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Clin. Cardiol. 22, (Suppl. III), III-16–III-22 (1999)
Kathryn M. Kolasa, Ph.D., R.D., L.D.N.
Department of Family Medicine, East Carolina University, School of Medicine, Greenville, North Carolina, USA
Background: The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure placed increased emphasis on lifestyle modification for the prevention and management of hypertension. The Dietary Approaches to Stop Hypertension (DASH) diet, rich in fruits, vegetables, nuts, and low-fat dairy foods, with reduced saturated and total fats, was found in clinical trials to lower blood pressure substantially and significantly. The DASH diet appears appropriate for use in the primary care setting, although it is unknown whether results will mirror those found in clinical trial.
Methods: A review of the literature of successful physician-based dietary interventions and of the Stages of Change model as it applies to dietary behavior was completed. Some changes needed to adapt the DASH diet to the outpatient family practice setting were identified and implemented among a predominantly non-Caucasian (56%), female (61%) population. The most common concerns and diagnoses among this population are essential hypertension, diabetes, and general medical examination.
Results: Under study conditions, DASH reported that patients experienced an average reduction of 6 mmHg systolic and 3 mmHg diastolic blood pressure. Results were better in those with high blood pressure — systolic dropped by 11 mmHg and diastolic dropped by 6 mmHg. This reduction occurred within 2 weeks of starting the plan. Our clinical experience matches these published results.
Conclusions: The DASH diet can be used successfully by patients in the primary care setting to lower blood pressure. The challenge of incorporating this intervention into primary care by more practitioners remains. The challenges for the patient and provider to sustain lifestyle modifications are formidable and also continuing.
Key words: Dietary Approaches to Stop Hypertension, Stages of Change model, patient education, primary care, blood pressure, diet, nutrition, hypertension
Hypertension is a common problem among patients visiting primary care offices, ranking as the number one reason for office visits in a survey of 84 Ohio family practices.1 We believe we have a similar prevalence in our own practice, which serves a population at high risk for the chronic conditions of obesity, hypertension, type 2 diabetes, and cardiovascular disease. The publication of the Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI)2 prompted us to explore the adaptation of these national guidelines to our practice.
Like many primary care practices, we are shifting our office focus from acute care to prevention and management of chronic condition care. We are in the process of piloting an ambulatory care pathway for type 2 diabetes and planning a pathway for hypertension. Lifestyle modification, including a significant emphasis on dietary behaviors, is to be included in these pathways based, in part, on JNC VI's expanded emphasis on lifestyle modification for hypertension prevention and management. The JNC VI guidelines included publication of the Dietary Approaches to Stop Hypertension (DASH) diet in its Appendix. A medical record audit of our practice noted that while diet and weight advice were provided to most of our patients with hypertension, there remained many opportunities for improvement in compliance and outcomes. As a result, we decided to test DASH in our primary care setting to see whether patients could adhere to the eating pattern and benefit their blood pressure status.
We have adopted an evidence-based approach to evaluating clinical research as we make changes in our clinical care. Evidence-based medicine combines individual clinical expertise with the best available clinical evidence gathered from systematic research into a topic. Following the guidelines for teaching evidence-based medicine,3 we completed a review of the paper Clinical Trial of the Effects of Dietary Patterns on Blood Pressure,4 as well as the paper that described the DASH trial design more fully.5 In addition, we reviewed the recent literature on the Stages of Change Model as applied to dietary behaviors. 6–10 Moreover, we reviewed the literature that described successful nutrition interventions in primary care offices.* A search of the World Wide Web for patient education materials to support the implementation of DASH was completed. The materials identified along with our current diet and hypertension patient education materials were reviewed for appropriateness to our patient population, which is primarily non-Causcasian (56%), female, (61%), and young (51% between 25 and 54 years; 20% >= 55 years). Moreover, essential hypertension is the most common concern/diagnosis at our Family Practice Center.
