Talking Nutrition Editors
Breast milk is the nutritional gold standard for infant nutrition and infant formula are therefore formulated to mimic its composition and functionality. The long-chain polyunsaturated fatty acids (LCPUFAs) DHA and ARA are the primary omega-3 and omega-6 (respectively) LCPUFAs found in breast milk. These fatty acids have important roles in brain and eye development and function, as well as supporting immunity during early life.1,2,3
Polymorphisms in the FADS genes influence how an infant’s body synthesizes DHA and ARA. Infants with specific genotypes may therefore require different intakes of these fatty acids to maintain an adequate status.
A new study, published in Nutrients, has investigated the effects of diet and FADS polymorphisms on the DHA and ARA status of formula fed and breastfed infants.4 176 infants took part in the COGNIS study, which was conducted in Spain, and the results highlight the significant impact that FADS polymorphisms have on DHA and ARA status in some formula fed infants.
Single nucleotide polymorphisms (SNPs) in the FADS genes have previously been shown to reduce DHA and ARA synthesis by reducing the activity of the D5 and D6 desaturase enzymes.5,6,7 ARA is most affected with up to 28 percent of the variation in ARA blood levels attributed to FADS polymorphisms.8 Reduced synthesis of DHA and ARA associated with such genetic variants is reported in approximately 30 percent of the European population and may be even higher in Asia and Mexico.9,10,11 Several studies have also described the effects of FADS polymorphisms on fatty acid status and the development of intelligence, immune function and the risk of allergies during childhood.12
To determine the effect of an infant formula supplemented with DHA and ARA on fatty acid levels of infants with different FADS genotypes as part of the COGNIS study, 176 infants under six months of age were randomly allocated to the standard formula or the experimental formula which was supplemented with DHA and ARA. Both formulas followed the guidelines of the Committee on Nutrition of the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN), and the international and national recommendations for the composition of infant formulas. Breastfed infants were added as a reference group.
Statistically different cellular levels of DHA and ARA were reported in some of the feeding groups when classifying infants by FADS polymorphism alleles. In breastfed infants, the DHA and ARA levels did not differ between carriers of the FADS major and minor alleles, possibly due to the higher concentrations found in breast milk.
The study found that FADS minor allele carriers (with reduced desaturase activity) in the experimental infant formula group had an ARA level significantly lower than the breastfed group. In fact, their ARA level was not different from that of the infants in the standard formula group, where the product was not supplemented with DHA and ARA. FADS major allele carriers (with higher desaturase activity) in the experimental infant formula group did not exhibit a decrease in desaturase activity, and levels of DHA and ARA in these infants were not statistically different from those of the breastfed group; however, they were significantly higher than those of the standard formula group.
The study therefore concluded that infants who are FADS minor allele carriers, may be at risk of a lower DHA and ARA status. These infants might therefore require higher levels of DHA and ARA supplementation to achieve a status more closely resembling those of breastfed infants.
The COGNIS study is published in Nutrients: ‘The Effect of an Infant Formula Supplemented with AA and DHA on Fatty Acid Levels of Infants with Different FADS Genotypes: The COGNIS Study.’
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