Vitamin D supplements can lower blood pressure in overweight seniors

Lack of vitamin D is a global health problem. The same is the case with overweight and hypertension, a combination that results in millions of deaths. Apparently, supplementing with vitamin D can lower blood pressure in people who are overweight, according to a study that is published in Journal of Endrocrine Society. It is important to be aware of the interactions between vitamin D, calcium, and magnesium.

An estimated one billion people around the world lack vitamin D. This is linked to an increased risk of cardiovascular diseases, infections, autoimmune diseases, and cancer. Published studies have shown a relation between low vitamin D status and an increased risk of hypertension. Vitamin D supplementation may have a positive effect on blood pressure, but studies have shown conflicting results. This may be because the doses that were given were too low to optimize blood levels of the nutrient, or perhaps the study participants were not vitamin D-deficient to begin with. Vitamin D also seems to work differently when given to young healthy people or older people that are overweight and have different health conditions. For that reason, researchers were specifically interested in looking at the effect of giving vitamin D to older, overweight individuals.
The new study included 221 people aged 65 years and older. They were all overweight and had a BMI above 30. The participants’ vitamin D levels in the blood were somewhere in the range between 25-75 nmol/L (10-30 ng/ml). The lower threshold is 50 nmol/L, whereas an optimal level should ideally be around 75-100 nmol/L. Participants with insulin resistance, prediabetes, or any serious diseases or organ failure were excluded from the study.
Everyone was given a daily supplement of vitamin D (12.5 micrograms) and calcium (1,000 mg), which fits in nicely with the recommendations for bone health in old age. In addition, one group was given a single large dose (250 micrograms) of vitamin D once every week, while the other group got matching placebo. That way, the active group got 36 micrograms more vitamin D every day on average, bringing their daily intake up to 48.5 micrograms, which is way above the official recommendations.
The duration of the study was one year, and the participants had their blood pressure measured every third month together with other measurements. The systolic and diastolic pressure dropped significantly after 6-12 months, especially in the group that got the highest amount of vitamin D. The researchers concluded that supplementation with vitamin D and calcium helps lower blood pressure in overweight individuals. Moreover, the vitamin D dose must be high enough to optimize blood levels of the nutrient. It should also be mentioned that magnesium, which many people lack, is needed for the body’s activation of vitamin D.

How can vitamin D regulate blood pressure?

The new study supports a large Spanish population study that also demonstrated a positive effect of vitamin D on blood pressure. In this study, the scientists addressed the underlying mechanisms. Vitamin D is important for calcium uptake, and it appears that low calcium levels in the blood can result in increased secretion of parathyroid hormone (PTH), which is linked to hypertension.
Also, vitamin D is involved in the so-called renin-angiotensin-adolsterone pathway (RAS) that regulates the body’s blood pressure and liquid balance. Finally, vitamin D helps lower blood pressure through its effect on the endothelial cells in the blood vessels and its ability to prevent stiff arteries.

References:

Maya Rahme et al. Blood pressure Decreases in Overweight Elderly Individuals on Vitamin D: A randomized Trial. Journal of the Endocrine Society, 2024

The Endocrine Society. Vitamin D supplements may lower blood pressure in older people with obesity. ScienceDaily 2024

Ana Valer-Martinez et al. Vitamin D and the Risk of Developing Hypertension in the SUN Project: A prospective Cohort Study. Nutrients 2024

Andrea Rosanoff et al. Essential Nutrient Interactions: Does Low or Suboptimal Magnesium Interact with Vitamin D and/or Calcium status. Advances in Nutrition 2016