Up to now, the metal absorption capacity of various foods and food and supplement ingredients has only been referenced in broad terms, Adams said. Representative statements read something like, "Cilantro absorbs heavy metals” without quantification. Adams said the new battery of tests shows the performance of substances in units of microgram per gram. The new data could open up new market opportunities, he said.
“We anticipate many companies referencing this research in an effort to formulate and market supplements that have high natural binding affinity for toxic elements,” Adams told NutraIngredients-USA
Dubbed the Metals Capturing Capacity, the tests subjects candidate substances to a simulated digestion process using a synthetic acid and a process designed to simulate the time duration, acid content, temperature and physical motions of human digestion. The digestive fluids are spiked with a known quantity of toxic elements, allowing the candidate food substance an opportunity to bind with and "capture" the toxic elements.
Adams says the process is conducted using a quality control safeguards such as using stock element solutions traceable back to NIST standards as well as using multiple control "blank spikes" to determine the baseline for zero capturing capacity.
Once digestion is complete, food solids are separated from liquids using a process designed to mimic the function of the intestinal walls. The resulting liquids are then subjected to atomic spectroscopy analysis via ICP-MS conducted at parts per billion (ppb) sensitivity.
The resulting element concentrations are compared to a blank spike containing no foods or other materials, and the difference between resulting concentrations in the tested substance liquid is the amount of toxic elements which were captured by the candidate food substance.
Adams found that foods with fiber portions intact tended to perform better on metals absorption. He also found that spirulina and chlorella algae peformed especially well on many tests.
Among his other findings were:
- Most foods have very high affinity for mercury, a "sticky" heavy metal. Even junk foods and processed foods can effectively remove dietary mercury during digestion.
- Only about five percent of foods can bind with lead. The lead-binding potential of cilantro has been vastly overstate and is actually not very high.
- Even fewer foods have natural affinities for cadmium or arsenic. Aluminum and radioactive isotopes such as cesium-137 are even more difficult to bind with.
Changes in market
Adams said that as the knowledge of the presence of metals in the environment and food supply becomes more well known, changes can be expected in the way foods and supplements are marketed.
“I believe that as the public becomes increasingly aware of the presence of toxic elements (heavy metals) in foods (including organic foods), we will see more efforts to certify foods as having low heavy metals. I am aware of one certification company working on this concept already,” he said.
Adams said he hopes his data—which is all in vitro at this point—will spark future research in human models. It could also help inform decision on regulations.
“This brings up the Prop 65 issue, which I believe needs to be repealed or reformed to reflect the actual amount of lead and other heavy metals that are ‘released’ by dietary supplements rather than the quantity of lead they merely contain in their composition. Lead in your gut doesn't harm you unless it gets absorbed into your blood, after all.” he said.