How Long to Detox From Fish Before Pregnancy?

Increased fish consumption of mothers before and during pregnancy leads to increased exposure to both mercury and the long-chain omega 3 DHA. Mercury may negatively affect brain development in one’s unborn baby, whereas DHA may stimulate brain development. As we saw, though, the results of this study showed that the negative effect of MeHg outweighs the beneficial effect of DHA for most species of fish. Unfortunately, in the last two national surveys women of childbearing age–ages 18 to 45–were less aware and knowledgeable about this problem than other women, despite FDA and EPA campaigns to inform every OB/GYN and pediatrician in the United States about the potential risks of mercury in fish. But I wanted to highlight the “before.” Not just during pregnancy, but even before one gets pregnant.

Since mercury sticks around, women may want to avoid polluted fish consumption for a year before they get pregnant in addition to just during pregnancy. The reason they suggest a year before getting pregnant is because the half-life of mercury in the body is estimated to be about two months. They fed folks 2 servings a week of tuna and other high mercury fish to push their mercury levels up, and then stopped the fish at week 14 and slowly but surely their levels came back down. I know a lot of moms are concerned about exposing their children to mercury containing vaccines, but if they ate just a serving a week or less of fish during pregnancy, the latest data shows their infants end up with substantially more mercury in their bodies than getting injected with up to 6 mercury containing vaccines.

But, with a 2-month half-life, within a year of stopping fish consumption your body can detox nearly 99% of the mercury. Unfortunately the other industrial pollutants in fish can take longer for our body to get rid of— a half life as long as 10 years for certain dioxins, and PBCs, and DDT metabolites found in fish. So to get that same 99% drop could take 120 years, which is a long time to delay one’s first child.

What do these other pollutants do? Well high concentrations of industrial contaminants are associated with 38 times the odds of diabetes. That’s as strong as the relationship between smoking and lung cancer! Isn’t diabetes mostly about obesity, though? Well these are fat-soluble pollutants, and so as people get fatter the retention and toxicity of persistent organic pollutants related to the risk of diabetes may increase, suggesting the shocking possibility that obesity may only be a vehicle for such chemicals. We may be storing pollutants in our spare tire like a hazardous waste dump.

Now the pollutants could just be a marker for animal product consumption—maybe that’s why there’s such higher diabetes risk since more than 90% of the persistent organic pollutants comes from animal foods, unless you work in a chemical factory and stumble across some toxic waste. And indeed in the U.S. every serving of fish a week is associated with a 5% increased risk of diabetes, which makes fish consumption about 80% worse than red meat.

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