Learning Codes: 4030, 4040, 4060, 5160, 5260; CDR Level I

In June 2006, the American Heart Association (AHA) released a revision of its diet and lifestyle recommendations for preventing cardiovascular disease (CVD). Reflecting new scientific evidence that has emerged after publication of the AHA recommendations in 2000, the 2006 recommendations are part of the AHA’s comprehensive plan to achieve specific goals for reducing risk while remaining flexible enough to meet the unique needs of children’s growth and development and adults’ and seniors’ needs for health and fitness as they age.1,2 Because dietitians will be asked to explain these recommendations, which are summarized in Table 1, this article provides detailed discussion and references.

These recommendations reaffirm a commitment to prevention. Maintaining a healthy diet and lifestyle to prevent disease development offers the greatest promise for dramatically impacting the population. Since obesity has arisen as a major nutritional problem in the United States, the AHA recommendations also contain extensive information on nutrition and physical activity to prevent or manage obesity and reduce its adverse effects.1 While these recommendations can be applied to the clinical management of most patients with (or at risk for) CVD, certain patients at higher risk may require more rigorous treatment.

Despite the advances in CVD prevention and treatment through drugs (eg, statins) and procedures (eg, angioplasty and stenting), diet and lifestyle therapies remain the foundation of clinical intervention for CVD prevention. The meticulous application of these interventions will contribute significantly to CVD risk reduction and enhance the benefit obtained by other approaches.1

Consume an Overall Healthy Diet
The majority of observational studies and clinical trials have focused on the effects of individual nutrients and foods on CVD risk. Rather than focusing on a single nutrient or food, individuals should improve their total diet. It is well-established that numerous dietary variables influence major CVD risk factors, as well as the risk of developing CVD.

Research on the health effects of the total diet verifies that healthy dietary patterns are associated with a significantly reduced CVD risk, CVD risk factors, and other chronic diseases such as diabetes.3-5 The total diet approach also helps ensure nutrient adequacy and energy balance.

The AHA recommends that individuals:

• consume a variety of fruits, vegetables, and grains (especially whole grains);

• choose fat-free and low-fat dairy products, legumes, poultry, and lean meats; and

• eat fish (preferably oily fish) at least twice per week.1

Aim for a Healthy Body Weight
Obesity, defined as a body mass index (BMI) of 30 or more kilograms per meter of height squared (kilograms per square meter), is an independent risk factor for CVD.6 A healthy body weight is defined as a BMI of 18.5 to 24.9; overweight is a BMI between 25 and 29.9. Excess body weight negatively affects CVD risk factors by increasing low-density lipoprotein (LDL) cholesterol levels, triglyceride levels, blood pressure (BP), and blood glucose levels. Excess body weight also reduces high-density lipoprotein (HDL) cholesterol and increases the risk of coronary heart disease (CHD), heart failure, stroke, and cardiac arrhythmias.1

The causes of the burgeoning increase in overweight and obesity in our society are multifactorial and include increased portion sizes; high calorie density foods; easy access to plentiful, inexpensive food; and a sedentary lifestyle. Commercial and cultural influences also encourage calorie intake in excess of calorie expenditure. Since no one factor is responsible, the optimal strategy to check the obesity epidemic must be multifactorial.1

Achieving and maintaining a healthy weight throughout life are critical to reducing CVD risk. Preventing weight gain should be emphasized, since losing weight and maintaining the loss are more difficult (eg, greater calorie reduction and more physical activity) than preventing the weight gain.1

Aim for Recommended Cholesterol Levels
CVD risk rises proportionately with increasing LDL cholesterol levels. An LDL level of less than 100 milligrams per deciliter is considered optimal and 100 to 129 milligrams per deciliter is near or above optimal. An LDL level of 130 to 159 milligrams per deciliter is considered borderline high, 160 to 189 milligrams per deciliter is high, and greater than 190 milligrams per deciliter is very high.8,9 Current recommendations for LDL cholesterol goals depend on the estimated 10-year risk of developing CVD and the presence of CVD-related risk factors.7,8

While drug therapy is often prescribed for individuals at moderate or high risk, dietary changes are recommended for all individuals. The strongest dietary determinants of elevated LDL cholesterol concentrations are consumption of dietary saturated fatty acids and trans fatty acids. Trans fatty acids raise LDL cholesterol levels slightly less than saturated fatty acids, but they also lower HDL cholesterol, thereby increasing CVD risk. Saturated fatty acids raise both LDL and HDL cholesterol concentrations. Dietary cholesterol and excess body weight are positively related to LDL cholesterol levels but have less effect than dietary fatty acids.

