In the news: Vitamin D & Blood Pressure: Omega-3 & Periodontal Disease

Vitamin D Found to Reduce Blood Pressure

The previous issue of EduFacts discussed research related to hypertension and ocular health. Germane to that research topic are two new studies that suggest a role for vitamin D in maintaining normal blood pressure.

Low vitamin D status has been linked to elevated blood pressure in a number of population health studies, spurring researchers from China to evaluate the effects of vitamin D in patients with essential hypertension.

In this randomized controlled trial (1), 126 patients with grades I-II essential hypertension received either 2,000 IU vitamin D or a placebo daily in addition to an anti-hypertensive drug (nifedipine, a calcium-channel blocker, 30 mg/day).

At the end of 6 months, the vitamin D group had a 24-hour mean blood pressure -6.2 (systolic) and -4.2 mm/Hg (diastolic) lower than the placebo group for intention-to-treat analysis. For patients whose vitamin D levels were low (<30 ng/ml) at baseline, the drop in systolic and diastolic pressures was greater: -7.1 and -5.7, respectively. The authors conclude that vitamin D may be an effective adjuvant therapy in this patient population.

Causal Link Between Vitamin D & Blood Pressure?

Results from a new genetic investigation provide evidence that poor vitamin D status may play a causal role in the development of hypertension.

An international team of researchers evaluated genetic data from the D-CarDia collaboration and other consortia, involving more than 140,000 individuals (2). Using a mendelian randomization approach to reduce confounding and bias, they generated an allele score based on two common variants of genes that affect circulating vitamin D [25(OH)D] levels.

The team observed changes in diastolic pressure of -0.29 mm Hg and in systolic pressure of -0.37 mm Hg, for each 10% increase in vitamin D [25(OH)D] concentration. An 8% decrease in the odds of developing hypertension was also seen.

The authors conclude that increased plasma concentrations of 25(OH)D may reduce the risk of hypertension, and indicate that the findings warrant further investigation in an independent, similarly powered study. Since vitamin D insufficiency appears to be fairly common globally, replication of these findings could potentially lead to a cost-effective way to help prevent hypertension.

Omega-3 Fatty Acids & Periodontal Disease

Omega-3 fatty acids are associated with a number of health benefits, including reduction in the risk of CVD and AMD. Harvard researchers now provide evidence for another potential benefit, that of improving periodontal outcomes.

In a randomized controlled trial (3), participants with moderate periodontitis received low dose aspirin (81 mg) and either 2,000 mg of DHA or placebo daily for 3 months. Significantly decreased pocket depth and improvements in the gingival index were seen in the DHA group. The inflammatory biomarkers IL-1B and hsCRP were lower in gingival crevicular fluid of the DHA group compared to placebo.

The same research group had previously reported that higher dietary intakes of DHA and, to a lesser degree, EPA, were associated with lower prevalence of periodontitis among participants of the National Health and Nutrition Examination Survey (4).

References:

1. Chen WR, et al. Vitamin D and nifedipine in the treatment of Chinese patients with grades I-II essential hypertension: A randomized placebo-controlled trial. Atherosclerosis. 235:102-9, 2014.
2. Association of vitamin D status with arterial blood pressue and hypertension risk: A Mendelian randomization study. Lancet Diabetes Endocrinol. Jun 25, 2014 [Epub ahead of print].
3. Naqvi AZ, et al. Docoshexanenoic acid and periodontitis in adults: A randomized controlled trial. J Dental Res [Epub ahead of print].
4. Naqvi AZ, et al. n3 fatty acids and periodontitis in US adults. J Am Diet Assoc 110:1669-75, 2010.