What is the relationship between Vitamin D and hypertension?

From the Guidelines

Vitamin D supplementation may be beneficial for individuals with hypertension, particularly those who are vitamin D deficient, as it may help lower blood pressure and reduce the risk of cardiovascular events. Research suggests that vitamin D helps regulate the renin-angiotensin-aldosterone system (RAAS), which controls blood pressure by affecting blood vessel constriction and fluid balance 1. Vitamin D also improves blood vessel function and reduces inflammation, both important for maintaining healthy blood pressure.

Key Findings

• Observational studies consistently indicate that 25(OH)D levels less than 15 ng/mL are associated with excess risk of cardiovascular events, when compared with levels >30-40 ng/mL 1.
• A meta-analysis of 8 RCTs in patients with a mean baseline blood pressure above 140/90 mmHg concluded that vitamin D reduces blood pressure modestly but significantly in hypertensive patients 1.
• The 2020 International Society of Hypertension Global Hypertension Practice Guidelines recommend lifestyle modifications, including salt reduction, healthy diet, and regular physical activity, as a first-line approach to managing hypertension 1.

Recommendations

• For those with hypertension and low vitamin D levels (below 30 ng/mL), supplementation with vitamin D3 (cholecalciferol) at 1,000-2,000 IU daily may be beneficial 1.
• Regular blood tests can monitor vitamin D levels to ensure they reach the optimal range of 30-50 ng/mL.
• While vitamin D supplementation alone isn't a replacement for standard hypertension treatments like medication, diet changes, exercise, and reduced sodium intake, it may serve as a helpful complementary approach, particularly in deficient individuals.

Lifestyle Modifications

• In addition to vitamin D supplementation, lifestyle modifications such as salt reduction, healthy diet, and regular physical activity are essential for managing hypertension 1.
• A dietary pattern that emphasizes fruits, vegetables, and low-fat dairy products, and is reduced in fat, may also help lower blood pressure 1.

From the Research

Relationship Between Vitamin D and Hypertension

The relationship between vitamin D and hypertension is complex and has been studied extensively in various research papers 2, 3, 4, 5, 6.

• Vitamin D is known for its role in bone and mineral homeostasis, but studies have also suggested its potential as an antihypertensive agent 2.
• Some studies have reported an association between vitamin D deficiency and higher systolic blood pressure, as well as a higher incidence of hypertension 3, 4.
• However, randomized control trials have yielded inconsistent results, and it is unclear whether vitamin D supplementation can improve cardiovascular health or prevent hypertension 3, 5, 6.
• The use of vitamin D supplements to prevent and treat hypertension is not adequately supported by evidence, and more research is needed to determine its effectiveness 5, 6.

Key Findings

• Studies with vitamin D receptor (VDR) knockout mice have shown an increased renin-angiotensin-aldosterone system (RAAS) activity and increased hypertension, suggesting a key role for vitamin D in regulating blood pressure 2.
• Human studies have reported mixed results, with some showing a weak association between vitamin D deficiency and hypertension, while others have found no significant impact on blood pressure 3, 4.
• Vitamin D supplementation has been shown to be safe, but its potential as an antihypertensive agent is still uncertain 2, 5.

Research Gaps

• Further research is needed to determine the relationship between vitamin D and hypertension, particularly in terms of the effectiveness of vitamin D supplementation in preventing or treating hypertension 3, 6.
• Large, well-controlled clinical trials are needed to settle the issue of whether vitamin D supplementation can improve cardiovascular health or prevent hypertension 6.