HDL cholesterol directly protects against atherosclerosis development and is inversely related to the risk of developing CVD.7 The major nonhereditary determinants of low HDL cholesterol levels are elevated blood glucose, diabetes, elevated triglycerides, very low-fat diets (less than 15% energy as fat), and excess body weight. There are no HDL cholesterol goals, but levels below 40 milligrams per deciliter in men and 50 milligrams per deciliter in women are considered one of the criteria for metabolic syndrome.9 While there are no triglyceride goals, levels of 150 milligrams per deciliter are considered one of the criteria for metabolic syndrome.9 There is generally an inverse relationship between HDL cholesterol and triglyceride levels, and the determinants of high triglycerides are usually the same as for low HDL cholesterol.

Aim for a Normal BP
BP is a consistent, continuous, and independent risk factor for CVD and renal disease. A normal BP is a systolic BP below 120 millimeters of mercury and a diastolic BP below 80 millimeters of mercury. CVD risk increases progressively throughout the range of BP, including the prehypertensive range (a systolic BP of 120 to 139 millimeters of mercury or diastolic BP of 80 to 89 millimeters of mercury). Thus, efforts to reduce BP to normal levels are necessary, even among individuals with prehypertension.

Dietary factors have a major role among the environmental factors that influence BP, and a large body of research indicates that multiple dietary factors affect BP.10 Dietary changes that lower BP include reduced salt intake, calorie deficit to promote weight loss (if overweight or obese), moderation of alcohol consumption (among those who drink), increased potassium intake, and consumption of an overall healthy diet based on the DASH (Dietary Approaches to Stop Hypertension) diet.10 The DASH diet is carbohydrate-rich and emphasizes fruits, vegetables, and low-fat dairy products. It includes whole grains, poultry, fish, and nuts and is reduced in fats, red meat, sweets, and sugar-containing beverages. Replacing some of the carbohydrate in the DASH diet with either plant protein sources or monounsaturated fat can further lower BP.4

Aim for a Normal Blood Glucose Level
A normal fasting blood glucose level is at or below 100 milligrams per deciliter. Diabetes is defined by a fasting glucose level equal to or greater than 126 milligrams per deciliter, and type 2 diabetes is the most common form. Hyperglycemia and insulin resistance are related to many cardiovascular complications, including CHD, stroke, peripheral vascular disease, cardiomyopathy, and heart failure. Achieving a modest weight loss by reducing calorie intake and increasing physical activity can decrease insulin resistance, improve glucose control, and reduce the metabolic abnormalities of diabetes. Weight loss and increased physical activity can delay and possibly prevent the onset of diabetes.11

Be Physically Active
Regular physical activity is crucial for maintaining physical and cardiovascular fitness, sustaining healthy weight, and maintaining weight loss. Regular physical activity improves CVD risk, metabolic syndrome risk factors (BP, lipid profiles, and blood sugar), and lowers the risk of developing other chronic diseases, including type 2 diabetes, osteoporosis, obesity, depression, and breast and colon cancers.1

Avoid Tobacco Products
The AHA strongly and explicitly approves of efforts to eliminate the use of tobacco products and minimize exposure to secondhand smoke. There is overwhelming evidence that tobacco products and secondary exposure to tobacco smoke increase CVD risk, cancer, and other serious illnesses. Particular attention should be given to preventing weight gain in habitual smokers who quit smoking. However, concern about weight gain does not justify continued use of tobacco products.1

Diet and Lifestyle Recommendations
The AHA 2006 Diet and Lifestyle Recommendations (see Table 2) are a prescription to promote cardiovascular health and reduce CVD risk. They allow maximal flexibility in their implementation among groups of individuals with a wide range of dietary preferences and nutritional requirements. Although the recommendations provide guidance about specific nutrients and types of foods, the importance of an overall healthy diet and lifestyle cannot be overstated. A focus on the total diet is preferred over a specific focus on individual dietary components.1

Balance Calorie Intake and Physical Activity
Individuals must match energy intake to energy expenditure to avoid weight gain after childhood. Individuals should be aware of the calorie content of the foods and beverages consumed and portion sizes to control caloric intake. The macronutrient composition of a diet (eg, the amount of fat, carbohydrate, and protein) has little effect on energy balance, unless manipulating the macronutrients influences total energy intake or expenditure. Individuals should implement and maintain a diet consistent with AHA recommendations while reducing caloric intake.1,12

The AHA recommends that all adults accumulate 30 minutes or more of physical activity most days of the week. Individuals obtain additional metabolic benefits if activity levels surpass this minimum recommendation. Adults attempting to lose weight or maintain weight loss and children should accrue at least 60 minutes of physical activity most days of the week. The physical activity can be accumulated throughout the day.

