Te schone kinderen hebben meer kans op ziektes later*
Uit een Filipijnse studie onder ruim 3.300 kinderen die vanaf de geboorte 22 jaar gevolgd werden blijkt dat een te schone omgeving veel meer kans geeft op ernstige ziektes later in het leven. Kinderen opgevoed in een “normale” omgeving bleken 85% minder ontstekingsmarkers in het bloed te hebben dan een doorsnee Amerikaan of Europeaan. Deze ontstekingsmarkers zijn voorboden van ernstige ziektes zoals hart- en vaatziekte.
New research: natural exposure to everyday germs may protect kids from disease as adults
Gone are the days when play time for kids often meant getting dirty making mud "pies", splashing in mud puddles and creeks, and climbing trees -- and when children washed their hands, mostly just before a meal, it was with plain soap and water. Modern day parents often take pride in keeping their little ones squeaky clean and as germ-free as possible, dousing them with antibacterial soaps and hand sanitizers. But new Northwestern University research suggests that normal exposure to everyday germs is a natural way to prevent diseases in
adulthood.
The study, published in the journal Proceedings of the Royal Society B: Biological Sciences, is the first to investigate whether microbial exposures early in life affect inflammatory processes related to diseases in adulthood. Remarkably, the Northwestern study suggests exposure to infectious microbes in childhood may actually protect youngsters from developing serious illnesses, including cardiovascular diseases, when they grow into adults.
"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," Thomas McDade, lead author of the study, said in a statement to the media. McDade is associate professor of anthropology in Northwestern's Weinberg College of Arts and Sciences and a faculty fellow at the Institute for Policy Research.
He added that humans have only recently lived in super clean environments and it could well be time to put down the antibacterial soap. That's because the new research suggests that inflammatory systems need a reasonably high level of exposure to common everyday germs and other microbes to develop and work properly in the body.
"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 evolutionary history to function optimally in adulthood," stated
McDade.
The Northwestern University researchers specifically studied how environments early in life might affect production of C-reactive protein (CRP), a protein that rises in the blood due to inflammation, in adulthood. Research concerning CRP, which is an important part of the immune system's fight against infection, has primarily focused on the protein as a possible predictor of heart disease. Scientists previously have mostly conducted CRP research in affluent settings, including the U.S., where there are relatively low levels of infectious diseases.
McDade and colleagues were interested in what CRP production looks like in the Philippines where residents have with a high level of infectious diseases in early childhood compared to Western countries. However, compared to Western countries, the people of the Philippines have relatively low rates of obesity (which is associated with CRP) and cardiovascular diseases.
How the research was conducted
The research team worked with data from a longitudinal study of Filipinos which began in the 1980s with 3,327 Filipino mothers in their third trimester of pregnancy. The mothers were interviewed about breast feeding and care giving and their households were assessed for socioeconomic levels, hygiene (including whether homes included domestic animals) and how many people lived in the home.
Researchers also visited with the mothers after their babies were born and then every two months for the first two years of the children's lives. From that point on, the researchers followed up with the children every four or five years until the research subjects were approximately 22 years of age. During this entire period, records were kept on the children documenting their height and weight and any infectious diseases they contracted.
Blood tests revealed Filipino participants in their early 20s had CRP concentrations on average of .2 milligrams per liter -- that's about five to seven times lower than the average CRP levels for Americans of the same
age.
"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 adulthood. Without this input, our research suggests, inflammation 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." (Februari 2010)
