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European Journal of Applied Sciences – Vol. 12, No. 4

Publication Date: August 25, 2024

DOI:10.14738/aivp.124.17502

Peregrina Lucano, A. A., Aguilar Uscanga, B. R., Solís Pacheco, J. R., & Rodríguez Arreola, A. (2024). Evaluating the Elemental

Composition of Mature Human Milk: Implications for Infant Health in the Guadalajara Metropolitan Area. European Journal of

Applied Sciences, Vol - 12(4). 522-535.

Services for Science and Education – United Kingdom

Evaluating the Elemental Composition of Mature Human Milk:

Implications for Infant Health in the Guadalajara Metropolitan

Area

Peregrina Lucano, Alejandro Aarón

Applied Pharmacokinetics Laboratory,

University Center of Exact Sciences and Engineering (CUCEI),

University of Guadalajara, Guadalajara, Jalisco, Mexico;

Aguilar Uscanga, Blanca Rosa

Human Milk Research Laboratory, Department of Farmacobiology,

University Center of Exact Sciences and Engineering (CUCEI,)

University of Guadalajara, Guadalajara, Jalisco, Mexico

Solís Pacheco, Josué Raymundo

Human Milk Research Laboratory, Department of Farmacobiology,

University Center of Exact Sciences and Engineering (CUCEI,)

University of Guadalajara, Guadalajara, Jalisco, Mexico

Rodríguez Arreola, Ariana

Human Milk Research Laboratory,

University Center of Exact Sciences and Engineering (CUCEI),

University of Guadalajara, Guadalajara, Jalisco, México

ABSTRACT

Environmental factors can significantly affect the health of infants through human

milk, including the presence of toxic metals from various sources. In the

metropolitan area of Guadalajara, current contamination levels are particularly

concerning. Consequently, a study was conducted using Inductively Coupled

Plasma Mass Spectrometry to analyze mature human milk from 30 housewives

with various health issues. The results showed concentrations of toxic elements

such as Pb, Zn, Cu, Hg, Cr, and as below 0.01 μg/L, while Al was above 0.51 μg/L

and Cd above 0.7 μg/L. Additionally, variations were observed in essential

elements such as Na, Mg, K, and Ca, with a notably high Na ratio in all cases, same

case in Rb. In conclusion, this study revealed the presence of low concentrations of

toxic metals in the breast milk of women from the metropolitan area of

Guadalajara, except for Al and Cd. Significant variations in essential elements were

also found, particularly a high Na ratio, which underlines the need to monitor

environmental contaminants that may affect infant health through breastfeeding

and identify their origin.

Keywords: human milk, toxic metals, contamination, infant health.

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Peregrina Lucano, A. A., Aguilar Uscanga, B. R., Solís Pacheco, J. R., & Rodríguez Arreola, A. (2024). Evaluating the Elemental Composition of

Mature Human Milk: Implications for Infant Health in the Guadalajara Metropolitan Area. European Journal of Applied Sciences, Vol - 12(4). 522-

535.

URL: http://dx.doi.org/10.14738/aivp.124.17502

INTRODUCTION

According to the World Health Organization (WHO), breastfeeding is the ideal food for the

child exclusively during the first six months of life and beyond these months alongside other

foods, as it is essential for children to reach their full potential in terms of growth, health, and

development. However, the fat and protein content of breast milk can make it a route of

excretion and a vehicle for the passage of toxic substances to the child, such as inorganic

elements and perfluorinated compounds, including toxic metals [1]. Studies conducted on

pediatric populations have demonstrated that metals such as cadmium, lead, mercury, copper,

zinc, and arsenic are potentially toxic, with hemotoxic, neurotoxic, and nephrotoxic effects

even at low blood concentrations. Lead, a highly harmful metal, can accumulate in the body

over time and affect multiple systems. It has been linked to cognitive deficits, behavioral

problems, and developmental delays in children exposed during critical periods of growth and

development [2, 3]. In the case of arsenic, which is naturally present in water and soil, it can

contaminate food and water sources. Prolonged exposure to this element has been associated

with a higher incidence of diverse types of cancer, cardiovascular diseases, and adverse

reproductive outcomes. On the other hand, Cadmium, primarily released into the

environment through industrial processes, can accumulate in the body and have adverse

effects on the kidneys, respiratory system, and skeletal system. Long-term exposure to

cadmium is linked to conditions such as osteoporosis, kidney damage, and lung diseases.

These are just some of the adverse effects that may occur [4, 5].

