Breast milk, in image the purest and most natural of foods, soon may become a benchmark for measuring the toxins we absorb from the environment.
In its report to the International Joint Commission, the Great Lakes Science Advisory Board suggested that regularly testing breast milk from women in the Great Lakes region may help identify trends in human exposure to contaminants such as PCBs and DDT, manmade chemicals that have been linked to cancer, birth defects and development problems.
Residues are present only in trace amounts in water, but the toxins biomagnify as they move up the food chain. Eating one trout from Lake Michigan, for example, exposes a person to more PCBs than would a lifetime of drinking the lake water. The chemicals accumulate in humans, too, but to what degree and with what effect still is largely unknown.
Initial studies in the Great Lakes region suggest that chemical contamination affects childhood development. In a long-term study of the children of 242 women who ate Lake Michigan fish two to four times a month, the babies were found to be smaller at birth, slightly premature and demonstrating weaker vital signs. Researchers conclude that most of the damage is done by contaminants transferred through the placenta, but feeding newborns breast milk can prolong the exposure.
For the moment, the report advises against testing breast milk on an individual basis. Analysis is expensive and toxin levels can vary widely between women.
The SAB report does recommend, however, that the International Joint Commission declare toxic substances that can biomagnify to be a hazard to human health. It also proposes using breast milk as an indicator for exposure to toxins in the future.
In the meantime, pregnant and nursing mothers can reduce their children`s risk of exposure by refraining from eating larger, fatty fish from the Great Lakes such as whitefish, salmon and lake trout.