Wednesday, July 4, 2007

The Revenge Effect of Too Much Purity

Jack Dini

(This appeared in Plating & Surface Finishing, 90, 24, November 2003)

In our zeal to remove every last bit of contaminant from everything we eat, drink, or breathe, we may be doing a disservice to our health.

Thomas DeGregori reports, “We may have been too successful in creating a more hygienic environment leading to other problems. Good hygiene makes good sense but obsessive hygienr---‘the antibacterial craze’---can be counterproductive since it is as meaningless to be free of all microorganisms, including the sometime harmful ones, as it is to be free of all ‘chemicals.’ Some researchers have found a correlation between too much hygiene and increased allergy. Studies have revealed an increased frequency of allergies, cases of asthma and eczema in persons who have been raised in an environment overly protective against mircroorganisms.” (1)

Fernando Martinez adds. “There is now convincing evidence indicating that the prevalence of allergic diseases in general, and of asthma in particular, is on the rise in high income societies. Many hypothesis have been proposed to explain these increases, but the most widely discussed and the most controversial is the so-called ‘hygiene hypothesis.’ This hypothesis was first enunciated in quite straightforward terms: the Western lifestyle has succeeded in markedly decreasing the incidence of infections in early life, and these infections may have a protective effect on the subsequent development of allergies.” (2)

Bjorn Lomborg lists the following findings that seem to support the ‘hygiene hypothesis.’ (3)

· Children who suffer many infections (and get their immune system exercised) apparently face a smaller risk of getting asthma.
· The youngest children in large families face a smaller chance of getting asthma because their older siblings have passed many infections on to them.
· A recent Italian study showed that men heavily exposed to microbes were less likely to experience respiratory allergy.
· Several other studies have also shown that exposure to measles, parasites, and tuberculosis seems to reduce the risk of getting asthma.
· Children receiving oral antibiotics by the age of 2 were more susceptible to allergies than children who had no antibiotics, and children with early and repeated viral infections seem to have a reduced risk of developing asthma.

Doctors in England have suggested that mass vaccination against chicken pox would bring on a more serious epidemic of shingles in adults. Their studies have shown that adults who don’t live with children, or who live with immunized children, are much more likely to develop shingles. (4)

These recent studies aren’t the first time that epidemiologists have found that cleanliness wasn’t the cure-all for disease prevention. In the 1920s and 1930s, cleanliness, far from combating polio, was promoting it. Edward Tenner observes, “When all infants acquired the virus in the first days of their lives, while still protected by antibodies from their mothers’ blood, paralysis was almost unknown.” (5) Tenner goes on to add that German measles only turned into a serious disease after fewer and fewer children were infected with it. He also notes, “that the more casual French attitude toward exposure to germs makes their effects less severe in late life.” And speaking of the French, you’ve undoubtedly heard or read that the French have a low incidence of heart disease. Many folks suggest this is because of the wine they drink. I wonder if it could be because of dirt and here’s why. Lynn Payer has written a fascinating book, Medicine and Culture, wherein she compares different cultural approaches to health and illness. She notes, “The English and Americans have a saying, ‘Cleanliness is next to Godliness,’ The French don’t. While Americans assume that if it’s clean it must be healthy, the French are quick to point out the health advantages of dirt, or at least the health advantages of tolerating dirt.” (6) She adds, “The French don’t get turista when they travel, according to one French doctor, because they’ve acquired the immunity at home.” The French life-style can allow exposure to certain germs, a form a natural vaccination favored by the French over man’s vaccination. (7)

Chemotherapy, which is often effective against many forms of cancer can have the undesired effect of suppressing the immune system, leading to bacterial infections that the weakened immune system cannot contain. (8) Children with leukemia experienced a significant drop in their antibody levels against measles and rubella as a result of chemotherapy. (9)

Here are some other examples where absolute purity isn’t the answer. Raphael Kazmann quotes Philip West of Louisiana State University, “Turning now to productive water, it is quite apparent that absolute purity is out of the question. If the Mississippi River, passing Baton Rouge and New Orleans consisted of distilled water, there would be no seafood industry such as we now have in Louisiana. Without copper ‘contaminating’ the water there would be no oysters. Traces of iron, manganese, cobalt, copper, and zinc are essential for the crabs, snapper, flounder, shrimp and other creatures that abound in Gulf waters. As unpleasant as it sounds, even the sewage discharges into the Missouri, Ohio, and Mississippi River systems pollute and thus ultimately nourish the water.” (10)

With animals, chemically induced hormetic (beneficial at low doses) effects have been claimed for crabs, clams, oysters, fish, insects, worms, mice, rats, ants, pigs, dogs and humans. E. J. Calabrese and his colleagues report, “The range of agents employed in such studies has been wide, including numerous antibiotics, polychlorinated biphenyls (PCBs), ethanol, polycyclic aromatic hydrocarbons (PAHs), heavy metals, essential trace elements, pesticides, and a variety of miscellaneous agents, including chemotherapeutic agents, solvents such as carbon tetrachloride, chloroform, cyanide, sodium, and others.” (11)

Arsenic poisoning from drinking water in Bangladesh has been called the largest mass poisoning of a population in history by the World Health Organization (WHO). Rebecca Rawls notes that the poisoning may be exacerbated by the lack of certain metals in the drinking water, which, if present, might mitigate some of arsenic’s ill effects. (12) Two of these ‘missing’ metals are selenium and zinc. Selenium, which can inhibit arsenic toxicity, was not found in 92% of the water samples tested and zinc, which promotes the repair of tissues damaged by arsenic, could not be found in 18% of the samples.


1. Thomas R. DeGregori, The Environment, Our Natural Resources, and Modern Technology, (Ames, Iowa, Iowa State Press, 2002), 130
2. Fernando D. Martinez, “The coming –of-age of the hygiene hypothesis,” Respiratory Research, 2, 129, 2001
3. Bjorn Lomborg, The Skeptical Environmentalist, (Cambridge, Cambridge University Press, 2001), 187
4. “It’s Good To Be Around Sick Kids,” Discover, 24, 35, January 2003
5. Edward Tenner, Why Things Bite Back, (New York, Alfred A. Knopf, 1996), 56
6. Lynn Payer, Medicine and Culture, (New York, Henry Holt and Company, 1996), 67
7. Lynn Payer, Medicine and Culture, 69
8. Michael Shnayerson and Mark J. Plotkin, The Killers Within, (New York, Little, Brown and Company, 2002), 4
9. Anna Nilsson, “Consider reimmunizing children after chemotherapy for acute lymphoblastic leukemia,” Hem/Onc Today, 3, 10, October 2002
10. Raphael G. Kazmann, “Environmental Tyranny-A Threat to Democracy,” in Rational Readings on Environmental Concerns, Jay H. Lehr, Editor, (New York, Van Nostrand Reinhold, 1992), 311
11. E. L. Calabrese, Margaret E. McCarthy and Elaina Kenyon, “The Occurrence of Chemically Induced Hormesis,” Health Physics, 52, 531, 1987
12. Rebecca L. Rawls, “Tackling Arsenic in Bangladesh,” Chemical & Engineering News, 80, 42, October 21, 2002

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