Mercury/RiceGrain: Combined Data 2018 Update

Mercury/RiceGrain: Combined Data 2018 Update

The following report on Mercury/RiceGrain: Combined Data 2018 Update will inform you of the amount of gluten found in this product during testing.

General Product Information

Manufacturer: Multiple

Mercury and the gluten-free diet

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.

UPDATE February 28, 2018: The researchers from Dartmouth College who tested rice products for mercury for Gluten Free Watchdog have just published a new article in the journal Food Chemistry entitled, “Essential micronutrient and toxic trace element concentrations in gluten containing and gluten-free foods” (abstract available at Among other micronutrients and trace elements, they assessed rice and rice-based products for mercury.

Mercury findings: Results were low for all foods tested, including rice.  However, “food containing rice had significantly higher mercury concentrations than those based on wheat or other grains.” Mercury concentrations did not differ significantly between rice types—brown, unenriched white, and enriched white.

Gluten Free Watchdog Testing: 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. Please see Complete Test Results for details.


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

If you are concerned about mercury and rice, avoid rice sourced from China.

Complete Test Results

Test results for this product are only available to subscribers. or subscribe to the premium plan to read this historical report!