Open Access Research

Associations between toenail arsenic concentration and dietary factors in a New Hampshire population

Joann F Gruber12, Margaret R Karagas2, Diane Gilbert-Diamond2, Pamela J Bagley3, M Scot Zens2, Vicki Sayarath2, Tracy Punshon1, J Steven Morris4 and Kathryn L Cottingham1*

Author Affiliations

1 Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA

2 Section of Biostatistics and Epidemiology, Dartmouth Medical School, Hanover, NH 03755, USA

3 Biomedical Libraries, Dartmouth College, Hanover, NH 03755, USA

4 Research Reactor Center, University of Missouri and Harry S Truman Memorial Veterans Hospital, Columbia, MO 65211, USA

For all author emails, please log on.

Nutrition Journal 2012, 11:45  doi:10.1186/1475-2891-11-45

Published: 29 June 2012

Abstract

Background

Dietary factors such as folate, vitamin B12, protein, and methionine are important for the excretion of arsenic via one-carbon metabolism in undernourished populations exposed to high levels of arsenic via drinking water. However, the effects of dietary factors on toenail arsenic concentrations in well-nourished populations exposed to relatively low levels of water arsenic are unknown.

Methods

As part of a population-based case–control study of skin and bladder cancer from the USA, we evaluated relationships between consumption of dietary factors and arsenic concentrations in toenail clippings. Consumption of each dietary factor was determined from a validated food frequency questionnaire. We used general linear models to examine the associations between toenail arsenic and each dietary factor, taking into account potentially confounding effects.

Results

As expected, we found an inverse association between ln-transformed toenail arsenic and consumption of vitamin B12 (excluding supplements) and animal protein. Unexpectedly, there were also inverse associations with numerous dietary lipids (e.g., total fat, total animal fat, total vegetable fat, total monounsaturated fat, total polyunsaturated fat, and total saturated fat). Finally, increased toenail arsenic concentrations were associated with increased consumption of long chain n-3 fatty acids.

Conclusion

In a relatively well-nourished population exposed to relatively low levels of arsenic via water, consumption of certain dietary lipids may decrease toenail arsenic concentration, while long chain n-3 fatty acids may increase toenail arsenic concentration, possibly due to their association with arsenolipids in fish tissue.

Keywords:
Arsenic; Epidemiology; Biomarkers; Lipids; Fatty acids; Fish; One-carbon metabolism; Folate