1. Introduction
Breastfeeding is the optimal food for infants and young children. It provides many health advantages, lowers disease risk, and improves the infant’s nutritional status [
1]. The most well-known milk substitutes are infant formulas that are used to replace breastmilk to cover an infant’s nutritional requirements during the first few months of life until the appropriate introduction of complementary feeding [
2]. However, infant formulas may contain pollutants, such as heavy metals, that pose a health risk to infants and young children through their bioaccumulation mechanism [
3]. Cow’s milk, which comprises the majority of infant formulas, may include these hazardous metals as a result of the cow’s consumption of tainted feedstuffs and water, and exposure to pollution. Further, water, utensils, containers, and equipment used in the manufacture, packing, and storage of infant formulas and complementary foods (such as pureed fruits, vegetables, and meat, and infantile cereals and biscuits) are additional sources of contaminants [
4]. Because of their unique physiology, toxicokinetics, body weight (BW) ratio, and rapid growth, infants are more vulnerable to hazardous chemical pollutants such as aluminum (Al) [
2].
Al is a common element in the hard layer of Earth that has long been thought to be harmless and safe for humans due to its limited bioavailability [
5]. However, epidemiological data linking chronic Al exposure to Alzheimer’s disease cast doubt on its safety [
6]. Additionally, chronic dietary Al consumption can have negative neurologic, skeletal, hematopoietic, immunologic, and other health impacts [
6]. The Joint Food and Agricultural Organization/World Health Organization (WHO) Expert Committee on Food Additives (JECFA) set a provisional tolerated weekly intake (PTWI) of Al of 2 mg/kg BW/week [
7]. Al comprises 8.8% (88 g/kg) of the hard layer of Earth by mass, and it can be found in a variety of rocks; it is usually released into the environment as a result of the natural weathering of rocks [
8]. Since Al can be dissolved in acidic conditions, acid rain can lead to toxic levels of dissolved Al in the surrounding water and soils [
8,
9]. Due to its high reactivity, and coupled with sodium, fluorine, or organic material, Al is complexed as silicates, oxides, and hydroxides. Plants are unharmed by those molecules. However, as the pH of the soil decreases (pH < 5), Al changes into toxic Al3+, which is easily absorbed by plants [
10].
The concentrations of Al increased over time in human plates [
11]. It can be found in drinking water (as flocculant), industrially produced foods (as additive and packaging material), and fresh vegetables and fruits (available in soil) [
12]. Moreover, utensils fabricated with Al and tea consumption are sources of Al in the human diet [
8]. Since food is one of the main sources of Al [
12], special attention should be paid to globally contaminated infant feeds and complementary foods [
4,
10,
13].
In a recent published national study, the early introduction of infant formula and complementary feeding were common among Lebanese mothers, although exclusive breastfeeding rates were low [
1]. Hence, the prevalence of bottle feeding between 0 and 6 months was 59.5%. In complementary feeding practices, only 47.1% of Lebanese mothers adhered to the WHO recommendations to introduce foods at 6 months [
1]. The majority of children are fed infant formula from the first month because it is convenient, readily available, and, in certain circumstances, because the mother is unable to breastfeed due to a medical condition [
14]. Breastfeeding or formula feeding should be supplemented with the age-appropriate safe feeding of nutritious solid foods starting at the age of 6 months. These foods can be prepared at home or purchased from the market, and the choice depends on the healthcare professional’s advice, the cognitive and physical status of infants, the mother’s employment status, and many social and economic conditions [
11]. However, it is widely recognized that infant formulas and baby foods contain various concentrations of heavy metals. The raw materials used to produce baby and young child foods, such as milk, vegetables, fruit, and cereals, can be contaminated with Al, which poses a health threat in certain doses to children aged under five years [
11]. Therefore, the aim of this study is to (1) assess the Al contamination level in infant formulas and baby foods available in the Lebanese market, and to (2) evaluate the pediatric health risk assessment through the calculation of exposure to aluminum due to the consumption of these foods among children aged under five years in Lebanon.
4. Discussion
The current study found that total Al exposure through infant formula and complementary food intake at all ages in both genders was below the tolerable weekly intake values set by JECFA (2 mg/kg of BW per week), but HQ values exceeded 1. The highest Al level was detected in cornflakes (0.361 ± 0.049 mg/kg) and pureed foods (0.362 ± 0.079 mg/kg). The pediatric health risk assessment calculated through the EDI of Al was in the range of 0.0051–0.02058 mg/kg BW/day for males and 0.0055–0.02188 mg/kg BW/day for females.
To the best to our knowledge, our study is the first to investigate the pediatric health risk for exposure to Al in infant foods marketed in Lebanon. The concentration range of Al detected in infant formulas in the present study (0.3 to 0.4 mg/kg) was higher than the reported concentration in 2020 in Lebanon by Elaridi et al. (2020; 0.00008 to 0.00793 mg/kg) [
4]. The increase in Al concentrations in these infant formula products in our study can be associated with the infant formula containers produced with Al. However, there is no research that conclusively shows that these packaged materials are a factor for the Al contamination of the powdered mixture.
