Should I keep taking my calcium tablets?

I AM worried about taking calcium supplements because of the increased risk of having a heart attack or stroke. Is it time to stop taking them?

THERE have been studies, including a review published last year in the journal Annals of Internal Medicine, suggesting calcium supplements may increase the risk of heart attack and stroke.

The theory is that calcium in excess may contribute to calcification, or furring, of the arteries.

But, while I understand your concern, the evidence is not as clear cut as you might think. In fact, it is highly conflicting.

Until research settles the dispute, the usual advice is that doses of more than 500mg at one time should be avoided.

Most people who take calcium supplements (usually with vitamin D) do so because they have osteoporosis, which weakens bones, making them more fragile and more likely to break.

There are several options for preventing or treating loss of bone mass, but the first step is eating foods rich in calcium, which helps to build bones, and vitamin D, which helps the body absorb calcium.

The recommendation for those with osteoporosis is a total daily intake of 1,200 mg of calcium along with 800 international units (IUs) of vitamin D. That has been the advice for many years.

It has long been known that there is a possible relationship between calcium consumption and cardiovascular events such as stroke.

In 2007, a seven-year study was published involving 30,000 postmenopausal women; half were taking 500mg of calcium a day, plus vitamin D twice daily, and half had a placebo.

The conclusion was that those with the higher calcium intake were not at higher risk of heart attack or stroke.

Then, in 2010, a review of data from several trials involving 8,000 people concluded there was an increased risk of heart attack in those taking calcium supplements.

This was followed by more research (published in 2011) which concurred.

However, the same year another major study suggested calcium supplementation may actually reduce the risk of hospitalisation and mortality in patients with pre-existing furring of the arteries — atherosclerotic cardiovascular disease. This is compelling evidence that calcium supplementation is safe.

You can see why there is controversy and confusion.

So what can we make of all this?

Although the ideal intake has not been established, postmenopausal women — who face higher risk of osteoporosis and weakened bones generally — are advised to consume calciumrich foods, such as green, leafy vegetables, tinned fish and dairy products, along with taking up to 500mg of calcium twice daily.

Strict vegans or vegetarians may find it difficult to get enough calcium and vitamin D from food, so should obtain expert recommendations tailored to their preferences from a qualified dietitian.