Diet Change to Reduce Residual Risk After Myocardial Infarction
A 56-year-old man presents for outpatient follow-up 6 weeks after a non-ST-elevation myocardial infarction (NSTEMI) treated with a percutaneous coronary intervention. He reports good adherence to dual antiplatelet therapy, a beta-blocker, an angiotensin-converting enzyme inhibitor, and atorvastatin 80 milligrams daily. His physical exam is notable only for a body mass index of 32 and visceral adiposity. Lab data from 2 days ago are shown below:
Fasting blood glucose: 114 mg/dl
Total cholesterol: 230 mg/dl
High-density lipoprotein cholesterol (HDL-C): 45 mg/dl
Non-HDL-C: 185 mg/dl
Low-density lipoprotein cholesterol (LDL-C): 130 mg/dl
Triglycerides: 275 mg/dl
When you inquire about his diet, the patient admits to routine consumption of eggs, bacon, sausage, sweetened cereals, donuts, lunch meats, hamburgers, hot dogs, French fries, and chips, and reports a low intake of fruits, vegetables, fish, whole grains, nuts, beans and legumes. He is single, typically eats out or purchases ready-made foods, and rarely cooks. You discuss diet interventions with the patient.
All of the following statements about diet intervention in post-MI patients are true, EXCEPT:
The correct answer is: D. Core competencies have standardized diet education across cardiac rehabilitation programs.
Although the American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR) has established nutrition-related core competencies for cardiac rehabilitation (CR) programs (Table 1),1 evidence suggests wide variation in how these are implemented. A 2012 survey of all CR programs in Ohio showed that almost all offered group nutrition lectures. However, only 27% provided individual diet counseling to all participants. In the remaining 73% of programs, only 43% of overweight patients, 63% of obese patients. and 80% of patients with diabetes received individual nutrition counseling.2 A 2004 national survey of 250 randomly selected CR programs also showed significant differences in Registered Dietician (RD) staff presence, which was more common in accredited CR programs and associated with more comprehensive nutrition education.3 Therefore, it is important to understand the specific diet interventions offered by a CR program. If individual counseling by an RD is not routinely provided, this service should be requested or a separate outpatient referral should be considered.
Table 1: AACVPR Nutrition Core Competency Skills
Dietary intake assessment
Diet education and counseling
Behavioral interventions to promote adherence and
Measurement and reporting of diet outcomes
Answer option A is true. Diet changes reduce coronary risk via multiple mechanisms, and the effect size is significant. Data from numerous lines of evidence demonstrate that dietary components significantly impact cardiovascular morbidity and mortality. Mechanisms include effects on blood lipids, blood pressure, blood glucose, body weight, insulin sensitivity, oxidative stress, inflammation, endothelial function, platelet activation, and arrhythmogenesis.4-7 Moreover, data demonstrate a significant effect size of combined diet changes on outcomes in post-MI patients. In a 2013 study of subjects in the Nurses' Health Study and Health Professionals Study who were post-MI and underwent diet assessment via the Alternative Healthy Eating Index (AHEI2010), which parallels the Mediterranean diet pattern, those in the highest quintile of the quality diet score had an adjusted pooled hazard ratio (HR) for all-cause mortality of 0.76 (95% confidence interval [CI] 0.6-0.96) and for cardiovascular mortality of 0.73 (95% CI 0.51-1.04) compared to those in the lowest quintile. A greater improvement in the index from pre- to post-MI was also associated with lower all-cause and cardiovascular mortality (HR 0.71, 95% CI 0.56-0.91, and HR 0.60, 95% CI 0.41-0.86, respectively).8 Although removing alcohol intake attenuated these estimates, the findings are aligned with other data that show a significant mortality reduction from a combination of diet changes post-MI.9,10
Answer option B is true. A large percentage of post-MI patients adhere poorly to diet recommendations. Despite wide dissemination of evidence-based diet recommendations (Table 2),11 evidence demonstrates that adherence to cardio-protective diets in patients with coronary disease (CHD) is sub-optimal. In the 2013 Nurses' Health and Health Professionals study cited above,8 the majority of subjects showed little change in diet scores post-MI. In a 2008 survey study of diet quality in subjects one year after the diagnosis of coronary heart disease, the average AHEI score was only 30.8 points out of a maximum of 80, and only 10-15% met recommendations for vegetable, fruit, and fiber intake, and trans-fat restriction (a higher AHEI score reflects a better diet).12 Similarly, in the cross-cultural Prospective Urban Rural Epidemiology (PURE) study, only 39% of > 7,500 subjects with a history of coronary heart disease or stroke reported adherence to healthy diets as assessed via the AHEI.13 Numerous individual, family, community and public barriers to diet change have been identified.14
Table 2: ACC/AHA 2013 Class I-IIb Diet Recommendations
For LDL and BP Lowering
For LDL Lowering
For BP Lowering
Answer option C is true. Cardiac rehabilitation improves diet outcomes, more so if there is Registered Dietitian involvement. CR has been shown to improve diet self-efficacy compared to non-participation.15 Moreover, CR diet and lipid outcomes have been shown to be superior when education is provided by an RD,16 which is associated with more individual counseling and experiential learning.3 The latter engages patients in healthy food sourcing, budgeting, and label reading, often via supermarket tours, and in cooking demonstrations, all of which may improve diet outcomes.17
Answer option E is true. Diet counseling by physicians has been hampered by lack of training, but this may be changing. The 2009 ACC competency statement on post-graduate education in prevention recommends that trainees understand the origins of dietary fats and cholesterol, their effects on blood lipids, and diets for managing lipid disorders.18 The new ACC COCATS 4 document on Training in Preventive Cardiovascular Medicine19 recommends that fellows become proficient in the principles of nutrition and obesity management. While lack of nutrition education during early medical training (on average, less than 20 hours during medical school)20 has been a barrier, this may be changing. Web-based, open-access nutrition curricula reportedly are in use by almost 50 residency programs.21 Also, at least 10 medical schools, some residency programs, and the Harvard School of Public Health have partnered with culinary schools and now offer "culinary medicine" curricula, aimed at teaching students, trainees, and practicing clinicians healthy food and cooking skills that they can use to translate diet and nutrition knowledge to their patients.22
- Hamm LF, Sanderson BK, Ades PA, et al. Core competencies for cardiac rehabilitation/secondary prevention professionals: 2010 update: position statement from the American Association of Cardiovascular and Pulmonary Rehabilitation. J Cardiopulm Rehab Prev 2011;31:2-10.