We judged the DASH diet (Fig. 1) to be an appropriate intervention for our patient population since the clinical trial4 described lowered blood pressure outcomes that would be important for our patients. However, we identified several behaviors and beliefs of our patient-care providers that would need modification for the successful use of DASH. First, providers would need to assess and counsel patients on the dietary pattern as a whole, rather than on the restriction of salt or sodium; that is, the caregivers needed to adopt a philosophy that included encouraging the consumption of a health-promoting dietary pattern rather than restricting individual foods or nutrients. Second, some modification of current patient teaching would be required. While most patient education materials for diet and hypertension provide general guidelines that are consistent with DASH (e.g., choose more vegetables and fruits; choose more whole grains, breads and cereals, pasta, rice, dry beans, and peas), some give specific advice that is not compatible. For instance, the DASH diet includes a category of "Nuts, Seeds, and Dry Beans" separate from the "Fats and Oils" group and recommends 4–5 servings from this category per week. This recommendation is based on the high levels of energy, protein, fiber, magnesium, calcium and potassium in these foods. The American Heart Association's (AHA) "Dietary Treatment of High Blood Pressure and High Cholesterol"11 food groupings, however, are not completely consistent with the DASH pattern. The AHA Step I diet planning system places nuts and seeds in the "Fats and Oils" group and the number of servings from this group is restricted, rather than recommended as in DASH. In AHA Step I, all the fat and oil servings generally are used for cooking and flavoring, unless an individual patient has a high caloric need. This leads to dietary advice that would restrict the consumption of nuts and seeds. Third, the literature suggests that physicians wait until a patient has a chronic disease before giving nutrition advice. A shift toward physicians providing more preventive nutrition advice is needed.
Finally, several researchers have documented that the use of simple dietary assessment and counseling tools in office practice are important in creating successful patient outcomes. Dietary screeners have been widely used in cardiovascular disease counseling.12–14 These screeners needed modification to meet the DASH eating pattern by including more servings of fruits, vegetables, and grains, and a transfer of seeds and nuts out of the snack group into a distinct seeds, nuts, and dried beans group (Fig. 2). Only a limited number of patient education materials that specifically support the DASH diet is available (Fig. 3), although more are expected in coming months.
Prochaska's Stages of Change Model (Table I) has been found to be applicable to dietary behavior; however, its application to inappropriate eating habits is more complex than with other unhealthful behaviors, including smoking cessation and substance abuse.6–10 Individuals do not necessarily progress through the stages of precontemplation, contemplation, preparation, action, and maintenance in a linear fashion when food consumption is considered. In addition, an individual could be in one stage (e.g., action) for a particular dietary behavior, such as eating more fruit, but be in different stage (e.g., precontemplation ) for another dietary behavior, such as eating more legumes, nuts, or seeds. Studies to date, however, document that food knowledge and an increasingly positive attitude about the role of diet in disease prevention increase across the stages. To apply these research findings, then, health care providers must assist patients to advance from one stage to the next to help assure a successful nutrition intervention. The following three DASH-related cases from our practice illustrate such a process for both patient and provider.
Ms. B. (Table II) is in the precontemplation stage. She was unaware both that her blood pressure was elevated and that following the DASH diet could help lower her blood pressure. She was aware, however, that she was overweight. Dieting was not an option for Ms. B. who was afraid that any diet would leave her hungry and, therefore, was not motivated to embark on one. The appropriate role for her health care provider is to describe the role DASH might play in lowering her blood pressure and to provide an appropriate patient education handout. On the subsequent office visit, it was not surprising that the patient had made no changes in her diet; however, she did present with a willingness to hear more about DASH. She indicated she was pleased that she was not told she had to lose weight. Moreover, she believed she would not be hungry following the DASH plan because it appeared to allow adherents to consume a substantial amount of food. The provider's role at this stage is to reinforce Ms. B.'s interest in DASH and negotiate the first behavior change.
