Media playback is unsupported on your device

Vitamin D deficiency 'increases dementia risk'

7 August 2014 Last updated at 10:32 BST

Older people who are Vitamin D deficient are at a substantially increased risk of developing dementia, a study in the journal Neurology has found.

Speaking on BBC Radio 4's Today programme, one of the authors of the study, Dr Iain Lang from the University of Exeter, said: "This is the first time this has been done on this scale and we're quite surprised that the results are so big."

And he added: "I don't think this is the key to dementia but it's a really important step in finding out what might be going on there."

First broadcast on BBC Radio 4's Today programme Thursday 7 August.