It is important to encourage behaviors and time management skills that will facilitate achieving and maintaining these activity goals over time. Sedentary activities (eg, watching television, surfing the Web, and playing computer games) should be reduced. Opportunities for movement that occur in daily life (eg, walking the dog, taking the stairs instead of the elevator, walking for 30 minutes at the lunch hour) should be embraced.1

Consume Vegetables and Fruits
Most vegetables and fruits are rich in nutrients, low in calories, and high in fiber. They help meet nutrient requirements without adding substantially to overall energy intake. In short-term randomized trials, diets rich in vegetables and fruits lower BP and improve other CVD risk factors.5 In longitudinal observation studies, persons who habitually consume such diets have a lower risk of developing CVD, especially stroke.13

A variety of deeply colored whole fruits and vegetables are recommended (eg, berries, spinach, carrots, peaches), since they are higher in micronutrient content and cardioprotective phytochemicals than other fruits, vegetables, and juices.1 A diet rich in fruits and vegetables helps reduce the energy density of the diet and control energy intake.1

Choose Whole Grain, High-Fiber Foods
Dietary patterns that are high in whole grain products and fiber are associated with improved diet quality and a lower CVD risk. Soluble or viscous fibers (particularly beta-glucan and pectin) promote reductions in LDL cholesterol levels beyond those achieved by a diet low in saturated and trans fatty acids and cholesterol.14 Soluble fiber may reduce endogenous cholesterol production by increasing short-chain fatty acid synthesis.1 Insoluble fiber is associated with decreased CVD risk and slower progression of CVD in high-risk individuals.14 At least one half of grain intake should come from whole grains.1

Consume Fish Regularly
Fish, notably oily fish, is rich in the very long-chain omega-3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Consuming two servings (roughly 8 ounces) per week of fish high in EPA and DHA is linked with a reduced risk of both sudden death and death from CHD in adults.1,15

Due to contamination of certain fish with mercury and other organic compounds, consumers should check with local and state authorities about types of fish and watersheds that may be contaminated. They should also check the FDA Web site for the most up-to-date information on recommendations for specific subgroups of the U.S. population (eg, children and pregnant women). The benefits of eating fish far outweigh the potential risks for adult men and postmenopausal women when eaten within the guidelines established by the FDA and Environmental Protection Agency.1

Limit Fats and Cholesterol
The AHA recommends that people consume less than 7% of energy as saturated fat, less than 1% of energy as trans fat, and less than 300 milligrams of dietary cholesterol per day. There is a positive linear relationship between saturated fat, LDL cholesterol, and CVD risk. Individuals should:

• choose lean meats and vegetable alternatives (eg, beans);

• select fat-free (skim), 1% fat, and low-fat dairy products; and

• minimize intake of partially hydrogenated fats.1

Diets low in saturated fat, trans fat, and cholesterol decrease CVD risk primarily by reducing LDL cholesterol.1 The major source of saturated fat is animal fat (meat and dairy) and the primary sources of trans fat are partially hydrogenated fats, used to prepare commercially fried and baked products. Eggs, dairy, and meat are the major sources of dietary cholesterol.

