The prevalence of heavy metals such as mercury, lead, cadmium, and arsenic are increasing in our environment due to human activity. Industrial processes such as mining, manufacturing, and burning of fossil fuels are releasing more and more of these contaminants from the earth and into the air, water, soil, and food. It is therefore becoming increasingly important to uncover ways to protect ourselves from this increasing threat to human health.
The evidence is growing rapidly informing us that heavy metal toxicity can be minimized with restoration of specific microbial species to the human gastrointestinal (GI) tract, microbes diminished or lost from the microbiomes of most modern people.
Take a very exciting report in which the common fermenting microbe, Lactobacillus brevis 23017, decreased fecal content of mercury by over 600%, while also decreasing mercury levels in muscle tissue. (In the above graphic, “Hg-5d” is the increase in fecal mercury obtained in an experimental animal by administering oral mercury. “LAB+Hg-5d” reflects the decrease in fecal mercury content when L. brevis was administered along with mercury.) In other words, L. brevis binds mercury in the GI tract, making it unavailable for absorption. Although these observations were made in experimental animals, the effect is so significant that it is likely to apply to humans, although we really need a human clinical trial to validate. But it potentially means that we may be able to do away with such things as chelation and turn to microbes instead.
Some other microbes that have been shown to bind and discard heavy metals include:
- Lactobacillus reuteri P16—binds lead
- Lactobacillus plantarum—binds cadmium
- Lactobacillus plantarum CCFM8661—binds lead
- Lactobacillus casei (multiple strains)—binds lead
- Leuconostoc mesenteroides (strain unspecified)—binds lead
- Faecalibacterium prausnitzii—binds lead and arsenic
- Lachnospiraceae, Ruminococcaceae (various species)—bind arsenic
No one has yet conducted a human clinical trial to demonstrate whether such effects achieve meaningful reductions in, say, urinary levels of mercury or lead or cadmium in blood. My bet is that at least some of these reductions will be substantial. Unlike drugs, we don’t have to worry about side-effects, only side-benefits. L. plantarum, for instance, not only binds lead but also reduces blood sugar, insulin resistance, and blood pressure. L, casei increases immune responses against viruses and provides spectacular improvements in sleep quality and duration. We also do not know how important strain specificity is–if the CCFM8661 strain of L. plantarum is effective in eliminating lead, for instance, will the commercially available 299v strain mimic these effects? Not yet known.
I don’t believe that we are that far away from putting microbes to work as the strategy-of-choice in preventing and reducing levels of heavy metals in the body. This is an evolving conversation and no one is yet ready to say, for instance, “Ferment or replace these 3 or 4 species to remain free of health issues from heavy metals for a lifetime,” but we are getting awfully close. That said, there is no harm in obtaining one or more of the microbial strains that are already commercially available and, using my method of prolonged fermentation in the presence of prebiotic fibers, fermenting to high microbial counts and consuming.