Although sources of vitamin D might be scarce, it’s vital we get enough of this nutrient. Often known as the sunshine vitamin, the primary source of vitamin D is actually the sun itself. But why do we need vitamin D?

Dietitian Helen Bond explains that vitamin D is a fat-soluble vitamin, which is stored in the body. “It is well known for its role in building and maintaining healthy bones and teeth,” she says. “That’s because vitamin D helps the body to absorb and use the minerals calcium and phosphorus. This essential nutrient also promotes healthy muscle function and helps support the immune system.”

There’s also research to suggest that adequate levels of vitamin D can support our mood and help avoid or overcome depression. Because of the sun being a key source of vitamin D, it does mean that in many countries it can be hard to obtain enough vitamin D to hit adequate intakes. Darker months, where the sun rises later and sets earlier, can prevent much of the population from getting enough sunlight on their skin. Or, perhaps the sun isn’t strong enough.

The Recommended Dietary Allowance (RDA) for adults is 15 micrograms (µg) daily for men and women, and for adults over 70 it rises to 20 µg daily.

“National dietary surveys reveal that adults only get around 2.9 µg a day, on average from food, while children and teenagers get around 2.3 µg a day,” says Bond.

There are studies that link vitamin D deficiency with cancer, cardiovascular disease and diabetes, to name a few. So it’s important we get enough of this vitamin. Bond says that there are only a few foods that naturally contain vitamin D, so make sure to add these to your diet to reap the benefits of this vitamin. You can also take the best vitamin D supplement during the winter months.

1. The sun and supplementation

“Outside these months, sunshine does not provide enough UVB rays needed to make significant amounts of vitamin D in the skin – even if it is a sunny day. Therefore, it’s recommended that during the autumn and winter months, adults should eat foods rich in vitamin D and take a daily supplement containing at least 10 μg of vitamin D,” says Bond.