Hypertension and diabetes are two known risk factors for chronic kidney disease. It is vital that all patients follow a renal diet whether on dialysis or transplanted. Sodium and potassium must always be monitored by obtaining the appropriate labs. It is also extremely important to consult with a nutritionist or dietitian to ensure that the proper diet is followed, especially if one is experiencing problems with hypertension and/or diabetes. Proper nutrition is a key factor in living your best life! Of course, your nephrologist and/or general practitioner should always monitor your overall health concerns. We urge you to read this article, and if you have any questions or concerns, please consult a medical practitioner.
The following article is a review of the importance of blood pressure management. The information is provided by Renal and Urology News (https://www.renalandurologynews.com)
Expanding Medical Nutrition Therapy for Blood Pressure Management in CKDÂ
Lindsey Zirker is a renal dietitian who works with Kidney Nutrition Institute in Titusville, Florida. She specializes in autoimmune and advanced practice medical nutrition therapy for people with kidney disease.
Blood pressure management is a cornerstone of chronic kidney disease (CKD) care. While excess sodium intake is a well-established contributor to hypertension, emerging evidence suggests that a broader
approach — one that includes optimizing key micronutrients — may provide additional benefits.
It is estimated that only 30%-50% of those with high blood pressure are sodium-sensitive1, and some studies have found increased cholesterol and triglycerides in sodium-restricted diets in those with and without CKD.2,3 Additionally, many other micronutrients play direct roles in regulating the renin-angiotensin-aldosterone system (RAAS), vascular function, and fluid balance. Taken together, there is more to consider when designing dietary interventions for hypertension.
Understanding these micronutrients’ roles, their common deficiencies in CKD, and appropriate dietary targets can enhance blood pressure management strategies in nephrology practice.
5 Micronutrients and Their Role in RAAS Regulation
The RAAS is a critical hormonal system in blood pressure regulation, influencing vascular tone, sodium retention, and fluid balance. Several micronutrients interact with this system.  Key micronutrients involved include potassium, magnesium, vitamin D, vitamin B6, and zinc.4
PotassiumÂ
- Role in RAAS: Potassium suppresses renin secretion and reduces vasoconstriction by counteracting the effects of sodium. It enhances nitric oxide production, promoting vasodilation and reducing arterial stiffness.4
- Deficiency in CKD: Although blanket potassium restrictions are no longer considered evidence-based5, many practitioners and online resources still recommend potassium restrictions for those with CKD regardless of patient intake or serum levels. These outdated recommendations and fears of hyperkalemia often result in potassium over-restriction.
- Suggested Intake: The American Heart Association recommends at least 4700 mg of potassium daily for healthy blood pressure.6 However, research suggests 3900 mg may be insufficient for significant impact in CKD patients.7 Since many CKD guidelines cap intake at 4000 mg, higher levels may be needed for blood pressure benefits.7
MagnesiumÂ
- Role in RAAS: Magnesium inhibits angiotensin converting enzyme (ACE) activity, reduces aldosterone secretion, and improves endothelial function. It also counteracts the effects of intracellular calcium overload in vascular smooth muscle, preventing excessive vasoconstriction.4
- Deficiency in CKD: Magnesium deficiency is common due to dietary restrictions, medication interactions (eg, diuretics, proton pump inhibitors), reduced absorption from plant-based diets, and increased urinary losses in non-dialysis CKD.1
- Suggested Intake: Aiming for 350-420 mg/day from food sources may help support vascular health.4 Magnesium supplementation can play a helpful role if dietary intervention with a dietitian doesn’t achieve adequate intake.
Vitamin B6Â
- Role in RAAS: Vitamin B6 is involved in neurotransmitter synthesis and regulates homocysteine metabolism, which can impact endothelial function and vascular health. It also plays a role in modulating inflammatory pathways that may influence blood pressure regulation4.
- Deficiency in CKD: Vitamin B6 deficiency is common in CKD due to increased nutrient needs, dietary restrictions, and increased losses in urine. Low levels have been associated with hypertension in individuals without CKD.1
- Suggested Intake: Current studies recommend 5mg daily of B6 for those with CKD.1  No studies were found at this time that considered B6 supplementation or intake on the impact of blood pressure in those with CKD.
Vitamin DÂ
- Role in RAAS: Vitamin D downregulates renin expression, reducing RAAS overactivity. Deficiency is linked to increased renin and angiotensin II levels, contributing to hypertension and endothelial dysfunction.4
- Deficiency in CKD: Vitamin D deficiency, where patients have serum levels below 20 ng/mL, is estimated to be 70-80%.8  This is thought to be related to reduced sun exposure, aging, dietary restrictions, increased urinary losses, and reduced renal conversion of vitamin D.8
- Suggested Intake: For CKD patients, vitamin D status should be monitored regularly, and supplementation should be based on individualized serum levels. Typical recommendations range from 4000-7000 IU/day for cholecalciferol (D2 or D3) given as a daily or weekly dose.9  Ideal serum levels are unknown at this time, however systematic reviews recommend levels >30ng/mL or higher.8
ZincÂ
- Role in RAAS: Zinc modulates ACE activity and influences nitric oxide production, which impacts vascular function. Deficiency is associated with increased blood pressure, oxidative stress and endothelial dysfunction.
- Deficiency in CKD: Zinc deficiency is common due to reduced dietary intake (especially with low protein or plant-based diets), reduced absorption, and increased urinary losses due to medications (such as diuretics or proton pump inhibitors [PPIs]) and kidney damage.10
- Suggested Intake: The recent KDOQI guidelines recommend the RDA (8mg/ day for women, 11mg/ day for men).5  However, this may be inadequate given the significant risks for deficiency, especially with increased urinary wasting.  Therefore, in the absence of clear guidelines, regular monitoring is necessary.
Medical Nutrition Therapy’s ImportanceÂ
It is important to note that nutrients rarely act alone. Research often shows benefits from nutrient-rich diets but mixed results from isolated supplementation. This underscores the need for medical nutrition therapy to prioritize overall nourishment rather than focus on a single nutrient at a time.
Renal dietitians play a key role in monitoring nutrient intake and serum levels to provide individualized patient recommendations. Research on micronutrient needs in CKD is limited, with therapeutic guidelines for micronutrients with regard to blood pressure scarcer still.  Integrating individualized micronutrient assessments into nephrology practice, sharing developments in clinical judgment, and publishing case reports will greatly enhance the knowledge base and ability to develop guidelines to improve blood pressure control and overall health in patients with CKD.
