Think again about keeping little ones so squeaky clean

Dec 08, 2009

A new Northwestern University study suggests that American parents should ease up on antibacterial soap and perhaps allow their little ones a romp or two in the mud --- or at least a much better acquaintance with everyday germs.

The study is the first to look at how microbial exposures early in life affect inflammatory processes related to diseases associated with aging in adulthood.

Most provocatively, the Northwestern study suggests that exposure to infectious microbes early in life may actually protect individuals from cardiovascular diseases that can lead to death as an adult.

"Contrary to assumptions related to earlier studies, our research suggests that ultra-clean, ultra-hygienic environments early in life may contribute to higher levels of inflammation as an adult, which in turn increases risks for a wide range of diseases," said Thomas McDade, lead author of the study, associate professor of anthropology in Northwestern's Weinberg College of Arts and Sciences and a faculty fellow at the Institute for Policy Research.

Relatively speaking, humans only recently have lived in such hyper-hygienic environments, he stressed.

The research suggests that inflammatory systems may need a higher level of exposure to common everyday bacteria and microbes to guide their development. "In other words, inflammatory networks may need the same type of microbial exposures early in life that have been part of the human environment for all of our to function optimally in adulthood," said McDade, also a member of Northwestern's Cells to Society (C2S).

The Northwestern study is the first research on microbial effects on inflammatory systems in infancy that relate in later life to diseases associated with aging. Advancing the scientific literature on the developmental origins of disease, the study arguably is the most significant research on long-term effects of early environments on human physiological function and health in adulthood.

The research took advantage of a longitudinal study of Filipinos, following participants in utero through 22 years of age, to get a better understanding of how environments early in life affect production of C-reactive protein (CRP) production in adulthood.

Levels of the protein rise in the blood due to inflammation, an integral part of the immune system's fight against infection. CRP research mostly has centered on the protein as a predictor of heart disease, independent of lipids, cholesterol and blood pressure, though researchers still dispute that association. Researchers have been looking at excess body fat as a primary source of pro-inflammatory cytokines that produce CRP and behavioral factors related to diet, exercise and smoking. And the CRP research largely has been conducted in relatively affluent settings, such as in the United States, with low levels of .

The Northwestern researchers were interested in what CRP production looks like in the Philippines, a population with a high level of infectious diseases in early childhood compared to Western countries. Relative to Western countries, the Philippines also has relatively low rates of obesity and cardiovascular diseases, consistent with the Northwestern research findings.

Blood tests showed that C-reactive protein was at least 80 percent lower for study participants in the Philippines when they reached young adulthood, relative to their American counterparts, though the Filipinos suffered from many more infectious diseases as infants and toddlers. Filipino participants in their early 20s had average CRP concentrations of .2 milligrams per liter -- five to seven times lower than average CRP levels for Americans. CRP concentrations for Americans in their early 20s were on average around 1 to 1.5 milligram per liter.

"Early Origins of Inflammation: Microbial Exposures in Predict Lower Levels of C-reactive Protein in Adulthood," will be published online December 9 in the journal Proceedings of the Royal Society B: Biological Sciences. Besides Northwestern's McDade, the co-authors are Julienne Rutherford, University of Illinois at Chicago; Linda Adair, University of North Carolina, Chapel Hill; and Christopher Kuzawa, associate professor of anthropology in Weinberg at Northwestern.

The Northwestern study drew its data from a longitudinal study that began in the early 1980s with 3,327 Filipino mothers in the third trimester of pregnancy. The mothers were interviewed for behaviors related to care giving, and breast feedings were recorded. The household environment was assessed in terms of socioeconomic resources, hygiene (whether domestic animals, such as pigs and dogs, roamed freely) and density of inhabitants.

Researchers visited with the mothers at the delivery of their infants and subsequently every two months for the first two years of the children's lives. Thereafter, the researchers followed up with the children every four or five years until they reached their early 20s. The records they kept on the children include data on infectious diseases, growth in height and weight.

"In the U.S we have this idea that we need to protect infants and children from microbes and pathogens at all possible costs," McDade concluded.

"But we may be depriving developing immune networks of important environmental input needed to guide their function throughout childhood and into . Without this input, our research suggests, may be more likely to be poorly regulated and result in inflammatory responses that are overblown or more difficult to turn off once things get started."

Source: Northwestern University (news : web)

Explore further: US scientists make embryonic stem cells from adult skin

add to favorites email to friend print save as pdf

Related Stories

Protein may predict heart attack and early death, not stroke

Oct 19, 2009

People with high levels of a protein called C-reactive protein (CRP), a marker for inflammation in the blood, may be at higher risk for heart attack and death but not stroke, according to a study published in the October ...

Recommended for you

Leeches help save woman's ear after pit bull mauling

Apr 18, 2014

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...

New pain relief targets discovered

Apr 17, 2014

Scientists have identified new pain relief targets that could be used to provide relief from chemotherapy-induced pain. BBSRC-funded researchers at King's College London made the discovery when researching ...

User comments : 5

Adjust slider to filter visible comments by rank

Display comments: newest first

jerryd
not rated yet Dec 08, 2009

Nothing new here. This has been known for many yrs in asthma among others.
RobertKarlStonjek
not rated yet Dec 08, 2009
We muck out the children's stall daily ~ fresh hay on the ground and grits in the trough...should we refrain from this obsession and only do it weekly?
Velanarris
not rated yet Dec 09, 2009
It's also well known that the instances of autoimmune disease are highest among those in the first world while being lowest in third world countries.

It's common sense, if you don't exercise your body, your muscles get fat and sloppy. If your immune system doesn't exercise, it gets fat and sloppy as well.
saklat
not rated yet Dec 09, 2009
Like your great grandmother probably said " You've got to eat your peck of dirt before you die." or, more recently, "Children are to be given a "dirt pill" to provide the germs they missed out on as toddlers as part of a revolutionary treatment for asthma. Researcher Susan Prescott said asthmatic children would receive daily medication that would include a mixture of different strains of probiotic bacteria and antioxidants.
—Ean Higgins, "Dirt pills may help to ease kids' asthma," The Australian, April 27, 2006"
KBK
5 / 5 (1) Dec 09, 2009
My Bro-in-law worked inside what was the highest level and size clean lab in Canada, about 15 years back.

He said they had to get outside and get dirty, twice a day. Otherwise, their immune systems would shut down on them and they would be open to infectious situations.

This is what the lab owners had them do, twice a day: Get out, encounter some germs and dirt, please.

The empirical evidence from clean lab use indicated this exact aspect when such clean labs began to come on line in a big way. So now we have a 'study' that shows this point that clean lab folks have known for decades, now.

More news stories

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Study says we're over the hill at 24

(Medical Xpress)—It's a hard pill to swallow, but if you're over 24 years of age you've already reached your peak in terms of your cognitive motor performance, according to a new Simon Fraser University study.

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.