February 2015 Issue

The Heart Beat: Updated Stroke Prevention Guidelines — They're Shining a Spotlight on Nutrition
By Clare Tone, MS, RD
Today's Dietitian
Vol. 17 No. 2 P. 12

In October, the American Heart Association (AHA) and the American Stroke Association (ASA) released the updated Guidelines for The Primary Prevention of Stroke. Written for health professionals, this 90-page document provides 30 new guidelines in addition to many updated from the 2011 edition.1

James Meschia, MD, chair of neurology at the Mayo Clinic in Florida and lead author of the updated guidelines, emphasizes its preventative focus. "With approximately 500,000 first-time strokes occurring each year in the United States, advances in prevention remain of vital importance." As frontline players in chronic disease prevention, nutrition professionals will want to take note of many key recommendations, including a first-ever nod to the Mediterranean diet for its role in reducing stroke risk. Other highlights include a continued emphasis on the DASH diet, a cardiovascular risk calculator to guide statin use, along with body weight and physical activity guidelines.

Dietitians are hailing it as a solid document based on good research. It should come as no surprise to see a focus on diet and lifestyle for stroke prevention following The Lancet's publication of the INTERSTROKE study in 2010.2 "They really are putting this concept of prevention, of lifestyle change, front and center," says Janet Bond Brill, PhD, RDN, a cardiovascular nutritionist and author of the books Blood Pressure Down, Cholesterol Down, and Prevent a Second Heart Attack. "The 2010 Lancet study found that 90% of stroke risk is tied to the 'big 10' modifiable risk factors. We need to put this information front and center for all health care providers to focus on the primary prevention of stroke." According to the INTERSTROKE study, the top 10 modifiable risk factors are hypertension, diet, abdominal obesity, physical activity, diabetes mellitus, apolipoproteins, cardiac causes, smoking, alcohol, and psychosocial factors (stress and depression).2

Lisa Cimperman, MS, RD, LD, a spokesperson for the Academy of Nutrition and Dietetics and clinical dietitian at University Hospital Case Medical Center in Cleveland, cites the Predimed study, published in the April 2013 issue of the New England Journal of Medicine, as influential in the development of these stroke prevention guidelines. "I think we're seeing the direct effects of Predimed, which showed significant decreased cardiovascular disease with the Mediterranean diet."3
Since cardiac causes are recognized as one of the top 10 modifiable risk factors for stroke, the link between the Mediterranean diet and heart health is finding its place in stroke prevention strategies.

The DASH and Mediterranean Diets
What continues to be emphasized by the updated AHA/ASA guidelines is the level of strong evidence behind the DASH diet for the prevention of hypertension.4 Since high blood pressure is the most significant modifiable risk factor for stroke, any step taken to reduce it goes a long way in preventing it. Therefore, the guidelines call for a DASH-style diet, which emphasizes fruits, vegetables, grains, low-fat dairy products, and reduced saturated fat with a careful balance of lean animal proteins.
Reducing sodium and increasing potassium is clearly outlined, consistent with the 2010 US Dietary Guidelines for Americans. Specifically, sodium intake of less than 2,300 mg/day for the general population and potassium intake of at least 4,700 mg/day is recommended. For people at higher risk of stroke, such as blacks, anyone with hypertension, chronic kidney disease, or those over the age of 51, sodium should be reduced to less than 1,500 mg/day.5

Despite longstanding recommendations to cut sodium and increase potassium, Americans still struggle to correct this ratio. Brill points to the built-in obstacles in our fast-food culture. "Our food supply is completely laden with sodium and depleted of potassium," she says. "Sodium makes cheap food palatable and is a very inexpensive additive to food. Potassium is found in whole foods—the foods that the Mediterranean diet and DASH diet emphasize."

One of the new recommendations is the specific inclusion of a Mediterranean diet, with its focus on fish, olive oil, red wine, and plant foods, supplemented with nuts to lower stroke risk. The document cites results from numerous studies, including Predimed, showing the cardiovascular benefits of a Mediterranean diet. Penny Kris-Etherton, PhD, RD, a distinguished professor of nutrition at Pennsylvania State University, isn't surprised. "The Predimed Trial reported a 34% to 49% reduction in stroke in individuals who followed a Mediterranean dietary pattern either with mixed nuts or extra-virgin olive oil," she says. "The reduction in stroke was particularly impressive in the mixed nut group. This group consumed 15 g per day of walnuts plus 7.5 g per day each of almonds and hazelnuts." This amounts to about one-quarter cup of nuts per day.3

While at first glance the Mediterranean and DASH diets may seem different, Brill prefers to emphasize their similarities. "I think it's very confusing to the American public when they see these diets as different when they're virtually the same. If you get down to the little differences, the DASH diet is fat-controlled. The Mediterranean diet says eat olive oil—tons of it. There's more of an emphasis on fish in the Mediterranean diet and low saturated fat. You also have the beautiful red wine thrown in, which DASH doesn't mention. DASH talks about cutting the sodium. So I think we need to combine these two, and then we'll have the perfect diet."

