Wednesday, March 19, 2008

DHA makes smarter babies


I’ve been talking a lot about omega 3 and I’m sorry if this is of no interest to you! There was a comment (thanks Naznin!) re: DHA in breastmilk recently so I think this is an important topic to talk about.

During pregnancy, Omega 3 fats are incorporated in the fetal brain and lipids in the retina (eye). We know that the DHA form of omega 3 in particular plays an important role in optimal development of the central nervous system (ie. brain) and visual sharpness of babies. Developing infants can't efficiently make their own DHA and need to get it through their mother’s placenta during pregnancy and from breastmilk after birth.
The amount of DHA in a mother’s diet determines the amount of DHA in her breastmilk. This is why it’s important that moms and moms-to-be understand the need for them to get enough DHA in their diet. We know that Alpha-linolenic acid (
ALA) (ie. flaxseeds, walnuts) form of omega 3 isn’t well converted to DHA so the moms’ best bet is to get a direct source of DHA.


According to the International Society for the Study of Fatty Acids and Lipids working group, maternal intake of DHA should be greater or equal to 300mg. Studies have shown that the average Canadian pregnant woman’s DHA intake is only about 80mg/day.
Breastmilk is a source of DHA only if the mother’s DHA intake is adequate, which, as we’re seeing, it’s not. Nutritional education of pregnant women is necessary to fix this problem.

A reasonable explanation for why DHA intake in pregnant women is low is because DHA is found predominantly in fish/seafood, a food that is often avoided/limited by pregnant women. They’ve found that women eat fish once or so every 10 days during pregnancy because of concerns with respect to contaminants (eg, methyl-mercury in a few fish which can increase the risk of impaired brain development in the infant).

The Food and Drug Administration (U.S.) has recommended that women who are pregnant eliminate shark, swordfish, king mackerel, and golden snapper from their diets while limiting their consumption of other fish to 3 servings/week to minimize exposure to methyl mercury.

From Health Canada’s website: Predatory fish such as shark, swordfish, fresh and frozen tuna (not canned), have higher levels of mercury and should be consumed only occasionally. The health benefits of eating fish outweigh the risk of exposure to mercury if Health Canada consumption guidelines are followed. If you are an adult, limit your intake of these fish to no more than one meal per week. Pregnant women, women of child-bearing age and young children should be especially careful and limit their intake of these fish to no more than one meal a month.

A recent Canadian study found that the consumption of 2-3 servings weekly of salmon or rainbow trout, which would provide a daily averaged DHA intake of at least 300 mg/day during pregnancy, would not approach the tolerance levels for mercury, polychlorinated biphenyls, or dioxins and furans as set by Health Canada, the NRC (U.S.), or the World Health Organization.

However, if you don’t want to eat fish, algal oil (now available in capsules and just oil form) is a great source of DHA and, as I’ve blogged about previously, foods are being enriched with DHA now.

There is evidence from published clinical trials that women with higher DHA intakes (up to 1100 mg DHA daily), gave birth to infants with higher cognitive development scores and young children with higher IQ scores and mental processing scores up to 4 years of age.

A 2004 study published in Child Development found that babies whose mothers had high blood levels of DHA at delivery had advanced attention spans into their second year of life. During the first six months of life these infants were two months ahead of babies whose mothers had lower DHA levels.

Other current research suggests adequate levels of DHA may help reduce the risk of pre-term labor and decrease the risk of postpartum depression, improve babies’ sleep patterns and immunity (better allergy protection) and reduce to risk of allergic disease. Wow!

Once born, babies still need DHA and their only source of nutrition (incl. DHA) for growth and development is their mother's milk. Health Canada has reported that DHA represents an average of only 0.14% of the total fat in breast milk (due to current low DHA intakes) and it should be at least 0.35% - an amount that has been shown to result in better brain and visual functioning of infants. The direct consumption of DHA, at relatively low levels, provides a fairly rapid and marked improvement in the DHA level found in breast milk. An intake of 300 mg DHA/day during lactation has been found to elevate breast milk levels to 0.39% DHA.

Higher intakes of DHA (>200mg/day and up to 1183mg/day) during breastfeeding have resulted in babies scoring higher on cognitive tests after 30 months, greater visual development and acuity in term infants as well as optimized arousal in newborn infants.

Should moms choose DHA-fortified formula? I’ll blog about this another day but of course, breastfeeding is the best source of nutrition for your baby and also offers a plethora of other benefits! So, simple answer is: No. Increase your intake of DHA.

Sources:

http://dhaomega3.org ; http://www.ajcn.org/cgi/content/abstract/82/1/125?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=fish+oil&andorexactfulltext=and&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT http://jn.nutrition.org/cgi/content/abstract/135/2/206 ; http://nutrition.about.com/b/2005/09/27/dha-for-smarter-babies.htm ;
http://www.drlaura.com/sah/sahm.html?mode=view&tile=1&id=10576 ;
;
http://www.hc-sc.gc.ca/iyh-vsv/environ/merc_e.html

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