average, we know that those who consume more alcohol and those, say, an average of two alcohol alcoholic drinks per day, are at very significantly increased risk for atrial fibrillation, up to 40% increased risk for two or more drinks per day.

The idea of why alcohol is related to atrial fibrillation is one that's really interesting and likely a few things going on there. One is alcohol has a direct toxic effect on cardiac muscle. Alcohol can increase inflammation and contribute to hypertension, which we know is a strong risk factor associated with atrial fibrillation.

Brooks: And 40% is really a remarkable jump.

Devries: Absolutely. Yeah, the link to alcohol consumption is pretty clear.

Brooks: So speaking of beverages, there's another drink that I'm wondering about. You and I had talked in a recent podcast about coffee and how it has some notable health benefits, but is caffeine a trigger for arrhythmias? Should coffee be avoided in order to prevent atrial fibrillation?

Devries: Great question, and certainly there are some individuals who are really sensitive to caffeine and even small intakes will cause palpitations, possibly even trigger atrial fibrillation. But surprisingly, for the vast majority, there doesn't seem to be a link between typical patterns of caffeine consumption and atrial fibrillation.

In fact, what is really surprising is that several studies show a protective effect to reduce the risk of atrial fibrillation associated with more modest intakes of coffee, say on the order of two to three cups per day. So for the vast majority of people, not a problem, and modest intakes may even be helpful to prevent atrial fibrillation.

Brooks: All right, so that's good news for most of us. So we've talked a bit about diet quality. I'd like to circle back to something you mentioned earlier, and that is overweight and obesity. It sounds like there's a connection between these conditions and the risk of developing atrial fibrillation. Can you talk a little bit more about that?

Devries: Yes, that is certainly an issue. Overweight and obesity are clearly associated with the risk of new-onset AFib, as well as, for those who have paroxysmal atrial fibrillation, a greater burden of atrial fibrillation and higher likelihood of conversion to permanent atrial fibrillation.

Brooks: So what is it about excess weight that seems to promote AFib?

Devries: Interestingly, excess weight is closely linked to an increase in left atrial size and left atrial volume. Additionally, these conditions are associated with increased amounts of adipose tissue that actually infiltrate the pericardium as well as the walls of the atria themselves. And very importantly, with weight loss, left atrial size and volume decrease as does pericardial fat.

Brooks: That is interesting. So, sounds like getting to a healthy weight is a good move, not surprisingly. If a patient with AFib does lose weight, how effective is that in reducing their risk?

Devries: It's a really important move to make. For example, a study of patients with atrial fibrillation— this one had an average BMI of 33 and an average weight of 220 pounds—weight loss of 10% or greater was associated with a sixfold increased probability of living arrhythmia-free, compared to those with minimal weight loss. So if you can get to 10% or more weight loss, that's a really big deal.

Brooks: Yeah, it sounds like it. Okay, so beyond eating a healthy diet and getting to a healthy weight, can you also speak to other things that might help reduce the risk of atrial fibrillation?

Devries: Yes, there are several other factors that can be addressed and an important and sometimes overlooked one is obstructive sleep apnea. And it can be hard to diagnose in this population because many who suffer from sleep apnea are not overweight and they may not complain of daytime somnolence that we typically associate with sleep apnea.

So for that reason, someone who's undergoing evaluation for atrial fibrillation, it would be a very reasonable move to consider a sleep study. And the good news is that if they're found to have sleep apnea, treating that does decrease the risk of atrial fibrillation.

Smokers have double the risk of atrial fibrillation compared to those who don't smoke, and smoking cessation definitely helps to maintain sinus rhythm.

In addition, control of blood pressure and glycemia are also important and they can also reduce the likelihood of atrial fibrillation.

And the last category to address is physical activity. Moderate physical activity is also protective against atrial fibrillation. So that's a really important part to add to a lifestyle program. A regular practice of yoga can be beneficial to reduce recurrent atrial fibrillation—in one study, interestingly, a twice-weekly practice of yoga for one hour per session reduced the episodes of paroxysmal atrial fibrillation by nearly 50%.

Brooks: Wow. I love that about yoga. Fifty percent reduction is amazing. Steve, I know that patients with recurrent atrial fibrillation are often referred for an ablation procedure. How important is weight loss and other lifestyle changes after an ablation?

Devries: A really important question. Even after an ablation procedure where the initial success rate can be upwards of 70%, lifestyle modification still plays a major role to ensure the durability of those results. One large study of patients, all of whom had an ablation procedure, showed that those who enrolled in a lifestyle modification program for about three and a half years had nearly fivefold greater chance of living without arrhythmias compared to controls.

Now in that study, the lifestyle intervention group lost an average of about 13% of their initial body weight, which translated to about 30 pounds on average. In addition, most in the lifestyle modification group stopped smoking, were treated for sleep apnea, and significantly lowered their alcohol intake.

So that kind of points to the importance of an all-around lifestyle modification program that includes close attention to diet as well as some of the other factors that we talked about.

Brooks: And that's so significant, right? That combined benefit—the procedure and the lifestyle change—is so much more powerful than just one or the other.

Devries: Exactly.

Brooks: All right we've covered a lot of ground about ways to address atrial fibrillation, some of which are surprisingly low-tech and effective. Do you have any other closing thoughts to leave us with on this topic?

Devries: Absolutely. When you think about atrial fibrillation, I think most people agree it can be a very challenging issue to manage for sure. But what the data we talked about today so vividly points out is that despite all the huge gains that have been made with high-tech pharmaceuticals and procedures, that close attention to nutrition and lifestyle are absolutely essential for optimal results.

Brooks: For sure. Thank you so much, Steve.

Devries: It's been a pleasure. Thank you, Jeanette.

Brooks: Yeah, and for those of you who are listening who want to learn more about how diet and lifestyle can be remarkably effective in all aspects of patient care, we invite you to check out the nonprofit Gaples Institute's interactive nutrition course for clinicians.

It's a four-credit CME course that goes way beyond just biochemistry and gives practical, realistic strategies for guiding patients toward better health. You can learn more at NutritionForDocs.org. And there is a discount available for AMA members who enroll. I'm Jeanette Brooks and on behalf of Steve and myself and everyone at the Gaples Institute, thank you for listening, and we look forward to joining you next time on Medicine With a Fork.

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Disclosure Statement: Unless noted, all individuals in control of content reported no relevant financial relationships.

If applicable, all relevant financial relationships have been mitigated.

Financial Support Disclosure Statement: Dr. Devries is the salaried executive director and Jeanette Brooks is the salaried director of e-learning for the Gaples Institute, an educational nonprofit that offers accredited continuing medical education courses for sale to health professionals. Courses are developed entirely through philanthropy to the Gaples Institute, a nonprofit that does not seek or receive corporate support. Neither Dr. Devries nor Jeanette Brooks receive royalties or personal consideration of any kind from the sale of these courses. This podcast was developed with no corporate support.