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Aluminum in infant formulas commercialized in Brazil: Occurrence and exposure assessment
Journal of Food Composition and Analysis 82 (2019) 103230
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Original Research Article
Aluminum in infant formulas commercialized in Brazil: Occurrence and exposure assessment
T
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Esther Lima de Paivaa,b, , Raquel Fernanda Milanib, Marcelo Antonio Morganob, Adriana Pavesi Arisseto-Bragottoa a b
Faculty of Food Engineering, State University of Campinas (UNICAMP), PO Box 13083-862, Campinas, SP, Brazil Institute of Food Technology (ITAL), PO Box 139, 13070-178, Campinas, SP, Brazil
A R T I C LE I N FO
A B S T R A C T
Keywords: Aluminum Infant formulae Suckling infants Exposure assessment Food analysis Food composition
Considering the immaturity of babies’ gastrointestinal system, particularly those of newborn infants, elevated aluminum (Al) concentrations can be toxic, and exposure to this contaminant due to the substitution of breast milk by infant formulae may represent a risk. The main sources of Al contamination in these products include the variability in the raw material (milk or soy), the formula composition, the contamination during processing and the presence of additives or mineral supplements. However, there are few recent reports in the literature on the occurrence of Al in milk-based or soy-based infant formulae. Thus, the aim of the present work was to study the presence of Al in samples of infant formulae acquired on the local market in Campinas, Sao Paulo, Brazil and estimate children exposure to this element. The Al contents were determined using optical emission spectrometry with an inductively coupled plasma source. The results obtained presented maximum values of 1.46, 5.94 and 4.49 mg kg−1 for starter, follow-up and specialized formulae, respectively. As from these data, it was estimated that the consumption of infant formulae (0–6 months) could reach 22.4% of the Al tolerable weekly intake (TWI), whereas a maximum value of 29.4% was observed for children between 12–24 months. The results obtained in this study show that the Al levels in infant formulae could suggest a potential concern for infants, and should therefore be monitored.
1. Introduction
Since the diet is the main source of exposure to Al, special attention should be given to the consumption of infant formulas due to the high concentrations of this element in these products (Burrell and Exley, 2010). When breast feeding is not possible or insufficient, infant formulae are used to supply the nutritional demands of suckling infants (Kazi et al., 2010), and this is done from the first months of life according to the energy and nutritional deficiencies related to physiological characteristics (Perales et al., 2006). Reports can be found in the literature stating that babies, especially premature infants, who require greater food complementation, show low Al tolerance, being even more sensitive to the exposure to this element than adults (Saracoglu et al., 2007). The European Food Safety Authority (EFSA) established a Tolerable Weekly Intake (TWI) for Al of 1 mg/kg body weight (bw) (EFSA, 2008), whilst in its 74th meeting, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) confirmed the value of the PTWI (Provisional Tolerable Weekly Intake) for Al as being 2 mg/kg bw, which is applied to all the Al compounds in foods, including food additives (FAO/WHO, 2011; CAC, 2016a). JECFA observed that the PTWI is likely to be
Aluminum (Al) is the third most abundant element in the earth’s crust (8%) and the first amongst the metals. Due to its elevated reactivity, it is found combined with oxygen to form its main ore, bauxite (Al2O3), as well as in the form of silicates, oxides and hydroxides combined with other elements such as sodium and fluorine, and complexed with organic material (Hardisson et al., 2017). Al is also found as a component naturally present in potable water and in additives composed of Al salts (Cozzolino, 2005). The normal entry pathways of Al into the human body are via the lungs, the skin and principally via the gastrointestinal tract (food and medication) (CAC, 2016a). Exposure to Al has been associated with anemia, impairment of bone formation and neurotoxic effects such as Alzheimer's disease (AD). Considerable evidence exists that Al may play a role in the aetiology or pathogenesis of AD, but whether the link is causal is still open to debate (Flaten, 2001). Al toxicity depends on the exposure route and the solubility of its compounds, which tend to accumulate in the brain, bones, kidneys and liver (Bondy, 2014).
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Corresponding author at: Faculty of Food Engineering, State University of Campinas (UNICAMP), PO Box 13083-862, Campinas, SP, Brazil. E-mail address: [email protected] (E.L. de Paiva).
https://doi.org/10.1016/j.jfca.2019.06.002 Received 21 November 2018; Received in revised form 4 June 2019; Accepted 4 June 2019 Available online 05 June 2019 0889-1575/ © 2019 Elsevier Inc. All rights reserved.
Journal of Food Composition and Analysis 82 (2019) 103230
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2.3. Instrumentation
exceeded in some population groups, particularly children, who regularly consume foods containing Al-based additives or ingredients. The Committee also inferred that exposure to this metal by infants fed infant formulae is high and recommended further studies with these products. It should be mentioned that there are no reports in the literature on the contamination of milk-based or soy-based infant formulae commercialized in Brazil. The main analytical techniques applied in the determination of Al in foods which allow for elevated sensitivity are: absorption spectrometry with a graphite oven (Chuchu et al., 2013; Burrell and Exley, 2010), atomic emission spectrometry with an inductively coupled plasma source (ICP AES) and mass spectrometry with an inductively coupled plasma source (ICP MS) (Chao et al., 2014; Mckenzie et al., 2010). Considering the above evidences, the objectives of the present study were: i) establish and validate a method for the determination of the Al content in infant formulas; ii) quantify the Al concentrations using optical emission spectrometry with an inductively coupled plasma source (ICP OES) and iii) estimate the exposure of babies and children to Al due to the consumption of these products in Brazil.
The samples were digested in a closed microwave-assisted digestion system (Start E, Milestone, Sorisole, Italy) equipped with 24 teflon flasks with internal volumes of 50 mL. The total Al content was determined using an ICP OES (model 5100 VDV, Agilent Technology, Tokyo, Japan) equipped with a double-step nebulization camera, a sea-spray nebulizer and 99.996% pure liquid argon (Air Liquide, São Paulo, Brazil). The optimized operational conditions of the equipment were: radio frequency generator power (1400 W); nebulizer argon flow rate (0.5 L min−1); principal argon flow rate (12 L min−1 Ar); auxiliary argon flow rate (1 L min−1 Ar); sample flow rate (0.5 L min−1); axial vision mode; number of replicates (n = 3) and wavelength for Al (396, 152 nm). 2.4. Sample digestion A sample of 0.5 g of infant formula was weighed into a digestion flask, and 8 mL of purified HNO3 plus 2 mL H2O2 were added and maintained in contact overnight. The flasks were then sealed, transferred to the microwave digester and digested using 4 heating ramps applying 1000 W of power: a) room temperature to 70 °C in 5 min; (b) from 70 °C to 120 °C in 5 min; (c) from 120 °C to 170 °C in 5 min; and (d) maintained at 170 °C for 25 min. After cooling, the flasks were opened and the resulting solution transferred to a 25 mL Falcon tube. The external calibration method was used to determine the Al content by ICP OES through a standard curve in the range from 2 to 200 μg L−1.
