There is a link between low vitamin D and elevated blood pressure

Elevated blood pressure is one of the most widespread, life-threatening cardiovascular diseases. Anti-hypertensive drugs don’t address the underlying cause and are even associated with side effects. Lack of vitamin D, which can cause different cardiovascular diseases, is also quite common. According to a large Spanish population study, having higher levels of vitamin D in the blood can lower the risk of hypertension. In their research paper, the scientists address the mechanisms through which vitamin D is thought to control blood pressure.

According to WHO, around 12.3 billion people in the ages 30-79 years have been diagnosed with elevated blood pressure. The condition affects all groups in society, especially low-to-middle income individuals. Among those younger than 50 years, men are primarily affected, whereas women’s risk go up after menopause. Elevated blood pressure increases the risk of atherosclerosis, stroke, heart failure, blood clots, and chronic kidney disease. Elevated blood pressure is also a cornerstone of metabolic syndrome, which is a precursor of type 2 diabetes. Most people who get treatment for their elevated blood pressure continue on lifelong medication without receiving help for the underlying causes. Also, the medicine is associated with frequent side effects such as nausea, stomach pain, cold hands and feet, headaches, sleep disturbances, and impotence.
Vitamin D is known to play a role in the circulatory system, but studies of vitamin D supplementation have shown conflicting results. This may be because, in many cases, the study participants were not vitamin D deficient to begin with. Alternatively, the supplements that were used were unable to optimize blood levels of vitamin D.
In the new Spanish population study (SUN Project), the scientists looked closer at the link between vitamin D levels in the blood and the risk of developing hypertension. The study included 16,437 people. Both genders were evenly represented, and the average age was 36 years. The participants were asked to fill out questionnaires with information about their diet habits, including their intake of foods rich in vitamin D such as oily fish, eggs, liver, and butter. They were also asked questions about their lifestyle, including their exposure to sunlight and the amount of time spent outdoors (the sun is our major source of vitamin D). Based on these questionnaires, the scientists calculated the participants’ blood levels of vitamin D, after adjusting for possible confounders. The volunteers were followed for 12.3 years, and 2,338 new cases of hypertension were identified.
The study revealed a significant relation between the participants’ blood levels of vitamin D and their risk of elevated blood pressure. The quartile with the highest vitamin D levels had a 30 percent lower risk of elevated blood pressure compared with the quartile that had the lowest vitamin D levels. The scientists conclude that the estimated level of vitamin D in the blood is linked to the risk of hypertension. The study, which is published in Nutrients, indicates that vitamin D has a protective effect. The researchers call for more studies of vitamin D and blood pressure to find out which levels of the nutrient offer optimal protection.
According to a previous review article that is also published in Nutrients, most people who take 50-100 micrograms of vitamin D daily are able to optimize their levels of the nutrient and lie in the range between 75-100 nmol/L. This is an amount of vitamin D that most fair-skinned people living at our latitudes can synthesize on a summer’s day. The problem is that factors such as spending too much time indoors, having dark skin, being old, the use of factor cream, overweight, and type 2 diabetes can impair our ability to synthesize vitamin D, which is why many people need to take a supplement all year round.

How does vitamin D protect against hypertension?

Nearly all cells in the body have vitamin D receptors (VDR), and vitamin D is known to regulate a host of different genes and metabolic processes. For example, it is believed to be involved in the so-called renin-angiotensin-adolsterone system (RAAS), which is a system that controls blood pressure and fluid levels in the body. Vitamin D is also important for the body’s uptake of calcium. Low vitamin D levels can result in an increased secretion of parathyroid hormone (PTH), which is linked to elevated blood pressure. Vitamin D is also able to regulate blood pressure by affecting the endothelial cells of blood vessels and preventing stiff arteries. Vitamin D’s ability to control blood sugar levels also contributes to preventing metabolic syndrome and type 2 diabetes, both of which are linked to hypertension and other cardiovascular disorders. In addition, vitamin D counteracts chronic inflammation and oxidative stress, which are underlying imbalances that are often seen in connection with hypertension.

References

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

William B. Grant. A Narrative Review of the Evidence for Variations in Serum 25-Hydroxyvitamin D Concentration Thresholds for Optimal Health. Nutrients 2022