What Infant Toenails Can Tell You
Both potential and new parents should know that infant toenails can tell them how much arsenic their newborn has been exposed to before birth. This information is important because arsenic is a toxin that can have a detrimental impact on a child’s health.
What the study showed
A research team from Dartmouth College in New Hampshire evaluated the level of arsenic in the toenails in utero and in newborns using a method called plasma mass spectrometry. A total of 170 mother-infant pairs participated in the study.
Toenails are an excellent target for the measurement of arsenic in the body. Since the toenails of the fetus begin to develop during the first trimester, they provide clinicians with a great source to measure arsenic exposure early in the pregnancy.
Among the 170 pairs, the authors found that a doubling of a mother’s postpartum arsenic toenail arsenic concentration was associated with a 54 percent rise in their baby’s toenail arsenic concentration when compared with 20 percent for a doubling of the mother’s arsenic concentration in urine. At the same time, a doubling of a mother’s toenail and urine concentrations of arsenic was associated with a 68 percent increase in a baby’s toenail concentration of arsenic.
The researchers observed similar findings in another group composed of 130 mother-infant pairs from Rhode Island. So what are the dangers of arsenic?
A woman’s exposure to arsenic comes mainly from water and diet. According to a 2012 study from the University of Washington School of Law, many of the public water systems in the United States have unhealthy levels of arsenic. Unfortunately, it takes money to correct this problem, and much of the issue exists in poorer communities, hence the toxin remains a challenge.
Foods that are associated with possible arsenic contamination include rice, apple juice, grape juice, beer, and some baby milk formulas. Nutritional supplements also may contain small amounts of the toxin. Regular exposure to arsenic has been associated with cardiovascular disease, developmental disorders, neurological problems, reproductive system issues, greater infant mortality, and various cancers.
In a new report in the Journal of Developmental Origins of Health and Disease, a team of experts assessed the effects of arsenic on genome-wide DNA methylation of genes involved with cancer in newborns. In this case, the researchers evaluated maternal urine and cord blood. They found that arsenic in the urine during early gestation was associated with cord blood DNA methylation. DNA methylation plays a significant role in the development of nearly every type of cancer.
The authors also observed that lower DNA methylation was associated with higher arsenic exposure and that boys were more affected than were girls. Another finding was that exposure to arsenic during early pregnancy had more of an impact than did later exposure.
In addition, a 2013 review of the impact of arsenic, cadmium, and manganese in children evaluated 18 studies. Thirteen of the studies found that arsenic had a negative effect on neurodevelopment and behavioral disorders.
What this study means
According to the study’s senior author, Professor Margaret Karagas, “infant toenails appear to be a reliable biomarker for estimating arsenic exposure during the critical window of gestation.” Women who plan to get pregnant and those who are already pregnant should discuss the risk of arsenic exposure with their healthcare provider and have their drinking water evaluated for arsenic levels.
Broberg K et al. Arsenic exposure in early pregnancy alters genome-wide DNA methylation in cord blood, particularly in boys. Journal of Developmental Origins of Health and Disease 2014 Aug; 5(4): 288-98
Davis MA et al. Infant toenails as a biomarker of in utero arsenic exposure. Journal of Exposure Science & Environmental Epidemiology 2014 Jun 4. DOI:10.1038/jes.2014.38
Levine RL. The need for congressional action to finance arsenic reductions in drinking water. Journal of Environmental Health 2012 Nov; 75(4): 20-25
Pilsner JR et al. Influence of prenatal arsenic exposure and newborn sex on global methylation of cord blood DNA. PLoS One 2012; 7(5): e37147
Rodriguez-Barranco M et al. Association fo arsenic, cadmium and manganese exposure with neurodevelopment and behavioural disorders in children: a systematic review and meta-analysis. The Science of the Total Environment 2013 Jun 1; 454-455:562-77
Wu F et al. Association between arsenic exposure from drinking water and plasma levels of cardiovascular markers. American Journal of Epidemiology 2012 Jun 15; 175(12): 1252-61