Mehmet Oz is a physician who’s made the most of the opportunities afforded him as a television celebrity. He supports complementary and alternative medicine, which draws in criticism from advocates for evidence-based medicine. Dr. Oz most recently emerged in the news with a “study” highlighting the health risks from arsenic in fruit juices, which given the size of his megaphone engendered nationwide controversy. The FDA took him to task over it, and I picked it up from reading PZ Myer’s blog. PZ does a public service drawing attention to the issue and in particular highlighting FDA’s opinion of Dr. Oz’s data, but didn’t convey anything about the nature of the risks, either significant or insignificant, about arsenic in apple juices. Deborah Blum has a great story about what real arsenic risks look like, depicting arsenism in Bangladesh including a brain-curdling picture of someone with an arsenic-related hyperkeratosis (a disabling thickening and roughening of the skin). She also takes Dr. Oz to task for doing bad risk assessment and bad risk communication.
Originally, I had thought that before it’s too late and peoples’ attentions are drawn elsewhere, there’s an opportunity to convey some risk information about arsenic. Couldn’t get together in a fashion that’s readable to the folks who would actually benefit from it, in the time allowed (at this posting, Dr. Oz and arsenic-contaminated apple juice have disappeared from the news cycle). After awhile, blog fatigue set in – I already have an informed opinion about arsenic risks; my family and I don’t drink the amber-colored sugar water that passes for commercial apple juice (the youth drink the orangy stuff that passes for orange juice, but that’s a different topic); the burning need to inform readers about arsenic risks is subsiding as short attention spans turn to other matters.
Look, here’s the short answer: arsenic is all around us. It occurs naturally in rocks and soil, rivers and streams and groundwater. Certain human activities such as mining and pesticide use can introduce arsenic into the environment; note: the use of arsenical pesticides was discontinued decades ago, however, concentrations of arsenic in soil resulting from pesticide use can still be found around orchards. Ingestion of arsenic is well known to produce an array of toxic effects, however that fact needs to be tempered with the understanding that the “dose makes the poison” (which is the title of one of the best plain-language guides on toxicology – a bit dated, but still sound information). Arsenic has been associated with adverse effects with human populations in different parts of the world including Taiwan and Bengladesh who were exposed to levels in drinking water exceeding 300 parts per billion (ppb) over a long period of time (much higher levels than found in apple juice). The distinguishing adverse effects associated with chronic ingestion of arsenic are skin lesions (hyperkeratoses and hyperpigmentation) and skin cancer. Other adverse effects from ingestion exposure include cancer of the internal organs (liver, bladder and kidney) and a vascular disease known as “blackfoot disease” (note: blackfoot disease is a condition endemic in an area of Taiwan where there are naturally elevated arsenic concentrations in drinking water). The U.S. Environmental Protection Agency (EPA) is also evaluating other potential health risks such as liver, bladder and kidney cancer as part of its work in developing a new drinking water standard for arsenic. What we know about chronic health risks is from ingestion of high levels in drinking water. Ingestion of low levels in food and water? Reasoned speculation would be that the contribution to total cancer risks would be small – but that’s not a point you could argue as a fact, and it gets to be difficult to address it scientifically, because it’s a hypothesis that’s not readily falsifiable. Would need to do some calculations to elucidate that better – check back later. . . .
In the meantime, read “The Dose Makes the Poison”, and struggle through some monographs produced by the National Academy of Sciences, at least the executive summaries, published in 1983, 1999 and 2001. And find somewhere else to get informed about arsenic health risks other than Dr. Oz.