A cardiologist's guide to dietary counseling

By Alpana Mohta, MD, DNB, FEADV, FIADVL, IFAAD | Medically reviewed by Yasmine S. Ali, MD, MSCI, FACC, FACP
Published March 21, 2024

Key Takeaways

  • Dietary counseling is a crucial part of managing cardiometabolic risk factors, such as hypertension, diabetes, obesity, and dyslipidemia. 

  • Current guidelines recommend diets that limit processed foods, trans-fats, and sugar-sweetened beverages for patients with cardiovascular disease.

  • The Mediterranean, DASH, and plant-based diets are endorsed for their cardioprotective qualities, while emerging diets, such as the ketogenic diet and intermittent fasting, are still under study for their long-term effects.

Cardiovascular disease (CVD) remains the primary cause of mortality in the US, despite progress in medical treatments and dietary interventions aimed at heart health.[] Lifestyle adjustments, particularly nutritional changes, are crucial in managing cardiometabolic risk factors like hypertension, diabetes, obesity, and dyslipidemia. 

The American Heart Association (AHA) emphasizes the importance of a healthy diet in its “Life’s Essential 8” for cardiovascular health, reported in 2022 in Circulation.[]

And yet, less than 1% of US adults meet the ideal criteria for a heart-healthy diet.

Let’s explore the various diets spotlighted for their heart-health benefits.

The most effective model

The Mediterranean diet, influenced by the eating patterns of countries like Southern Greece, Italy, and Spain, is the most effective dietary model for coronary artery disease prevention.[] It comprises whole grains, fruits, vegetables, legumes, unsalted nuts, and extra virgin olive oil (EVOO). Fish, poultry, and dairy are consumed in moderation, along with limited red meat and sweets. 

According to authors writing in Vascular Health and Risk Management, the diet's benefits are attributed to its rich content of antioxidants and anti-inflammatory properties, which help modulate the gut microbiome, pro-atherogenic genes, and lipid profiles.[]

Studies, including the landmark Seven Countries Study, have consistently shown its effectiveness in reducing CVD risks, including lower rates of coronary heart disease and improvements in cholesterol levels.

Other research, including the Lyon Diet Heart Study (secondary prevention) and the PREDIMED trial (primary prevention), have also demonstrated the diet's benefits in reducing heart attack risks, stroke, and CVD-related deaths. 

Plant-based eating

A healthy plant-based diet also emphasizes fruits, vegetables, whole grains, legumes, and nuts, but minimizes or eliminates animal products. The PREDIMED trial and the Coronary Artery Risk Development in Young Adults (CARDIA) cohort have shown strong associations between plant-based diets and reduced incidence of CVD.[] 

As discussed in Vascular Health and Risk Management, this diet also addresses concerns about processed meats and their links to hypertension and endothelial dysfunction.

One caveat, however, is that patients on a purely vegetarian or vegan diet may require heme iron supplementation or other forms of protein, vitamin B12, vitamin D, vitamin A, calcium, and zinc.

Related: When daily vitamins become a death sentence: What doctors need to know

Special considerations exist for women eating a vegan diet, especially in mid-life and beyond, as dietary forms of calcium are crucial to maintaining good bone health.

Combat hypertension

Developed by the NIH, the Dietary Approaches to Stop Hypertension (DASH) diet is designed to combat hypertension.[] It is characterized by high intakes of vegetables and fruits, along with consumption of low-fat dairy, whole grains, fish, poultry, seeds, and nuts, while restricting sugary beverages, high-fat dairy, and fatty meat products. The diet is practiced in two versions: limiting sodium to 2,300 mg daily and a more stringent version capping it at 1,500 mg daily.

Research, including the Dietary Intervention to Stop Coronary Atherosclerosis in Computed Tomography (DISCO) RCT, has shown that the DASH diet lowers cholesterol and the risk of coronary atherosclerosis.[]

Related: New study suggests even the heart struggles to escape microplastics, posing risks for cardiovascular disease

Low carb, high fat

The merits of the ketogenic diet are discussed in Vascular Health and Risk Management. This regimen is characterized by its very low carbohydrate, high fat, and moderate protein composition. It activates antioxidant and anti-inflammatory genes, notably through the beta-hydroxybutyrate (BHB) metabolite.

Studies have shown benefits regarding reduced diabetes medication use, lower hemoglobin A1c (HbA1c) levels, and weight loss, particularly in patients with type 2 diabetes.

However, concerns arise due to the potential elevation of triglycerides, LDL cholesterol, and non-HDL cholesterol, increasing CVD risk, especially in patients with latent genetic dyslipidemias.[] 

Timing matters

Intermittent fasting, including alternate-day fasting and time-restricted eating, aims to induce ketosis, reduce oxidative stress, and synchronize feeding with circadian rhythms.

Alternate-day fasting involves alternating between fasting and feasting days and has been shown to reduce weight, BMI, and total cholesterol, albeit in short-term studies.

Nutrition recommendations for patients

The AHA released a dietary guidance statement in 2021 to promote cardiometabolic health.[] Let's dive into how you can integrate these guidelines into your patient conversations with the following tips.

  • Encourage patients to balance their meal portions with physical activity to maintain a healthy weight. Walking after a meal, for instance, has been shown to reduce insulin resistance and improve the cardiometabolic profile.

  • Advise families to adopt healthy eating habits from a young age, focusing on overall diet rather than specific foods.

  • Suggest including colorful fruits and vegetables in their meals, known as "eating the rainbow.” At least five servings of whole fruits and vegetables per day are recommended: The more, the better.

  • Recommend eating whole fruits instead of drinking fruit juices, and adding leafy greens.

  • Advise choosing whole grains, such as whole wheat, quinoa, barley, and farro, over refined grains for weight management and cholesterol control.

  • Encourage eating plant-based proteins, such as legumes and nuts, and moderate fish consumption (two to three servings per week). 

  • Avoid ultra-processed foods.

  • Suggest lean poultry or fish over red or processed meats.

  • Recommend using liquid plant oils, such as EVOO or canola oil, and unsaturated fats found in walnuts and flax seeds instead of tropical oils or partially hydrogenated fats. 

  • Advise cutting down on salt, added sugars, and sugar-sweetened beverages.

What this means for you

As a cardiologist, understanding the nuances of dietary counseling is vital in managing patients with heart disease. Poor diet quality and high consumption of ultra-processed foods are primary contributors to cardiometabolic diseases. All heart-healthy diets prioritize fruits, vegetables, legumes, nuts, and whole grains and emphasize the importance of whole, unprocessed foods.

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