Toxin and Toxicant Exposure
Toxins are poisonous compounds produced by living organisms; sometimes the term “biotoxin” is used to emphasize the biological origin of these compounds. Man-made chemical compounds with toxic potential are more properly called toxicants. Toxins and toxicants can exert their detrimental effects on health in a number of ways. Some broadly act as mutagens or carcinogens (causing DNA damage or mutations, which can lead to cancer), others can disrupt specific metabolic pathways (which can lead to dysfunction of particular biological systems such as the nervous system, liver, or kidneys).
The diet is a major source of toxin exposure. Toxins can find their way into the diet by several routes, notably contamination by microorganisms, man-made toxicants (including pesticides, residues from food processing, prescription drugs and industrial wastes), or less frequently, contamination by toxins from other “non-food” plant sources.1,2 Some of the toxic heavy metals (lead, mercury, cadmium, chromium), while not “man-made,” have been released/redistributed into the environment at potentially dangerous levels by man, and can find their way into the diet as well. Microbial toxins, secreted by bacteria and fungi, can be ingested along with contaminated or improperly prepared food.
Even the method of food preparation has the potential for converting naturally-occurring food constituents into toxins.3 For instance, high temperatures can convert nitrogen-containing compounds in meats and cereal products into the potent mutagens benzopyrene and acrylamide, respectively. Smoked fish and cheeses contain precursors to toxins called N-nitroso compounds (NOCs), which become mutagenic when metabolized by colonic bacteria.
Outside of the diet, respiratory exposure to volatile organic compounds (VOCs) is a common risk which has been associated with several adverse health effects, including kidney damage, immunological problems, hormonal imbalances, blood disorders, and increased rates of asthma and bronchitis.4
One of the greatest sources of non-dietary toxicant exposure is the air in the home.5 Building materials (such as floor and wall coverings, particle board, adhesives, and paints) can “off-gas” releasing several toxicants that can be detected in humans.6 For example, a toxic benzene derivative commonly used in disinfectants and deodorizers was detected in 98% of adults in the Environmental Protection Agency’s (EPA) “TEAM” study.7 In another EPA study, three additional toxic solvents were present in 100% of human tissue samples tested across the country.8
Newly built or remodeled buildings can have substantial amounts of chemical “off-gassing,” giving rise to what has been called “sick building syndrome.”9 Carpet is an especially big offender, potentially releasing several neurotoxins; in testing of over 400 carpet samples, neurotoxins were present in more than 90% of the samples, quantitatively sufficient in some samples to cause death in mice.10 Ironically, shortly after the TEAM report, 71 ill employees evacuated the new EPA headquarters in Washington DC complaining claiming health problems, which were eventually attributed to the 27,000 sq. feet of new carpet.11
Carpets also trap environmental toxins; the “Non-Occupational Pesticide Exposure Study” (NOPES) found an average of 12 pesticide residues per carpet sampled, and determined that this route of exposure likely provides infants and toddlers with nearly all of their non-dietary exposure to the notorious pesticides DDT, aldrin, atrazine, and carbaryl.12
Avoiding Toxin/Toxicant Exposure
While it is not possible to completely eliminate toxin/toxicant exposure from all sources, there are ways to minimize it:
- Limit the introduction of VOCs in the home by using VOC-free cleaning products, low-VOC paints, and choosing throw rugs instead of new carpeting13;
- Store food in bisphenol A (BPA)-free or phthalate-free containers, and avoid reheating foods in plastic containers;
- Look for organic produce, which is grown without pesticides, and will contain less residue than conventionally-produced fruits and vegetables (although be aware that organic produce isn’t necessarily “pesticide free”)14;
- Washing fruits or vegetables can decrease some pesticide residue, although it is not effective against all pesticide types,15 and commercial fruit and vegetable wash solutions may not be any more effective than water alone.16 Peeling skins off of produce may help to further lower pesticide levels;
- Limit intake of processed foods. Even ones that are free of synthetic preservatives may contain detectable amounts of toxic compounds that were introduced (by chemical transformation) during processing. For example, numerous toxins are produced by the high temperatures used to manufacture some processed food ingredients.17
- Although the risk of acute toxicity from undercooking meat (food poisoning) is likely a greater risk than toxin exposure from overcooking it, there are ways to reduce toxin production during meat preparation: avoid direct exposure of meat to open flame or hot metal surfaces; cook meat at or below 250°F via stewing, braising, crockpot cooking (slow food preparation methods that utilize liquid); turn meat often during cooking, avoid prolonged cooking time at high temperatures, and refrain from consuming charred portions.18