Title: Long-chain polyunsaturated fatty acids and development of term infants
- Carlo Agostoni
- Contemporary Pediatrics, Gastroenterology, Hepatology and Child Feeding
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- Long-chain polyunsaturated fatty acids and development of term infants
Positive associations between breastfeeding and de-velopmental achievement in childhood have been repor-ted for over 70 years. Longer term effects have been poorly explored. In interpreting these datathe single roles of breastfeeding practice, human milk as food and nu-trients and long-chain polyunsaturated fatty acids (LCPUFA: arachidonic acid, AA, and docosahexaenoic acid, DHA) from human milk or formulas should be clearly differen-tiated.
Mature human milk contains 0.5-0.6% AA and 0.3% DHA(1). Highervalues(even double) are found in colos-trum. Fatty acids are included for 85-90% of their quote in triglycerides (representing 98-99% total fat of human milk) and 10-15% in phospholipids (1-2% total fat of human milk). From the scant available data it is still discus-sed whether there is a metabolic regulation of the DHA and AA content of human milk.
Autoptic investigations on infants deceased for "cot" death have shown thatthose breastfed had higher levels of DHA in the cerebral cortex and the retinal structures compared to the standard formuła fed ones. A better visual performance and higher developmental scores along with higher LCPUFA pools have been observed in breastfed infants when compared with standard formula-fed counterparts in most (but not all) studies. In infants breastfed by mothers supplemented with DHA a positive association has been found between DHA milk levels and neurodevelopmental scores at 1 year, but not at age of 2. The isolated effects of dietary LCPUFA on visual and neurodevelopmental parameters have been studied with enriched formulas (differing in LCPUFA mixtures, sources and amounts) in artificially-fed term infants using different methodologies with controversial results. Most studies have investigated the outcome at short-term when infants are still on study diets, while fewer have looked atthe me-dium-term outcome, that is, after the end of the supple-mentation period. In these assessments at medium-term positive effects have been observed on visual acuity at 12 months (2) and neurodevelopmental achievement at 10 months (3). Interestingly, inthe latterstudyadevelop-mental advantage in the LCPUFA-supplemented group has been found with an "ad-hoc" planned problem-solving test. In othertwo studies evidencing no (or even negative) effects the enriched formulas contained Iow DHA levels (0.12% if AA+DHA, 0.20% if only DHA) (4, 5). The fatty acid composition of celi membranes is a dynamie system, thus functional effects may be transient unless involving morę complex mechanisms such as memory and asso-ciative processes. Longer-term obsen/ations are now ex-pected from examinations on the first supplemented groups.
In conclusion, a cause-effect relationship between the LCPUFA content of human milk and the developmental achievement is still not proven while many other factors could accountforthe developmental advantage observed in babies that have been brestfed. Several studies have shown that dietary AA and DHA when supplied together and in concentrations comparable to those in maturę human milk are possiblyassociated with an improvement of visual acuity and neural development in term formula-fed infants. We speculate that dietary LCPUFA might have positive pharmacological-like effects in formula-fed babies.