significant, as this essential nutrient can block heavy metal bioavailability and reduce toxicity. However, in turn, mercury can deplete selenium, making it insoluble and reducing its protective abilities as an antioxidant, opening the body up to free radical attack.
Mercury’s ability to cross the blood–brain and placental barriers allows it to deplete important stores of selenium components located there, which are essential to critical bodily functions. Mercury’s powerful affinity for this element disrupts the metabolic processes of selenocysteine, and by binding into mercury selenides, it makes them unavailable for protein synthesis.166
Selenium is naturally absorbed by most foods when present in soils. While many people’s diets are deficient in selenium, too much, if repeatedly ingested at sustained high levels, can also be damaging. Selenium is available in vitamin supplements as selenium methionine and is a significant nutrient in several dietary sources, which have known antagonistic effects with mercury.167
Brazil nuts are known for yielding the highest serving of food-based selenium, with more than 767 percent the established daily value (DV) in just a single one-ounce serving. The actual selenium content in the harvested nuts, of course, depends on the availability of selenium in the soil. So concentrations in such nuts may vary widely. However, many warn against eating more than one or two of these nuts per day on a regular basis, due to concerns about the possibilities of selenium toxicity (though high levels of selenium must accumulate over time before any adverse effects could occur). Numerous seeds including sunflower, chia, and others contain significant levels of selenium, as do many commonly consumed meats, though none of them reach the concentrations of Brazil nuts.168
Ironically, tuna fish and oysters, known for their high mercury content, are the next largest food-based sources of selenium, with some researchers demonstrating the ability of the selenium inside these seafoods to bind with mercury and make both unavailable for bioabsorption, though the ratio between the two elements is highly relevant to the risk of mercury exposure.169 Whether the mercury is organic or inorganic is relevant as well; methylmercury irreversibly blocks selenium-related enzymes from functioning correctly.
Registered pharmacist and nutritionist Barbara Mendez notes that even low-level mercury poisoning can cause a number of symptoms that might easily be mistaken for other health issues, including rashes, inflamed gums, mood disturbances, insomnia, anxiety, and depression.170 Mendez recommends a diet that helps optimize liver function, including garlic, cilantro, Brazil nuts, pumpkin seeds, and ground flaxseed. In studies, garlic has been effective against methylmercury-induced cytotoxic (toxic to living cells) effects.171
The therapeutic compounds BAL, DMPS, and DMSA have all been shown to chelate mercury. Researchers at the University of Lisbon’s Research Institute for Medicines and Pharmaceutical Sciences found selenite helped detoxify cells and make these chelators more effective.172
Researchers who exposed mice to mercuric chloride pesticide were able to ward off oxidative stress and liver cell damage using propolis, the resinous botanical mixture honey bees mix with their beeswax to glue their hives together. A treatment for inflammatory disease and infections, propolis was found to protect antioxidant defenses against mercury poisoning in the mice.173
There are possibilities for mitigating the harm imposed by mercury-based pesticides as well as the environmental pollution imposed by industrial contamination, though concerned individuals should focus on personal strategies to limit their exposure.
ATOMIC NUMBER: 82
GROUP 14: CARBON, SILICON, GERMANIUM, AND TIN
Lead is a shiny, bluish-white heavy metal that dulls to gray when it comes into contact with air. Its legendary usage is closely tied to the rise and fall of civilization, used in water-carrying pipes, glazed pottery, cooking utensils, and even the preservation of wines by the ancient Romans, who produced some 40 percent of the world’s lead alongside their abundant quantities of silver and other precious metals.
Plumbing itself draws its name from plumbum, the Latin word for lead (abbreviated as Pb), a luxury afforded only to the patrician class in what was once the world’s greatest empire. The poisonous effects of lead were known to antiquity, and lead was noted among some thinkers of the time for its effect on shipbuilders. High levels of lead have been found in the bones of patrician gravesites, leading historians to believe it played a role as a regular part in the decadent lifestyle of the upper class, who suffered stillbirths, lower fertility, brain damage, and deformities as Rome’s glory faded.174
But these lessons, misplaced in the dark ages, had to be relearned again in the modern industrial age. The “epidemic” effects of lead exposure were starkly noticed alongside spikes of disease in the nineteenth century during the production and manufacture of spreading industrialization.
Industrial assault of lead
In considering the modern-day hazards of lead exposure, tainted paint chips and the environmental disaster that was leaded gasoline might immediately come to mind. Although a small amount of lead is naturally occurring, the industrial revolution that began in the latter half of the eighteenth century created the conditions for widespread contamination all over the world. Today, everything from agricultural pesticide use to cosmetics, bullets, batteries, and pipes, to industrial practices such as mining and smelting continue to contribute to overall environmental lead contamination.
Unsafe at any level
No safety threshold for lead has ever been established—a multitude of studies have proven time and again lead is downright dangerous to health at any level. Government organizations such as the EPA have admitted there is no safe allowable level of lead intake.175 Even in small amounts, this cumulative toxin competes with calcium, iron, and zinc, blocking absorption of these necessary nutrients and wreaking havoc.
Unlike other metals, which play a role in biochemical reactions, lead is just a pollutant. It has no known essential function within the human body, and science has long acknowledged that lead is poisonous to every bodily system. Once lead enters the air, it can travel far distances before it falls to the ground where it readily contaminates water and soil. This cycle inevitably leads to lead-tainted crops that are cooked into lead-tainted dinners. Exposure to cigarette smoke, even secondhand, can also mean exposure to dangerous amounts of lead.
As such, the EPA regulates it under seven different acts: the Toxic Substances Control Act (TSCA), the Residential Lead-Based Paint Hazard Reduction Act of 1992 (Title X), the Clean Air Act (CAA), the Safe Drinking Water Act (SDWA), the Clean Water Act (CWA), the Resource Conservation and Recovery Act (RCRA), and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).176
Unrestricted and pervasive exposure in foods
Although we are exposed to lead in the air we breathe and the water we drink, many organizations, including the European Food Safety Authority, have concluded that the majority of human lead exposure actually comes from the food we eat.177
However, even with all the bad press about lead—as with toys from China and cosmetics—and despite the fact that we know lead inflicts neurological damage on the brain and contributes to cancer, there is no fundamental framework for limiting exposure to food-based lead contamination. Despite the effort to control the impact of this dangerous substance on the environment under the guise of the EPA, there are no limits on the concentration of lead allowed in food sold in the United States, apart from
