Recent headlines have again been extolling the need for everyone to take vitamin D supplements, especially during the winter months.

Public health advice has now changed, and whereas previously only pregnant women, young children and housebound adults were thought to need a boost of this nutrient, the Government now recognises that low levels of vitamin D are widespread and we simply cannot manufacture it in our bodies during winter.

In my own clinic I frequently ask clients to have their vitamin D levels checked, particularly if they have an inflammatory condition like arthritis, are at risk of heart disease, have digestive problems or experience mental wellbeing issues like anxiety and depression.

The latest research review to hit the headlines showed how effective vitamin D is at reducing acute asthma attacks in adults with mild to moderate asthma. The review was limited by the fact there were only seven trials to examine, but the results were encouraging.

So after years in the wilderness, why is vitamin D now in the spotlight? Well, advances in research over the past 20 years have discovered that vitamin D is needed for much more than just bone health.

We now know there are vitamin D receptors on every cell in your body. Receptors are like doorways on the surface of a cell: vitamins, minerals and hormones use these doorways to go inside the cell and get to work.

Vitamin D works alongside the friendly bacteria in your gut to control and regulate your immune system – if you are prone to infections like colds and flu then your immune system may be struggling, and this may be due to low levels of vitamin D.

One of the many causes of inflammation is thought to be low levels of vitamin D. People often find their arthritis and joint pains improve when on holiday in hot sunny places: this may be because of the extra vitamin D they are receiving from the sunshine.

As we move towards the shorter darker days of autumn and winter Seasonal Affective Disorder – or SAD – can occur. Symptoms include low mood, depression, anxiety, poor sleep and lack of energy. Again, a lack of vitamin D is a key factor. Even on bright crisp winter days we are unable to manufacture the vitamin in our skin because the sun’s rays are not strong enough. We have to wait for springtime before we can make our own vitamin D again.

There are few good food sources of this crucial nutrient. Eggs, butter, oily fish (salmon, mackerel, sardines, pilchards) and sun-dried mushrooms are good sources but even these foods cannot supply enough to maintain healthy levels. This is why the new public health advice is for everyone to consider taking a supplement during winter. Health food stores offer a range of options from capsules to pleasant minty flavoured mouth sprays which are great for kids!

Don’t be caught out this winter, give your vitamin D the boost it needs.

- Sally Duffin is a nutritional therapist and writer based in Holgate, York.