The £4 supplement that could lower blood pressure, reducing the risk of stroke, dementia and heart attack

Taking one vitamin D supplement a day for a month can cause a drop in blood pressure – reducing the risk of strokes and heart attacks, research shows.

The so-called “sunshine vitamin” has long been praised as beneficial for bone health and crucial for fighting disease.

But now researchers in Lebanon, who followed more than 200 obese adults in their 70s, found it also ‘significantly’ lowered blood pressure in those who took it for a month.

The team found that one 600 IU (or 15 mg) tablet achieved the optimal effect; increasing the dose made little difference in benefit.

High blood pressure is one of the country’s biggest killers, responsible for one in four deaths, according to NHS England.

It is often referred to as a ‘silent’ threat because, according to the British Heart Foundation, around a third of people with the condition are believed to be undiagnosed.

Not only is it the leading cause of heart disease, it can also lead to kidney disease and vascular dementia.

Dubbed a ‘silent killer’, more than 14 million adults in Britain have high blood pressure – medically known as hypertension

Now experts believe they may have discovered a cheap and low-risk method to treat the problem, which affects blood flow to and from the heart.

In the study, researchers divided 221 adults, with an average age of 71 years and a BMI of 30.2 (classified as obese), into two groups.

The first group was assigned vitamin D tablets of 600 international units (IU) per day – the Institute of Medicine’s recommended daily dose. Most vitamin D tablets available at regular pharmacies contain approximately 400-800 IU per pill.

The second 110 volunteers were prescribed super-strength tablets of 3,750 IU/day.

After a year of follow-up, the team found that both groups had lowered their blood pressure by an average of 3.5 mm Hg.

This is the systolic pressure or the top number on a blood pressure monitor. Normal blood pressure is believed to be less than 120.

Those who received the higher dose saw their levels drop by an average of 4.2 mm HG, while the lower group experienced a drop of 2.8 mm HG.

But in the Journal of the Endocrine Society, they concluded that this difference was small and would have little impact on the change in heart health risk.

Experts have long praised vitamin D – available for £4 at Boots – as beneficial for bone and muscle health.

The vitamin’s main role is to help the tissue in our bones absorb calcium, making the bone stronger and less prone to fractures.

A deficiency leads to rickets in children, and a similar condition, osteomalacia, in adults: softening and weakening of the bones causing pain and deformities.

It is also thought to lower the risk of type 1 diabetes, respiratory disease and other conditions.

But Brits of all ages aren’t getting enough, with contributing factors including poor diet, not spending enough time outdoors and not taking supplements to make up for the deficiency.

The latest UK National Diet and Nutrition Survey shows that between 2008 and 2012, almost a quarter of adults aged 19 to 64 and one in five adults over 65 had inadequate blood levels.

The amount of vitamin D in the body can be determined by a blood test – and the results are reported in units of nanomoles per liter, written as nmol/l.

A level of 25 nmol/l or lower is considered deficient – ​​this was identified about twenty years ago as falling below this was associated with an increased risk of rickets.

However, other previous research has suggested that taking too many vitamin D supplements can lead to hypercalcemia, a condition in which too much calcium builds up in the blood, potentially causing deposits in the arteries or soft tissues.

It can also predispose people to painful kidney stones.