Today I completed an online CME activity from Medscape. The research reviewed for the article was published in the Journal of Clinical Nutrition and involved a study of 550 newborns in Spain. The researchers were looking at the impact of fish consumption on birth outcomes with regard to mercury content. As we promote fish consumption for positive neurological benefits we must also weigh the risk of toxicants now found in fish, such as mercury and polychlorinated biphenyls. Mercury is a neuro toxin and has been found to affect fetal growth.
This study measured the amount of mercury in fetal cord blood and reviewed the mothers’ history of intake of fish; type and amount. The outcomes were low birth weight and low birth length for gestational age. The overall impact that the scientists were reviewing was whether or not fish consumption or type of fish consumption would lead to SGA babies or small for gestational age.
The study was not ideal and is not conclusive but gives us food for thought, as it were, and direction for further study.
Intake of canned light tuna was found to be protective. It increased birth weight. Intakes of large oily fish such as sword and tuna, was related to higher mercury levels and low birth weight and low birth length.
Intake of lean or smaller oily fish, such as mackerel, salmon and sardines reduced the risk of short in length for SGA.
All of us should be mindful that swordfish, shark and tuna can be high in mercury and other toxicants and may be harmful to our health, where as fish like salmon are health promoting and fish like tilapia and mahi mahi are less toxic.