- Zullo M, Jackson LW, Whalen CC, Dolanksy MA. Evaluation of the recommended core components of cardiac rehabilitation programs: opportunity for quality improvement. J Cardiopulm Rehab Prev 2012;32:32-40.
- Cavallaro V, Dwyer J, Houser RF, et al. Influence of dietician presence on outpatient cardiac rehabilitation nutrition services. J Am Diet Assoc 2004;104:611-14.
- Hu F, Willett WC. Optimal diets for prevention of coronary heart disease. JAMA 2002;288:2569-78.
- Okeefe JH, Gheewala NM, O'Keefe JO. Dietary strategies for improving post prandial glucose, lipids, inflammation and cardiovascular health. J Am Coll Cardiol 2008;51:249-55.
- Mente A, de Koning L, Shannon HS, Anand SS. A systematic review of the evidence supporting a causal link between dietary factors and coronary heart disease. Arch Inter Med 2009;169:659-69.
- Mozaffarian D, Appel LJ, Van Horn L. Components of a cardioprotective diet: new insights. Circulation 2011;123:2870-91.
- Li S, Chiuve SE, Flint A, et al. Better diet quality and decreased mortality among myocardial infarction survivors. JAMA Intern Med 2013;173:1808-19.
- Iestra JA, Kromhout D, van der Schouw YT, Grobbee DE, Boshuizen HC, van Staveren WA. Effect size estimates of lifestyle and dietary changes on all-cause mortality in coronary artery disease patients. Circulation 2005:112;924-34.
- deLorgeril M, Salen P, Martin JL, Monjaud I, Delaye J, Mamelle N. Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction: Final report of the Lyon Diet Heart Study. Circulation 1999;99:779-85.
- Eckel RH, Jakicic JM, Ard JD, et al. 2013 AHA/ACC Guideline on lifestyle management to reduce cardiovascular risk: A report from the ACC/AHA task force on practice guidelines. J Am Coll Cardiol 2014;63(25 PA):2960-84.
- Ma Y, Li W, Olendzki BC, et al. Dietary quality 1 year after diagnosis of coronary heart disease. J Am Diet Assoc 2008;108:240-7.
- Teo K, Lear S, Islam S, et al. Prevalence of a healthy lifestyle among individuals with cardiovascular disease in high, middle and low income countries: PURE Study. JAMA 2013;309:1613-21.
- Rippe J, Waite MA. Implementing heart healthy diet guidelines. Moving from ideal to real. Am J Lifestyle Med 2012;6:96-112.
- Sharp PB, Sayler J. Self-efficacy and barriers to healthy diet in cardiac rehabilitation participants and non-participants. J Cardiovasc Nursing 2012;27:253-62.
- Holmes AL, Sanderson B, Maisiak R, Brown A, Bittner V. Dietician services are associated with improved patient outcomes and the MEDFICTS dietary assessment questionnaire is a suitable outcome measure in cardiac rehabilitation. J Am Diet Assoc 2005;105:1533-40.
- Reicks M, Trofholz AC, Stang JS, Laska MN. Impact of cooking and home food preparation interventions among adults: Outcomes and implications for future programs. J Nutr Educ Behav 2014;46:259-76.
- Bairey-Merz CN, Alberts MJ, Fine LJ, et al. ACCF/AHA/ACP 2009 competence and training statement: a curriculum on prevention of cardiovascular disease. A report of the American College of Cardiology Foundation/American Heart Association/American College of Physicians Task Force on Competence and Training (Writing Committee to Develop a Competence and Training Statement on Prevention of Cardiovascular Disease). American Academy of Neurology, American Association of Cardiovascular and Pulmonary Rehabilitation, American College of Preventive Medicine, American College of Sports Medicine, American Diabetes Association, American Society of Hypertension, Association of Black Cardiologists, Centers for Disease Control and Prevention, National Heart, Lung, and Blood Institute, National Lipid Association, and Preventive Cardiovascular Nurses Association. J Am Coll Cardiol 2009;54:1336-63.
- Smith SC Jr, Bittner V, Gaziano JM, et al. COCATS 4 Task Force 2: Training in Preventive Cardiovascular Medicine. J Am Coll Cardiol 2015;65:1754-62.
- Adams KM, Kohlmeier M, Zeisel SH. Nutrition education in U.S. medical schools: latest update of a national survey. Acad Med 2010;85:1537-42.
- Devries S, Dalen JE, Eisenberg DM, et al. A deficiency of nutrition education in medical training. Am J Med 2014;127:804-6.
- Association of American Medical Colleges (AAMC). The Kitchen as a Classroom: Medical Students Get a Culinary Education (AAMC website). 2014. Accessed on 3/29/2015.