The SPRINT Study: Lowering Blood Pressure
Targets for Older Adults
By Matthew Ruscigno, MPH, RD
The recent landmark Systolic Blood Pressure Intervention Trial (SPRINT) by the National Institutes of Health found that aggressively treating hypertension reduced cardiovascular deaths so significantly that the study had to be halted out of concern for the control group.1 Hypertension is a risk factor for heart disease and stroke, the first and fifth leading causes of death for Americans, respectively. An estimated two-thirds of the population aged 65 and older have high blood pressure.2 It’s well established that lowering blood pressure reduces risk of cardiovascular disease (CVD). What made this study different is the evidence that lowering systolic blood pressure below 120 mm Hg—in contrast with the current recommendations of below 140 mm Hg—has significant, potentially life-saving benefits.
Evidence for Lowering Systolic Blood Pressure Recommendations
SPRINT researchers recruited approximately 10,000 individuals without diabetes aged 50 and older with systolic blood pressure between 130 and 180 mm Hg who were at increased risk of a cardiovascular event. Participants were randomized into a treatment group, aiming to keep systolic blood pressure at 120 mm Hg and a control group in which systolic blood pressure was maintained at current recommendations: between 135 and 139 mm Hg. Antihypertensive agents were administered to maintain proper blood pressure. Originally planned for five years of follow-up, SPRINT was halted in about three years, when the treatment group showed a 27% decrease in relative risk for all-cause mortality and after an astounding 43% decrease in relative risk for life-ending cardiovascular events. The researchers specified that the results were consistent across all study populations, including groups with the highest rates of hypertension such as those over age 75 and African Americans.
What It Means
The World Health Organization describes hypertension as a global public health crisis that affects 1 billion people worldwide, yet is largely preventable.3 This study builds on evidence that current recommendations for systolic blood pressure may be too high. One-third of the American population has hypertension, and as the No. 1 risk factor for the leading cause of death in the country, more aggressive treatment may be necessary.
The SPRINT study didn’t include or evaluate dietary factors for either of the study groups, though it’s well established that diet influences blood pressure and can be a crucial tool in lowering hypertension rates. The Dietary Approaches to Stop Hypertension (DASH) study has shown that a low-sodium diet rich in fruits, vegetables, and whole grains considerably lowers blood pressure.4 Moreover, data from the Adventist Health Study-2, a cohort of 96,000 participants, supports these findings. Compared with omnivores, vegans’ and vegetarians’ systolic blood pressure is lower by 6.8 mm Hg and 9.1 mm Hg, respectively, in those not taking antihypertensive medications.5 Obesity increases one’s risk of hypertension, but vegans and vegetarians in this cohort maintained lower blood pressure when researchers controlled for BMI. Vegans and vegetarians also were found to have lower blood viscosity, which may be a factor in blood pressure. Plant foods may be beneficial because they’re naturally lower in sodium and higher in potassium. Potassium, an electrolyte, works opposite sodium to moderate blood pressure, is a vasodilator, and increases blood flow. It also increases nitric oxide production, which also may be beneficial. Some research suggests that an increase in dietary potassium or supplementation can be as effective as medication for lowering blood pressure, especially in salt-sensitive groups.6,7 Diet can play an indirect role in preventing hypertension when used to maintain a healthy BMI and a direct role by including fruits and vegetables.
Aggressively lowering blood pressure could save thousands of lives. The following strategies can help dietitians and other health care providers, as well as clients and patients:
• Spread the knowledge. In clinical settings, make sure health care providers are aware of the SPRINT results.
• Follow a low-sodium diet that includes a variety of fruits, vegetables, and whole grains. Joseph Gonzales, RD, formerly of Nutritionfacts.org, now a nutrition consultant with Blue Cure, says, “Diet has a significant impact on managing hypertension. Some plant foods, like whole grains, flaxseed, and hibiscus tea appear to have an antihypertensive effect, and there’s promising research on their role in treating hypertension.”8-10 Phytochemicals like anthocyanins also may have hypotensive properties.
• Limit processed foods. “Highly processed foods are generally both high in sodium and low in potassium,” says Andy Bellatti, MS, RD, a corporate wellness dietitian, “which is the exact opposite of what we need to keep blood pressure well regulated.”
• Maintain a healthy BMI. Increased body weight is a risk factor for high blood pressure.5
• Exercise daily. Regular physical activity can help lower blood pressure.11
— Matthew Ruscigno, MPH, RD, is the past chair of the Vegetarian Nutrition Dietetic Practice Group of the Academy of Nutrition and Dietetics, and has a private practice in Los Angeles.
1. SPRINT Research Group, Wright JT Jr, Williamson JD, et al. A randomized trial of intensive versus standard blood-pressure control. N Engl J Med. 2015;373(22):2103-2116.
2. Nwankwo T, Yoon SS, Burt V, Gu Q. Hypertension among adults in the United States: National Health and Nutrition Examination Survey, 2011-2012. NCHS Data Brief. 2013;(133):1-8.
3. World Health Organization. A global brief on hypertension: silent killer, global public health crisis. http://apps.who.int/iris/bitstream/10665/79059/1/WHO_DCO_WHD_2013.2_eng.pdf?ua=1. Published April 2013.
4. Ndanuko RN, Tapsell LC, Charlton KE, Neale EP, Batterham MJ. Dietary patterns and blood pressure in adults: a systematic review and meta-analysis of randomized controlled trials. Adv Nutr. 2016;7(1):76-89.
5. Pettersen BJ, Anousheh R, Fan J, Jaceldo-Siegl K, Fraser GE. Vegetarian diets and blood pressure among white subjects: results from the Adventist Health Study-2 (AHS-2). Public Health Nutr. 2012;15(10):1909-1916.
6. Haddy FJ, Vanhoutte PM, Feletou M. Role of potassium in regulating blood flow and blood pressure. Am J Physiol Regul Integr Comp Physiol. 2006;290(3):R546-R552.
7. Gu D, Zhao Q, Chen J, et al. Reproducibility of blood pressure responses to dietary sodium and potassium interventions: the GenSalt Study. Hypertension. 2013;62(3):499-505.
8. Tighe P, Duthie G, Vaughan N, et al. Effect of increased consumption of whole-grain foods on blood pressure and other cardiovascular risk markers in healthy middle-aged persons: a randomized controlled trial. Am J Clin Nutr. 2010;92(4):733-740.
9. Caligiuri SP, Aukema HM, Ravandi A, Guzman R, Dibrov E, Pierce GN. Flaxseed consumption reduces blood pressure in patients with hypertension by altering circulating oxylipins via an α-linolenic acid-induced inhibition of soluble epoxide hydrolase. Hypertension. 2014;64(1):53-59.
10. Hopkins AL, Lamm MG, Funk JL, Ritenbaugh C. Hibiscus sabdariffa L. in the treatment of hypertension and hyperlipidemia: a comprehensive review of animal and human studies. Fitoterapia. 2013;85:84-94.
11. Börjesson M, Onerup A, Lundqvist S, Dahlöf B. Physical activity and exercise lower blood pressure in individuals with hypertension: narrative review of 27 RCTs [published online January 19, 2016]. Br J Sports Med. doi: 10.1136/bjsports-2015-095786.