American researchers suggest, contrary to assumptions based on earlier studies, ultra-clean, ultra-hygienic environments in childhood contribute to higher levels of inflammation, which in turn increase the risk of wide ranging diseases in adulthood. Inflammation occurs when the body is fighting infection or injury.

Lead study author Thomas McDade, says, exposure to infectious microbes early on in life offers protection from cardiovascular diseases that could lead to death in adulthood.

According to the research, to guide the development of inflammatory systems, a higher level of exposure to common everyday bacteria and microbes is required.

Using data from a longitudinal study of Filipinos that tracked participants in utero through age 22, the researchers examined C-reactive protein production i. e. a protein whose levels rise as a result of inflammation, and which is a risk factor for heart disease. In comparison with western countries, the Filipinos have a higher level of infectious diseases in early childhood.

McDade says, blood tests showed C-reactive protein to be at least 80% lower for study participants in the Philippines in young adulthood, relative to their American counterparts.

In conclusion, the study recommends letting children play in the mud and get a daily dose of germs and bacteria, which could help protect them for heart disease later in life.