Lipid and polyunsaturated fatty acid contents in infant formulas in reference to the Codex Alimentarius Lipídios e ácidos graxos poli-insaturados em fórmula infantil: comparação Codex Alimentarius

Codex Alimentarius stan-72 (2011) discriminate the adequate values of fatty acids and lipids for infant formula. Total lipids and polyunsaturated fatty acids were quantified in fourteen infant formulas samples and compared the results with the recommended values. Extraction and quantification of lipids followed Roese Gottielb method. Analysis of fatty acid, methylated by Hartman and Lago procedure, was carried out through gas chromatography was performed with the use of internal standard 23:0. In the analyzed samples, at least one parameter was in disagreement with Codex Alimentarius


INTRODUCTION
Essential fatty acids (EFAs) comprise a class of molecules that are not produced by human beings despite the fact that they are necessary for their proper functioning. This deficiency occurs due to the lack of specific enzymes capable of double bond formation (desaturases), or breakage (hydrogenases), between carbons 3 and or between 6 and 7, of fatty acids (FAs). For example, linoleic (LA, 18:2 ω-6) and α-linolenic (ALA, 18:3 ω-3) acids are synthesized exclusively by members of the plant kingdom. The absence of such nutrients in a diet is associated with many syndromes and diseases 1,2 .
EFAs can be modified by mammals in several ways, among which are chain elongation or shortening, through partial beta-oxidation and unsaturation insertion. These modifications give rise to long-chain polyunsaturated fatty acids (LC-PUFAs).
However, the ω-3, ω-6, and ω-9 FA families compete for the enzymes responsible for such modifications, which ultimately which is a product of LA metabolism 2,3,4 .
The LC-PUFAs play several metabolic and physiological roles.
One role is as structural components of biological membranes, being capable of modifying membrane fluidity and so influencing signal transduction and transcription regulation by the balance on eicosanoid synthesis 2,5 .
Infants are not able to produce LC-PUFAs from their precursors due to liver immaturity and should have their requirement supplied by the maternal milk. Human maternal milk contains three times the amount of ARA and DHA present in cow milk, the last one consequently not being appropriate for babies. Yet, when breast-feeding is not possible, the use of infant formula (IF) is presented as an alternative for baby feeding. Despite the advances in technological process, IFs still retain great differences in composition when compared with maternal milk 6,7 . In LC-PUFAs are exceptionally essential for premature babies having low lipid reserves. Because of their limited caloric reserve, premature babies have to mobilize part of the LC-PUFAs to support their caloric requirement when exogenous intake is inadequate.
Besides, premature babies have a nutritional deficit because they do not receive the intra-uterine supplement of ARA and DHA, which occurs in the late phase of gestation. Such nutritional deficiency may contribute to inadequate growth, dermatitis, and a higher susceptibility to infections, among other disorders 7,9,10 .
The balance between ω-3 and ω-6 FA families is important for the maintenance of health and normal development. As the participation of ω-6 FAs grows on occidental diets, ARA-derived metabolites, i.e., eicosanoids, tend to be formed in a greater amount than metabolites derived from the ω-3 FA family, specifically EPA. ARA-derived eicosanoids are normally biologically active in very small amounts. If they are formed in a large proportion, they may contribute to the formation of blood clots and atheromata, advent of inflammatory and allergic disorders, and cellular proliferation. The ω-6:ω-3 proportion should be preserved at 5:1 to maintain equilibrium in the formation of eicosanoids and the correspondent neurotransmitters and prostaglandins, which are vital for normal cerebral function. For infants, the ratio between ω-6 and ω-3 FAs may vary from 5:1 to 15:1 11,12,13 .
The Codex Alimentarius stan 72 14 presents the identity standard for IFs, with recommended contents for total lipids and PUFAs.
Some definitions of the standard are described below: Infant formula means 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.

Follow-up infant formula consists of any product, in liquid
or powdered form, used as substitute for maternal milk to feed babies after the sixth month of age, when prescribed, and infants.
In Table 1

MATERIAL AND METHOD Samples
Fourteen IF samples were analyzed. Seven were commercial IFs indicated to 0-to 6-month-old babies (IF 1, IF 3, IF 4, IF 6, IF 8, IF 11,and IF 13); five were IFs for 6-to 12-month-old babies (IF 2,

Reagents and standards
Solvents and reagents used at the fat extraction and methyl ester preparation stages were of analytical grade: petroleum ether, ethyl ether, 95% ethanol, NH 4 OH, KOH, Na 2 SO 4 , and NaOH.
n-Hexane and methanol were of chromatographic grade.
Two methyl esters of FAs 13:0 and 23:0 (Sigma, high-purity grade) were used as internal standards for the chromatographic analyses.
In order to identify the components of the IF samples, two mix-

Identification and quantification of lipids and PUFAs
The extraction and quantification of lipids from the IF samples All samples were analyzed in triplicate, and the results are presented as mean ± standard deviation (SD).

RESULTS AND DISCUSSION
Quantification values for the amounts of lipids, LA, ALA, ARA, and DHA present in commercial IF samples are displayed in Table 2.
Among the analyzed IFs for 0-to 6-month-old babies and those for i.e., LA content greater than 70 mg·100 kJ -1 . Only six samples Out of the 14 analyzed IF samples, just 1 (IF 1) had an ALA content value above the advised minimum limit of 12 mg/100 kJ.
The remaining 13 displayed values up to 75% lower than the limit. ALA is an indispensable FA, because it is the precursor for DHA synthesis, and its minimum intake is important for infant development 2,21 . A study conducted by Straarup et al. 24 in Denmark demonstrated that in only 4 out of 28 analyzed IFs, ALA levels were above the minimum advised by that country's legislation. The maximum content of ALA is regulated by the LA-to-ALA ratio. Data on such ratios for the analyzed commercial IFs are presented in Figure. Among all the analyzed IFs, one for 0-to 6-month-old babies (IF 4) and two for 6-to 12-month-old babies (IF 5 and IF 12) had LA-to-ALA ratios that were not within the advised range, above the upper limit. Straarup et al. 24  Despite the fact that maternal milk is the best feed for a newborn, the use of IF is a common occurrence in Brazil, and control of its entire nutritional contents, not only for lipid contents, should be intensified because adequate child development depends mainly on feeding with appropriate nutrient-bearing foods.

CONCLUSION
All the IFs analyzed in this study, which are sold in the State of São Paulo, have at least one lipid compound (total lipid or PUFA) in disagreement with the Codex Alimentarius standard. Commercial IFs should be continuously monitored in regard to lipid and FA contents, beside other components, as recommended by legislation, while the use of such products becomes frequent and their nutritional quality can influence child development.   IF1 IF2 IF3 IF4 IF5 IF6 IF7 IF8 IF9 IF10 IF11 IF12 IF13 IF14 Infant formulas LA/ALA