Rating Diets for Heart Health: A Comprehensive Review

The evolution of dietary guidelines from isolated nutrients to recommendations for broader dietary patterns is the result of increasing knowledge of the synergy between nutrients and their food sources as they influence health. Macronutrient and micronutrient needs can be met through the consumption of various dietary patterns, but guidance is often required to facilitate the adherence of the entire population to sensible food choices to achieve a healthy dietary pattern. This is particularly true in this era with the proliferation of nutrition misinformation and misplaced emphasis. In 2021, the American Heart Association issued a scientific statement outlining the key principles of a heart-healthy dietary pattern that could be implemented in several ways.

The objective of this scientific statement is to evaluate the alignment of dietary patterns commonly practiced in the US with recently published American Heart Association criteria , to determine clinical and cultural factors that affect long-term adherence, and to propose approaches. for the adoption of healthy dietary patterns. This scientific statement is intended to serve as a tool for clinicians and consumers to evaluate whether these popular dietary patterns promote cardiometabolic health and suggests factors to consider when adopting any pattern to improve alignment with the 2021 American Heart Association Dietary Guidelines. Many patterns strongly aligned with the 2021 American Heart Association Dietary Guidelines (i.e., Mediterranean, DASH [Dietary Approaches to Stop Hypertension], Pescetarian, Vegetarian) can be adapted to reflect personal and cultural preferences and budget constraints . Therefore, optimal cardiovascular health would be best supported by developing a food environment that supports compliance with these patterns wherever food is prepared or consumed.

Many popular dietary patterns score high for heart health; However, some contradict the American Heart Association’s dietary guideline and did not qualify as heart healthy, according to a new scientific statement published today in the flagship peer-reviewed journal Circulation .

“The number of different and popular dietary patterns has proliferated in recent years, and the abundance of misinformation about them on social media has reached critical levels,” said Committee Chair Christopher D. Gardner, Ph.D., FAHA. of Writing the new scientific statement and Rehnborg Farquhar, Professor of Medicine at Stanford University in Stanford, California. “The public, and even many health professionals, may be rightly confused about heart-healthy eating, and may feel like they don’t have the time or training to evaluate different diets. We hope this statement serves as a tool for clinicians and the public to understand which diets promote good cardiometabolic health .”

Cardiometabolic health refers to a group of factors that affect metabolism (the body’s processes that break down nutrients in food and build and repair tissues to maintain normal function) and the risk of heart and vascular diseases. These factors include blood glucose, cholesterol and other lipids, blood pressure, and body weight. While abnormal levels of one factor can increase the risk of heart disease, abnormalities in more than one factor increase the risk even further and the disease is more severe.

The statement rates how well popular dietary patterns align with the American Heart Association’s Dietary Guidelines . The guide includes ten key characteristics of a dietary pattern to improve cardiometabolic health, which emphasizes limiting unhealthy fats and reducing excess carbohydrate consumption. This balance optimizes overall metabolic and cardiovascular health, and limits the risks of other health conditions such as type 2 diabetes and risk factors such as obesity that can result from excessive consumption of carbohydrates, particularly processed carbohydrates and sugary drinks, which are associated with increased risk of cardiovascular disease. The new scientific statement is the first to look at how closely popular dietary patterns adhere to those characteristics, and the guide focuses on being adaptable to individual budgets as well as personal and cultural preferences.

The committee reviewed the defining characteristics of several dietary patterns that should be followed long term. Dietary patterns were grouped by similarity in key characteristics, resulting in 10 categories :

Each diet was evaluated against 9 of the 10 characteristics of the American Heart Association guideline for a heart-healthy eating pattern . The only item not used in the score was “eating to achieve adequate energy balance to maintain a healthy weight,” as this is influenced by factors other than dietary choices, such as physical activity level, and applies equally to all diet categories. Defining characteristics of the diets received points based on how well each characteristic aligned with the Association’s guideline: 1 point for fully meeting the guideline, 0.75 points for mostly meeting the guideline, and 0.5 points for partially meeting the guideline. If an aspect of the diet did not meet the guideline, zero points were awarded for that component. The resulting scores were totaled and adjusted to arrive at a score between 0 and 100, with 100 indicating the closest adherence to the American Heart Association dietary guideline.