2. Material and methods 2.1. Samples A total of 76 samples of four different brands of infant formulae were acquired in different markets in the city of Campinas, SP, Brazil. The samples were divided into three distinct categories according to the Brazilian Health Regulatory Agency (ANVISA, 2011a,b): standard starter infant formulas (for individuals from 0 to 6 months) (n = 10), standard follow-up infant formulas (for individuals from 6 to 12 months and from 12 to 36 months) (n = 37), and specialized starter and followup infant formulas (for individuals from 0 to 6 months, 6 to 12 months, and 12 to 36 months) (n = 29). The non-reconstituted samples were homogenized in a grinder (model M20, Ika, Germany) and the determinations of Al carried out in triplicate. According to Codex Alimentarius (CAC, 2016b), starter formulas (0–6 months) are defined as a breast-milk substitute specially manufactured to satisfy, by itself, the nutritional requirements of infants during the first months of life up to the introduction of appropriate complementary feeding, whilst special starter formulas are those intended for special medical purposes which means a substitute for human milk or infant formula that is specially manufactured to satisfy, by itself, the special nutritional requirements of infants with specific disorders, diseases or medical conditions during the first months of life up to the introduction of appropriate complementary feeding. Standard follow-up formula (6–12 months) means a food intended for use as a liquid part of the weaning diet for the infant from the 6th month on and for young children (CAC, 2017).
2.5. Exposure assessment of aluminum The intake of Al, expressed in milligrams of the metal per kg of body weight, was estimated for individuals from 0 to 6 months, 6 to 12 months, and 12 to 24 months, considering the occurrence levels found in the evaluated samples as well as consumption data of infant formulae by suckling infants and children. The estimates of daily intake were calculated employing the deterministic model (Kroes et al., 2002), using the mean and maximum contents of Al in the evaluated samples, calculated considering the values obtained in products destined to the different age groups. Different mean body weight values for each age range were assumed: 7.6 kg (0–6 months), 8.5 kg (6–12 months), and 11.85 kg (12–24 months), according to the child growth standards of the World Health Organization (WHO, 2018). The daily consumption of infant formula was defined according the label recommendations. Once exists distinct preparation modes among the analyzed brands and age groups, a mean value of the maximum recommended number of baby bottles per day was considered. The obtained exposure scenarios were: 1) six preparations (baby bottles) per day (168 g of infant formula) for 0–6 months; 2) four preparations (baby bottles) per day (112 g of infant formula) for 6–12 months; 3) three preparations (baby bottles) per day (84 g of infant formula) for 12–24 months. To evaluate the risk associated with the exposure to Al through the consumption of infant formulae, the estimated values of intake were compared with the PTWI of 2 mg/kg bw established by the JECFA (FAO/WHO, 2011), as well as with the TWI of 1 mg/kg bw established by the EFSA (EFSA, 2008).
2.2. Reagents and standards All the reagents used in the study were of analytical grade or above. Water (18.2 MΩ cm) was purified using reverse osmosis (Gehaka, São Paulo, Brazil) while a sub-boiling distiller was employed for the purification of nitric acid (Distillacid, Berghof, Eningen, Germany). To determine Al, the sample was first submitted to acid digestion using distilled HNO3 and 30% H2O2 (m/v) (Merck, Darmstadt, Germany). The analytical curves were prepared from a certified 100 mg L−1 standard solution (Specsol, Quimlab, Jacareí, Brazil) in a 0.5% HCl solution (v/v) (Merck, Darmstadt, Germany). The accuracy and precision of the method were evaluated using the following certified reference materials: fish protein (DORM-4, National Research Council, Canada), egg powder (EGGS-1, National Research Council, Canada) and a diet (Typical Diet, NIST SRM 1548a).
2.6. Statistical analysis The descriptive statistics were performed using Microsoft Excel 2010 software, including arithmetic means, median, standard deviation (SD) and Al range concentration in samples of infant formulas. In addition, data analysis was carried out using a non-parametric test on the median contamination values once the sample populations were of different sizes and non-normal distribution. The Kruskal-Wallis statistical test was applied for comparison of two or more groups of data 2
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Table 1 Results obtained in the evaluation of the accuracy of the analytical method for the determination of Al using certified reference materials and recovery tests (n = 3). Certified Reference Materials
Table 2 Total Al content present in standard cow milk-based infant formulae. Consumption indication
Number of samples
Aluminum
Fish protein (mg kg−1) Typical diet (μg kg−1) Egg power (μg kg−1)
Certified Values
Values Obtained
Recovery (%)
1280 ± 340 72 ± 2 540 ± 86
1209 ± 6 55 ± 2 500 ± 2
95 ± 6 87 ± 1 97 ± 1
Starter
Follow-up Recovery experiments
Added Values (μg kg−1)
Values Obtained (μg kg−1)
Recovery (%)
Spike Spike Spike Spike
10 50 100 200
10.6 ± 1.4 51 ± 7 100 ± 4 200 ± 1
106 103 100 100
1 2 3 4
Brands
± ± ± ±
19 14 4 16
A B C D Total A B C D Total
3 2 2 3 10 12 8 7 10 37
Al (mg kg−1) Mean ± SD
Median
Range
1.26 ± 0.21 0.98 ± 0.56 0.95 ± 0.24 1.21 ± 0.62 1.0 ± 0.1 1.71 ± 0.09 1.72 ± 0.23 1.45 ± 0.36 1.59 ± 0.75 1.62 ± 1.33
1.29 1.38 0.80 1.30 1.19 1.46 1.52 1.91 0.83 1.43
0.87–1.45 0.33–1.46 0.76–1.17 1.05–1.32 0.75–1.35 0.71–3.87 1.08–5.94 0.17–2.95 0.42–2.57 0.60–3.84
The bold values are related to the total number of samples in column one and to the total values of mean, median and range, in column 2, 3 and 4, respectively.
vanilla), colours, and cocoa powder. In the sample containing cocoa powder, an amount of 5.94 mg kg−1 was observed. The presence of Al in cocoa products has already been reported by Bertoldi et al. (2016), who analyzed 61 samples of cocoa seeds and chocolates produced in 23 countries in East and West Africa, Asia, and South and Central America. The concentrations found for cocoa seeds varied from 41 μg kg−1 (Central America) to 275 μg kg−1 (East Africa) whereas levels between 10.6 μg kg−1 (Central America) and 21.5 μg kg−1 (South America) were observed for semi-bitter chocolate tablets. These values show that cocoa products, depending on the region cultivated, the proportion used in the formulation and the form of processing, could be an additional source of Al contamination in foods. Table 3 shows the mean values and the concentration intervals for Al in each type of specialized infant formula studied according to the composition described on the labels. The results varied from 0.14 to 4.49 mg kg−1 and the highest values found in these samples were related to the addition of extensively hydrolyzed milk proteins (3.61 mg kg−1) and soy based formulation (4.49 mg kg−1). The high Al levels found in soy-based products are in accordance to other studies available in the literature. Woollard et al. (1990) carried out a study in New Zealand about the presence of Al in infant formulae from different countries and found concentrations varying from 250 μg kg−1 to 5000 μg kg−1 in milk-based formulae and from 5 mg kg−1 to 50 mg kg−1 in soy-based products. In Pakistan, Kazi et al. (2009) reported mean Al contents in milk-based formulas from 640 μg kg−1 to 1520 μg kg−1, whereas those of soy-based products varied from 1740 μg kg−1 to 2720 μg kg−1. Other authors (Chuchu et al., 2013) studied ready-to-drink milk formulae and powdered milk samples available on the market in the United Kingdom, and found Al contents in samples without soy varying from 100 to 430 μg L−1 and in those containing soy varying from 656 to 756 μg L−1. Sola-Larranaga and
using StatGraphics Software Centurion XVI.I. from Francestat (Neuillysur-Seine, France). 3. Results and discussion 3.1. Method validation The method was validated according to the National Institute of Metrology, Standardization and Industrial Quality (INMETRO) in relation to accuracy, precision, linearity of the analytical curves and the detection and quantification limits (INMETRO, 2017). Accuracy was verified using certified reference materials (CRM) of fish protein, diet and powdered egg, with recovery values ranging between 87% and 97% (Table 1). In addition, a starter formula containing low Al levels was used to perform spike experiments in analytical triplicate (n = 3) at four different concentrations (10, 50 100 and 200 μg kg−1). Further, the obtained values presented in Table 1 already take into account the total Al concentration present in the referred sample. Recovery values ranged from 100 to 106%. Precision was evaluated in the same CRM using 16 analytical repetitions (8 repetitions per day), with mean coefficients of variation of 15%, which meets the recommendations of the Association of Official Analytical Chemists (AOAC, 2013) and INMETRO (2017) under the conditions studied. The linearity of the analytical curves was demonstrated from the coefficients of determination (r2) ≥ 0.999. The detection (LOD) and quantification (LOQ) limits for Al were: LOD (3 s) = 73 μg kg−1; LOQ (5 s) = 122 μg kg−1, respectively, where “s” is the value of the standard deviation of ten analytical blank repetitions, considering a dilution factor of x 50. The linear curve for Al ranged from 2 to 200 μg L-1.
