A Mediterranean Diet for Optimal Heart Health: Extending the Results of ARREST-AF to All Our Patients

As electrophysiologists, we desire optimal health for our patients and maximum benefit from the procedures we perform. The ARREST-AF study demonstrated how aggressive risk factor modification (RFM) may improve atrial fibrillation (AF) ablation success by a factor of fivefold.¹ RFM targets included weight loss, blood pressure, glycemic control, and lipid profiles. Study patients attended a physician-directed RFM clinic every three months with face-to-face counseling for weight reduction. Meals consisted of high-protein and low glycemic index, calorie-controlled foods to achieve ≥10% weight loss and body mass index (BMI) ≤25 kg/m². If patients had lost <3% of weight after three months, very low-calorie meal replacement products were used for one to two meals per day. Low-intensity exercise was initially prescribed for 20 minutes three times weekly, increasing to ≥200 min of moderate-intensity activity per week.

This diet and exercise program improved each of the RFM targets, with additional angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) therapy to maintain BP <130/80 mmHg, a specialized diabetes clinic to maintain HbA1C ≤6.5%, and combination statin and fibrate therapy to maintain LDL <100 mg/dL and TG <200 mg/dL.¹ Significant atrial reverse remodeling accompanied RFM, including reduction in left atrial (LA) volume from 42.5 mL/m² to 30.4 mL/m², regression of LA fibrosis, improved endothelial function, and reduction of inflammatory markers at post ablation follow-up.²

Substituting a Mediterranean Diet

ARREST-AF highlighted the importance of successful RFM and the extent to which healthy living may reverse cardiac pathology. Like the ARREST-AF cohort, many of our patients follow unhealthy lifestyle patterns and are somewhat malnourished due to poor food choices, limited knowledge, and economic constraints. Unfortunately, the comprehensive RFM protocol of ARREST-AF is difficult to replicate in a community practice setting where specialty clinics providing regular in-person follow-up are not available. A Mediterranean diet has clearly demonstrated cardiovascular benefit, and our approach to RFM begins by helping patients adopt it as completely as possible.^3,4 We have developed detailed instructions and provide these as printouts as part of the after-visit summary generated by the EMR for each patient encounter (Table 1), including names and addresses of local stores carrying key ingredients (bulk raw nuts and certified-pure extra virgin olive oil [EVOO], such as Colavita^® [Figure 4]). Here we share resources developed by our clinic that may be useful for other practices seeking to improve RFM for their patients.

Benefits and Principles of a Mediterranean Diet

A Mediterranean diet has been associated with lower all-cause and cardiovascular disease (CVD) morbidity and mortality during 10-year follow-up which also occurred in those with ongoing unhealthy lifestyle characteristics (i.e., smokers, obese, and sedentary persons).³ Benefits were associated with a reduction in inflammatory markers suggesting mechanisms beyond an appropriate combination of nutrients. Similar results were confirmed in a group of 780 male firefighters, ages 18+ years from the Midwestern United States with improved metabolic syndrome score, LDL and HDL cholesterol, and diminished weight gain, demonstrating the effectiveness of this diet among younger working counterparts in non-Mediterranean countries.4 Both olive oil and mixed nuts were identified as key ingredients delivering cardiovascular benefits.^3,4 A Mediterranean diet supplemented with EVOO has also been shown to improve cognitive function.⁵ Associated structural changes include increased MRI-measured brain volume and cortical thickness compensating for approximately 5 years of aging.⁶ Supplementing with mixed nuts promotes weight loss with lower waist circumference and a shift towards more benign forms of LDL cholesterol (increased LDL size, decreased LDL particle number).⁷ Furthermore, a Mediterranean diet is associated with longer telomeres (repetitive DNA sequences at the ends of chromosomes that protect chromosomal integrity) predicting increased life expectancy and lower rates of age-related chronic diseases.⁸ Finally, a Mediterranean diet was recently shown to improve bone health and protect against osteoporosis-related fractures.⁹

While there is no set Mediterranean diet, the overarching theme is that of a plant-based, whole foods regimen. Ingredients are readily available and a Mediterranean diet may be adopted at reasonable cost. Fresh fruits and vegetables are emphasized, along with whole grains, beans, nuts, and olive oil.³ Only whole grain cereals (Figure 1A), breads (Figure 1B), pastas, and rice should be used. Fish is recommended at least twice per week (Alaskan/pacific salmon, trout, mackerel, and herring are healthy choices; grill, bake, or broil to prepare, while avoiding breaded or fried fish), low-fat dairy products only (skim milk, fat-free yogurt, low-fat cheese), and red meat no more than twice per month. A glass of red wine several days per week may accompany a traditional Mediterranean diet. Given recent findings, however, indicating that even a little alcohol may impair diastolic function, it may be more prudent to reserve alcohol for special occasions (such as a birthday) or to abstain entirely.¹⁰

Prescribing a Mediterranean Diet

Our prescription (Table 1) calls for starting the day by drinking two tall glasses of filtered water. After the first glass, we suggest eating a cupped handful of mixed nuts (Figure 1) followed by drinking one-half to one reamed lemon, for a variety of cardiovascular benefits and to promote total body alkalinity (Figure 3A).¹⁰ This is followed by whole grain cereal (Figure 2A) with almond or coconut milk, and unsweetened Greek yogurt as a source of probiotics.^12,13 The majority of meals and snacks throughout the day are obtained from a variety of fruits and vegetables. Dinner is completed by 6 pm, with no additional food or drink other than water prior to bedtime.

