Why does your urine have a strong odor after eating asparagus?

Answer

The ingredient in asparagus that is responsible for the typical urine odor is probably asparugic acid. This is a typical ingredient of asparagus. By itself it has no smell, but in our body it is broken down (“metabolized”) to form a number of sulfur-containing substances, including mercaptan, which you can smell.

These and other wastes from our metabolism are quickly excreted by the kidneys in the urine. This is important because at higher concentrations these substances can be toxic to our body. Some people have done the experiment and found that as early as 15 minutes after eating asparagus, the urine started to smell.

This is a nice illustration of the fact that our body is like a chemical factory. It has also been found that not everyone is equally sensitive to this smell, which is determined by heredity. Some people make this smell, but can’t smell it.