Myelin decay in the brain leads to cognitive and physical decline.  But you can help keep your brain healthy and improve its ability to repair itself.
D000367:Age Factors; D001921:Brain / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D003072:Cognition Disorders / Q000378:metabolism*; D006801:Humans; D008569:Memory Disorders / Q000378:metabolism*; D009186:Myelin Sheath / Q000378:metabolism*; D009416:Nerve Regeneration / Q000502:physiology