Vitamin D is essential for the body. It works with calcium to keep bones and teeth healthy and is particularly important for growing children, who can develop bone disease rickets if they are deficient.

It’s also important for pregnant women, who are advised by the NHS to take a supplement to ensure their baby gets enough for healthy development.

But even if you’re not in those categories, it’s still vital you get enough vitamin D. It boosts your immune system and mood and has even been linked to a lower risk of breast cancer, breast cancer, Parkinson’s and heart disease.

It is possible to get enough from your diet and from sun exposure but busy lives, a disappointing summer and cold, dark winter days mean that almost half of the population of the UK is thought to be deficient.

How much vitamin D should you get each day?

The official recommendation is 40 International Units (IU) of vitamin D a day – or 10 micrograms (mg) for adults. And for children and babies over six months it’s 280 IU or 7mg a day.

Dietary vitamin D or sun exposure?

Around 90 per cent of our vitamin D comes from sunlight, and just 10 per cent from diet.

One of the reasons many UK residents are now deficient in vitamin D is thanks to a greater awareness the skin cancer risk the sun poses. We are now far more careful about going out in the sun and are more likely wear sun cream. Women are also concerned about the aging effects of sunlight and often wear sunscreen on their faces year-round.

Though it’s important to heed skin cancer warnings, it seems we need more sun in our lives. Advice is often conflicting but most experts say a short period of sun exposure, without sunscreen, is important for the synthesis of vitamin D.

Just make sure you apply sunscreen or get out of direct sunlight before you start to go pink. In practice, in the mid day summer sun, this is usually after around 10 minutes. In the winter you could stay out all day without worrying, but the rays are also unlikely to be strong enough for your body to make vitamin D. Your body stores the vitamin for up to 90 days so stocking up in summer is a good idea – but not all summers allow this.

Winter vitamin D

The lack of daylight, let alone sun, in the winter makes it difficult to get enough vitamin D and your body will use up its stores rapidly.

In the winter, not only is it scarce, but the sun’s UVB (vitamin D-producing) rays are also weak.

How can you get enough vitamin D?

If you can, try and get 20 minutes of sun exposure in the middle of the day during winter. Try to ensure you have some exposed skin that doesn’t have any SPF on and keep warm by keeping moving rather than shivering on a bench.

On days where it’s gloomy, overcast or pouring with rain, you may just have to accept defeat.

Oily fish can contain up to 400IU of vitamin D per 100g, but it’s unlikely you’ll eat a portion every single day and some groups aren’t recommended to eat more than two portions a week due to contaminants found in the fish.

Egg yolks are also a good dietary source, containing around 18IU of vitamin D, but it’s not recommended you eat too many of those either. Beef liver and mushrooms have some vitamin D, but as you’re probably realising – it’s difficult to get enough from your food.