Vitamin D supplements linked to reduced risk of dying
Publication Date:20/09/2007
Taking vitamin D supplements may slightly increase the chance of older people living longer, a study has found.
What do we know already?
Vitamin D is important for staying healthy. It helps to help maintain strong bones, and also plays an important part in lots of other things your body does. You get some vitamin D from certain foods, but most of the vitamin D you get is from sunshine. Ultraviolet rays in sunlight trigger vitamin D production in the skin.
Scientists have been interested in the link between lack of sun exposure and certain diseases for years. There is some research which suggests that the chances of dying from cancer, heart disease and diabetes increase the further people live from the equator. The further you are from the equator the less ultraviolet light reaches the earth, especially in the winter months. Other research has found that people who are diagnosed with heart disease or certain cancers during the summer are likely to live longer than those who are diagnosed in the winter.
These observations have led to the theory that vitamin D may have a role in protecting against cancer and heart disease. Studies of vitamin D in the body have found that vitamin D helps to regulate cell growth and may prevent some cells overproducing.
What does the new study say?
The study looked at 18 separate studies of vitamin D supplements involving nearly 60,000 people, all of them over 50 and most of them frail and elderly. It found that people who took vitamin D supplements were slightly less likely to die during the six years they were followed up than those who did not. They also found that the amount of vitamin D in the blood of people who took supplements was 1.4 to 5.2 times higher than in people who didn't take supplements.
But the number of people to benefit was very small. Out of 1,000 people who took vitamin D, 82 died in the next six years. Out of 1,000 people who didn't take vitamin D, 85 died. This means that if 1,000 people took vitamin D for 6 years three more would be alive at the end of that time than if none had taken it.
The doses of vitamin D people in the studies took varied. But the study found that average dose supplements seemed to be linked to a lower risk of dying.
Where does the study come from?
The study was done by researchers from the International Agency for Research on Cancer in Lyon, France, and from the European Institute of Oncology in Milan, Italy. It was published in a journal called the Archives of Internal Medicine.
How reliable are the findings?
This was a good study. It looked at 18 individual, good-quality studies and the results from nearly 60,000 people who either took vitamin D, a dummy pill (placebo) or nothing. But there is still a possibility that the finding that vitamin D reduces the risk of death could have happened by chance. More studies need to look at this.
There are also some other important questions that still need to be answered, such as what is the best dose of vitamin D to take, who should take supplements and at what age they should start taking them.
What does this mean for me?
This study was mostly of older people. We don't know if vitamin D supplements have any benefits for younger people. However, if you're over 50, you may want to think about whether you get enough vitamin D from your diet and being out in the sun.
What should I do now?
The Food Standards Agency (FSA) says that most people should be able to get the amount of vitamin D they need by eating a varied and balanced diet and by getting some sun. Vitamin D is found in oily fish and eggs and in fortified foods, such as margarine, breakfast cereals, bread and powdered milk. The FSA doesn't say how long you need to be out on the sun to get enough vitamin D. But the National Institutes of Health in the US recommends 10 to 15 minutes a day, at least twice a week, without sunscreen (which blocks UV rays). Because of the risk of skin cancer, it's important not to stay out in the sun too long. If you are out in the sun for long periods, you should cover up or use sunscreen.
If you decide to take vitamin D supplements, the FSA recommends taking 10 micrograms (0.01 mg) a day. You are more likely to be deficient in vitamin D, and so might want to think about taking a supplement, if you:
- are of Asian origin
- always cover up all your skin when you're outside
- rarely get outdoors (if you are in a nursing home, for example)
- eat no meat or oily fish
- are older.
Pregnant and breastfeeding women should take 10 micrograms (0.01 mg) of vitamin D each day.
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This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.
