Michael Greger M.D. FACLM asks in his NutritionFacts.org blog, “What dietary change can simultaneously help detoxify mercury, lead, and cadmium from the body?”
I’ve previously explored the issue of lead contamination in calcium supplements, such as bone meal, but bone meal isn’t all that can be contaminated. “Substantial quantities of lead have been reported in some over-the-counter calcium supplement preparations,” and testing has revealed continued public health concern over bone meal. Thankfully, bone meal isn’t as popular these days, so most of us aren’t likely to get exposed directly to the lead in bonemeal anymore. We may, however, get exposed indirectly through the animals we eat, as I show at 0:31 in my video How to Lower Heavy Metals with Diet.
In the United States, five billion pounds of meat and bone meal are produced annually as slaughterhouse by-products. What do we do with these millions of tons every year? We feed it back to farm animals, particularly chickens. Now, most of the lead in the bone meal passes right through the animals into their waste, but we take that waste—that cow, pig, and chicken feces—and feed it right back to the animals once again. So, you can see how the levels of contaminants might build up in their bodies.
You may remember that Dr. Greger talked before about what all this might mean for making something like chicken soup, but the original concern about these kinds of feeding practices, such as feeding cows to pigs, chickens, and even other cows, was about spreading prion diseases, like mad cow. This kind of recycling not only magnifies prions, however; it also magnifies other toxic substances, including lead. So a more plant-based diet may be able to lower lead exposure, and an even more plant-based diet could theoretically lower exposure even more.
What happens when you put it to the test? Should we really expect to find a benefit? As you can see at 1:42 in his video, even though lead is one of the toxins found in meat, half of our dietary exposure probably comes from plant foods. In fact, dietary modeling studies in Europe suggest that vegetarians would be exposed to about the same amount of lead compared to the general population, with the exception of those who eat a lot of wild game, which can have a thousand times more lead than most other foods, as you can see at 2:02 in his video.