Jyri Lankinen, 15 years

1. It helps the body absorb calcium and improves the condition of bones. I have also read that vitamin D can help prevent some illnesses.

2. It is added to dairy products. Button mushrooms also contain some vitamin D. And you can also take tablets.

3. I use dairy products and my family takes supplements. I want to keep my body and bones as healthy as possible throughout my life.

Nina Siukosaari, 15 years

1. Vitamin D is important for our bones.

2. According to my mum, from button mushrooms. Also from sun, fish and milk.

3. I think so, because I drink a lot of milk. I have never thought that I might need to take tablets too.

Pauliina Varjonen, 15 years

1. Vitamin D and calcium make our bones stronger.

2. It is added to milk. Fish, eggs and sun are also good sources of vitamin D.

3. I might not get enough vitamin D in winter, but I do get more over the summer. I used to take tablets, but didn't buy more after running out. I should probably have asked my parents for more.

Robert Koskenniemi, 15 years

1. Our bones do not absorb calcium without it and our bones do not grow.

2. Sun and milk.

3. I drink one litre of milk every day and it says on the carton that it gives me an adequate daily dose of vitamin D.

Anni Tele, 15 years

1. To maintain healthy bones and boost immunity.

2. Different dairy products, sun and mushrooms.

3. I get vitamin D from different dairy products and I also eat tablets. My mum is a health teacher and has told me about the benefits of vitamins.