Health Risk Assessments of Selected Trace Elements and Factors Associated with Their Levels in Human Breast Milk from Pretoria, South Africa.

Joshua O Olowoyo,Phiona M Mametja,Linda R Macheka

doi:10.3390/ijerph18189754

Joshua O Olowoyo, Phiona M Mametja + Show 1 more

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https://doi.org/10.3390/ijerph18189754

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Abstract

While breast milk is the recommended food for infants up to at least six months, exogenously derived compounds such as trace elements have been widely reported in human milk which may make it become toxic or a source of pollutants to the infants. Numerous short- and long-term health effects have been associated with high body—burdens of trace elements, which are amplified in infants. The current study determined the levels and possible contributing factors of six trace elements in breast milk of nursing mothers from a local hospital in Pretoria. Extraction of trace elements employed a digestion technique using perchloric and nitric acid in a ratio of 1:3, while Inductively Coupled Plasma–Membrane Spectrophotometry was used to identify and quantify their levels in breast milk. Concentrations of Cr and Mn were the highest in breast milk, with values ranging from 0.30 to 5.72 µg/L and 0.23 to 5.13 µg/L, respectively. Levels of Co, As, Pb and Cd ranged from <LOD to 0.2 µg/L, <LOD to 2.29 µg/L, 0.05 to 1.06 µg/L, and 0.004 to 0.005 µg/L, respectively. Levels of Cr, Mn and As were higher than the recommended limits from WHO (World Health Organization) in some milk samples. Dietary assessments showed minimal risk for the infants through breastfeeding at this stage; however, prolonged exposure to other sources of these toxic trace elements may pose a serious health risk for the infants. The nature of employment, infant birth weight, passive smoking and maternal diet were the significant factors noted to contribute to trace metal levels in breast milk.

Highlights

The long-term benefits of breastfeeding, both to infant and maternal health, have motivated the World Health Organization (WHO) to recommend it for newborns up until the age of at least six months [1,2]
The descriptive statistics of the concentrations of the trace elements in breast milk are presented in Table 2, together with comparisons with the acceptable ranges of these elements in human breast milk [52] and general dietary guideline values according to the World Health Organization [51]
The results showed the distribution levels of trace elements in breast milk to be in the order Cr > Mn > As > Pb > Co > Cd (Table 2)

Summary

Introduction

The long-term benefits of breastfeeding, both to infant and maternal health, have motivated the World Health Organization (WHO) to recommend it for newborns up until the age of at least six months [1,2]. Exogenously derived elements, such as trace elements, have been widely reported in breast milk, thereby putting infants at risk of trace element accumulation and related health effects [5,6,7,8,9]. While several studies have investigated and quantified the natural composition of trace elements such as zinc, iron, manganese and copper in breast milk [4,10,11,12], these same elements may cause detrimental health effects to breastfeeding infants, such as reduced thymus gland function, impaired cognitive development, fetal growth disorders, neurological disorders and increased neonatal fatalities, when they are present above permissible limits [13]. Accumulation of trace elements in breast milk is often a result of transfer from maternal reserves in the blood through the mammary glands [14,15], while maternal exposure occurs through the food chain, contaminated drinking water sources as well as through dermal contact and in-

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