Plant-Based Diet Linked to Lower Heart Failure Risk

Batya Swift Yasgur MA, LSW

May 02, 2019

Plant-based diets are associated with a lower risk for incident heart failure (HF) in adults without known heart disease, new research suggests.

Researchers followed more than 16,000 adults (mean age, 64 years) with no known coronary heart disease (CHD) or HF at baseline, comparing those who adhered to a plant-based diet with those who consumed a Southern diet, consisting of more fried and processed foods and sweetened drinks.

They found that the plant-based diet was associated with a 41% lower risk for incident HF with the highest vs lowest adherence, while the Southern diet was associated with a 72% higher risk for HF with higher vs lower adherence, after adjustment for potential demographic, lifestyle, and medical confounders.

"The take-home message of our findings is to emphasize more vegetables, plant proteins like lentils, nuts, chickpeas, tofu, beans, etc, and limit consumption of meat; [this] is the future of health," lead author Kyla Lara, MD, MS, postgraduate fellow of cardiology and general internal medicine, Icahn School of Medicine, Mount Sinai, New York City, told theheart.org | Medscape Cardiology.

"Educating patients on what these entail is the first step in changing the lifestyle of our patients," she said.

The study was published in the April 30 issue of the Journal of the American College of Cardiology.

Five Dietary Patterns

HF is projected to affect more than 8 million people by 2030, necessitating a critical need for population-based preventive strategies, the authors write.

Previous research has demonstrated inverse associations with incident hypertension in people adhering to the Mediterranean or DASH (Dietary Approaches to Stop Hypertension) diets; however, these studies were "limited to participants from populations that lacked racial and ethnic diversity," the authors note.

"We wanted to look at dietary patterns in people without coronary disease or heart failure and see if we could find any associations, positive or negative, with the development of new heart failure," Lara said.

"Our study focused on US American adults, both black and white, living in the stroke belt and continental US," she added.

The researchers drew on data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a national cohort study consisting of 30,239 black and white adults (≥45 years) recruited from January 2003 to October 2007.

The researchers narrowed their sample size to 16,068 black and white participants (mean age, 64.0 ± 9.1 years; 58.7% female; 33.6% black; 34.0% residents of the stroke belt) who were required to be free of HF and CHD at baseline.

Participants were asked to respond to a 150-question survey, based on 107 food items. From the responses, 56 food groups were identified, which were then categorized into five types of diets:

1.     Convenience: heavily meat-based dishes, pasta, Mexican dishes, pizza, and fast food,

2.     Plant-based: vegetables, fruits, beans, and fish,

3.     Sweets/fats: heavily sugar- or fat-based food—eg, desserts, bread, sweet breakfast foods, chocolate, and other sugar,

4.     Southern: heavy on fried food, processed meats, eggs, added fats, and sugar-sweetened beverages,

5.     Alcohol/salads: heavy on wine, liquor, and beer as well as leafy greens and salad dressing.

Measurements of blood pressure, height, weight, waist circumference (WC), urine, and fasting blood samples were collected at baseline.

Participants received a score for each dietary pattern, and were then grouped into one of four quartiles of adherence to each pattern, with quartile 1 (Q1) being the lowest adherence and quartile 4 (Q4) representing the highest adherence to each.

Participants were interviewed every 6 months. In those who reported hospitalization, medical records were retrieved and adjudicated based on signs/symptoms of HF, laboratory studies, and assessment of left ventricular function documented in the medical record.

Medical covariates included hypertension, dyslipidemia, diabetes, atrial fibrillation (AF), and chronic kidney disease (CKD).

Participants were followed for a median of 8.7 years, with telephone interviews conducted every 6 months.

Anti-inflammatory Effects

There were 363 new HF hospitalizations during the follow-up period.

In the fully adjusted analyses, there was a 41% lower risk for new HF hospitalizations for participants who were most adherent (Q4) to the plant-based dietary pattern, compared with those who were least adherent (Q1).

In contrast, highest adherence (Q4) to the Southern dietary pattern was associated with a 72% higher risk for HF hospitalization in models adjusted for age, sex, and race.

However, after adjustment for other potential confounders (education, income, region of residence, total energy intake, smoking, physical activity, and sodium intake), the association between the Southern diet and incident HF risk was attenuated and no longer statistically significant.

After multivariable adjustment, the researchers found no statistically significant associations among the remaining dietary patterns.

When the researchers stratified HF hospitalizations by subtype, they identified 133 cases of HF with preserved ejection fraction (HFpEF), 157 cases of HF with reduced ejection fraction (HFrEF), and 73 cases of HF with intermediate EF or without documented EF.