Table 3 Total Al contents (mg kg−1) in specialized infant formulae.
3.2. Occurrence of aluminum in infant formulae Table 2 shows the number of different brands of samples analyzed, mean values, standard deviations, median and concentration intervals obtained for Al in standard infant formulae (cow milk-based), considering the indications for consumption. For starter formulas, the levels varied from 0.33 to 1.46 mg kg−1 whilst for follow-up products, the concentrations were between 0.17 and 5.94 mg kg-1. No statistic difference was observed among median values from distinct producers according to Kruskal-Wallis test. The obtained mean values for starter and follow-up formulas were 1.0 mg kg−1 and 1.62 mg kg-1, respectively. Higher values were found for follow-up formulae compared to starter ones due to the greater variety of composition and additional ingredients. Among the analyzed standard samples, high Al concentrations were found in milk-based formulae produced with flavors (strawberry and 3
Specialized formulas
Number of samples
Mean ± SD
Range
Preterm Without lactose Inborn error diet Hydrolyzed milk protein Extensively hydrolyzed milk protein Partially hydrolyzed milk protein Composed of free amino acids Adapted Iron fortified Milk proteins Soy-based
2 2
1.78 ± 1.1 2.07 ± 0.7
0.85–2.65 1.52–2.72
3 3
0.76 ± 0.8 1.83 ± 1.6
0.64-0.96 0.14–3.61
3
1.93 ± 1.1
0.93–3.19
2
1.73 ± 0.7
1.11–2.42
3 4 7
1.14 ± 0.7 1.84 ± 0.2 3.24 ± 0.6
0.31–1.9 0.37–1.2 2.02–4.49
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Navarro-Blasco (2006) obtained a high mean value of 414 μg L−1 for Al in soy-based formulas with a range of 383 to 466 μg L−1 for available samples in Spain. The highest Al concentrations in soy-based formulas probably reflect the prior accumulation of the element in the plant as a result of cultivation in acid soils, which represent about 40% of the soils available for agriculture (Hoekenga et al., 2003; Liao et al., 2006). The chemical form of Al strongly depends on the pH value of the medium and its solubility significantly increases in acid (pH < 6.0) or alkaline (pH > 8.0) medium. In this context, the anthropogenic activities that contribute to the occurrence of acid rain, for example, can substantially increase the liberation of Al in the soil, sub-soil and surface waters (Bi et al., 2004). According to Exley et al. (2002) the solubility of Al in the soil can be intensified as a response to the nitrification process, which promotes the absorption and fixation of soluble minerals present in the soil. The complex manufacturing process employed to produce specialized infant formulae appears to play an important role in the degree of contamination by Al as well. As can be seen in Table 3, a higher mean Al content was also found in preterm formulas (2.65 mg kg−1) followed by those elaborated for metabolic disorders composed of free amino acids (2.42 mg kg−1). The high average Al content observed in the preterm formulae was consistent and similar to those reported by Plessi et al. (1997) and Hawkins et al. (1994), who observed levels of 480 μg kg−1 and 328 μg kg−1, respectively, in these products. These higher concentrations in preterm products could be explained by the type of processing of these formulae or the use of ingredients containing Al (Navarro-Blasco and Alvarez-Galindo, 2003). In a study conducted by Sola-Larranaga and Navarro-Blasco (2006) in different types of infant formulas, high mean Al values were found for preterm and specialized formulas (283 μg L−1 and 270 μg L−1, respectively). The high mean contents found in some specialized formulae suggest that the need to greatly modify the raw material with aggressive treatments (such as protein hydrolysis) can result in a greater exposure of the product to a larger amount of Al during manufacture due to the addition of chemicals and contact with machines and powder particles (Navarro-Blasco and Alvarez-Galindo, 2003). The great variation in Al content found in this study is in agreement with data reported in the literature (Navarro-Blasco and AlvarezGalindo, 2003; Ikem et al., 2002; Plessi et al., 1997).
aged from 6 months of age, whereas a toddler formula is similar to follow-up but specially designed for infants from 1 to 2 years old. The intakes estimated for mean consumers ranged from 0.011 to 0.025 (mg kg−1 bw) and those for high consumers varied from 0.032 to 0.052 (mg kg−1 bw). The estimated intakes were compared with the PTWI of 2 mg/kg bw established by JECFA (FAO/WHO, 2011) and the TWI of 1 mg/kg body weight (bw) established by EFSA (2008). Fig. 1 illustrates the obtained results expressed as % of PTWI and TWI. The mean estimated exposure values compared to PTWI and TWI (Fig. 1A) represent, in relation to recommendations of the package label, respectively, values of 7.7% and 15.4% (0–6 months), 8.75% and 17.5% (6–12 months), and 3.85% and 7.7% (12–24 months). The results obtained in this study were similar to those reported by NavarroBlasco and Alvarez-Galindo (2003), who found mean values of 8–10% of the PTWI for the age range of 0–6 months. Despite this, it could be suggested that the obtained values may not pose a risk regarding Al contamination. However, some studies have reported that consumption orientations are not always followed by the parents, and could result in cases of greater exposure to Al (Synnott et al., 2007). The maximum estimated exposure values compared to PTWI and TWI (Fig. 1B), were, respectively: 11.2% and 22.4% (0–6 months), 18.2% and 36.4% (6–12 months) and, 14.7% and 29.4% (12–24 months). This scenario illustrates regular consumers of highly contaminated products, such as soy-based and chocolate-based formulas, and may suggest a potential concern regarding to Al exposure in particular cases. It should be noted that the results reported in the present study may be underestimated due to some reasons. The Al concentrations are related to the powder (non-reconstituted) product and, consequently, water contamination with this element is not being considered. Taking into account that the limit for Al in drinking water is 0.2 mg L−1 (ANVISA, 2011a,b), a significant increase on Al intake could be observed in some cases. In addition, for children over 6 months, other foods (eg, cereals, vegetables, fruits and juices) are incorporated into the diet and may increase the intake of Al (Chekri et al., 2019). A very wide research regarding Al content in food products and beverages was performed in Germany. The founded Al content ranged from 5 to 47 mg L−1 for fruit juices and fruit juice beverages (Stahl et al., 2011). The impact of other potential Al sources in the total intake of this contaminant will be verified in further studies. 4. Conclusions
3.3. Exposure and risk assessment
The study demonstrated elevated levels of Al in infant formulae available on the Brazilian market. The highest Al contents were found in soy-based, specialized products and in standard formulas with the addition of cocoa powder. The estimated exposure to Al showed that for a consumption of six baby bottles/day, maximum values of up to 18.2% and 36.4% of the PTWI and TWI, respectively, could be reached for individuals between 6–12 months. These results suggest that the exposure of suckling infants to this contaminant, considering that the incorporation of water and other foods into the diet may increase the intake of Al, represents a health concern. The data obtained in this study could contribute to a global evaluation of possible health risks with respect to Al exposure, indicating the needs to establish ways of controlling the quality of the ingredients used in infant formulae production and to develop studies to clarify the mechanism of toxicity related to Al.
