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Published on Leave a comment on Will We Use Intestinal Worms To Treat Diseases?

There has been much discussion recently over why the incidence of allergies and chronic diseases is rising in Western industrialized countries. Some theories have been proposed, such as the hygiene hypothesis (that early childhood environments are too sterile and so that the developing immune system isn't properly "trained"), or that medicines such as antibiotics kill off beneficial bacteria, whille others say it is due to our Western diet and lifestyle. However, recently some researchers have proposed that the absence of intestinal worms, called helminths, in our bodies is actually negative for our health and could be a reason for the rising incidence of allergies and these diseases.

Over the centuries intestinal worms (such as hookworms) have caused a lot of human suffering, and therefore have been viewed as disease causing parasites. Western industrialized countries made major efforts (such as improved sanitation) to get rid of all intestinal worms in humans, and were generally successful. It is now rare to hear of someone in these countries having intestinal worms.

Dr. William Parker, an associate professor of surgery at Duke University in North Carolina, has written an interesting and thought-provoking article about the role of helminths in human health. He states: "A barrage of scientific evidence points toward helminths as being important regulators of immune function." In other words, we need them in order for our immune system to function properly.

Research actually shows that introducing certain species of intestinal worms, such as roundworms or flatworms, into the human gut successfully treats certain diseases in humans. But medicine has been slow to adopt such a view. Dr. Parker writes that viewing certain helminths as beneficial for proper immune functioning would be a "paradigm shift" in medicine.

By the way, the research looking at intestinal worms found benefits from low levels of helminths, not huge amounts. Having higher levels of helminths (such as roundworms) results in various symptoms (e.g. fever, abdominal pain, diarrhea)

Do go read the full article. Excerpts are from Dr. William Parker's article in Aeon: We Need Worms   ...continue reading "Will We Use Intestinal Worms To Treat Diseases?"

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An argument for the need for human exposure to the microbes in rural environments. However, the role of diesel exhaust and other urban air pollutants is not discussed here (for example, diesel exhaust is linked to asthma). From Science Daily:

Rural microbes could boost city dwellers' health, study finds

The greater prevalence of asthma, allergies and other chronic inflammatory disorders among people of lower socioeconomic status might be due in part to their reduced exposure to the microbes that thrive in rural environments, according to a new scientific paper co-authored by a University of Colorado Boulder researcher.

The article, published in the journal Clinical & Experimental Immunology, argues that people living in urban centers who have less access to green spaces may be more apt to have chronic inflammation, a condition caused by immune system dysfunction.

When our immune systems are working properly, they trigger inflammation to fight off dangerous infections, but the inflammation disappears when the infection is gone. However, a breakdown in immune system function can cause a low level of inflammation to persist indefinitely. Such chronic inflammation can cause a host of health disorders.

Some scientists have hypothesized that the increase of chronic inflammation in wealthier Western countries is connected to lifestyles that have essentially become too clean. The so-called "hygiene hypothesis" is based on the notion that some microbes and infections interact with the immune system to suppress inflammation and that eliminating exposure to those things could compromise your health.

The authors agree that microbes and some types of infections are important because they can keep the immune system from triggering inflammation when it's not necessary, as happens with asthma attacks and allergic reactions.

But they say the infections that were historically important to immune system development have largely been eliminated in developed countries. The modern diseases we pick up from school, work and other crowded areas today do not actually lead to lower instances of inflammatory disorders.

During our evolutionary history, the human immune system was exposed to microbes and infections in three important ways: commensal microbes were passed to infants from their mothers and other family members; people came into contact with nonpathogenic microbes in the environment; and people lived with chronic infections, such as helminths, which are parasitic worms found in the gut and blood.

In order for those "old infections" to be tolerated in the body for long periods of time, they evolved a mechanism to keep the human immune system from triggering inflammation. Similarly, environmental bacteria, which were abundant and harmless, were tolerated by the immune system. According to Rook, a professor at UCL, "Helminthic parasites need to be tolerated by the immune system because, although not always harmless, once they are established in the host efforts by the immune system to eliminate them are futile, and merely cause tissue damage."

In contrast, relatively modern "crowd infections," such as measles or chicken pox, cause an inflammatory response. The result is that either the sick person dies or the infection is wiped out by the inflammation and the person becomes immune from having the same infection again in the future.

Collectively, the authors refer to the microbes and old infections that had a beneficial impact on the function of our immune systems as "old friends." Exposure to old friends plays an important role in guarding against inflammatory disorders, the authors said. Because the "old infections" are largely absent from the developed world, exposure to environmental microbes -- such as those found in rural environments, like farms and green spaces -- has likely become even more important.

The authors say this would explain why low-income urban residents -- who cannot easily afford to leave the city for rural vacations -- are more likely to suffer from inflammatory disorders. The problem is made worse because people who live in densely populated areas also are more likely to contract crowd infections, which cause more inflammation.