DIET AND HEART DISEASE. 2021

The current guidelines from the American Heart Association (AHA) focus on dietary interventions to reduce the risk for cardiovascular disease, and other chronic illnesses.

1. Mediterranean-style diet is associated with a lower risk for type 2 diabetes.
2. In addition, the Dietary Approaches to Stop Hypertension (DASH) diet has been associated with a slower decline in age-associated cognitive tasks, and the Mediterranean diet can reduce cognitive decline as well. Finally,
3. higher consumption of nuts, low-fat dairy products, and legumes, along with moderate alcohol consumption, is associated with a lower risk for severe renal disease.
4. Higher consumption of artificially sweetened beverages, sugar-sweetened beverages, and red meat is associated with worse renal outcomes.

The current guidelines provide some interesting opinions and facts regarding current dietary trends.

Study Synopsis and Perspective

In a new scientific statement on diet and lifestyle recommendations, the AHA is highlighting, for the first time, structural challenges that impede the adoption of heart-healthy dietary patterns.

This is in addition to stressing aspects of diet that improve cardiovascular health and reduce cardiovascular risk, with an emphasis on dietary patterns and food-based guidance beyond naming individual foods or nutrients.

VERY IMPORTANT STATEMENT: STEP BACK AND LOOK

“The way to make heart-healthy choices every day,” said Dr Lichtenstein, from the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, in a statement, “is to step back, look at the environment in which you eat, whether it be at home, at work, during social interaction, and then identify what the best choices are. And if there are no good choices, then think about how you can modify your environment so that there are good choices.”

The statement, published in Circulation, underscores growing evidence that nutrition-related chronic diseases have maternal-nutritional origins, and that prevention of pediatric obesity is a key to preserving and prolonging ideal cardiovascular health.^[1]

The features are as follows:

• Adjust energy intake and expenditure to achieve and maintain a healthy body weight. To counter the shift toward higher energy intake and more sedentary lifestyles over the course of past 3 decades, the statement recommends at least 150 minutes of moderate physical activity per week, adjusted for individual’s age, activity level, sex, and size.
• Eat plenty of fruits and vegetables; choose a wide variety. Observational and intervention studies document that dietary patterns rich in varied fruits and vegetables, with the exception of white potatoes, are linked to a lower risk for cardiovascular disease (CVD). Also, whole fruits and vegetables, which more readily provide fiber and satiety, are preferred over juices.
• Choose whole grain foods and products made mostly with whole grains rather than refined grains. Evidence from observational, interventional, and clinical studies confirms the benefits of frequent consumption of whole grains over infrequent consumption or over refined grains in terms of CVD risk, coronary heart disease (CHD), stroke, metabolic syndrome, cardiometabolic risk factors, laxation, and gut microbiota.
• Choose healthy sources of protein, mostly from plants (legumes and nuts).
• Higher intake of legumes, which are rich in protein and fiber, is associated with lower CVD risk, whereas higher nut intake is associated with lower risks for CVD, CHD, and stroke mortality/incidence. Replacing animal-source foods with plant-source whole foods, beyond health benefits, lowers the diet’s carbon footprint. Meat alternatives are often ultraprocessed, and evidence on their short- and long-term health effects is limited. Unsaturated fats are preferred, as are lean, nonprocessed meats.
• Use liquid plant oils rather than tropical oils (coconut, palm, and palm kernel), animal fats (butter and lard), and partially hydrogenated fats. Saturated and trans fats (animal and dairy fats, and partially hydrogenated fat) should be replaced with nontropical liquid plant oils. Evidence supports the cardiovascular benefits of dietary unsaturated fats, especially polyunsaturated fats primarily from plant oils (eg, soybean, corn, safflower, and sunflower oils; walnuts; and flax seeds).
• Choose minimally processed foods instead of ultraprocessed foods. Because of their proven association with adverse health outcomes, including overweight and obesity, cardiometabolic disorders (type 2 diabetes, CVD), and all-cause mortality, the consumption of many ultraprocessed foods is of concern. Ultraprocessed foods include artificial colors and flavors and preservatives that promote shelf stability, preserve texture, and increase palatability. A general principle is to emphasize unprocessed or minimally processed foods.
• Minimize intake of beverages and foods with added sugars. Added sugars (commonly glucose, dextrose, sucrose, corn syrup, honey, maple syrup, and concentrated fruit juice) are tied to elevated risk for type 2 diabetes, high cholesterol, and excess body weight. Findings from meta-analyses on body weight and metabolic outcomes for replacing added sugars with low-energy sweeteners are mixed, and the possibility of reverse causality has been raised.
• Choose and prepare foods with little or no salt. In general, the effects of sodium reduction on blood pressure tend to be higher in Black people, middle-aged and older people, and those with hypertension. In the United States, the main combined sources of sodium intake are processed foods, those prepared outside the home, packaged foods, and restaurant foods. Potassium-enriched salts are a promising alternative.
• If you don’t drink alcohol, don’t start; if you choose to drink, limit intake.
• Although relationships between alcohol intake and cardiovascular outcomes are complex, the 2020 Dietary Guidelines Advisory Committee recently concluded that those who do drink should consume no more than 1 drink per day and should not drink alcohol in binges; the 2020 Dietary Guidelines for Americans continues to recommend no more than 1 drink per day for women and 2 drinks per day for men.
• Adhere to the guidance regardless in all settings. Food-based dietary guidance applies to all foods and beverages, regardless of where prepared, procured, and consumed. Policies should be enacted that encourage healthier default options (for example, whole grains, minimized sodium and sugar content).