The estimated intakes of Al for the different proposed scenarios (mean and high consumers), calculated as milligrams of the metal per kg of body weight are shown in Table 4. With regard to the age range classification for the exposure scenario analysis, the 0–6 age range of infant formulas are designed to meet all the nutritional requirements of infants as the major breast milk replacement. The follow-up formula constitutes the principal liquid source of nourishment in a progressively diversified diet for infants Table 4 Estimated intakes of Al (mg kg−1 bw) according to the age range. Age range (months)
Daily formula consumption (kg)
Al occurrence (mg kg−1)a
Al daily intake (mg kg−1bw)
Mean
Maximum
Mean consumers
High consumers
1.005 1.910 1.624
1.468 4.144 5.944
0.022 0.025 0.011
0.032 0.052 0.042
Acknowledgments 0-6 6 - 12 12 - 24
0.168 0.112 0.084
The authors acknowledge the São Paulo Research Foundation (FAPESP) [Grant number 2017/11334-8]; the Brazilian National Council for Scientific and Technological Development (CNPq) [141085/2017-7] and the Brazilian Federal Agency for Support and
a For mean and maximum Al occurrence levels, both standard and specialized products were considered within the corresponded age range.
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Fig. 1. Estimated intakes of total aluminum from infant formulae expressed as % of PTWI and TWI. (A) Mean values (mean consumers) and (B) maximum values (high consumers). PTWI (provisional tolerable weekly intake) = 2 mg/kg body weight (FAO/WHO, 2011) and TWI (tolerable weekly intake) = 1 mg/kg body weight (EFSA, 2008). Considerations: Consumption recommendation according to instructions on the package label.
Evaluation of Graduate Education (CAPES) [Finance code 001]. The authors also acknowledge professor Rodrigo Moraes from FAJ University which contributed to statistical applied analysis.
Bi, S., Wang, C., Cao, Q., Zhang, C., 2004. Studies on the mechanism of hydrolysis and polymerization of aluminium salts in aqueous solution: correlations between “Corelinks” model and “Cage-like” Keggin-Al13 model. Coord. Chem. Rev. 248, 441–455. Bondy, S.C., 2014. Prolonged exposure to low levels of aluminum leads to changes associated with brain aging and neurodegeneration. Toxicology 315, 1–7. Burrell, S.-A., Exley, C., 2010. There is (still) too much aluminium in infant formulas. BMC Pediatr. 10 (63), 1–4. CAC (Codex Alimentarius Commission), 2016a. Working document for information and use in discussions related to contaminants and toxins in the GSCTFF. 10th Session Rotterdam. Available at: http://ftp.fao.org/codex/Meetings/cccf/cccf9/cf09_13e. pdf. Accessed in 22 May 2018. CAC (Codex Alimentarius Commission), 2016b. Codex Standard for infant formula and formulas for special medical purposes intended for infants. CODEX STAN 72–1981. CAC (Codex Alimentarius Commission), 2017. Codex Standard for follow-up formula. CODEX STAN 156-1987. Chao, H., Guo, C., Huang, C., Chou, Y., 2014. Arsenic, cadmium, lead, and aluminium concentrations in human milk at early stages of lactation. Pediatr. Neonatol. 55 (2), 127–134. Chekri, R., Calvez, E.L., Zinck, J., Leblanc, J.-Charles, Sirot, V., Hulin, M., No¨el, L., Guérin, T., 2019. Trace element contents in foods from the first French Total Diet Study on infants and toddlers. J. Food Compos. Anal in press. Chuchu, N., Patel, B., Sebastian, B., Exley, C., 2013. The aluminium content of infant formulas remains too high. BMC Pediatr. 13 (162), 1–5. Cozzolino, S.M.F., 2005. Biodisponibilidade de nutrientes. Editora Manole. EFSA (European Food Safety Authority), 2008. Safety of aluminium from dietary intake 1 Scientific Opinion of the Panel on Food Additives, Flavourings, Processing Aids and Food Contact Materials (AFC) Adopted on 22 May 2008, 1–34. EFSA J. 754, 1–34. Exley, C., Schneider, C., Doucet, F.J., 2002. The reaction of aluminum with silicic acidic
Appendix A. Supplementary data Supplementary material related to this article can be found, in the online version, at doi:https://doi.org/10.1016/j.jfca.2019.06.002. References ANVISA (Agência Nacional de Vigilância Sanitária), 2011a. Portaria nº 2.914, de 12 de dezembro de 2011. Dispõe sobre os procedimentos de controle e de vigilância da qualidade da água para consumo humano e seu padrão de potabilidade. Available at: http://site.sabesp.com.br/site/uploads/file/asabesp_doctos/ PortariaMS291412122011.pdf. Accessed in 28 September 2018. . ANVISA (Agência Nacional de Vigilância Sanitária), 2011b. RDC nº 43, de 19 de setembro de 2011. Dispõe sobre o regulamento técnico para fórmulas infantis para lactentes. Available at: http://bvsms.saude.gov.br/bvs/saudelegis/anvisa/2011/res0043_19_ 09_2011.html. Accessed in 07 October 2018). . AOAC (Association of Official Agricultural Chemists), 2013. Appendix K: Guidelines for Dietary Supplements and Botanicals. Bertoldi, D., Barbero, A., Camin, F., Caligiani, A., Larcher, R., 2016. Multielemental fingerprinting and geographic traceability of Theobroma cacao beans and cocoa products. Food Control 65, 46–53.
