Mercury and the Gluten-Free DietTricia Thompson
Bottom line: Rice sent by Gluten Free Watchdog to the Trace Element Analysis Core Laboratory at Dartmouth College contained very small amounts of total mercury.
What is causing the concern about mercury and the gluten-free diet? Two recently published studies have caused concern about the gluten-free diet and mercury. The latest study “Unintended Consequences of a Gluten-Free Diet” published in the journal Epidemiology by Bulka CM et al, found higher levels of blood total mercury in people self-reporting following a gluten-free diet as compared to those not following a gluten-free diet. This analysis was based on a review of NHANES data.
Another study “Increased Mercury Levels in Patients with Celiac Disease following a Gluten-Free Regimen” published in the journal Gastroenterology Research and Practice by Elli L et al, compared blood mercury levels in healthy controls, untreated individuals with celiac disease and treated individuals with celiac disease. Mercury levels were significantly higher in individuals with treated celiac disease. The study controlled for fish intake and amalgam fillings.
What are these studies telling us? It is too soon to say and any interpretation is speculative at this point.
Gluten Free Watchdog had six brands of rice tested for Mercury at Dartmouth College. Brands tested were requested by subscribers to Gluten Free Watchdog and represent products consumed by the gluten-free community in the US. Results for total mercury ranged from below the limit of detection of 0.002 micrograms per gram to 0.004 micrograms per gram. As a point of reference, China (which has had an issue with mercury contaminated rice) has a regulatory limit for total mercury in grains, including rice of 0.02 mg/kg (which is the same as 0.02 micrograms per gram).
Note: According to the lab, 19 other rice samples were tested for mecury in addition to the samples submitted by Gluten Free Watchdog. All results were similarly low.
Eat a variety of naturally gluten-free grains. It is cliché, but as William Cowper said, “Variety’s the very spice of life, that gives it all its flavour.”
Eat low mercury fish. For a great info graphic from FDA and the EPA see https://www.fda.gov/Food/FoodborneIllnessContaminants/Metals/ucm534873.htm
If you are concerned about mercury and rice, avoid rice sourced from China.
Subscribers to Gluten Free Watchdog, for brands tested and specific results please login, click on https://www.glutenfreewatchdog.org/product/mercuryrice-grain-combined-data/573 and then click on “Test Report Summary” and “Complete Test Results.”