A Heart-Healthy Diet for Cardiovascular Disease Prevention: Where Are We Now?

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TL;DR

The Mediterranean, DASH, and healthy plant-based diets are the most evidence-backed dietary patterns for cardiovascular disease prevention, endorsed by major cardiology societies. Emerging diets like ketogenic and intermittent fasting show promise for weight loss but lack long-term data on cardiovascular benefits and may carry risks such as adverse lipid changes. Barriers including food insecurity, poor access to healthy foods, and limited nutrition education among healthcare professionals must be addressed to improve adoption of heart-healthy diets.

Full summary

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**Background:** Cardiovascular disease (CVD) remains the leading cause of death in the United States despite advances in medical management. Lifestyle modifications, particularly dietary changes, are the foundation of CVD prevention guidelines. The relationship between diet and cardiovascular health has been studied for decades, beginning with the Seven Countries Study (1958–1964) which showed lower myocardial infarction rates in countries consuming diets rich in fruits, vegetables, grains, beans, and fish. The INTERHEART Study demonstrated that daily consumption of fruits and vegetables along with regular physical activity was associated with a 40% reduction in MI [OR=0.60 (95% CI=0.51–0.71)]. The PURE study in over 130,000 individuals from 18 countries found that diets rich in fruits, vegetables, and legumes were associated with 19% lower risk of all-cause mortality [HR=0.81 (95% CI=0.68–0.96)] over 7 years. Despite this evidence, less than 1% of US adults met 'ideal' criteria for the AHA's healthy diet metric in 2013–2014.

**Methods:** This is a narrative review providing a comprehensive overview of established and emerging diets for cardiovascular health. The authors synthesized evidence from major epidemiological studies, randomized controlled trials, meta-analyses, and professional society guidelines. They examined the Mediterranean diet, DASH diet, healthy plant-based diets, ketogenic/very low carbohydrate diets, and intermittent fasting/time-restricted eating patterns. The review also addressed the role of the gut microbiome, barriers to dietary adherence, and approaches to nutritional counseling.

**Key Results:** The PREDIMED trial randomized 7,447 high-risk participants to Mediterranean diet with extra virgin olive oil (EVOO), Mediterranean diet with nuts, or a low-fat control diet. After 4.8 years, there was approximately a 30% reduction in MI, stroke, or CVD death in the Mediterranean diet with EVOO group (HR=0.69; 95% CI=0.53–0.91) and the nuts group (HR=0.72; 95% CI=0.54–0.95). Diabetes incidence was 52% lower (95% CI=27–86%) in the pooled Mediterranean diet groups. The Lyon Diet Heart Study found a greater than 70% reduction in recurrent non-fatal MI and greater than 50% reduction in mortality with the Mediterranean diet in secondary prevention. The DASH diet reduced blood pressure by 5–6 mmHg systolic and 3 mmHg diastolic, and lowered LDL-C by 11 mg/dL. In the CARDIA cohort followed for nearly 32 years, the highest versus lowest quintile of plant-based diet score was associated with a 52% reduction in incident CVD (HR=0.48; 95% CI=0.28–0.81). Each additional serving per day of ultra-processed foods was associated with a 7% increased risk of incident CVD (HR=1.07; 95% CI=1.03–1.12) in the Framingham Offspring Study. For emerging diets, a meta-analysis found the ketogenic diet conferred unfavorable effects on LDL-C, apoB, and total cholesterol in normal weight adults. Regarding time-restricted eating, one study found no significant weight loss difference between TRE with calorie restriction versus calorie restriction alone (net difference=−1.8 kg; 95% CI=−4.0 to 0.4; P=0.11).

**Clinical Implications:** The Mediterranean, DASH, and healthy plant-based diets remain the most evidence-based dietary patterns for CVD prevention and are endorsed by the AHA and ACC. These diets emphasize fruits, vegetables, legumes, whole grains, and lean proteins while minimizing processed foods, trans-fats, and sugar-sweetened beverages. The AHA's 2021 dietary guidance recommends adjusting energy intake for healthy body weight, eating a variety of colorful fruits and vegetables, choosing whole grains, consuming healthy protein sources (predominantly plant-based), using liquid plant oils, and minimizing added sugars, salt, and ultra-processed foods. Emerging diets like ketogenic and intermittent fasting require more long-term study before they can be recommended for cardiovascular health. The gut microbiome represents an emerging frontier, with dietary metabolites like TMAO linked to increased CVD risk. Barriers to implementation include food insecurity (which tripled during the COVID-19 pandemic), food deserts, socioeconomic disparities, and inadequate nutrition education in medical schools (averaging only 20 hours). A multidisciplinary team-based approach including nutrition specialists, culturally-tailored recommendations, and community-based programs like culinary medicine and food pharmacies are needed to overcome these barriers and improve cardiovascular outcomes.