Dietary PUFA for Preterm and Term Infants: Review of Clinical Studies

Abstract

Human milk contains n-3 and n-6 LCPUFA (long chain polyunsaturated fatty acids), which are absent from many infant formulas. During neonatal life, there is a rapid accretion of AA (arachidonic acid) and DHA (docosahexaenoic acid) in infant brain, DHA in retina and of AA in the whole body. The DHA status of breast-fed infants is higher than that of formula-fed infants when formulas do not contain LCPUFA. Studies report that visual acuity of breast-fed infants is better than that of formula-fed infants, but other studies do not find a difference. Cognitive development of breast-fed infants is generally better, but many sociocultural confounding factors may also contribute to these differences. The effect of dietary LCPUFA on FA status, immune function, visual, cognitive, and motor functions has been evaluated in preterm and term infants. Plasma and RBC FA status of infants fed formulas supplemented with both n-3 and n-6 LCPUFA was closer to the status of breast-fed infants than to that of infants fed formulas containing no LCPUFA. Adding n-3 LCPUFA to preterm-infant formulas led to initial beneficial effects on visual acuity. Few data are available on cognitive function, but it seems that in preterm infants, feeding n-3 LCPUFA improved visual attention and cognitive development compared with infants receiving no LCPUFA. Term infants need an exogenous supply of AA and DHA to achieve similar accretion of fatty acid in plasma and RBC (red blood cell) in comparison to breast-fed infants. Fewer than half of all studies have found beneficial effects of LCPUFA on visual, mental, or psychomotor functions. Improved developmental scores at 18 mo of age have been reported for infants fed both AA and DHA. Growth, body weight, and anthropometrics of preterm and term infants fed formulas providing both n-3 and n-6 LCPUFA fatty acids is similar in most studies to that of infants fed formulas containing no LCPUFA. A larger double-blind multicenter randomized study has recently demonstrated improved growth and developmental scores in a long-term feeding study of preterm infants. Collectively, the body of literature suggests that LCPUFA is important to the growth and development of infants. Thus, for preterm infants we recommend LCPUFA intakes in the range provided by feeding of human milk typical of mothers in Western countries. This range can be achieved by a combination of AA and DHA, providing an AA to DHA ratio of approximately 1.5 and a DHA content of as much as 0.4%. Preterm infants may benefit from slightly higher levels of these fatty acids than term infants. In long-term studies, feeding more than 0.2% DHA and 0.3% AA improved the status of these fatty acids for many weeks after DHA; AA was no longer present in the formula, enabling a DHA and AA status more similar to that of infants fed human milk. The addition of LCPUFA in infant formulas for term infants, with appropriate regard for quantitative and qualitative qualities, is safe and will enable the formula-fed infant to achieve the same blood LCPUFA status as that of t...

Importância dos ácidos graxos essenciais e os efeitos dos ácidos graxos trans do leite materno para o desenvolvimento fetal e neonatal

“…Os ácidos LA e ALA não podem ser sintetizados nas células mamárias pela ausência das enzimas ∆12 e 15, necessárias para a inserção da dupla ligação na posição n-6 ou n-3 da cadeia de carbono do ácido graxo, sendo, portanto, considerados nutrientes dietéticos essenciais 4 (Figura 1). Antes do nascimento, todos os ácidos graxos n-6 e n-3 acumulados pelo feto provêm da circulação materna através da transferência placentária, e depois do nascimento originamse do leite materno quando a amamentação materna for exclusiva 4,16 . Essa dependência é demonstrada por estudos que indicam forte correlação positiva materno-fetal para todos os ácidos graxos essenciais e seus AGPI-CL 4,17,18 .…”

“…O fato da transferência placentária ser seletivamente maior para o ARA e DHA do que para outros AGPI, determina concentrações sangüíneas fetais mais elevadas desses AGPI-CL por várias semanas após o nascimento da criança 22 . Isso é importante devido ao efeito positivo que esses ácidos graxos representam no crescimento fetal, principalmente para crianças nascidas prematuras, e no desenvolvimento do sistema nervoso central 10,16,21 .…”

“…Portanto, a ingestão dietética adequada desses AGPI-CL ou de seus precursores durante o período perinatal é essencial para o crescimento fetal e neonatal, para o desenvolvimento e para as funções neurológica, comportamental e de aprendizagem 16 . Além disso, a nutrição intrauterina pode influenciar no risco do desenvolvimento de doenças crônicas na fase adulta 25 , sugerindo que o padrão de nutrição no início da vida pode "marcar" (metabolic imprinting) o indivíduo, conduzindo, portanto, a uma "programação" metabólica.…”

“…Particular interesse tem sido dado ao sistema dopaminérgico, devido à importante função da dopamina no desenvolvimento cognitivo no início da infância, como modulador de atenção e motivação, e em processos visuais 16,30 .…”

Influence of maternal and socioeconomic factors on breast milk fatty acid composition in urban, low‐income families

“…In Bangladesh, the national median breast‐feeding duration is 31.2 months (National Institute of Population Research and Training [NIPORT], 2013) making it a vital source of neonatal energy, fat, and other nutrients. Research conducted in western countries has greatly expanded knowledge of the biological effects of fatty acid (FA) composition; the role of essential FAs on infant growth, neurodevelopment, visual acuity, and gut integrity; and the epidemiological factors affecting breast milk composition (Fleith & Clandinin, 2005; Qawasmi, Landeros‐Weisenberger, & Bloch, 2013; Teitelbaum & Walker, 2001). The work in lower‐income countries has been more limited, particularly in the Indian subcontinent, and there is a dearth of well‐powered studies investigating the epidemiological factors that affect the composition of breast milk and hence potentially, the development and health of the infant.…”