Fruits and Vegetables 

A diverse selection of fruits and vegetables is recommended. Fruits rich in antioxidants and representing major sources of flavonoids are emphasized, like apples, pears, blueberries, blackberries, raspberries, strawberries, cherries, and red grapes, as these promote healthy weight loss.¹⁴ For vegetables, we recommend a colorful variety including several avocados per week, as well as carrots, cucumbers, celery, radishes, beets, and bell peppers (red, orange, yellow, and green).¹⁵ Raw vegetables with hummus or nut butter are surprisingly satisfying and also frequently sufficient for a complete lunch or dinner. Seasoning with garlic and curcumin/turmeric is highly recommended given the anti-cancer properties of these spices.^16,17 Organic produce is of the highest priority, with all fruits and vegetables washed in a tub or sink with one cup of vinegar to remove bacteria and pesticides (Figure 3B).¹⁸

Olive Oil 

In prescribing a Mediterranean diet, studies frequently specified a minimum consumption of 50 mL/day (3 tablespoons/day) EVOO, and 30 grams daily of mixed nuts consisting of 50% walnuts, 25% almonds, and 25% hazelnuts.^7,8,19 Accordingly, we recommend that our patients consume 2-3 tablespoons daily of certified pure EVOO (Figure 4). EVOO may be used as salad dressing throughout the day or swallowed raw during breakfast, which many of our patients prefer, to help achieve an early sense of satiety to curb hunger later in the day.

Mixed Raw Nuts 

Nuts with the strongest evidence for cardiovascular benefit, such as walnuts, almonds, peanuts, and pistachios, are most desirable (Figure 1).²⁰ Most nuts are high in monounsaturated fatty acids (MUFAs), and walnuts are the only tree nut that contain a significant amount of omega-3 fatty acids (47% of total weight), which are a form of polyunsaturated fatty acids (PUFAs). Consumption of omega-3 fatty acids reduces the incidence of CVD, and particularly benefits those at risk for CAD.²¹ These benefits have largely been attributed to forms of omega-3s found in fish (EPA and DHA). Interestingly, the omega-3s found in walnuts are mainly linoleic acid and alpha-linolenic acid (ALA), with linoleic acid mimicking EPA and DHA as found in fish oil. In particular, walnut consumption reduces levels of apolipoprotein B, one of the most atherogenic lipid particles, likely accounting for much of the cardiovascular benefit.²²

The American Heart Association has given its “Heart-Check” designation to almonds, meaning that almonds are low in saturated fat and trans fat with ≥10% of the daily value in select nutrients. Almonds have been shown to lower LDL cholesterol in a dose-dependent manner while assisting in weight loss, reducing both belly fat and leg fat.²³ Pistachios have also been shown to reduce total and LDL cholesterol and to attenuate blood pressure rise in response to stress.²³ In the Nurse’s Health Study, diabetic women who consumed 28 grams of peanuts (1 tablespoon peanut butter) at least 5 times per week reduced their heart disease risk by 44%.²⁵

Finally, we include Brazil nuts in our Mediterranean diet prescription, with the goal for most patients to consume 3-5 Brazil nuts per week, and specify that patients with a known cardiomyopathy consume 1-2 nuts daily. Selenium deficiency is a well-known cause of non-ischemic cardiomyopathy, reversible after treatment with selenium.²⁶ Brazil nuts are the greatest plant source of selenium, and daily consumption of 1-2 Brazil nuts may normalize selenium status.²⁷

Accordingly, our prescription calls for mixed raw nuts (we suggest to purchase in bulk) with a predominance of walnuts and almonds, a generous representation of peanuts and pistachios, at least several Brazil nuts per week (1-2 daily for those with cardiomyopathy), and a smattering of other nuts as available. Because peanuts are not a tree nut and grow underground, they may be more susceptible to pesticides; therefore, we suggest to buy organically grown peanuts whenever possible.

SUMMARY

ARREST-AF demonstrated how healthy living might improve outcomes for catheter ablation of atrial fibrillation, with partial reversal of the underlying pathologic substrate. When intensive RFM programs are difficult to implement, similar benefit may be achievable by adopting a Mediterranean diet. Patient engagement and compliance improve when recommendations and detailed instructions are provided by the electrophysiology service, including instructions for preparation of fruits and vegetables, and purchase of mixed raw nuts and EVOO at local stores.

Our patient handout on the Mediterranean diet is available – please feel free to copy and adapt: 
https://www.jamesknellermd.com/life_style/mediterranean-diet/

Disclosure: The author has no conflicts of interest to report regarding the content herein. 

References

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