4.1. Comparison with Other Arab Countries
There is a scarcity of data concerning the Al content in infant formulas and baby foods in the literature. In Saudi Arabia, Al concentration in infant formulas (1.6 to 1.9 mg/kg) is higher than that reported in our study (0.3 to 0.4 mg/kg) [
20]. The same Saudi study reported the mean concentration of Al in cereals (9.88 ± 7.77 mg/kg), biscuits (5.83 ± 3.60 mg/kg), and pureed foods (6.45 ± 3.89 mg/kg) [
20]; these concentrations were higher than the findings reported in our study.
4.2. Comparison with International Studies
In comparison to many other data concerning Al concentrations in infant formulas, our results are lower than those of Canada (0.018 to 1.10 mg/kg) [
21], Brazil (0.14 to 5.94 mg/kg) [
13], the United Kingdom (0.69 to 5.27 mg/kg) [
22], and Turkey (0.7 to 6.987 mg/kg) [
11]. The Al levels ascertained in this study conform to the maximal permissible limit for Al of 400 μg/kg determined by FAO/WHO in infant formulas [
17]. Additionally, our findings show that Al levels in baby biscuits (0.3 to 0.4 mg/kg) were lower than those of Turkey (1.8 to 15.48 mg/kg) [
11]. According to the European Food Safety Authority (EFSA) in 2008, high Al levels (5000 to 10,000 g/kg) were frequently found in breads, cakes, and pastries, with biscuits having the highest levels [
23]. Further, the levels of Al in infant pureed foods varied from 0.2 to 0.4 mg/kg in the current study. The lowest amounts were found in samples from the second brand, including semolina, rice, carrots and turkey, zucchini with potatoes, fine sweet corn with mashed potatoes and turkey, fine vegetables and rice with veal, and carrots and potatoes with lamb (0.2 mg/kg). The highest levels (0.4 mg/kg) were in the first brand in all its samples. The levels of Al in pureed foods in our study were comparable to those reported in a study in France (0.189 to 0.653 mg/kg) [
23], but lower than those in Ghana (2.89 to 11.07 mg/kg) [
24] and Brazil (0.21 to 4.17 mg/kg) [
25]. The levels of Al in infant cereals (0.3 mg/kg) in our study were lower than those reported in a study in Brazil (0.92 to 8.82 mg/kg) [
25]. Moreover, our data show that the Al levels in cornflake samples were the highest (0.4 mg/kg), yet there is no study in the literature in which cornflake Al levels are described.
4.3. Risk Assessment of the Exposure of Lebanese Infants to Aluminum from Infant Formulas and Complementary Foods
Our results show a low EDI (<0.286 mg/kg BW/day) for all age groups. Referring to a previous national study published in 2020, our data show a lower mean EDI than that in their findings (EDI = 0.029 mg/kg BW/day) [
4]. Our findings are similar to the results reported by a Brazilian study that showed a mean EDI of 0.01 mg/kg BW/day [
13]. Further, our results were higher than those of a Turkish study published in 2022 that showed that the mean EDI was 0.00603 mg/kg BW/day [
11]. Moreover, another Turkish study published in 2014 [
26] and a British survey [
27] showed higher EDI compared to our findings, with mean EDI values of 0.0335 and 0.1636 mg/kg BW/day, respectively. A French study also stated a higher EDI mean value (0.318 mg/kg BW/day) [
28]. Our data also show lower mean EDI compared to that in a Nigerian study (EDI = 0.02 mg/kg BW/day) [
2].
The calculated HQ for all age groups was > 1, which is consistent with our findings that Al exposure may be associated with a health risk. In the literature, there is a scarcity of studies in which HQ is investigated to assess possible health risk to Al exposure caused by the ingestion of baby foods. Only one Turkish study showed an HQ of 15, which is lower than the average HQ value in our study (25.5) [
11].
On the other hand, the toxicological contribution of Al exposure was on average below 4%, which is similar to a recent Turkish study [
11]. However, our findings are lower than those of Brazil (6.7%) [
13], Nigeria (12.1%) [
2], and Turkey (57.2%) [
26]. The highest toxicological contribution in our study was among infants aged 8–10 months (5.72% and 6.11%, for males and females, respectively); this can be explained as follows: as babies grow, their intake of complementary foods increases from ¼ cup to a full cup, which leads to increased exposure to Al. Some studies suggest that the toxicological contribution to PTWI ranges from 37.9 to 66.8% [
26].
Table 6 provides an overview of the few studies that investigated the exposure and the toxicological contribution of Al in infant formulas and baby food products.
4.4. Strength and Limitations
This study is the first of its kind in Lebanon to evaluate the Al concentration and the pediatric health risk assessment to Al in an infant population through the consumption of infant formulas and baby food products marketed in Lebanon. However, our study has the following limitations. The sample size is somewhat limited, as most of the brands represented by those samples are only offered in the Lebanese market. Additionally, due to the lack of Lebanese data, the information on baby weight used to calculate exposure was based on the CDC. Moreover, due to a dearth of research in this field in the Lebanese landscape, pediatric feeding data were derived from data on the labels of infant formulas and child food products rather than actual consumption. Lastly, the overall exposure to Al was not calculated on the basis of the consumption of other food categories that might also include Al. Therefore, future research should focus on collecting information about the baby food consumption and growth trends of Lebanese infants, using it to determine how much Al is being ingested by these infants through infant formulas and complementary foods.