I am a dork sometimes and like to read things about food and how it works in our bodies etc.. the benefits, the risks, the good and the bad... I found this fact quite interesting...
"I've heard that black pepper stays in our body for many years and is a health hazard. Is that true?"
No, it's not true. First of all, black pepper is a complex food composed of many different substances. No complex food that we eat stays inside our body whole and intact. Complex foods don't even get absorbed into our body as whole, intact foods. Instead, they are broken down into much smaller parts in our digestive tract before they ever get absorbed.
Therefore, at the very most, it would only be some isolated component of black pepper (not black pepper itself) that was absorbed into our body (via our bloodstream) and then stayed either in storage or in transit for a long period of time. However, this also is not the case. For example, one of the substances that can act as a type of irritant in black pepper (and provoke a sneeze, for example) is a well-studied alkaloid called piperine. In animal studies, researchers have found that it takes between 6-24 hours for over 90% of this substance to be cleared from the body. Other important substances found in black pepper, like the polysaccharides that have been shown to have potential immune-supportive properties, would also be readily metabolized.
For a food component to stay inside our body for any extended period of time, it would have to be stored inside some body tissue that kept it fairly strongly attached. Minerals found in food can sometimes be stored in this way when they become part of the bone matrix. It's possible for the bone matrix to hold on to some of its mineral content throughout the course of a lifetime. However, the whole, intact foods that we eat only serve as the initial carriers of these minerals from the outside world into our body. The foods themselves do not stay inside us undigested.