Several clinical trials have shown that replacing saturated fats with polyunsaturated fats reduces the risk of developing CHD. Prospective observational studies have demonstrated that diets rich in monounsaturated fats reduce CHD risk. The AHA, Institute of Medicine, and the National Cholesterol Education Program all agree that consuming 25% to 35% of energy from fat is appropriate for a healthy dietary pattern.1

Minimize Added Sugars
The primary reasons to consume fewer beverages and foods with added sugars are to lower total calorie intake and promote nutrient adequacy. Individuals who ingest large amounts of beverages with added sugars tend to consume more calories and gain weight. Evidence suggests calories consumed as liquid are not as filling as calories from solid food, which may negatively affect achieving and maintaining a healthy body weight.1

Consume Little or No Salt
There is a progressive dose-response relationship between sodium intake and BP: As salt (sodium chloride) intake increases, so does BP. A reduced sodium intake can prevent hypertension, lower BP in individuals on antihypertensive medication, and assist hypertension control. A decreased sodium intake is also linked with a blunted age-related rise in systolic BP and a reduced risk of cardiovascular events and congestive heart failure. A potassium-rich diet reduces BP and blunts the BP-raising effects of a high sodium intake.16 The AHA recommends 2.3 grams of sodium per day as an upper limit of intake.1

Consume Alcohol Only in Moderation
Moderate alcohol intake (wine and other alcoholic beverages) is associated with reduced cardiovascular events. However, unlike other potentially beneficial dietary components, alcohol consumption cannot be recommended to reduce CVD risk due to the serious adverse health and social consequences of a high alcohol intake.1

If alcoholic beverages are consumed, they should be consumed with meals and limited to no more than two drinks per day for men and one drink per day for women. A 12-ounce bottle of beer, a 4-ounce glass of wine, and a 1.5-ounce shot of 80-proof spirits all contain the same amount of alcohol (0.5 ounces) and are considered a “drink equivalent.” Alcohol has a higher calorie density than protein or carbohydrate and is considered a source of “empty calories.”1

When Eating Out, Eat Well
Many types of foods consumed away from home, especially fast foods, are high in saturated fat, trans fatty acids, cholesterol, added sugars, and sodium and are low in fiber and micronutrients. There is a positive relationship between frequency of meal consumption at fast-food restaurants and total energy intake, weight gain, and insulin resistance.17 Attaining a healthy diet requires individuals to make wise choices when they eat food away from home.1

Other Dietary Factors
The AHA recommends plant foods rich in antioxidants, not antioxidant supplements, to reduce CVD risk. Although observational studies suggested that high intakes of antioxidant vitamins from food and supplements were associated with a lower CVD risk, clinical trials of antioxidant vitamin supplements did not confirm this benefit and some trials have documented potential adverse effects.1,18

There is minimal evidence of a cardiovascular benefit from consuming soy protein or isoflavone supplements instead of dairy or other proteins. Although earlier research suggested that soy protein had a favorable effect on LDL cholesterol, research conducted over the past five years has not confirmed those results.1,19

At this time, there is not adequate evidence that folate and other B vitamin supplements reduce CVD risk by reducing homocysteine levels. Folate, and to a lesser extent vitamins B6 and B12, is inversely associated with blood homocysteine levels. However, trials of homocysteine-reducing vitamin therapy have been unsatisfactory.1

Phytochemicals (eg, flavonoids and sulfur-containing compounds) found in fruits and vegetables may help reduce the risk of atherosclerosis. However, most of these compounds are not well-characterized, and their modes of action are not established. Following the AHA dietary recommendations (Table 2) is the most sensible way to ensure optimum intake of macronutrients, micronutrients, and associated bioactive compounds.1

The AHA recommends that patients without documented CHD eat a variety of fish, preferably oily, at least twice per week. Patients with documented CHD should consume 1 gram total of EPA plus DHA per day, preferably from oily fish. EPA plus DHA supplements could be considered in consultation with a physician. Individuals with hypertriglyceridemia under a physician’s care can consume supplements providing 2 to 4 grams of EPA plus DHA per day.15

Plant stanols/sterols lower LDL cholesterol levels by up to 15% and are a therapeutic option for individuals with elevated LDL cholesterol levels.20 Maximum effects are observed at plant stanol/sterol intakes of 2 grams per day. They are available in a wide variety of foods, drinks, and soft gel capsules. Individuals need to consume plant stanols/sterols daily, just as they would use lipid-lowering medication.1

A substantial and expanding body of evidence has connected many aspects of diet in the pathogenesis of CVD and risk factors. Lifestyle modifications can successfully control CVD risk factors and lower CVD risk. Individuals should aim for a desirable body weight, be physically active, avoid tobacco exposure, and follow a diet and lifestyle consistent with AHA dietary recommendations.1

— Ellen Coleman, MA, MPH, RD, is a nutrition consultant at The Sport Clinic in Riverside, Calif.

