Food Safety Focus (79th Issue, February 2013) – Food Safety Platform
DHA in Formula Products for Infants and Young Children — More is Not Better
Reported by Ms. Melissa LIU, Scientific Officer,
Risk Assessment Section,
Centre for Food Safety
In the last issue, we introduced macronutrients in breastmilk and infant formula. In this issue, we will discuss docosahexaenoic acid (DHA), a nutrient often added to formula products for infants and young children.
What is DHA?
DHA is a long-chain polyunsaturated fatty acid which has a critical role in normal retinal and brain development of foetus and the first two years of life. DHA presents in varying amounts in human breastmilk, fish oils, and marine algae. Apart from its dietary sources, the body can produce DHA from α-linolenic acid, which is found in plant oils as well as breastmilk and infant formula.
Breastfeeding is best for babies (courtesy of the Department of Health)
Controversy of Adding DHA in Formula Products
Some formula manufacturers add DHA-containing ingredients in their formula products. This is mainly to mimic the composition of breastmilk (mean DHA content ranges from 0.2-1.0% of fatty acids), and to take into consideration the typically higher blood level of DHA in breastfed infants than that in infants fed with formulae not containing DHA.
However, when coming to the question about the actual benefit of adding DHA to formula products, the issue is still controversial. There are studies suggesting that some infants, such as premature infants, may benefit from direct consumption of DHA. Some studies also suggest that including DHA in infant formulae may have positive effects on visual function and neural development of infants over a short term.
However, other studies in infants do not confirm the above benefits, nor are there any long-term beneficial effects demonstrated. For children aged two or above, there is currently insufficient evidence to link increased intake levels of DHA to improved physical or mental development or specific functional benefits. As such, the European Union only accepts claims mentioning that DHA intake contributes to the normal visual development of infants up to 12 months, while claims mentioning function of DHA intake on brain development of non-breastfed infants or eye development for infants and children above 12 months are not accepted.
In fact, there are concerns that for nutrients added to formula products, including DHA, their structures and functions may not be the same as those present in breastmilk as they are extracted from cows milk or other ingredients (such as marine oils in the case of DHA). Therefore, taking into account that DHA could be synthesised in the body from α-linolenic acid, the Codex Alimentarius Commission (Codex) does not consider DHA to be an essential composition of infant formula and follow-up formula products.
DHA Intake in Infants and Young Children
Theoretically, when DHA is taken in large amount or inappropriate ratio to other fatty acids, metabolism of other fatty acids in the body may be affected, which might eventually have impact on a number of body functions such as renal function, blood coagulation and immunological reactions.
However, this is normally not a concern to breastfed infants who can usually obtain the right amount of dietary DHA from breastmilk. For infant formula, in view of the possible benefits to certain babies, addition of DHA is generally acceptable. Codex recommends that DHA, if added, should normally not exceed 0.5% of total fat content unless due to unavoidable technical constraints and should be present in specific ratio to certain fatty acids, i.e. arachidonic acid (AA) content should reach at least the same concentration as DHA, and the content of eicosapentaenoic acid (EPA) should not exceed that of DHA. Such level does not pose any known major safety concern or adverse effects on growth. Therefore, when it is desired to feed infants with DHA added formula, it is advisable to choose one that fulfils the Codex recommendation.