Under scientific research, there is no direct correlation between dark skin on the waist and poor kidney function. The main reason may be related to pigment accumulation, poor blood circulation, anemia, etc. It is important to pay attention to good living habits, usually not recommended long-term smoking, drinking alcohol and excessive fatigue. Irregular lifestyle can cause pigmentation to accumulate, which may lead to darkening of the skin around the waist. Of course, herniated lumbar discs and necrosis of the femoral head can also cause poor blood circulation around the waist, which can lead to dark skin around the waist. In the case of anemia, darkening of the skin may also occur. Pay attention to eat more iron-rich fresh fruits, vegetables and meat, and exercise properly to improve the body’s immune system. Of course, fruits and vegetables rich in vitamin C will also achieve the effect of removing black, so the waist skin black and poor kidney function is not directly related, do not worry too much.