Poor functioning of the mitochondria is linked to a decline in health.
http://medicalxpress.com/news/2015-06-hi...sease.html
http://medicalxpress.com/news/2015-06-hi...sease.html
Quote: Mice that have a genetic version of mitochondrial disease can easily be mistaken for much older animals by the time they are nine months old: they have thinning grey hair, osteoporosis, poor hearing, infertility, heart problems and have lost weight. Despite having this disease at birth, these mice have a "secret weapon" in their youth that staves off signs of aging for a time.