Background: Human milk is a biofluid that can contain heavy metals such as arsenic, cadmium, lead, and mercury. These toxins can adversely affect endocrine, respiratory, immune, and nervous systems. Infants may have higher dietary arsenic exposure than adults due to their more restricted diets and greater intake per unit body mass. We identified commonly purchased vitamins, lactation bars, and supplements, to measure the concentration of heavy metals. The goal of the study was to measure and determine if vitamins and lactation foods could be a source of exposure. Methods: We tested 9 popular vitamins and 16 lactation bars and supplements all marketed toward breastfeeding mothers to determine the presence of heavy metals. All vitamins, bars, and supplements were analyzed using inductively coupled plasma mass spectrometry, for the total concentration of arsenic, mercury, cadmium, and lead, with the lowest detection limit of 0.001 μg/L. Results: The majority of the samples had total arsenic levels below detectable quantities (detection limit of 1 part per trillion [0.001 μg/L]), one sample of syrup had a concentration of 0.112 ± 0.005, 0.132 ± 0.009, and 0.108 ± 0.010 μg of arsenic/g. We also tested nine popular prenatal vitamins for the amount of arsenic in one serving of vitamins per day and showed exposure to arsenic in one vitamin of 7.108 μg of arsenic/day. All lactation foods and vitamins tested had undetectable amounts of cadmium, mercury, and lead. Conclusion: Most of the vitamins and bars that were tested had below the detectable limit of arsenic, cadmium, lead, and mercury; we did find one vitamin and one rice syrup that had significantly higher levels. Our data suggest that it is highly feasible to manufacture vitamins and lactation foods and supplements with significantly lower concentrations of heavy metals.
Keywords: arsenic; breast milk; breastfeeding; dietary exposure; lactation; lactation supplement.