Letters to the Editor
Dietary Management of Hypertension: What Works vs. What Matters
Am Fam Physician. 2016 Jan 15;93(2):84-86.
to the editor: Drs. Oza and Garcellano provide a useful overview of nonpharmacologic approaches for the management of hypertension. The problem is that hypertension is a surrogate, disease-oriented outcome. What family physicians should care about is not elevated blood pressure per se, but patient-oriented outcomes that matter.
It is true that elevated blood pressure raises the risk of myocardial infarction, stroke, renal failure, and death. However, it is imperative that physicians not cause more of these adverse events in attempting to control blood pressure.
For example, a previous letter in AFP reports how beta blockers may lower blood pressure but nonetheless increase patient-oriented harms (e.g., cardiovascular events and deaths).1 Nonpharmacologic approaches for the management of hypertension may do the same.
Reducing dietary sodium intake may lower blood pressure (at least minimally on average)2 but may produce other cardiovascular effects that are undesirable (e.g., through renin, aldosterone, adrenaline, noradrenaline, cholesterol, and triglycerides).3 Beyond disease-oriented outcomes, dietary sodium restriction may increase cardiovascular and all-cause mortality in patients with diabetes mellitus and increase hospitalizations and mortality in patients with congestive heart failure.3 Hospital admissions and deaths are outcomes that matter.
The Institute of Medicine (now the National Academy of Medicine) found insufficient evidence to support the recommendation to limit sodium restriction to 2,300 mg per day.4 However, it did find evidence of adverse outcomes with sodium restriction of less than 2,300 mg per day in patients with diabetes, kidney disease, or cardiovascular disease.
As my colleagues and I discuss in an article on dietary advice in clinical practice, a common theme for myths in nutrition is a reductionist view that emphasizes selected food constituents instead of whole foods.5 Dietary sodium intake certainly matters for health, but is meaningful only in the context of other food components (e.g., potassium, magnesium, calcium). Moreover, patients eat foods, not isolated food components.5
Oza and Garcellano begin their article with the reasonable (and actionable) advice to consume a diet high in vegetables, fruits, and whole grains, and later suggest that prepackaged and prepared foods might be less than ideal. I agree; the foods that support healthy blood pressure (and more importantly, overall better health) come from living botanical plants, not industrial processing plants.5 Family physicians should focus on whole foods, whole diets, and patient-oriented outcomes. The effect of sodium on blood pressure is not really the point.
Author disclosure: Dr. Lucan is on the scientific and nutritional advisory board of Epicure, a Canadian food product and cookware company.
REFERENCESshow all references
1. Lucan SC. Coronary artery disease prevention: as easy as 1, 2, 3? Am Fam Physician. 2010;82(10):1167....
2. DiNicolantonio JJ, Lucan SC. The wrong white crystals: not salt but sugar as aetiological in hypertension and cardiometabolic disease. Open Heart. 2014;1(1):e000167.
3. DiNicolantonio JJ, Lucan SC, O'Keefe JH. Letter by DiNicolantonio et al. regarding article, “Reducing Sodium Intake to Prevent Stroke: Time for Action, Not Hesitation.” Stroke. 2014;45(6):e106–e107.
4. Institute of Medicine. Sodium intake in populations: assessment of evidence. http://iom.nationalacademies.org/~/media/Files/Report%20Files/2013/Sodium-Intake-Populations/SodiumIntakeinPopulations_RB.pdf. Accessed August 10, 2015.
5. Lesser LI, Mazza MC, Lucan SC. Nutrition myths and healthy dietary advice in clinical practice. Am Fam Physician. 2015;91(9):634–638.
6. Lucan SC. Patients eat food, not food categories or constituents. Am Fam Physician. 2011;83(2):107–108.
in reply: We thank Dr. Lucan for taking the time to comment on our article. Dr. Lucan raises some valid points to consider when managing high blood pressure. We agree that family physicians should focus on recommending whole foods, and should care about patient-oriented outcomes rather than disease-oriented outcomes. We also agree that elevated blood pressure raises the risk of myocardial infarction, stroke, renal failure, and death, so it is imperative that physicians not cause more of these events in attempting to control blood pressure.
Dr. Lucan also points out that reducing dietary sodium intake lowers blood pressure, but may produce other undesirable cardiovascular effects. Recent studies published in the New England Journal of Medicine have shown a link between a low-sodium diet and adverse cardiovascular outcomes.1–3 However, the American Heart Association has not changed its recommendation of dietary sodium restriction for persons with hypertension.
A reduction of 5 mm Hg in systolic blood pressure has been associated in observational studies with mortality reductions of 14% from stroke, 9% from heart disease, and 7% from all causes.4 Family physicians should tailor the treatment plan to each patient based on his or her individual risk factors and the patient's understanding of a healthy diet, and should monitor for adverse events.
Author disclosure: No relevant financial affiliations.
REFERENCESshow all references
1. O'Donnell M, Mente A, Rangarajan S, et al.; PURE Investigators. Urinary sodium and potassium excretion, mortality, and cardiovascular events [published correction appears in N Engl J Med. 2014;371(13):1267]. N Engl J Med. 2014;371(7):612–623....
2. Mozaffarian D, Fahimi S, Singh GM, et al.; Global Burden of Diseases Nutrition and Chronic Diseases Expert Group. Global sodium consumption and death from cardiovascular causes. N Engl J Med. 2014;371(7):624–634.
3. Mente A, O'Donnell MJ, Rangarajan S, et al.; PURE Investigators. Association of urinary sodium and potassium excretion with blood pressure. N Engl J Med. 2014;371(7):601–611.
4. Eckel RH, Jakicic JM, Ard JD, et al. 2013 AHA/ACC guideline on lifestyle management to reduce cardiovascular risk: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines [published correction appears in J Am Coll Cardiol. 2014;63(25 pt B):3027–3028]. J Am Coll Cardiol. 2014;63(25 pt B):2960–2984.
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