News article

Genetic Study Suggests ‘Causal Link’ Between Vitamin D Status And Blood Pressure

Posted:  Friday, July 04, 2014

Hypertension, also known as high blood pressure, is a medical condition in which the blood pressure in the arteries is elevated. High blood pressure causes your arteries to stretch beyond normal.

Previous research has suggested a strong link between low levels of vitamin D and high blood pressure, but a direct cause-and-effect relationship has not been shown.

Vitamin D is nicknamed the sunshine vitamin because the body produces vitamin D when exposed to sunlight. People also get vitamin D through foods such as eggs, milk, yogurt, tuna, salmon, cereal and orange juice.

Sometimes, your body can produce too many cells in the muscle that lines your blood vessels. A build-up of these cells can lead to plaque, which makes it harder for blood to travel throughout your body. Researchers have found vitamin D receptors on these cells, and vitamin D can bind to these receptors. This may help to reduce the risk of cells building up in your blood vessels.

Also, vitamin D may help in reducing the activity of the system that controls your blood pressure. This system is called the renin-angiotensin system. When this system is overactive, blood pressure can increase.

In the new study, researchers analyzed genetic data from more than 146,500 people of European descent in Europe and North America. For each 10 percent increase in vitamin D levels, there was an 8 percent decrease in the risk of developing high blood pressure.

"In view of the costs and side effects associated with antihypertensive drugs, the potential to prevent or reduce blood pressure and therefore the risk of hypertension with vitamin D is very attractive," study leader Elina Hypponen, a professor from the University of South Australia, said in a journal news release.

But, while the study findings hint at a causal relationship, according to the study authors, it doesn't definitively prove the link.

Further research is needed to confirm that low levels of vitamin D can cause high blood pressure and that taking vitamin D supplements can reduce that risk, Hypponen said.

While the study is "an important step" in understanding how vitamin D levels may influence the development of high blood pressure, "much remains unknown," Dr. Shoaib Afzal and Dr. Borge Nordestgaard, from Copenhagen University Hospital and the University of Copenhagen in Denmark, wrote in an accompanying editorial.

Vitamin D is known to be important for keeping teeth and bones healthy, and supplements are already recommended by the Department of Health for pregnant women and children and babies under five. Exposure to sunlight is a major source of vitamin D, which can also be found in foods such as oily fish and eggs.

They said further studies and clinical trials to prove that vitamin D supplementation can prevent or treat high blood pressure are needed before this approach could be recommended.

Experts say: “This large study brings to light another potential cause of high blood pressure, which is an impressive progression in the medical field. More studies are necessary though to better understand and confirm this link between low vitamin D levels and high blood pressure.

“There are lots of simple ways to manage your blood pressure levels including cutting down on salt, keeping physically active, maintaining a healthy body weight, keeping alcohol within recommended limits and avoiding stressors where possible.

“Medication will also be prescribed where necessary, otherwise keeping up with a heart healthy lifestyle is always key. If you are over 40 and have not had a health check why not visit your GP surgery and request one.”