The latest volley in the ongoing debate about how much fish is too much, or too little, for pregnant women has been tossed by the Child & Family Research Institute, and paid for by the Canadian government.
The results of its study: "The typical North American diet of eating lots of meat and not much fish is deficient in omega-3 fatty acids and this may pose a risk to infant neurological development."
Omega-3 fatty acids are found in oily fish, like salmon, sardines and herring, as well as in lower concentrations in chicken and eggs.
Omega 3 fatty acids are important for the babys developing eyes and brain, said Dr. Sheila Innis, the studys principal investigator, in a prepared statement. She is the head of the nutrition and metabolism program at the Child & Family Research Institute at BC Childrens Hospital, and professor, department of pediatrics, University of British Columbia. During pregnancy and breastfeeding, fat consumed by the mum is transferred to the developing baby and breastfed infant, and this fat is important for the babys developing organs. Our next task is to find out why the typical North American diet puts mothers at risk. Then we can develop dietary recommendations to help women consume a nutritious diet that promotes optimal health for mums and babies.
The problem is that some fish, including salmon harvested from certain waters, can have high levels of mercury and other contaminants (smaller fish like herring and sardines are typically low in contaminants). Mercury can damage the developing brain, just as omega-3 fatty acids can help its normal development. The risk of permanent brain damage is on one hand, and the normal development of the brain on the other.
Getting enough omega-3 fatty acids while avoiding mercury and other contaminants (like PCBs) that can be found in some fish (thanks to our habit of polluting rivers and oceans with industrial wastes) is the riddle mothers are faced with.
Environmental Defense publishes a Seafood Selector designed to make this choice easier. It identifies which fish have the least contaminants, the most omega-3 fatty acids and those that are fished in a sustainable manner. That last one isn't a matter of personal health, but ocean health, and it's important for green consumers.
Here's how the latest research was described by the institute:
The researchers found that the women who ate lots of meat and little fish were deficient in omega-3 fatty acids, and their babies didnt do as well on eye tests as babies from mothers who werent deficient. The results were noticeable as early as two months of age. The study is ongoing as the researchers intend to follow the childrens development until four years of age.
For the study, the researchers recruited 135 pregnant women and randomly assigned them to either a group that took an omega-3 fatty acid supplement or one that took a placebo. All the women continued eating their regular diets. The supplement added the equivalent of two fatty fish meals per week, an amount that the researchers estimated would prevent deficiency. The researchers tested the womens blood samples at 16 and 36 weeks of pregnancy and measured the amount of DHA (docasohexaenoic acid), a type of omega-3 fatty acids thats known to be important for brain and eye function.
After the babies were born, the researchers did vision tests to evaluate the infants ability to distinguish lines of different widths. Its an innovative way of evaluating neurological maturity in babies who are unable to talk. Since the eyes are connected to the brain, they reflect the brains development.
The aim of this study was to contribute to a growing body of knowledge that focuses on the dietary needs of pregnant and breastfeeding women. More research is needed to identify recommended daily amounts of omega-3 fatty acids.
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