Mr. T.K. (Table III) is in the contemplation stage. He had noticed DASH handouts in the office waiting room and completed a DASH screener while waiting. He asked the physician if DASH was appropriate for him. Together they reviewed which dietary changes would be most helpful for Mr. T.K. to make. He was intrigued that if he adopted the entire diet he could likely determine its effectiveness in a 2-week period. The physician provided handout materials and inquired if Mr. T.K. would like a referral to a registered dietitian who could assist him efficiently with the dietary change.
Mr. B. (Table IV) is in the preparation stage. Without nutrition counseling he had made several changes after his last office visit, when he was diagnosed with type 2 diabetes. He had increased his fruit and vegetable consumption from two servings to five servings per day. He was unsure, however, that he could increase the number of servings to 10 each day. He had also purchased a wide array of dietary supplements. The physician congratulated him on dietary changes made and inquired about his confidence and ability to make further changes. In this case, it appears that the patient needs assistance in problem solving and confidence building, which requires more time and skill than the physician could offer. In actuality, the patient was consuming more than five servings of fruits and vegetables, but was confused about serving size. A referral to a registered dietitian was indicated here.
A variety of researchers have documented the need for several counseling visits so they can provide patients optimally with the needed knowledge, skills, and attitudes to make agreed-upon dietary changes. Too often, however, the support ends when the patient has entered the action stage. Patients in the action phase have made changes that have lasted 6 months. The physician needs to assist these patients into the maintenance phase by congratulating them and ensuring them that they have the support (e.g., frequency of appointments, patient education materials, referral to a registered dietitian) needed to continue adoption of the DASH diet. Patients in the maintenance phase are pleased with the results of adopting DASH. They have made the changes for more than 6 months, but their need for reinforcement and continued education has not ended. They need reinforcement from the physician to maintain the behaviors or, as needed, to recover from a relapse. For example, a patient facing a first holiday season or vacation after adopting the DASH diet may need specialized handouts or reminders of the importance of the changes to long-term health. A "tune-up" referral to a registered dietitian can help yield sustained lifestyle modification.
Patients need to be given specific information about reasonable expectations for blood pressure lowering when they follow the DASH diet. Furberg et al.15 summarized the outcomes of more than 100 published, randomized clinical trials evaluating hypertension prevention and treatment, and described the effects as modest. The lifestyle modifications included weight loss, exercise, reduced alcohol or sodium, and supplementation of potassium, magnesium, calcium, fish oil, or dietary fiber. Appel et al.4 found that a diet rich in fruits, vegetables, and low-fat dairy foods with reduced saturated and total fat substantially lowered blood pressure in their study populations, which contained both normotensive and hypertensive individuals. For those with hypertension, the DASH diet reduced systolic and diastolic blood pressure by 11 and 5.5 mmHg, respectively, more than the control diet. For those without hypertension, the DASH diet resulted in a 3.5 mmHg systolic and a 2.1 mmHg diastolic reduction.
At this time, there are no published reports describing the impact of DASH in a nonstudy environment. We have had limited experience in the outpatient setting over the last 9 months. Generally, we have found that patients are more positive about attempting the DASH diet than they were about previous restrictive diets. While we do not have statistics to confirm our impressions, some of our providers have recommended the DASH diet to their patients who have matched or exceeded the blood pressure lowering effect described in the DASH trial. Some providers have not yet adopted DASH as a tool for their patients, and some patients continue to be unable or unwilling to modify their dietary behavior.
It is our impression that DASH can be adapted for use in the primary care setting by making several changes, both in the attitudes of providers and patients and in educational materials. Some patients appear to benefit from this approach to lifestyle modification. However, several challenges remain. The first is to determine the best way to incorporate the DASH diet into the primary care practice and assess its effectiveness. The second is how to provide patients and providers with the strategies they need to sustain positive lifestyle modifications.
The work described in this paper was done without grant support. The work was supported by the Department of Family Medicine, East Carolina University.
Address for reprints:
Kathryn M. Kolasa
Department of Family Medicine
East Carolina University
Greenville, NC 27858, USA