Infant Development

The Benefits of DHA and ARA During Infancy

Arachidonic acid (ARA) and docosahexaenoic acid (DHA) are long chain polyunsaturated fatty acids (LCPUFA) belonging to the omega-6 and omega-3 fatty acid families, respectively. LCPUFAs are important components of cells and are found in particularly high concentrations in nerve cell membranes, including those of the brain and retina. DHA is the most abundant omega-3 fatty acid in the brain and the retina of the eye, representing about 97% and 93% of all omega-3 fatty acids in the brain and eyes, respectively. ARA is the most abundant of all omega-6 fatty acids in the brain, representing about 48% of all omega-6 fatty acids.

DHA and ARA are considered conditionally essential nutrients for the development and function of infant cognition and vision. These fatty acids also contribute to an infant's vascular and immune functions. The metabolism and functional activity of these two fatty acids are interconnected, and the health benefits they provide for infants are best characterized when considered together.

The physiological demand for DHA and ARA begins early in life. DHA and ARA accumulate in the brain during pregnancy and lactation, a rapid time of brain growth and development for the infant. More than 100 studies have been conducted evaluating the benefits of DHA and ARA in infant health and development. Studies were conducted with both breast-fed infants and formula-fed infants, with breastfeeding considered to be the optimal method for infant feeding. On the basis of the clinical evidence, recommendations have been made by several international expert groups and regulatory bodies to assure the adequate intake of DHA and ARA during infancy.

Below are research highlights from studies examining the role of DHA and ARA in infant health and development.

Cognition

• Many studies demonstrate improved mental development for infants fed DHA- and ARA-supplemented formula versus infants without DHA and ARA. These benefits extend well beyond the period of supplementation and continue into childhood.
• Term infants receiving DHA- and ARA-supplemented infant formula have similar scores on tests of development (DQ, Brunet-Lézine) to those receiving breast milk and significantly higher scores than infants not receiving DHA- and ARA-supplemented formula.
• Studies supplementing term infants with DHA and ARA (DHA 0.36%; ARA 0.72% total fatty acids TFA) report improved scores on tests of cognition (means end problem solving) at 9 months of age as compared to infants that are not supplemented. This test correlates favorably with vocabulary and IQ at 3 years of age.
• Term infants fed DHA- and ARA-supplemented formula (DHA 0.36%; ARA 0.72% TFA) score seven points higher on tests of cognition (Bayley Mental Development Index) at 18 months than infants fed unsupplemented formula.
• A follow-up study at age 4 reports higher visual acuity (clarity) and verbal IQ scores in those children receiving supplemented formula compared with children that did not.
• Five-year-old children whose mothers received 200 mg DHA while breast-feeding for the first four months of life perform better on a test of cognition (sustained attention) as compared to infants whose mothers were not supplemented.

Vision

• Infants who were breast-fed and then weaned to formula supplemented with DHA and ARA demonstrate more mature visual acuity (clearness of vision) than infants weaned to formula without DHA and ARA.
• Infants fed DHA- and ARA-supplemented formula exhibit better visual acuity (clearness of vision) than infants receiving formula without DHA and ARA (equivalent to 1.5 lines on the eye chart). These results are similar to breast-fed infants.
• At 12 months of age, infants supplemented with DHA- and ARA-enriched formula as the sole source of nutrition for the first four months of life (DHA 0.32%; ARA 0.64% total fatty acids) demonstrate improved visual acuity (clearness of vision) as compared to infants who did not receive supplemented formula.

Preterm Infants Require Additional DHA

• Infants rapidly accumulate DHA from their mother during the last months of gestation. Thus infants born prematurely do not have time to accumulate DHA to the same level as the full-term infant.
• Preterm infants fed formula or breast milk supplemented with DHA and ARA exhibit positive effects on growth as assessed by weight, length and head circumference. These infants show improved visual and mental development as compared to infants fed formula or receiving breast milk without supplemental DHA and ARA.
• Preterm infants receiving breast milk with an additional 32 mg DHA/100 ml milk and 31 mg ARA/100 ml milk from one week post-birth for approximately nine weeks duration, demonstrate cognitive benefits at six months corrected age using tests of recognition memory and problem solving. On follow up at 20 months chronological age, these children achieved higher scores on a measure of sustained attention.
• DHA supplementation above 1% total fatty acids may enhance brain development, particularly in infants with birth weights ≤ 1,250g.

Immune Response

• Preterm infants supplemented with DHA- and ARA-preterm infant formula exhibit similar immune function status, (as measured by lymphocyte populations, cytokine production and antigen maturity) more consistent with that of the breast milk-fed infant. This may affect the ability of the infant to respond to immune challenges.
• Term infants receiving DHA- and ARA-supplemented formula as compared to those without DHA and ARA have an immune status (cell distribution and cytokine profile) more similar to infants fed breast milk.
• DHA- and ARA-supplemented infant formula (0.32–0.36% and 0.64–0.72% of total fatty acids, respectively) provided during the first four months of life are associated with a delayed onset and reduced incidence of upper respiratory infections and common allergic diseases up to three years of age.
• Infants fed DHA- and ARA-enriched infant formula (0.36% DHA; 0.72% ARA total fatty acids) have fewer episodes of bronchiolitis and bronchitis at ages five, seven and nine months compared to infants fed non-supplemented formula.
• Infants born to atopic (allergic) pregnant women randomized to receive a high dose marine oil supplement during the second half of pregnancy demonstrate an improved response to allergy testing (antigen skin prick test) at age one and less severe atopic dermatitis compared to infants whose mothers received placebo supplements.

Cardiovascular Health

• Signs of cardiovascular disease have been detected early in life. Unfavorable blood lipids and high blood pressure are now increasingly seen in young children. Supplementation of DHA in a younger population improves blood lipid profiles and restores endothelial function in children with high cholesterol levels.
• Infants fed formula supplemented with DHA and ARA have significantly lower blood pressure compared to infants fed non-supplemented formula, similar to that of breast-fed infants. Because blood pressure tends to track from childhood into adult life, it has been suggested that early intake of DHA and ARA may reduce the risk of cardiovascular disease later in life.