New Delhi, Aug. 5 -- Scientists in China studied tissues from around 70 people aged 14 to 68 to understand when ageing starts at the cell level. The research was published in the journal Cell. This is what they found.

The ageing process speeds up between 45 and 55. Proteins, which are made in cells using mRNA instructions, begin to form less properly with age. This signals the start of ageing.

The scientists examined many body parts, such as the heart, liver, pancreas, lungs, skin and muscles. They found that different organs age at different speeds.

The spleen, adrenal gland and aorta showed early ageing signs from age 30. The aorta had the biggest changes in protein levels between 45 and 55.

These changes in protein production help ...