Recognizing Impediments

The AHA/American Stroke Association (ASA)scientific statement closes with the declaration: “Creating an environment that facilitates, rather than impedes, adherence to heart-healthy dietary patterns among all individuals is a public health imperative.” It points to the National Institutes of Health’s (NIH’s) 2020-2030 Strategic Plan for NIH Nutrition Research,^[2] which focuses on precision nutrition as a means “to determine the impact on health of not only what individuals eat, but also of why, when, and how they eat throughout the life course.”^[1]

Ultimately, precision nutrition may provide personalized diets for CVD prevention. But the “food environment,” often conditioned by “rampant nutrition misinformation” through local, state, and federal practices and policies, may impede the adoption of heart-healthy dietary patterns. Factors such as “targeted food marketing [for example, of processed food and beverages in minority neighborhoods], structural racism, neighborhood segregation, unhealthy built environments, and food and nutrition insecurity create environments in which unhealthy foods are the default option.”

These factors compound adverse dietary and health effects and underscore a need to “directly combat nutrition misinformation among the public and health care professionals.” They also explain why, despite widespread knowledge of heart-healthy dietary pattern components, little progress has been made in achieving dietary goals in the United States.

Study Highlights

• Diet is one of the most important modifiable risk factors for CVD. High adherence to a healthy diet can reduce the risk for cardiovascular mortality by 14% to 28% compared with low adherence.
• Energy needs decline with age by an average of 70 to 100 kcal/day for each decade of life. Balancing energy consumption is the first recommendation from the current guidelines.
• The consumption of fruits and vegetables is encouraged. Deeply colored fruits and vegetables, such as leafy greens and peaches, tend to be more nutrient-dense vs lighter-colored foods. 
• The guidelines encourage consumption of all forms of fruits and vegetables: fresh, frozen, canned, and dried. Frozen fruits and vegetables offer similar or higher nutrient content compared with fresh fruits and vegetables, but they have a longer shelf-life and are often less expensive.
• The replacement of refined grain with whole grains is associated with a lower risk for coronary heart disease.
• Higher consumption of legumes is associated with a reduced risk for CVD. The guidelines cite soybeans, lentils, chickpeas, and split peas as good examples of legumes.
• Higher consumption of nuts is associated with lower risks for coronary heart disease as well as a reduced risk for stroke incidence and mortality. 
• The authors caution against the rush to plant-based meat alternatives as a healthier option. These products are ultraprocessed and contain added sugar, saturated fat, salt, stabilizers, and preservatives. There is little evidence regarding the health effects of meat alternatives at this time.
• Two to 3 servings of fish per week is associated with lower risks for all-cause mortality, coronary heart disease, stroke, and heart failure. Replacing foods rich in saturated fat with fish is particularly salutary, although fried fish does not provide the same health benefits.
• The authors recommend replacing full-fat dairy products with nonfat and low-fat dairy products, although they acknowledge that the data to support this recommendation are evolving and controversial.
• Consumption of red meat should be limited, as should consumption of processed meat. Processed meat has an even stronger positive association with CVD than red meat.
• However, the consumption of unprocessed poultry does not appear to significantly affect the risk for CVD.
• The consumption of polyunsaturated fats provides a moderate advantage over the consumption of monounsaturated fats in the prevention of CVD.
• Added sugars are to be avoided. Meta-analyses of clinical trials have reported mixed outcomes for low-energy sweeteners on body weight and metabolic outcomes.
• Low-abundance mono- and disaccharides may provide a healthier option than added sugars, but there are not enough data on these products as yet.
• Sodium consumption should be minimized, particularly among Black individuals, middle-aged and older adults, and patients with hypertension. Replacing sodium with potassium is a promising strategy to reduce blood pressure.
• Alcohol consumption is associated with higher risks for hemorrhagic stroke and atrial fibrillation. There is a J- or U-shaped relationship between alcohol consumption and coronary heart disease, with the lowest risk apparent among adults who consume 1 or 2 alcoholic beverages per day. The AHA does not support the initiation of alcohol consumption for cardiovascular health.
• It is better to obtain essential nutrients from dietary sources vs supplements. There is insufficient evidence to support the routine use of high-dose supplements for cardiovascular health.
• Reducing the consumption of saturated fat can reduce the risk for CVD by approximately 30%, which is similar to what might be expected with statin therapy. 
• The recommendations caution against the use of coconut oil, which raises LDL cholesterol compared with other plant-based oils but has not been demonstrated to have other health benefits.

Clinical Implications

• The Mediterranean-style diet is associated with a lower risk for type 2 diabetes and cognitive decline. The DASH diet has also been associated with a slower decline in age-associated cognitive tasks. Finally, higher consumption of nuts, low-fat dairy products, and legumes, along with moderate alcohol consumption, are associated with a lower risk for severe renal disease. Higher consumption of artificially sweetened beverages, sugar-sweetened beverages, and red meat is associated with worse renal outcomes.
• The current guidelines do not find enough evidence to recommend plant-based meat alternatives, artificially sweetened beverages, or alcohol consumption for the routine prevention of cardiovascular disease. The recommendations state that although processed meat and red meat are associated with higher risks for cardiovascular disease, unprocessed poultry is not.
• Implications for the healthcare team: The healthcare team should use the specific advice from the AHA to help guide patients on their dietary choices.