Patient Engagement Is Key
The new guidelines also have generated some buzz concerning blood lipids, a well-recognized modifiable risk factor for stroke. Elevated blood lipid levels can raise cardiovascular disease risk, which in turn raises stroke risk, and high cholesterol levels in the blood can build up in arteries, including those in the brain. The guidelines have replaced blood cholesterol numbers with a cardiovascular risk calculator to guide decisions about statin therapy. The calculator asks a series of simple questions (including total and HDL cholesterol levels) to generate 10-year and lifetime cardiovascular risk scores. The goal is to make things easier, for both clinicians and patients, to maximize patient engagement—a key to improved patient outcomes.

This theme of simplicity and patient engagement is echoed elsewhere in the new stroke prevention guidelines. For example, for the first time this document encourages patients to self-monitor their blood pressure. According to Meschia, "Patients will find the new guidelines empowering as well. For example, it's now an explicit recommendation of the AHA that patients engage in home blood pressure monitoring as a means of early detection of hypertension and of improving blood pressure control."

Brill applauds the approach, saying, "They make it easy. That's why I love these new guidelines; they really make it pretty simple. Making it simpler for health care providers is a great thing."

Obesity and Physical Activity
When it comes to obesity, the guidelines recommend patients with a BMI greater than 30 "be referred for intensive multicomponent behavioral interventions for weight loss."1 Mounting evidence shows a graded relationship between increasing weight and higher stroke risk independent of other risk factors. In fact, it appears that abdominal body fat may be a stronger predictor of stroke risk than BMI, but because health care practitioners consider the latter an easy tool, it's used in the document to define weight-loss goals.

The protective role of exercise is unequivocal. The stroke prevention guidelines cite numerous studies, including two meta-analyses and the research summarized in the 2008 Physical Activity Guidelines for Americans, showing a 25% to 30% reduced risk of stroke in exercisers. The stroke prevention guidelines recommend moderate- to vigorous-intensity aerobic physical activity at least 40 minutes per day three to four days per week.1

From Guidelines to Practice
Nutrition professionals are poised for an increasing role in the primary prevention of stroke. With the emphasis on body weight and blood pressure monitoring, RDs can add key assessment tools to daily practice. A simple waist circumference measurement can provide more insight than a routine BMI measurement. Likewise, checking a patient's blood pressure during a counseling visit can help screen for high blood pressure and may open the door for a "teachable moment" regarding the role of diet and hypertension. "A lot of people have high blood pressure and don't know it," Brill says. "I think it would be wonderful for dietitians to screen for high blood pressure in their counseling sessions." Cimperman agrees: "The more RDs can expand their skill sets, the better."

Dietitians will find the user-friendly risk calculator an important educational tool. It can be launched in a Web browser directly from the AHA website, where the smartphone app also can be downloaded. (See Resources for more information.) There's no doubt that with its emphasis on prevention and patient engagement, the new updated stroke prevention guidelines will challenge patients when it comes to behavior modification. "Implementation requires motivated individuals," Cimperman says. Her keys for success? "Start small. Build up. Success is the sum of several small changes. Engage family and friends with the same goals." She's also ready to share research with patients. "Understanding promotes compliance. Clients are getting more and more savvy. I like them to know what and how changes may affect their health."

Brill's No. 1 piece of advice for dietitians: "Learn what the top 10 modifiable risk factors are; they should be a red flag when your patients come in. Then assess your patients using the easy online tool and go over the risk factors to determine how to work together to control them."

The new stroke prevention guidelines provide a roadmap for nutrition professionals to become more influential in preventing strokes by mitigating the risk factors that link directly to diet and lifestyle.

— Clare Tone, MS, RD, is a freelance writer, high-altitude gardener, and nutrition instructor at Metropolitan State University in Denver.

References
1. Meschia JF, Bushnell C, Boden-Albala B, et al. Guidelines for the primary prevention of stroke: a statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2014;45(12):3754-3832.

2. O'Donnell MJ, Xavier D, Liu L, et al. Risk factors for ischaemic and intracerebral haemorrhagic stroke in 22 countries (the INTERSTROKE study): a case-control study. Lancet. 2010;376(9735):112-123.

3. Estruch R, Ros E, Salas-Salvado J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med. 2013;368(14):1279-1290.

4. Appel LJ, Moore TJ, Obarzanek E, et al. A clinical trial of the effects of dietary patterns on blood pressure. DASH Collaborative Research Group. N Engl J Med. 1997;336(16):1117-1124.

5. US Department of Agriculture, US Department of Health and Human Services. Dietary Guidelines for Americans, 2010. 7th ed. Washington, D.C.: US Government Printing Office; 2010.

 

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Resources
• Guidelines for the Primary Prevention of Stroke: A Statement for Healthcare Professionals From the American Heart Association/American Stroke Association: http://stroke.ahajournals.org/content/early/2014/10/28/STR.0000000000000046

• American Heart Association Cardiovascular Risk Calculator: http://my.americanheart.org/professional/StatementsGuidelines/PreventionGuidelines/Prevention-Guidelines_UCM_457698_SubHomePage.jsp

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