Notably, the statement did not review commercial diet programs, such as Noom or Weight Watchers; feeding programs designed to be followed for less than 12 weeks; dietary practices such as intermittent fasting or time-restricted eating ; or diets designed to control non-cardiovascular diseases (such as gastrointestinal conditions and food allergies or intolerances).

The writing group found that the dietary patterns reviewed varied widely in their alignment with the American Heart Association guideline, with scores ranging from 31 to 100. The scores were grouped into four levels and noted aspects of the diets that help them adhering to the guidance, as well as potential challenges in complying with it. The only element of the guide that was part of each diet pattern was to “ minimize the intake of foods and beverages with added sugars .” The statement also identifies opportunities to improve the healthy aspects of each eating pattern.

The four highest-rated patterns are flexible and provide a wide range of healthy foods to choose from. The DASH-style eating pattern received a perfect score by meeting all of the Association’s guidelines. These eating patterns are low in salt, added sugar, alcohol, tropical oils, and processed foods, and high in vegetables, fruits, whole grains, and non-starchy legumes. Protein tends to come primarily from plant sources (such as legumes, beans, or nuts), along with fish or shellfish, poultry, and lean meats and low-fat or fat-free dairy products.

The Mediterranean-style diet is also highly rated. Because it does not explicitly address added salt and includes moderate alcohol consumption (rather than avoiding or limiting alcohol), it has a slightly lower score than the DASH. Additionally, most of the characteristics of a vegetarian eating pattern align with the AHA dietary guideline. Pescatarian and vegetarian eating plans that include eggs, dairy products, or both were also in the top tier.

“If implemented as intended, top-tier dietary patterns better align with American Heart Association guidance and can be adapted to respect cultural practices, food preferences, and budgets to allow people to always eat the right way.” way, long term,” Gardner said.

Vegan and low-fat diets also emphasize the consumption of vegetables, fruits, whole grains, legumes and nuts, while limiting alcohol and foods and drinks with added sugars. However, restrictions on the vegan eating pattern can make it more difficult to follow this type of diet long-term or when eating out. Following a vegan eating pattern may increase the risk of vitamin B-12 deficiency, which can cause red blood cell abnormalities leading to anemia; therefore, doctors may recommend supplementation.

Low-fat diets often treat all fats equally, while the Association’s guidance suggests replacing saturated fats with healthier fats, such as monounsaturated and polyunsaturated fats. Those who follow a low-fat diet may overconsume less healthy carbohydrate sources, such as added sugars and refined grains. However, these factors can be overcome with proper advice and education for people interested in these eating patterns.

These dietary patterns have low to moderate alignment with the Association’s guidance.

One reason for some people to follow a very low-fat (often vegan) diet may be that some studies have shown its potential to slow the progression of fatty buildup in the arteries. A healthy low-carb eating pattern has been shown to affect weight loss, blood pressure, blood sugar, and cholesterol equally compared to a healthy low-fat diet. However, both patterns restrict the food groups that are emphasized in the Association’s guide.

Very low-fat diets lost points for restricting nuts and healthy (non-tropical) vegetable oils. This eating pattern can also lead to deficiencies in vitamin B-12, essential fatty acids, and protein, leading to anemia and muscle weakness.

Low-carb diets restrict fruits (due to sugar content), grains, and legumes. When restricting carbohydrates , followers tend to decrease fiber consumption while increasing saturated fat consumption (from meats and animal foods), both of which contradict the Association’s guidance.

The statement suggests that loosening restrictions on food groups such as fruits, whole grains, legumes and seeds can help people maintain a lower-carbohydrate eating pattern while promoting long-term heart health.