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Mayer, S., Urietai, I., Verger, P., Visconti, A., 2002. Assessment of intake from the diet. Food Chem. Toxicol. 40 (2–3), 327–385. Liao, W.R.S., Wan, H., Shaff, J., Wang, X., Yan, X., Kochian, L.V., 2006. Phosphorus and aluminum interactions in soybean in relation to aluminum tolerance. Exudation of specific organic acids from different regions of the intact root system. Plant Physiol. 141 (2), 674–684. Mckenzie, J.S., Jurado, J.M., Pablos, F.De., 2010. Characterization of tea leaves according to their total mineral content by means of probabilistic neural networks. Food Chem. 123, 859–864. Navarro-Blasco, Alvarez-Galindo, J.I., 2003. Aluminium content of Spanish infant formula. Food Addit. Contam. 20 (5), 470–478. Perales, S., Barberá, R., Largada, M.J., Farré, R., 2006. Bioavailability of zinc from infant foods by in vitro methods (solubility, dialyzability and uptake and transport by Caco2 cells). J. Sci. Food Agric. 86, 971–978. Plessi, M., Bertelli, D., Monzani, A., 1997. Determination of aluminum and zinc in infant formulas and infant foods. J. Food Compos. Anal. 42, 36–42. Saracoglu, S., Saygi, K.O., Uluozlu, O.D., Tuzen, M., Soylak, M., 2007. Determination of trace element contents of baby foods from Turkey. Food Chem. 105, 280–285. Sola-Larranaga, Navarro-Blasco, 2006. Preliminary chemometric study of minerals and trace elements in Spanish infant formulae. Anal. Chim. Acta 555, 354–363. Stahl, T., Taschan, H., Brunn, H., 2011. Aluminium content of selected foods and food products. Environ. Sci. Eur. 23 (37), 1–11. Synnott, K., Bogue, J., Edwards, C.A., Scott, J.A., Higgina, S., Norin, E., 2007. Parental perceptions of feeding practices in five European counties: an exploratory study. Eur. J. Clin. Nutr. 61, 946–956. WHO (World Health Organization), 2018. Child Growth Standards – Charts Weight-forAge. Available at: http://www.who.int/childgrowth/standards/weight_for_age/en/. Accessed in 25 May 2018. . Woollard, D.C., Pybus, J., Woollard, G.A., 1990. Aluminium concentrations in infants formulas. Food Chem. 37 (2), 81–94.
solution: an important mechanism in controlling the biological availability of aluminum. Coord. Chem. Rev. 228, 127–135. FAO/WHO (Food and Agriculture Organization of the United Nations and World Health Organization), 2011. Rome: Summary Report of the Seventy-Fourth Meeting of JECFASeventy-Fourth Meeting of the Joint FAO/WHO Expert Committee on Food Additives2011. Seventy-Fourth Meeting of the Joint FAO/WHO Expert Committee on Food Additives. Flaten, T.P., 2001. Aluminium as a risk factor in Alzheimer’s disease, with emphasis on drinking water. Brain Res. Bull. 55 (2), 187–196. Hardisson, A., Revert, C., González-, D., 2017. Aluminium exposure through the diet. hSOA J. Food Sci. Nutr. 3, 1–10. Hawkins, N.M., Coffey, S., Lawson, M.S., Delves, T., 1994. Potential aluminiumtoxicity in infant fed special infant formula. J. Pediatr. Gastroenterol. Nutr. 19, 377–381. Hoekenga, O.A., Vision, T.J., Shaff, J.E., Monforte, A.J., Lee, G.P., Howell, S.H., Kochian, L.V., 2003. Identification and characterization of aluminum tolerance loci in Arabidopsis (Landsberg erecta x Columbia) by quantitative trait locus mapping. A physiologically simple but genetically complex trait. Plant Physiol. 132, 936–948. Ikem, A., Nwankwoala, A., Odueyungbo, S., Nyavor, K., Egiebor, N., 2002. Levels of 26 elements in infant formula from USA, UK, and Nigeria by microwave digestion and ICP – OES. Food Chem. 77, 439–447. INMETRO (Instituto Nacional de Metrologia, Qualidade e Tecnologia), 2017. Orientação sobre validação de métodos de ensaios químicos. Instituto Nacional de Metrologia, Normalização e Qualidade Industrial, Revisão 6, Julho. Kazi, T.G., Jalbani, N., Baig, J.A., Afridi, H.I., Kandhro, G.A., Arain, M.B., Shah, A.Q., 2009. Determination of toxic elements in infant formulae by using electrothermal atomic absorption spectrometer. Food Chem. Toxicol. 47 (7), 1425–1429. Kazi, T.G., Jalbani, N., Baig, J.A., Arain, M.B., Afridi, H.I., Jamali, M.K., Memon, A.N., 2010. Evaluation of toxic elements in baby foods commercially available in Pakistan. Food Chem. 119 (4), 1313–1317. Kroes, R., Müller, D., Lambe, J., Löwik, M.R.H., van Klaveren, J., Kleiner, J., Massey, R.,
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Original Research Article
Aluminum in infant formulas commercialized in Brazil: Occurrence and exposure assessment
T
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Esther Lima de Paivaa,b, , Raquel Fernanda Milanib, Marcelo Antonio Morganob, Adriana Pavesi Arisseto-Bragottoa a b
Faculty of Food Engineering, State University of Campinas (UNICAMP), PO Box 13083-862, Campinas, SP, Brazil Institute of Food Technology (ITAL), PO Box 139, 13070-178, Campinas, SP, Brazil
A R T I C LE I N FO
A B S T R A C T
Keywords: Aluminum Infant formulae Suckling infants Exposure assessment Food analysis Food composition
Considering the immaturity of babies’ gastrointestinal system, particularly those of newborn infants, elevated aluminum (Al) concentrations can be toxic, and exposure to this contaminant due to the substitution of breast milk by infant formulae may represent a risk. The main sources of Al contamination in these products include the variability in the raw material (milk or soy), the formula composition, the contamination during processing and the presence of additives or mineral supplements. However, there are few recent reports in the literature on the occurrence of Al in milk-based or soy-based infant formulae. Thus, the aim of the present work was to study the presence of Al in samples of infant formulae acquired on the local market in Campinas, Sao Paulo, Brazil and estimate children exposure to this element. The Al contents were determined using optical emission spectrometry with an inductively coupled plasma source. The results obtained presented maximum values of 1.46, 5.94 and 4.49 mg kg−1 for starter, follow-up and specialized formulae, respectively. As from these data, it was estimated that the consumption of infant formulae (0–6 months) could reach 22.4% of the Al tolerable weekly intake (TWI), whereas a maximum value of 29.4% was observed for children between 12–24 months. The results obtained in this study show that the Al levels in infant formulae could suggest a potential concern for infants, and should therefore be monitored.
1. Introduction
Since the diet is the main source of exposure to Al, special attention should be given to the consumption of infant formulas due to the high concentrations of this element in these products (Burrell and Exley, 2010). When breast feeding is not possible or insufficient, infant formulae are used to supply the nutritional demands of suckling infants (Kazi et al., 2010), and this is done from the first months of life according to the energy and nutritional deficiencies related to physiological characteristics (Perales et al., 2006). Reports can be found in the literature stating that babies, especially premature infants, who require greater food complementation, show low Al tolerance, being even more sensitive to the exposure to this element than adults (Saracoglu et al., 2007). The European Food Safety Authority (EFSA) established a Tolerable Weekly Intake (TWI) for Al of 1 mg/kg body weight (bw) (EFSA, 2008), whilst in its 74th meeting, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) confirmed the value of the PTWI (Provisional Tolerable Weekly Intake) for Al as being 2 mg/kg bw, which is applied to all the Al compounds in foods, including food additives (FAO/WHO, 2011; CAC, 2016a). JECFA observed that the PTWI is likely to be
Aluminum (Al) is the third most abundant element in the earth’s crust (8%) and the first amongst the metals. Due to its elevated reactivity, it is found combined with oxygen to form its main ore, bauxite (Al2O3), as well as in the form of silicates, oxides and hydroxides combined with other elements such as sodium and fluorine, and complexed with organic material (Hardisson et al., 2017). Al is also found as a component naturally present in potable water and in additives composed of Al salts (Cozzolino, 2005). The normal entry pathways of Al into the human body are via the lungs, the skin and principally via the gastrointestinal tract (food and medication) (CAC, 2016a). Exposure to Al has been associated with anemia, impairment of bone formation and neurotoxic effects such as Alzheimer's disease (AD). Considerable evidence exists that Al may play a role in the aetiology or pathogenesis of AD, but whether the link is causal is still open to debate (Flaten, 2001). Al toxicity depends on the exposure route and the solubility of its compounds, which tend to accumulate in the brain, bones, kidneys and liver (Bondy, 2014).
