Original article
Alimentary tract
Accumulation of Heavy Metals in People on a Gluten-Free Diet

Preliminary analysis was presented at Digestive Disease Week 2015, Washington, District of Columbia, May 17–19, 2015.
https://doi.org/10.1016/j.cgh.2017.01.034Get rights and content

Background & Aims

Specific foods such as fish and rice have high concentrations of metals such as arsenic, mercury, lead, cadmium, and cobalt. Many gluten-free diets (GFDs) include these foods, so we evaluated whether a GFD was associated with increased metal bioaccumulation.

Methods

We performed a population-based, cross-sectional study using data collected from the National Health and Nutrition Examination Survey (NHANES), from 2009 through 2012, collecting information on the diagnosis of celiac disease and adherence to a GFD. We tested NHANES blood samples to identify individuals with undiagnosed celiac disease, using assays for immunoglobulin A tissue transglutaminase followed by a confirmatory test for endomysial antibody. Among a total of 11,354 NHANES participants, celiac disease was diagnosed in 55 participants, based on test results or a reported clinical diagnosis. We collected NHANES survey data on blood levels of lead, mercury, and cadmium from subjects who were on a GFD (n = 115) and participants who were not on a GFD (n = 11,239). Levels of total arsenic in urine samples were available from 3901 subjects not following a GFD and 32 individuals following a GFD. NHANES participants were asked questions about fish and shellfish consumption. We performed multivariate logistic regression analyses to associate gluten-related conditions with blood concentrations of mercury, cadmium, and lead and urine concentration of total arsenic, adjusting for demographic characteristics, as well as for rice consumption or seafood intake. Geometric means were reported for urinary concentrations of total arsenic and blood concentrations of mercury, cadmium, and lead for demographic groups and subjects with gluten-related conditions (subjects without celiac disease who avoid gluten).

Results

Persons following a GFD had significantly increased total blood mercury levels (1.37 mcg/L) compared with persons not on a GFD (0.93 mcg/L) (P = .008), as well as increased blood levels of lead (1.42 vs 1.13 mcg/L; P = .007) and cadmium (0.42 vs 0.34 mcg/L; P = .03). Urine samples from subjects on a GFD had higher concentrations of total arsenic (15.15 mcg/L) than urine samples from subjects not on a GFD (8.38 mcg/L) (P = .002). After controlling for demographic characteristics, levels of all heavy metals remained significantly higher in persons following a GFD, compared with those not following a GFD. After exclusion of persons with celiac disease, people without celiac disease on a GFD (n = 101) had significantly increased blood concentrations of total mercury (1.40 mcg/L) than persons without celiac disease and not on a GFD (n = 10,890) (0.93 mcg/L; P = .02) and higher blood concentrations of lead (1.44 vs 1.13 mcg/L; P = .01) and higher urine concentrations of total arsenic (14.69 mcg/L [n = 3632] vs 8.32 mcg/L [n = 28]; P = .01). Blood samples from persons without celiac disease avoiding gluten had higher levels of cadmium (0.42 mcg/L) than persons without celiac disease and not following a GFD (0.34 mcg/L), but this difference was not significant (P = .06).

Conclusions

In an analysis of data collected from NHANES, persons on a GFD had significantly higher urine levels of total arsenic and blood levels of mercury, lead, and cadmium than persons not avoiding gluten. Studies are needed to determine the long-term effects of accumulation of these elements in persons on a GFD.

Section snippets

Study Population

The National Health and Nutrition Examination Survey (NHANES) is a program of studies designed to evaluate the health and nutritional status of adults and children in the United States.14, 15 The surveyed population in NHANES mostly represents the US noninstitutionalized, civilian population because of its complex, multistage, probability-based sampling design. Data from approximately 5000 persons per year, which includes standardized household interviews, physical examinations, and testing of

Characteristics of Study Participants

Figure 1 shows the flow chart for the study population of NHANES 2009 to 2012 surveys. Among the 12,391 adult participants in the NHANES 2009 to 2012 surveys, 1037 persons who neither were examined (n = 416) nor tested for blood heavy metals and the gluten-related questions (n = 621) were excluded. The participants were 11,354 adults with measured blood levels of lead, mercury, and cadmium, and a subset of 3933 adults had their urinary total arsenic measured. The mean age of the 11,354

Discussion

Recently, the general public has developed a perception that a GFD provides health benefits for everyone, resulting in substantial growth of the gluten-free market, as well as an increased proportion of the general population who seek and follow a GFD. Certainly, patients with CD greatly benefit from a GFD, despite such less desirable outcomes as nutritional deficiencies. The present study shows a significant increase in levels of blood lead, cadmium, and mercury, as well as urinary total

Acknowledgments

The authors thank Tricia L. Brantner for serologic testing and the staff of the Immunodermatology Laboratory of the Mayo Clinic for conducting the endomysial antibody assays, as well as Deborah I. Frank for her assistance in the preparation of the manuscript.

References (32)

  • T. Kulai et al.

    Assessment of nutritional adequacy of packaged gluten-free food products

    Can J Diet Pract Res

    (2014)
  • Y. Wei et al.

    Rice consumption and urinary concentrations of arsenic in US adults

    Int J Environ Health Res

    (2014)
  • M.A. Davis et al.

    A dietary-wide association study (DWAS) of environmental metal exposure in US children and adults

    PLoS One

    (2014)
  • K.N. Jallad

    Heavy metal exposure from ingesting rice and its related potential hazardous health risks to humans

    Environ Sci Pollut Res Int

    (2015)
  • L. Elli et al.

    Increased mercury levels in patients with celiac disease following a gluten-free regimen

    Gastroenterol Res Pract

    (2015)
  • T.M. Ezzati et al.

    Sample design: Third National Health and Nutrition Examination Survey

    Vital Health Stat 2

    (1992)

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    Conflicts of interest The authors disclose no conflicts.

    Funding This work was supported in part by the Centers for Disease Control and Prevention (contract M26561).

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