These two eating patterns, which are often used for weight loss, do not align very well with the Association’s dietary guideline. The strengths of very low carbohydrate eating patterns are the emphasis on the consumption of vegetables, nuts and non-starchy fish, along with minimizing the consumption of alcohol and added sugars. In studies of up to 6 months in duration, improvements in body weight and blood sugar have been shown with these diets. However, after a year, most of the improvements were no different from the results of a less restrictive diet. Restrictions on fruits, whole grains and legumes can lead to reduced fiber intake. Additionally, these diets are high in fat without limiting saturated fat. The consumption of high levels of saturated fat and low levels of fiber are related to the development of cardiovascular diseases.

“There is really no way to follow Level 4 diets as intended and still be aligned with the American Heart Association dietary guideline ,” Gardner said. “They are very restrictive guidelines and difficult for most people to follow in the long term. While there are likely to be short-term benefits and substantial weight loss, they are not sustainable. “A diet that is effective in helping a person maintain weight loss goals, from a practical perspective, must be sustainable.”

The statement suggests opportunities for dietary research and interventions to promote health equity, recognizing the importance of social determinants of health in shaping dietary patterns. Advocating for change at each of these levels helps all populations achieve health equity.

• Individuals: Educational efforts must be culturally relevant to increase their effectiveness for people from underrepresented racial and ethnic groups. Studies that examine the dietary patterns of various African, Asian, and Latin American cultures may be useful in creating the knowledge base for these types of educational efforts.
   
• Relationships and social networks: Families, friends and traditions are important factors that influence eating patterns. Programs are needed to promote relationships that support healthy eating in diverse population groups, and particularly those who take advantage of the family structure as a means of social support. One example is the American Heart Association’s new campaign Juntos En La Mesa , designed to help Hispanic/Latino families cook and eat a heart-healthy diet that celebrates their cultural flavors while improving the health of their families.
   
• Communities: Structural racism is a contributing factor to diet-related diseases. Historically marginalized populations must be involved in all phases of research and in the development of programs and interventions. Dietary intervention studies should incorporate healthier versions of dietary patterns from racially and ethnically diverse cultures.
   
• Policies: Policies can address disparities in dietary patterns by race and ethnicity, dismantling historically unfair practices that limit access to healthy foods. Legislation at local, national and global levels can provide long-term support for healthy eating for large numbers of people and shape more equitable and healthy societies.

When learning more about various dietary patterns and how effective they can be, Gardner notes that people may hear conflicting information from different studies of the same diet. “We often find that people do not fully understand popular eating patterns and do not follow them as expected. When that is the case, it is difficult to determine the effect of ’diet as intended’ and distinguish it from ’diet as followed’. “Two research findings that seem contradictory may simply reflect that there was high adherence to following the diet in one study and low adherence in the other.”

This scientific statement was prepared by the volunteer writing group on behalf of the Council on Lifestyle and Cardiometabolic Health; the Cardiovascular and Stroke Nursing Council; the Hypertension Council; and the American Heart Association Council on Peripheral Vascular Diseases . The American Heart Association ’s scientific statements promote greater awareness of cardiovascular disease and stroke and help facilitate making informed health care decisions. Scientific statements describe what is currently known about a topic and what areas need more research. While scientific statements inform guideline development, they do not make treatment recommendations. The American Heart Association guidelines provide the Association’s official clinical practice recommendations.

Co-authors are Vice President Maya Vadiveloo, Ph.D., RD, FAHA; Kristina S. Petersen, Ph.D., APD, FAHA; Cheryl AM Anderson, Ph.D., MPH, FAHA; Sparkle Springfield, Ph.D.; Linda Van Horn, Ph.D., RDN, FAHA; Amit Khera, MD, M.Sc., FAHA; Cindy Lamendola, MSN, ANP-BC, FAHA; Shawyntee M. Mayo, MD and Joshua J. Joseph, MD, MPH, FAHA. The public data of the authors can be found in the article.

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