Brain function can start declining 'as early as age 45'

The brain's ability to function can start to deteriorate as early as 45, suggests a study in the British Medical Journal.

University College London researchers found a 3.6% decline in mental reasoning in women and men aged 45-49.

They assessed the memory, vocabulary and comprehension skills of 7,000 men and women aged 45 to 70 over 10 years.

Dr Anne Corbett is from the Alzheimer's Society.