What vitamin D does
Vitamin D helps you absorb calcium and keeps bones, teeth and muscles healthy. It also supports the immune system.
How much
Adults need about 10–20 µg (400–800 IU) a day.
Where it comes from
- Sunlight on your skin is the main source — but from October to March in northern countries the sun is too weak.
- Very few foods contain much. UV-treated mushrooms and fortified plant milks and spreads help (Sun your mushrooms).
What to do
Many health authorities recommend a vitamin D supplement during autumn and winter for everyone, and all year for people who rarely get sun, cover their skin or have darker skin. Vitamin D3 from lichen is a vegan option; D2 works too.