There was a 97% increased risk in adherents to the Southern dietary pattern for HFrEF, which was found to be statistically significant.

In fully adjusted analyses that included potential mediating variables, however, there were no statistically significant associations of the dietary patterns with incident HFrEF or HFpEF hospitalizations.

Inverse associations were observed in men and participants with an eGFR above 60 mL/min per 1.73 m2, a BMI below 30 kg/m2, no history of diabetes, and a smoking history in Q4 of the plant-based dietary pattern. However, the interactions between these subgroups were not significant.

In contrast, a statistically significant interaction in the Southern dietary pattern was observed and showed a stronger positive association with HF in participants younger than 65 years.

Lara emphasized that their study did not compare diets with one another, but rather placed each participant in a quartile for each of the dietary patterns, depending on how they answered the food frequency questionnaire.

"The Mediterranean diet is a much better option than the Southern dietary pattern, since it emphasizes healthy fats like olive oil, nuts, avocadoes, and fish, and recommends avoiding fried foods and red meat, which are central to the Southern diet," she observed.

She suggested several potential reasons why a plant-based diet might be protective against HF.

"Current theories include the effects of antioxidants and anti-inflammatory effects, which are highly abundant in plant-based diets," she noted.

"Reactive oxygen species promote hypertrophy, aortic stiffness, interstitial fibrosis, and can potentially decrease myocardial contractility, all of which can contribute to the development of heart failure," she explained.

"On the other hand, plant antioxidants decrease the amount of reactive oxygen species, and with plant-based diets, we can also see decreased serum concentrations of CRP [C-reactive protein], IL-6, [interleukin-6] and soluble intercellular adhesion molecule-1, which are inflammatory biomarkers," she added.

Lara said that future research will focus on plant-based diets in patients entering cardiac rehabilitation and will start exploring the microbiome, plant-based diets, and cardiovascular health.

Improved Cardiac Outcomes

Commenting on the study for theheart.org | Medscape Cardiology, Robert Ostfeld MD, MSc, director of preventive cardiology and founder and director of Montefiore Einstein Cardiac Wellness Program, Bronx, New York, who was not involved with the research, said that the findings of this study "accord with my own clinical experience."

He reported that he has found "that the more one adopts a plant-based diet, the better the outcomes, including improving angina, reversing hypertension and diabetes, lowering cholesterol, and losing weight."

Ostfeld, who is also associate professor of medicine at Albert Einstein College of Medicine, suggested multiple mechanisms that might account for these benefits.

"Minimally processed plant-based foods are rich in fiber, antioxidants, and phytonutrients, which can improve the health of our microbiome, reduce inflammation, and reduce oxidative stress," he noted.

"Furthermore, by consuming a plant-based diet, one can avoid potentially harmful effects of animal-based foods, such as heme iron, sialic acid, and cholesterol," he added.

Also commenting on the study for theheart.org | Medscape Cardiology, Kim Allan Williams, MD Sr, James B. Herrick Professor and chief, Division of Cardiology, Rush University School of Medicine, Chicago, said that "their [the researchers] data are consistent with the finding that red meat and the TMAO [trimethylamine N-oxide] generated by eating this are associated with worsening heart failure incidence, recurrence, and mortality."

Williams, who was not involved with the study, said that a plant-based diet has advantages over other heart-healthy diets because it contains "less saturated fat, trans fat, nitrates, nitrite BCAAs [branched chain amino acids], heme-iron, cholesterol, and TMAO."

In an accompanying editorial, Dong D. Wang, MD, MSc, Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, said that the study "represents an important step forward in establishing a robust evidence base for the dietary prevention of HF."

"The authors' finding on the potentially differential associations of dietary patterns with HFpEF as compared with HFrEF provides an early glimpse of precision dietary prevention of HF (i.e., recommending dietary approaches customized to HF subtypes with different pathophysiological basis)," Wang writes. "However, to achieve the precision prevention of HF, much research is needed to accrue robust and reproducible evidence.

"In addition, although the traditional classification into HFpEF and HFrEF was proven to be useful in differentiating distinct pathophysiology with therapeutic implications, a large proportion of variability in clinical manifestations of HF, especially HFpEF, remains unexplained," Wang notes. "Future epidemiological studies that include a more advanced disease classification through applying deep-phenotyping of large populations and the big data analytics would set the stage for the precision prevention of HF."

Lara reports no conflicting interests. The other authors' disclosures are listed on the original paper. Wang, Ostfeld, and Williams report no conflicting interests.

J Am Coll Cardiol. 2019;73:2036-2045, 2046-2048. Abstract, Editorial

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