Exposure to toxic metals has a significant impact on biomolecules, particularly proteins with

enzymatic activity. These proteins play a crucial role in numerous biological processes,

including the regulation of metabolism, immune response, and cell repair. Such exposure can

alter the structure and function of certain proteins, leading to impaired enzymatic activities

and, consequently, the normal functioning of biological systems. This disruption can trigger

multisystemic pathology, which is a critical aspect for understanding the bodily distribution of

these metals, as well as the mechanisms of their elimination and excretion [6, 7]. The main

systems affected by exposure to toxic metals include the gastrointestinal, central and

peripheral nervous, and hemic systems. In the gastrointestinal tract, these metals interfere

with nutrient absorption. In the neurological system, they can cross the blood-brain barrier,

affecting brain function and causing cognitive impairment (such as in cases of lead and

mercury exposure), neurological developmental disorders, and neurodegenerative diseases.

The hematopoietic system is compromised in terms of blood cell production and the onset of

anemia. Additionally, elements like arsenic and cadmium can increase the risk of developing

cancer in various tissues and organs. To adequately understand and address the effects of

toxic metals on the body, it is essential to consider their multisystemic pathology and the

most affected systems. This understanding will enable the development of strategies to

prevent exposure, detect and treat associated diseases, and implement effective measures to

eliminate and excrete these metals from the body [6, 8, 9].

The population can be exposed to these contaminants due to their widespread dissemination

in the environment [10]. Exposure to toxic metallic elements can occur in the environment air,

water, and soil particularly during occupational activities, as well as through the consumption

of contaminated food [11]. In the case of breastfeeding and/or pregnant women, exposure has

a more severe impact. Once heavy metals and metalloids enter the human body, their affinity

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European Journal of Applied Sciences (EJAS) Vol. 12, Issue 4, August-2024

for proteins allows them to mobilize within the organism, travelling through red blood cells or

other plasma components until they accumulate in various organs and tissues, including

bones, teeth, nails, and hair. These toxic agents can bioaccumulate in the maternal body and

subsequently transfer to the infant during pregnancy and breastfeeding, directly affecting the

health of the mother-child pair [12]. Through the method Inductively Coupled Plasma Mass

Spectrometry (ICP-MS), this study aimed to evaluate the levels of 29 elements: Li, Be, Na, Mg,

Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, In, Cs, Ba, Hg, Pb, Bi, U, in mature

human milk from women residing in the metropolitan area of Guadalajara. The objective was

to assess exposure to these elements and thereby identify potential health implications.

MATERIAL AND METHODS

Human Milk Collection

The concentrations of the 29 elements in mature breast milk were determined from 30

human milk samples collected from healthy primiparous and multiparous lactating mothers,

as well as from diabetics, smokers, drug addicts, with preeclampsia and syphilis in the

metropolitan area. from Guadalajara. These women are nursing assistants at the Old Civil

Hospital of Guadalajara “Fray Antonio Alcalde” in Jalisco, Mexico. According to data provided

by the hospital, the age of the mothers ranged between 14 and 32 years, all of them reported

being housewives. Three of them mentioned being smokers and two admitted to having

consumed some type of drug while breastfeeding. None of the mothers analyzed were

occupationally exposed to metals. The project received approval from an Ethics Committee

(HCG/CEI-0907/22 and research registration 141/22 approved on June 8, 2022), and

informed written consent was obtained from all human milk donor mothers in accordance

with the ethical principles outlined in the Declaration of Helsinki of 1964, revised in 2008, and

the regulations of the General Health Law on Health Research 2004, last reformed in 2008.

Human milk collection was performed using a manual pump after sanitizing the donor

mothers. The milk was then deposited in special polypropylene bags designed for BPA-free

breast milk with a wide neck, pre-sterilized for immediate use, with a capacity of up to 6 oz,

and equipped with a double anti-drip safety closure system for safe storage. These bags

feature reinforced edges and a double layer for secure refrigeration or freezing, while also

undergoing verification of organoleptic properties (smell, color) and possible contamination

to ensure authenticity. After collection, the samples were stored in a cooler and transported to

the Pharmacokinetics laboratory for further analysis.

Analysis of Metals in Human Milk:

For determination of elements in human milk, it was used an equipment CEM brand

microwave oven model MARS-5, Agilent Technologies model 7800 Inductively Coupled

Plasma Mass Spectrometer (ICP-MS) with Agilent Technologies SPS 4 autosampler and a 5%

ICP-MS HNO3 multi-element calibrator standard Perkin Elmer Pure Plus® with a

concentration of 10 μg/mL was used of Li, Be, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga,

As, Se, Rb, Sr, Ag, Cd, In, Cs, Ba, Hg, Pb, Bi and U.

Preparation of Human Milk Samples:

Sample preparation involved digestion with nitric acid (60-70%) Plasma PURE®, which was

heated in a microwave oven. A volume of 0.5 mL of the liquid human milk sample was

measured using a micropipette and placed in PFA Teflon tubes with a 25-mL capacity screw