Here, we give you the lowdown on the sources of vitamin D and how much of the vitamin you should get.

A heated debate seems to revolve around the benefits of vitamin D and the best ways of getting your required daily dosage. Most well known are the benefits of vitamin D for maintaining healthy bones — but did you know that vitamin D can even play a role in preventing everything from schizophrenia to cancer?

Where do we get vitamin D?

The main source of vitamin D is sunlight. Vitamin D is called the 'sunshine vitamin' because it is formed in the skin through exposure to ultraviolet rays from the sun. It is estimated that throughout the seasons, around 15 minutes exposure to the sun a few days a week is enough to provide the required amount of vitamin D. You can also get vitamin D through your diet — the main food sources being eggs, liver, milk and other dairy products, in addition to oily fish such as sardines, tuna and salmon.

So, getting out in the sunshine is now good for you? We’ve all heard the warnings about the dangers of exposing the skin to sunlight and the risks of skin cancer, and yet we are also being told that some sun exposure can be good for us and can even help fight cancer. Feeling confused? Then keep reading!

So what should you do?

Firstly, don’t get overexcited, as being told that sunlight is good for you does not give you the green light to peel off your clothes and do without sunblock in order to get hours of unprotected exposure to the sun! The risk of skin cancer from the sun is real, and so you should only stay in the sun for as long as is safe and necessary. Fair-skinned people only need around 15 minutes of direct sunlight to produce enough vitamin D to last for several days (although people with darker skin may need more exposure). And it’s not suggested that this exposure to the sun has to be every day; instead, a few short exposures a week is considered to be plenty. These exposures could be fitted into your day-to-day activities — for example, try walking in the sun at every given opportunity or even driving with the windows rolled down. It’s not hard to get your sun exposure if you try to fit it around your daily routine.

But what about those times when the sun is too weak to stimulate vitamin D production? And what about those of us that leave for work before light, spend all day inside and arrive home in the dark? Well, it’s difficult to get your recommended daily amount of vitamin D from food alone, but one way to ensure you get the recommended dosage would be to have a tablespoon of cod liver oil, which would provide you with 1,360IUs (International Units — which are the standard measurement of vitamins). The upper limit for vitamin D is 2,000IUs daily — so one tablespoon of cod liver oil every day should be enough. But if you don’t want to do this, then a vitamin D supplement is an acceptable alternative.

What about light therapy?

Some people turn to light therapy in the dark periods of the year, when they are affected by the so-called ‘ winter blues’ of Seasonal Affective Disorder (SAD). The problems of feeling tired and listless associated with SAD are often caused by a lack of light — and while light boxes don’t help to generate vitamin D production (as they do not emit ultraviolet radiation), light stimulation can reduce the effects of SAD. A daily session with a light box can help people feel happier and more alert, and also much more able to concentrate better and be more productive. Of course, full sunlight is the preferred option, as it also brings the added benefit of vitamin D production.

How much vitamin D is too much?

There is a legitimate risk of skin cancer when trying to get vitamin D from sunlight, and overexposure to the sun is certainly not what is being recommended by the experts. What is generally suggested is exposing the hands, face, arms and legs to the sun for around 15 minutes a day a few days a week. This will be enough to generate the required amount of vitamin D without increasing your risk of skin cancer. Longer exposure to the sun than this will mean you’re getting too much vitamin D.

The effects of too much vitamin D

Getting too much vitamin D has been associated with nausea, vomiting, poor appetite, constipation, weakness, and weight loss. It could also cause long-term damage to your liver and kidneys. But don’t worry: consuming too much vitamin D through diet alone is not likely unless you routinely consume large amounts of cod liver oil or you are loading up on too many vitamin D supplements. So, you will just need to monitor how long you stay in the sun!