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Corresponding author at: Faculty of Food Engineering, State University of Campinas (UNICAMP), PO Box 13083-862, Campinas, SP, Brazil. E-mail address: [email protected] (E.L. de Paiva).
https://doi.org/10.1016/j.jfca.2019.06.002 Received 21 November 2018; Received in revised form 4 June 2019; Accepted 4 June 2019 Available online 05 June 2019 0889-1575/ © 2019 Elsevier Inc. All rights reserved.
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2.3. Instrumentation
exceeded in some population groups, particularly children, who regularly consume foods containing Al-based additives or ingredients. The Committee also inferred that exposure to this metal by infants fed infant formulae is high and recommended further studies with these products. It should be mentioned that there are no reports in the literature on the contamination of milk-based or soy-based infant formulae commercialized in Brazil. The main analytical techniques applied in the determination of Al in foods which allow for elevated sensitivity are: absorption spectrometry with a graphite oven (Chuchu et al., 2013; Burrell and Exley, 2010), atomic emission spectrometry with an inductively coupled plasma source (ICP AES) and mass spectrometry with an inductively coupled plasma source (ICP MS) (Chao et al., 2014; Mckenzie et al., 2010). Considering the above evidences, the objectives of the present study were: i) establish and validate a method for the determination of the Al content in infant formulas; ii) quantify the Al concentrations using optical emission spectrometry with an inductively coupled plasma source (ICP OES) and iii) estimate the exposure of babies and children to Al due to the consumption of these products in Brazil.
The samples were digested in a closed microwave-assisted digestion system (Start E, Milestone, Sorisole, Italy) equipped with 24 teflon flasks with internal volumes of 50 mL. The total Al content was determined using an ICP OES (model 5100 VDV, Agilent Technology, Tokyo, Japan) equipped with a double-step nebulization camera, a sea-spray nebulizer and 99.996% pure liquid argon (Air Liquide, São Paulo, Brazil). The optimized operational conditions of the equipment were: radio frequency generator power (1400 W); nebulizer argon flow rate (0.5 L min−1); principal argon flow rate (12 L min−1 Ar); auxiliary argon flow rate (1 L min−1 Ar); sample flow rate (0.5 L min−1); axial vision mode; number of replicates (n = 3) and wavelength for Al (396, 152 nm). 2.4. Sample digestion A sample of 0.5 g of infant formula was weighed into a digestion flask, and 8 mL of purified HNO3 plus 2 mL H2O2 were added and maintained in contact overnight. The flasks were then sealed, transferred to the microwave digester and digested using 4 heating ramps applying 1000 W of power: a) room temperature to 70 °C in 5 min; (b) from 70 °C to 120 °C in 5 min; (c) from 120 °C to 170 °C in 5 min; and (d) maintained at 170 °C for 25 min. After cooling, the flasks were opened and the resulting solution transferred to a 25 mL Falcon tube. The external calibration method was used to determine the Al content by ICP OES through a standard curve in the range from 2 to 200 μg L−1.
2. Material and methods 2.1. Samples A total of 76 samples of four different brands of infant formulae were acquired in different markets in the city of Campinas, SP, Brazil. The samples were divided into three distinct categories according to the Brazilian Health Regulatory Agency (ANVISA, 2011a,b): standard starter infant formulas (for individuals from 0 to 6 months) (n = 10), standard follow-up infant formulas (for individuals from 6 to 12 months and from 12 to 36 months) (n = 37), and specialized starter and followup infant formulas (for individuals from 0 to 6 months, 6 to 12 months, and 12 to 36 months) (n = 29). The non-reconstituted samples were homogenized in a grinder (model M20, Ika, Germany) and the determinations of Al carried out in triplicate. According to Codex Alimentarius (CAC, 2016b), starter formulas (0–6 months) are defined as a breast-milk substitute specially manufactured to satisfy, by itself, the nutritional requirements of infants during the first months of life up to the introduction of appropriate complementary feeding, whilst special starter formulas are those intended for special medical purposes which means a substitute for human milk or infant formula that is specially manufactured to satisfy, by itself, the special nutritional requirements of infants with specific disorders, diseases or medical conditions during the first months of life up to the introduction of appropriate complementary feeding. Standard follow-up formula (6–12 months) means a food intended for use as a liquid part of the weaning diet for the infant from the 6th month on and for young children (CAC, 2017).
2.5. Exposure assessment of aluminum The intake of Al, expressed in milligrams of the metal per kg of body weight, was estimated for individuals from 0 to 6 months, 6 to 12 months, and 12 to 24 months, considering the occurrence levels found in the evaluated samples as well as consumption data of infant formulae by suckling infants and children. The estimates of daily intake were calculated employing the deterministic model (Kroes et al., 2002), using the mean and maximum contents of Al in the evaluated samples, calculated considering the values obtained in products destined to the different age groups. Different mean body weight values for each age range were assumed: 7.6 kg (0–6 months), 8.5 kg (6–12 months), and 11.85 kg (12–24 months), according to the child growth standards of the World Health Organization (WHO, 2018). The daily consumption of infant formula was defined according the label recommendations. Once exists distinct preparation modes among the analyzed brands and age groups, a mean value of the maximum recommended number of baby bottles per day was considered. The obtained exposure scenarios were: 1) six preparations (baby bottles) per day (168 g of infant formula) for 0–6 months; 2) four preparations (baby bottles) per day (112 g of infant formula) for 6–12 months; 3) three preparations (baby bottles) per day (84 g of infant formula) for 12–24 months. To evaluate the risk associated with the exposure to Al through the consumption of infant formulae, the estimated values of intake were compared with the PTWI of 2 mg/kg bw established by the JECFA (FAO/WHO, 2011), as well as with the TWI of 1 mg/kg bw established by the EFSA (EFSA, 2008).
2.2. Reagents and standards All the reagents used in the study were of analytical grade or above. Water (18.2 MΩ cm) was purified using reverse osmosis (Gehaka, São Paulo, Brazil) while a sub-boiling distiller was employed for the purification of nitric acid (Distillacid, Berghof, Eningen, Germany). To determine Al, the sample was first submitted to acid digestion using distilled HNO3 and 30% H2O2 (m/v) (Merck, Darmstadt, Germany). The analytical curves were prepared from a certified 100 mg L−1 standard solution (Specsol, Quimlab, Jacareí, Brazil) in a 0.5% HCl solution (v/v) (Merck, Darmstadt, Germany). The accuracy and precision of the method were evaluated using the following certified reference materials: fish protein (DORM-4, National Research Council, Canada), egg powder (EGGS-1, National Research Council, Canada) and a diet (Typical Diet, NIST SRM 1548a).
