Georg Steinhauser, a researcher at Vienna University of Technology has tackled a great mystery many of us encounter on a daily basis: navel lint. After three years of research and over 500 pieces of lint studied, Steinhauser believes that abdominal hair guides clothing fibers into the navel
The article abstract in journal Medical Hypotheses:
Hard facts on a soft matter! In their popular scientific book (Leyner M, Goldberg B. Why do men have nipples – hundreds of questions you’d only ask a doctor after your third martini. New York: Three Rivers Press; 2005), Leyner and Goldberg raised the question why “some belly buttons collect so much lint”. They were, however, not able to come up with a satisfactory answer. The hypothesis presented herein says that abdominal hair is mainly responsible for the accumulation of navel lint, which, therefore, this is a typically male phenomenon. The abdominal hair collects fibers from cotton shirts and directs them into the navel where they are compacted to a felt-like matter. The most abundant individual mass of a piece of lint was found to be between 1.20 and 1.29 mg (n = 503). However, due to several much larger pieces, the average mass was 1.82 mg in this three year study. When the abdominal hair is shaved, no more lint is collected. Old T-shirts or dress shirts produce less navel fuzz than brand new T-shirts. Using elemental analysis, it could be shown that cotton lint contains a certain amount of foreign material, supposedly cutaneous scales, fat or proteins. Incidentally, lint might thus fulfill a cleaning function for the navel.