Vitamin D - What's the hype about and why do we need it?

There has been a lot of media interest in vitamin D over the past few years. There has been much debate as to whether everyone living in the UK should be taking a vitamin D supplement.

In the past, the recommendation for supplementation with vitamin D has only really been for children under 5 years old, the elderly and those who are housebound. But, should the recommendation be that we all take a daily supplement?

It is established from research that a deficiency in vitamin D causes Rickets in children and Osteomalacia in adults, which are both conditions which affect bone health. There is some research which suggests that not getting enough vitamin D may be linked with diabetes, asthma and cognitive impairment in older adults. But this is not well established and is still being researched to determine whether this is, in fact, the case.

However, more recently, European research has found that children born to mothers who have a vitamin D deficiency during pregnancy may also have a higher risk of developing attention-deficit/hyperactivity disorder (ADHD), one of the most common chronic diseases in children.

What do you need to know about vitamin D?

One thing to know about vitamin D is that it is a fat-soluble vitamin, which means that in order for it to be absorbed, fat is required. There are very few foods which naturally contain vitamin D - oily fish, such as salmon, mackerel and sardines, eggs, fortified spreads, breakfast cereals and powdered milk, but when eaten, is absorbed as cholecalciferol.

With the limited availability of vitamin D from foods, you can see why the action of ultraviolet light from the sun is so important in order for us to get the vitamin D that we need.

For many years, medical professionals have suggested that, in the UK, we should take a vitamin D supplement during the winter months, as the limited exposure to the sun means that we do not get an opportunity to synthesis vitamin D for ourselves. And, over the winter we, in fact, use the stores of vitamin D that we have accumulated over the summer.

That is if we get a summer that has sufficient sun exposure in order to build up these stores, to begin with.

Why is vitamin D so important to our health and well-being?

Well, many of us will know that vitamin D has a role to play in the health of our bones. In fact, vitamin D has many other functions which are also important:

• Contributes to the normal function of the immune system*.
• Contributes to the maintenance of normal bones*.
• Contributes to the maintenance of normal muscle function*.
• Contributes to the maintenance of normal teeth*.
• Contributes to the normal absorption and utilisation of calcium and phosphorus*.
• Contributes to normal blood calcium levels*.
• Has a role to play in cell division*.
• Is needed for normal growth and development in children*.
• With calcium, is needed for normal growth and development of bone in children*.

*Approved EFSA health claims

How can you get more vitamin D in your diet?

There are a number of foods which are natural sources of calcium and have been fortified with vitamin D, as the two work together in establishing healthy bones.

There are also a lot of vitamin D supplements available on the market and it can be difficult to work out which is the best one for you. In this case, it can be useful to speak to a nutritionist and find out what would be the best way to supplement your vitamin D intake.