If you have these lines on your nails after 40, it is a clear sign that..

White lines (Muehrcke’s lines): These may be linked to liver or kidney problems, or low protein levels.

Bottom line: After age 40, changes in your nails—especially unusual lines—should not be ignored. They can be an early warning from your body, so it’s important to consult a healthcare provider if you notice anything unusual. Your nails might be revealing health issues before other symptoms appear.