Scientists have warned that taking two popular pills could increase your risk of a medical emergency. Research has shown that the combination of these supplements could raise your chances of suffering from a stroke by as much as 17 per cent.
While a healthy, balanced diet should ensure you get all the nutrients you need, this is not always achievable for some people – whether due to cost, accessibility, and if their body is able to absorb vitamins and minerals correctly. As a result, many people rely on daily supplements to stay healthy.
However, this could come with its own risks. A study by US scientists, which was published in the Annals of Internal Medicine in 2019, found an association between certain types of pills that combine vitamin D and calcium with strokes.
They warned this combination could lead to atherosclerosis, a condition that occurs when fatty substances build up in the arteries. If left untreated this can block the flow of blood to the heart or brain, resulting strokes or heart attacks.
Doctor Safi Khan, who led the research at West Virginia University, explained: “A combination of calcium and vitamin D was associated with a higher risk of stroke. Other supplements did not seem to have significant effect on mortality or cardiovascular outcomes.”
To carry out the study, the team reviewed 277 randomised controlled trials that involved up to one million participants. They analysed the effect of 16 different supplements and eight diets on mortality and the heart.
Among the findings was the fact that reducing salt intake and eating more omega-3 fatty acids, found in oily fish, helped prevent heart disease. Moreover, folic acid could help protect against strokes.
But it showed supplements made up of vitamin D and calcium increased the risk of stroke by 17 per cent. Study authors wrote: “Calcium plus vitamin D increased the risk for stroke.
“Other nutritional supplements, such as vitamin B6, vitamin A, multivitamins, antioxidants, and iron and dietary interventions, such as reduced fat intake, had no significant effect on mortality or cardiovascular disease outcomes.” Supplements combining calcium with vitamin D are typically taken to support good bone health, particularly in older people who already have a higher risk of stroke.
You can boost your calcium intake through diet, by eating more foods such as:
- Fish where you eat the bones – such as sardines and pilchards
- Soya drinks with added calcium
- Bread and anything made with fortified flour
- Milk, cheese and other dairy foods
- Green leafy vegetables – such as curly kale and okra, but not spinach
Adults need around 700mg of calcium a day, and the NHS says you “should be able” to get enough from your daily diet. Vitamin D is mainly absorbed through sunlight. But it can also be found in:
- Fortified foods – such as some fat spreads and breakfast cereals
- Egg yolks
- Oily fish – such as salmon, sardines, herring and mackerel
- Liver
- Red meat
You should speak to your GP before taking any supplements for a health reason.