Diet Advice for Blood Pressure Control Goes Beyond Sodium Restriction

Hypertension is no stranger to caregivers of patients with chronic kidney disease (CKD). Every health care provider working with those who have CKD is assessing, monitoring, or managing hypertension. Because hypertension can occur through multiple biochemical pathways, providers must be adroit in using various and sometimes multiple medications to ensure blood pressure is well managed.

Nutrition also often plays a role in the management of hypertension via a low sodium diet. Studies consistently show that sodium restriction is an effective way to support healthy blood pressure.¹ As previously mentioned, however, blood pressure control is achieved through different mechanisms and biochemical pathways. Recent research supports this and indicates that there are additional nutrition interventions that can support healthy blood pressure beyond a sodium restriction.

Potassium

In the non-CKD population, potassium is regularly recommended as a heart-healthy blood pressure-lowering mineral. The American Heart Association recommends a minimum of 4700 mg of potassium daily to achieve these benefits.² Studies considering higher potassium diets have shown improved blood pressure in those with CKD, although it is difficult to know if this is due to higher potassium intake or some other factor in high potassium diets, like increased fiber or antioxidant intake.³ Acknowledging that there are multiple factors in higher potassium diets that can positively impact blood pressure further support the idea of a more liberalized diet focused on healthy diet patterns rather than on individual nutrients for those with CKD.

There is historically a concern about high potassium intake leading to high serum levels of this nutrient. While there is a growing body of evidence that eases this concern, it is also worth considering that there are many medications used to manage blood pressure that are known to raise potassium levels. Providers recommending these medications use clinical judgment and monitoring to ensure patient safety. The same can be done with higher potassium diets and dietitian counseling to achieve optimal blood pressure and safe potassium levels.

Magnesium

Magnesium is an important cofactor for many different enzymes and processes — such as vascular tone and calcium and potassium ion channels — which in turn can impact blood pressure levels. Historically, magnesium intake has been restricted in those with CKD due to some evidence showing that declining function resulted in increased magnesium levels. More recent evidence suggests that low magnesium is common in CKD patients, and that those with magnesium levels in the “high to high normal” range are more likely to have improved survival and endothelial function and reduced vascular calcification which supports better blood pressure control.⁴

Causes of low magnesium in those with CKD are related to losses during dialysis, metabolic acidosis, and medications like diuretics.⁵ Further, low or inadequate magnesium intake and absorption is thought to be common in those with CKD as a result of poor intake. It is estimated that less than 50% of Americans eat the estimated average requirement of magnesium.⁶ Another reason for low magnesium is the frequent use of proton pump inhibitors, which further increase the risk of magnesium deficiency, in addition to other micronutrients.⁷

Magnesium seems to also be a synergistic mineral by showing improved blood pressure when combining increased magnesium and potassium intake with reduced sodium intake. It can also increase the effectiveness of many antihypertensive medications, which not only can improve outcomes but also reduce dosage needed for optimal blood pressure levels.⁵

Stress management

While not a nutrition intervention, a discussion of blood pressure control beyond sodium and medications would be incomplete without any mention of stress management. Ample evidence acknowledges the negative impact of stress on kidney health and healthy blood pressure management.⁸ Asking patients about what they do to help manage their stress (and referring out to therapists or social workers as needed) can help providers create a well-rounded plan for blood pressure control. 

Guidelines for blood pressure control

Here are some tips for achieving adequate blood pressure control. 

1. Review medications

Are there medications that are counteracting your goals (like antacids or proton pump inhibitors)?

Could the patient make dietary/ lifestyle changes to reduce the dose of a medication?

2. Ask about stress/ stress management

While all providers may not have the time or skill set to provide interventions, this can be a simple screening tool to refer out to providers who do have the time and skills.

3. Make sure patients have the right tools for your recommendations

This can be as easy as a referral to a dietitian or other provider, but it is critical as a provider to think through the implementation of the intervention and ensure a patient has the tools to be successful.

4. Mineral recommendations

Sodium:

• <2300 mg daily⁹

• Increased fruit and vegetable intake⁹

Potassium:

• Based on the patient’s individual need and clinician judgment⁹
• 3,500-4,700 mg daily^2,10

Magnesium:

• 500-1000 mg/day⁶
• Accurate magnesium testing and monitoring: Red Blood Cells (RBC) as opposed to serum magnesium¹¹
• Supplementation: Avoid magnesium oxide as it is poorly absorbed and can cause diarrhea.  More optimal, easily available forms are citrate or glycinate¹¹

Lindsey Zirker MS, RD, CSR is a renal dietitian who works with the Kidney Nutrition Institute in Titusville, Florida. She specializes in autoimmune kidney disease and advanced practice medical nutrition therapy for people with kidney disease.

References

1. Cobb M, Pacitti D. The importance of sodium restrictions in chronic kidney disease. J Ren Nutr. 2018;28(5):e37-e40. doi:10.1053/j.jrn.2018.02.001.
2. American Heart Association. https://www.heart.org/en/health-topics/high-blood-pressure/changes-you-can-make-to-manage-high-blood-pressure/how-potassium-can-help-control-high-blood-pressure. Accessed 1/18/23.
3. Song Y, Lobene AJ, Wang Y, Hill Gallant KM. The DASH diet and cardiometabolic health and chronic kidney disease: A narrative review of the evidence in East Asian countries. Nutrients. 2021;13(3):984. doi:10.3390/nu13030984
4. Leenders NHJ, Vervloet MG. Magnesium: A magic bullet for cardiovascular disease in chronic kidney disease? Nutrients. 2019;11(2):455. doi:10.3390/nu11020455
5. Kopple J, Massery S, Kalantar-Zadeh K, Fouque D. Nutritional Management of Renal Disease. 4th edition.2022.Cambridge, MA:Elsevier.
6. Houston M. The role of magnesium in hypertension and cardiovascular disease. J Clin Hypertens (Greenwich). 2011;13(11):843-847. doi:10.1111/j.1751-7176.2011.00538.x
7. Al-Aly Z, Maddukuri G, Xie Y. Proton pump inhibitors and the kidney: Implications of current evidence for clinical practice and when and how to deprescribe. Am J Kidney Dis. 2020;75(4):497-507. doi:10.1053/j.ajkd.2019.07.012
8. Bruce MA, Griffith DM, Thorpe RJ Jr. Stress and the kidney. Adv Chronic Kidney Dis. 2015;22(1):46-53. doi:10.1053/j.ackd.2014.06.008
9. Ikizler TA, Burrowes JD, Byham-Gray LD, et al. KDOQI Nutrition in CKD Guideline Work Group. KDOQI clinical practice guideline for nutrition in CKD: 2020 update. Am J Kidney Dis. 2020;76(3)(suppl 1):S1-S107. doi:10.1053/j.ajkd.2020.05.006
10. Poorolajal J, Zeraati F, Soltanian AR, Sheikh V, Hooshmand E, Maleki A. Oral potassium supplementation for management of essential hypertension: A meta-analysis of randomized controlled trials. PLoS One. 2017;12(4):e0174967. doi:10.1371/journal.pone.0174967
11. Lord R, Bralley A. Laboratory Evaluations for Integrative and Functional Medicine. 2^nd ed. Duluth, GA: Metamatrix Institute. 2012.

This article originally appeared on Renal and Urology News