References
1. Lichtenstein AH, Appel LJ, Brands M, et al. Diet and lifestyle recommendations revision 2006. A scientific statement from the American Heart Association Nutrition Committee. Circulation. 2006;114(1):82-96.

2. Krauss RM, Eckel RH, Howard B, et al. AHA Dietary Guidelines: Revision 2000: A statement for healthcare professionals from the Nutrition Committee of the American Heart Association. Circulation. 2000;102(18):2284-2299.

3. Knoops KT, de Groot LC, Kromhout D, et al. Mediterranean diet, lifestyle factors, and 10-year mortality in elderly European men and women: The HALE project. JAMA. 2004;292(12):1433-1439.

4. Appel LJ, Sacks FM, Carey VI, et al. The effects of protein, monounsaturated fat, and carbohydrate intake on blood pressure and serum lipids: Results of the OmniHeart randomized trial. JAMA. 2005;294(19):2455-2464.

5. van Dam RM, Rimm EB, Willett WC, et al. Dietary patterns and risk for type 2 diabetes mellitus in U.S. men. Ann Intern Med. 2002;136(3):201-209.

6. Rashid MN, Fuentes F, Touchon RC, et al. Obesity and the risk for cardiovascular disease. Prev Cardiol. 2003;6(1):42-47.

7. Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Executive summary of the third report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). JAMA. 2001;285(19):2486-2497.

8. Grundy SM, Cleeman JI, Merz CN, et al. Implications of Recent Clinical Trials for the National Cholesterol Education Program Adult Treatment Panel III Guidelines. Circulation. 2004;110(2):227-239.

9. Wilson PW, Grundy SM. The metabolic syndrome: A practical guide to origins and treatment: Part II. Circulation. 2003;108(13):1537-1540.

10. Appel LJ, Brands MW, Daniels SR, et al; American Heart Association. Dietary approaches to prevent and treat hypertension: A scientific statement from the American Heart Association. Hypertension. 2006;47(2):296-308.

11. Lindstrom J, Louheranta A, Mannelin M, et al; Finnish Diabetes Prevention Study Group. The Finnish Diabetes Prevention Study (DPS): Lifestyle intervention and 3-year results on diet and physical activity. Diabetes Care. 2003;26(1):3230-3236.

12. Klein S, Burke LE, Bray GA, et al; American Heart Association Council on Nutrition, Physical Activity, and Metabolism. Clinical implications of obesity with specific focus on cardiovascular disease: A statement for professionals from the American Heart Association Council on Nutrition, Physical Activity, and Metabolism: Endorsed by the American College of Cardiology Foundation. Circulation. 2004;110(18):2652-2967.

13. Hung HC, Joshipura KJ, Jiang R, et al. Fruit and vegetable intake and risk of major chronic disease. J Natl Cancer Inst. 2004;96(21):1577-1584.

14. Pereira MA, O’Reilly E, Augustsson K, et al. Dietary fiber and risk of coronary heart disease: A pooled analysis of cohort studies. Arch Intern Med. 2004;164(4):370-376.

15. Kris-Etherton PM, Harris WS, Appel LJ; Nutrition Committee. Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Circulation. 2002;106(21):2747-2757.

16. Sacks FM, Svetkey LP, Vollmer WM, et al. DASH-Sodium Collaborative Research Group. Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. N Engl J Med. 2001;344(1):3-10.

17. Pereira MA, Kartashov AI, Ebbeling CB, et al. Fast-food habits, weight gain, and insulin resistance (the CARDIA study): 15-year prospective analysis [published correction in Lancet. 2005;365(9464):1030]. Lancet. 2005;365(9453):36-42.

18. Kris-Etherton PM, Lichtenstein AH, Howard BV, et al; Nutrition Committee of the American Heart Association Council on Nutrition, Physical Activity, and Metabolism. Antioxidant vitamin supplements and cardiovascular disease. Circulation. 2004;110(5):637-641.

19. Sacks FM, Lichtenstein A, Van Horn L, et al; American Heart Association Nutrition Committee. Soy protein, isoflavones, and cardiovascular health: An American Heart Association science advisory for professionals from the Nutrition Committee. Circulation. 2006;113(7):1034-1044.

20. Grundy SM. Stanol esters as a component of maximal dietary therapy in the National Cholesterol Education Program Adult Treatment Panel III report. Am J Cardiol. 2005;96(1A):47D–50D.