Vitamin D is growing in popularity and since a few months ago, supplements have experienced quite a boom. This is due to many recent studies underlying its importance in almost every sphere of our lives. The problem is, as far as food goes, there are very few naturally occurring foods that have high enough doses to satisfy our needs, and the homogenization of our diet is not helping the case. This is why some countries with relatively little sunshine (like Finland) are “fortifying” their foods.
In the past few months, evidence has been growing that the “sunshine vitamin” not only has an important role in bone and muscle health, but might also help prevent a range of cancers, reduce the chance of developing rheumatoid arthritis, protect against multiple sclerosis and cut the risk of colds and flu.
If the benefits are real, should we all be taking vitamin D supplements and/or embedding it into industrially produced foodstuffs?
Vitamin D is in essence a label that covers a group of substances, including vitamin D2 and D3. The latter is the form made when sunlight hits your skin and is also found in other animals. Non-animal sources such as fungi and yeasts primarily produce the D2 form. Once in the body, these substances are converted into biologically active steroids that get around our bodies through the bloodstream.
“The musculoskeletal stuff is really good and really strong,” said Helen Bond, a spokesperson for the British Dietetic Association, pointing out that vitamin D is important in calcium and phosphate absorption.
Too little vitamin D can be serious: the skeletal disorders osteomalacia and rickets are known to be caused by a vitamin D deficiency, and the latter is on the rise in the UK, a finding some put down to the impact of poverty on poor nutrition.
“Intuition suggests that it can’t all be right,” said Julia Newton-Bishop, professor of dermatology and vitamin D expert from the University of Leeds. But while a recent review of evidence by the scientific advisory committee on nutrition only found strong evidence in the case of bone and muscle health, Newton-Bishop says a growing body of research is exploring other conditions.
Martin Hewison, professor of molecular endocrinology at the University of Birmingham, who carried out the recent study into vitamin D and rheumatoid arthritis, said evidence from cell studies backs up the idea that the vitamin is essential.
If you are considering taking supplements, it might be worth checking which form of vitamin D they contain. “Some people don’t want an animal form of vitamin D,” said Hewison. However, “What studies have shown is that if you want to raise your blood vitamin D levels, vitamin D3 is much more efficient at doing that.”
Dr Benjamin Jacobs, a consultant paediatrician and spokesperson for the Royal College of Paediatrics and Child Health, says supplements are not enough as it is hard to make sure people actually take them. Instead, he suggests the UK consider food fortification.
Some countries, including Canada and Finland, have embraced fortification of milk. But although infant formula and some breakfast cereals, plant-based milks and fruit juices are already fortified in the UK, most foods are not.