2.6. Statistical analysis The descriptive statistics were performed using Microsoft Excel 2010 software, including arithmetic means, median, standard deviation (SD) and Al range concentration in samples of infant formulas. In addition, data analysis was carried out using a non-parametric test on the median contamination values once the sample populations were of different sizes and non-normal distribution. The Kruskal-Wallis statistical test was applied for comparison of two or more groups of data 2
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Table 1 Results obtained in the evaluation of the accuracy of the analytical method for the determination of Al using certified reference materials and recovery tests (n = 3). Certified Reference Materials
Table 2 Total Al content present in standard cow milk-based infant formulae. Consumption indication
Number of samples
Aluminum
Fish protein (mg kg−1) Typical diet (μg kg−1) Egg power (μg kg−1)
Certified Values
Values Obtained
Recovery (%)
1280 ± 340 72 ± 2 540 ± 86
1209 ± 6 55 ± 2 500 ± 2
95 ± 6 87 ± 1 97 ± 1
Starter
Follow-up Recovery experiments
Added Values (μg kg−1)
Values Obtained (μg kg−1)
Recovery (%)
Spike Spike Spike Spike
10 50 100 200
10.6 ± 1.4 51 ± 7 100 ± 4 200 ± 1
106 103 100 100
1 2 3 4
Brands
± ± ± ±
19 14 4 16
A B C D Total A B C D Total
3 2 2 3 10 12 8 7 10 37
Al (mg kg−1) Mean ± SD
Median
Range
1.26 ± 0.21 0.98 ± 0.56 0.95 ± 0.24 1.21 ± 0.62 1.0 ± 0.1 1.71 ± 0.09 1.72 ± 0.23 1.45 ± 0.36 1.59 ± 0.75 1.62 ± 1.33
1.29 1.38 0.80 1.30 1.19 1.46 1.52 1.91 0.83 1.43
0.87–1.45 0.33–1.46 0.76–1.17 1.05–1.32 0.75–1.35 0.71–3.87 1.08–5.94 0.17–2.95 0.42–2.57 0.60–3.84
The bold values are related to the total number of samples in column one and to the total values of mean, median and range, in column 2, 3 and 4, respectively.
vanilla), colours, and cocoa powder. In the sample containing cocoa powder, an amount of 5.94 mg kg−1 was observed. The presence of Al in cocoa products has already been reported by Bertoldi et al. (2016), who analyzed 61 samples of cocoa seeds and chocolates produced in 23 countries in East and West Africa, Asia, and South and Central America. The concentrations found for cocoa seeds varied from 41 μg kg−1 (Central America) to 275 μg kg−1 (East Africa) whereas levels between 10.6 μg kg−1 (Central America) and 21.5 μg kg−1 (South America) were observed for semi-bitter chocolate tablets. These values show that cocoa products, depending on the region cultivated, the proportion used in the formulation and the form of processing, could be an additional source of Al contamination in foods. Table 3 shows the mean values and the concentration intervals for Al in each type of specialized infant formula studied according to the composition described on the labels. The results varied from 0.14 to 4.49 mg kg−1 and the highest values found in these samples were related to the addition of extensively hydrolyzed milk proteins (3.61 mg kg−1) and soy based formulation (4.49 mg kg−1). The high Al levels found in soy-based products are in accordance to other studies available in the literature. Woollard et al. (1990) carried out a study in New Zealand about the presence of Al in infant formulae from different countries and found concentrations varying from 250 μg kg−1 to 5000 μg kg−1 in milk-based formulae and from 5 mg kg−1 to 50 mg kg−1 in soy-based products. In Pakistan, Kazi et al. (2009) reported mean Al contents in milk-based formulas from 640 μg kg−1 to 1520 μg kg−1, whereas those of soy-based products varied from 1740 μg kg−1 to 2720 μg kg−1. Other authors (Chuchu et al., 2013) studied ready-to-drink milk formulae and powdered milk samples available on the market in the United Kingdom, and found Al contents in samples without soy varying from 100 to 430 μg L−1 and in those containing soy varying from 656 to 756 μg L−1. Sola-Larranaga and
using StatGraphics Software Centurion XVI.I. from Francestat (Neuillysur-Seine, France). 3. Results and discussion 3.1. Method validation The method was validated according to the National Institute of Metrology, Standardization and Industrial Quality (INMETRO) in relation to accuracy, precision, linearity of the analytical curves and the detection and quantification limits (INMETRO, 2017). Accuracy was verified using certified reference materials (CRM) of fish protein, diet and powdered egg, with recovery values ranging between 87% and 97% (Table 1). In addition, a starter formula containing low Al levels was used to perform spike experiments in analytical triplicate (n = 3) at four different concentrations (10, 50 100 and 200 μg kg−1). Further, the obtained values presented in Table 1 already take into account the total Al concentration present in the referred sample. Recovery values ranged from 100 to 106%. Precision was evaluated in the same CRM using 16 analytical repetitions (8 repetitions per day), with mean coefficients of variation of 15%, which meets the recommendations of the Association of Official Analytical Chemists (AOAC, 2013) and INMETRO (2017) under the conditions studied. The linearity of the analytical curves was demonstrated from the coefficients of determination (r2) ≥ 0.999. The detection (LOD) and quantification (LOQ) limits for Al were: LOD (3 s) = 73 μg kg−1; LOQ (5 s) = 122 μg kg−1, respectively, where “s” is the value of the standard deviation of ten analytical blank repetitions, considering a dilution factor of x 50. The linear curve for Al ranged from 2 to 200 μg L-1.
Table 3 Total Al contents (mg kg−1) in specialized infant formulae.
