Scientific Documents

DHA and support of the visual development of the unborn child and breastfed infant - Scientific substantiation of a health claim related to DHA and support of the visual development of the unborn child and breastfed infant pursuant to Article 14 of Regulation (EC) No 1924/2006 [1]

Summary (86 KB)

Opinion (144 KB)

Summary

Following an application from Merck Selbstmedikation GmbH submitted pursuant to Article 14 of Regulation (EC) No 1924/2006 via the Competent Authority of Germany, the Panel on Dietetic Products, Nutrition and Allergies was asked to deliver an opinion on the scientific substantiation of a health claim related to DHA and support of the visual development of the unborn child and breastfed infant.

The scope of the application was proposed to fall under a health claim referring to children’s development and health.

The food constituent that is the subject of the proposed claim is docosahexaenoic acid derived from tuna oil which is presented in soft gel capsules which contain >200 mg DHA, >50 mg eicosapentaenoic acid (EPA) and between 11.4 and 14.4 mg d-α-tocopherol. The food supplement is intended for pregnant and lactating women.

DHA is a well characterised fatty acid the absorption of which is well documented. DHA can be quantified in foods by established methods. The Panel considers that the food constituent, DHA, for which the claim is made is sufficiently characterised.

The claimed effect is that DHA provided via the mother contributes to the child’s visual development. The target population for the claimed effect is unborn children and breastfed infants. The target population for the supplementation with DHA is pregnant and lactating women.

The Panel considers that normal visual development is beneficial for children’s development and health.

The applicant identified a total of 41 publications as being pertinent to the health claim (15 randomised controlled trials (RCT), one non-randomised controlled trial, two observational cohort studies, three meta-analyses of human intervention studies, five systematic reviews, four other review publications, three guidelines/consensus opinions and eight mechanistic human studies).

The Panel considers that for the substantiation of the claim under consideration only human intervention or cohort studies reporting effects on visual function development in offspring of mothers who were exposed to defined intakes of DHA, either through supplementation or diet during pregnancy and/or lactation, provide the necessary evidence.

Therefore, intervention studies which assessed visual acuity in children who had been either breastfed or fed formula enriched with DHA are not regarded as pertinent for the substantiation of the proposed health claim, nor are RCT which describe the effects of DHA supplementation of pregnant women on the DHA concentrations in maternal and umbilical cord blood and in placenta and RCT conducted with DHA in lactating women which assess the effect on breast-milk DHA content.

Five RCT of DHA supplementation in pregnant or lactating women which include endpoints related to visual function assessment and an observational cohort study on the effects of maternal oily fish consumption and/or breastfeeding on children’s stereoacuity testing at age 3.5 years are considered pertinent to the claim under consideration.

DHA supplementation during pregnancy
Two RCT have assessed the effect of supplementation of women with DHA during pregnancy. In the first randomised double-blind placebo-controlled trial 100 healthy pregnant women consumed either fish oil capsules (200 mg DHA/day) or sunflower oil capsules (400 mg oleic acid/day) from week 15 of gestation until delivery. Visual evoked potential (VEP) recording, performed within the first five days of life and at 10 and 26 weeks of age showed no association of mean peak latency of the major components with DHA content in cord blood or postnatal breast milk. VEP recordings, done at 10 and 26 weeks of age, revealed no group difference. There was, however, a significant positive correlation between the DHA level in cord blood red blood cells (RBC) of infants and one index of earlier maturation of VEP. Retinal development, assessed during the first week of life, did not differ between the groups but was related to infant DHA status at birth. The Panel considers that no positive association between maternal DHA supplementation and visual development of the infants was established. In the second study pregnant women consumed approximately 200 mg DHA/day (n=16) or a placebo (n=14) from week 24 of pregnancy until term and visual acuity was measured in their infants at four months and six months of age. The Panel considers the study as inconclusive because of the small sample size and the non-consistency of a positive effect with increasing age of the infants.

DHA supplementation during lactation
Three RCT have assessed the effect of supplementation of breastfeeding women with DHA on visual development of the infants. In the first study 52 lactating women were randomised to consume either 0, 0.2, 0.4, 0.9 or 1.3 g DHA supplement/day starting 5 days postpartum and continuing until 12 weeks. Breast milk DHA content was related to infant plasma and RBC phospholipids DHA. VEP acuity of infants, assessed at 12 and 16 weeks of age did not differ between the dosage groups. In the second study 122 lactating women with habitual low fish consumption were randomised to consume a fish oil preparation containing 1.5 g n‑3 Long chain polyunsaturated fatty acids (n-3 LCPUFA) or an olive oil preparation starting within a week of delivery and continuing for four months. There was no effect of fish-oil supplementation on the visual acuity of infants at either two or four months of age. The Panel notes that a maternal DHA dose around 1.0 g/day did not promote better visual acuity in young infants than no maternal supplementation. In the third study 114 breastfeeding mothers were assigned to capsules with high-DHA algal oil (200 mg DHA/day) and 113 mothers to capsules with DHA-free vegetable oil for four months after delivery. Apart from a significantly lower transient VEP amplitude in the infant group whose mothers were supplemented with DHA there were no significant differences between groups of visual acuity measured at four and eight months of age. The Panel considers that the positive association between maternal DHA supplementation and one out of four infantile visual parameters measured at eight months of age is insufficient to establish a relationship between maternal DHA supplementation and visual development of the infant.

A cohort study in a subset of 435 full-term children from the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC) related stereoacuity data collected at the age of 3.5 years to breastfeeding duration, mother’s antenatal blood DHA content and oily fish consumption. Maternal oily fish consumption was associated with maternal blood DHA content and children whose mothers ate oily fish while pregnant were more likely to achieve high-grade stereopsis than were children whose mothers did not eat fish. The Panel considers that these data do not permit to establish a causal relationship between maternal DHA intake during pregnancy and stereoacuity development of their children.

The Panel concludes that there is insufficient evidence to establish a cause and effect relationship between the consumption of supplementary DHA during pregnancy and lactation and visual development in unborn children or breastfed infants.