Questions Answered
July 21, 2004

QUESTION: What can you tell me about indium – element 49 – and its role, if any, in human nutrition? Are there any Web sites (on the subject) I can find?

– Kevin Newsham,
San Diego

ANSWER: An Internet search turns up some amazing claims about the health benefits of indium. Among the plethora of ailments indium is purported to cure are: addictions, hair loss, the appearance of aging, cancer, birth defects, low and high blood pressure and weight problems. Most of these claims were presented without any supporting evidence, but a few sites refer to – but distort – scientific studies.

For example, one site claims that in 1971, Dr. Henry Schroeder discovered that indium supplements resulted in a lower body weight, especially in females, and may give women the extra boost to burn more calories and lose weight. Schroeder did publish a paper that year, in The Journal of Nutrition, describing the effects of low doses of indium (as indium chloride) on the growth and life span of mice. However, he reported that indium stunted the growth of mice, especially females, not that it turned them into fat-burning machines.

Also, in contrast to what one would expect if indium really were a cure-all, Schroeder found no statistically significant differences in the life spans, or numbers of tumors, in mice getting indium supplements compared to controls.

A radioactive isotope of indium is used in medicine, including in cancer treatment, but these uses exploit the radioactivity of the particular isotope, not indium's purported nutritional value.

Indium has no known biological function, and the scientific literature does not support the claims about indium's benefits on health.

QUESTION: What is the source and purpose of ear wax?

– Jackie Selby,
University City

Ear wax (or cerumen) is produced in the outer third of the ear, in the auditory canal. It is a mixture of secretions from the sebaceous or oil-producing glands and from modified apocrine or sweat glands. Cerumen lubricates the ear and prevents it from getting dry and itchy. It has antimicrobial and antibacterial properties and traps dust and debris.

Ear wax also helps to clean the ear because the skin in the auditory canal migrates very slowly out of the ear, carrying the wax that adheres to the skin along with the dirt trapped in the wax.

--------------------------------------------------------------------------------
Sherry Seethaler has a doctorate in science education and is a UCSD science writer and educator. Send your scientific questions to her at Quest, San Diego Union-Tribune, P.O. Box 120191, San Diego, CA 92112-0191. Or e-mail sseethaler@ucsd.edu. Please include your name, city of residence and phone number.