Insulin is a naturally occurring hormone made by the pancreas that helps our body use or store the glucose (sugar) it gets from food. For people with diabetes, either the pancreas does not make enough insulin to meet the body's requirements, or the body cannot properly use the insulin that is made.
The yellow color in normal urine comes from a substance known as urochrome. Urochrome is also known as urobilin and is the result of hemoglobin breakdown. Hemoglobin is the protein in red blood cells that enables oxygen to be taken around the body.
Carrots, carrot juice, and vitamin C can color urine orange, and B vitamins can turn it a fluorescent yellow-green. Asparagus sometimes gives urine a greenish tinge and a distinctive smell, said to resemble rotting cabbage. The cause of this smell is a matter for speculation.