3.2. Occurrence of aluminum in infant formulae Table 2 shows the number of different brands of samples analyzed, mean values, standard deviations, median and concentration intervals obtained for Al in standard infant formulae (cow milk-based), considering the indications for consumption. For starter formulas, the levels varied from 0.33 to 1.46 mg kg−1 whilst for follow-up products, the concentrations were between 0.17 and 5.94 mg kg-1. No statistic difference was observed among median values from distinct producers according to Kruskal-Wallis test. The obtained mean values for starter and follow-up formulas were 1.0 mg kg−1 and 1.62 mg kg-1, respectively. Higher values were found for follow-up formulae compared to starter ones due to the greater variety of composition and additional ingredients. Among the analyzed standard samples, high Al concentrations were found in milk-based formulae produced with flavors (strawberry and 3
Specialized formulas
Number of samples
Mean ± SD
Range
Preterm Without lactose Inborn error diet Hydrolyzed milk protein Extensively hydrolyzed milk protein Partially hydrolyzed milk protein Composed of free amino acids Adapted Iron fortified Milk proteins Soy-based
2 2
1.78 ± 1.1 2.07 ± 0.7
0.85–2.65 1.52–2.72
3 3
0.76 ± 0.8 1.83 ± 1.6
0.64-0.96 0.14–3.61
3
1.93 ± 1.1
0.93–3.19
2
1.73 ± 0.7
1.11–2.42
3 4 7
1.14 ± 0.7 1.84 ± 0.2 3.24 ± 0.6
0.31–1.9 0.37–1.2 2.02–4.49
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Navarro-Blasco (2006) obtained a high mean value of 414 μg L−1 for Al in soy-based formulas with a range of 383 to 466 μg L−1 for available samples in Spain. The highest Al concentrations in soy-based formulas probably reflect the prior accumulation of the element in the plant as a result of cultivation in acid soils, which represent about 40% of the soils available for agriculture (Hoekenga et al., 2003; Liao et al., 2006). The chemical form of Al strongly depends on the pH value of the medium and its solubility significantly increases in acid (pH < 6.0) or alkaline (pH > 8.0) medium. In this context, the anthropogenic activities that contribute to the occurrence of acid rain, for example, can substantially increase the liberation of Al in the soil, sub-soil and surface waters (Bi et al., 2004). According to Exley et al. (2002) the solubility of Al in the soil can be intensified as a response to the nitrification process, which promotes the absorption and fixation of soluble minerals present in the soil. The complex manufacturing process employed to produce specialized infant formulae appears to play an important role in the degree of contamination by Al as well. As can be seen in Table 3, a higher mean Al content was also found in preterm formulas (2.65 mg kg−1) followed by those elaborated for metabolic disorders composed of free amino acids (2.42 mg kg−1). The high average Al content observed in the preterm formulae was consistent and similar to those reported by Plessi et al. (1997) and Hawkins et al. (1994), who observed levels of 480 μg kg−1 and 328 μg kg−1, respectively, in these products. These higher concentrations in preterm products could be explained by the type of processing of these formulae or the use of ingredients containing Al (Navarro-Blasco and Alvarez-Galindo, 2003). In a study conducted by Sola-Larranaga and Navarro-Blasco (2006) in different types of infant formulas, high mean Al values were found for preterm and specialized formulas (283 μg L−1 and 270 μg L−1, respectively). The high mean contents found in some specialized formulae suggest that the need to greatly modify the raw material with aggressive treatments (such as protein hydrolysis) can result in a greater exposure of the product to a larger amount of Al during manufacture due to the addition of chemicals and contact with machines and powder particles (Navarro-Blasco and Alvarez-Galindo, 2003). The great variation in Al content found in this study is in agreement with data reported in the literature (Navarro-Blasco and AlvarezGalindo, 2003; Ikem et al., 2002; Plessi et al., 1997).
aged from 6 months of age, whereas a toddler formula is similar to follow-up but specially designed for infants from 1 to 2 years old. The intakes estimated for mean consumers ranged from 0.011 to 0.025 (mg kg−1 bw) and those for high consumers varied from 0.032 to 0.052 (mg kg−1 bw). The estimated intakes were compared with the PTWI of 2 mg/kg bw established by JECFA (FAO/WHO, 2011) and the TWI of 1 mg/kg body weight (bw) established by EFSA (2008). Fig. 1 illustrates the obtained results expressed as % of PTWI and TWI. The mean estimated exposure values compared to PTWI and TWI (Fig. 1A) represent, in relation to recommendations of the package label, respectively, values of 7.7% and 15.4% (0–6 months), 8.75% and 17.5% (6–12 months), and 3.85% and 7.7% (12–24 months). The results obtained in this study were similar to those reported by NavarroBlasco and Alvarez-Galindo (2003), who found mean values of 8–10% of the PTWI for the age range of 0–6 months. Despite this, it could be suggested that the obtained values may not pose a risk regarding Al contamination. However, some studies have reported that consumption orientations are not always followed by the parents, and could result in cases of greater exposure to Al (Synnott et al., 2007). The maximum estimated exposure values compared to PTWI and TWI (Fig. 1B), were, respectively: 11.2% and 22.4% (0–6 months), 18.2% and 36.4% (6–12 months) and, 14.7% and 29.4% (12–24 months). This scenario illustrates regular consumers of highly contaminated products, such as soy-based and chocolate-based formulas, and may suggest a potential concern regarding to Al exposure in particular cases. It should be noted that the results reported in the present study may be underestimated due to some reasons. The Al concentrations are related to the powder (non-reconstituted) product and, consequently, water contamination with this element is not being considered. Taking into account that the limit for Al in drinking water is 0.2 mg L−1 (ANVISA, 2011a,b), a significant increase on Al intake could be observed in some cases. In addition, for children over 6 months, other foods (eg, cereals, vegetables, fruits and juices) are incorporated into the diet and may increase the intake of Al (Chekri et al., 2019). A very wide research regarding Al content in food products and beverages was performed in Germany. The founded Al content ranged from 5 to 47 mg L−1 for fruit juices and fruit juice beverages (Stahl et al., 2011). The impact of other potential Al sources in the total intake of this contaminant will be verified in further studies. 4. Conclusions
3.3. Exposure and risk assessment
The study demonstrated elevated levels of Al in infant formulae available on the Brazilian market. The highest Al contents were found in soy-based, specialized products and in standard formulas with the addition of cocoa powder. The estimated exposure to Al showed that for a consumption of six baby bottles/day, maximum values of up to 18.2% and 36.4% of the PTWI and TWI, respectively, could be reached for individuals between 6–12 months. These results suggest that the exposure of suckling infants to this contaminant, considering that the incorporation of water and other foods into the diet may increase the intake of Al, represents a health concern. The data obtained in this study could contribute to a global evaluation of possible health risks with respect to Al exposure, indicating the needs to establish ways of controlling the quality of the ingredients used in infant formulae production and to develop studies to clarify the mechanism of toxicity related to Al.
The estimated intakes of Al for the different proposed scenarios (mean and high consumers), calculated as milligrams of the metal per kg of body weight are shown in Table 4. With regard to the age range classification for the exposure scenario analysis, the 0–6 age range of infant formulas are designed to meet all the nutritional requirements of infants as the major breast milk replacement. The follow-up formula constitutes the principal liquid source of nourishment in a progressively diversified diet for infants Table 4 Estimated intakes of Al (mg kg−1 bw) according to the age range. Age range (months)
Daily formula consumption (kg)
Al occurrence (mg kg−1)a
Al daily intake (mg kg−1bw)
Mean
Maximum
Mean consumers
High consumers
1.005 1.910 1.624
1.468 4.144 5.944
0.022 0.025 0.011
0.032 0.052 0.042
Acknowledgments 0-6 6 - 12 12 - 24
0.168 0.112 0.084
The authors acknowledge the São Paulo Research Foundation (FAPESP) [Grant number 2017/11334-8]; the Brazilian National Council for Scientific and Technological Development (CNPq) [141085/2017-7] and the Brazilian Federal Agency for Support and
a For mean and maximum Al occurrence levels, both standard and specialized products were considered within the corresponded age range.
4
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Fig. 1. Estimated intakes of total aluminum from infant formulae expressed as % of PTWI and TWI. (A) Mean values (mean consumers) and (B) maximum values (high consumers). PTWI (provisional tolerable weekly intake) = 2 mg/kg body weight (FAO/WHO, 2011) and TWI (tolerable weekly intake) = 1 mg/kg body weight (EFSA, 2008). Considerations: Consumption recommendation according to instructions on the package label.
Evaluation of Graduate Education (CAPES) [Finance code 001]. The authors also acknowledge professor Rodrigo Moraes from FAJ University which contributed to statistical applied analysis.
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