Researchers find that exposing mothers and infants to probiotic bacteria can promote a healthy immune system and potentially reduce the development of allergies.
Probiotics are bacteria that normally reside in the gut and on other mucus membranes throughout the body. Research has identified many potentially beneficial effects of these probiotic bacteria including production of B vitamins, protecting us against infectious organisms, aiding in digestion, and lowering cholesterol.
Much research has also suggested that the immune system is constantly interacting with the contents of the gut so a healthy balance of bacteria is crucial to optimal immune function.
Numerous studies have found that probiotics appear to reduce the incidence of allergies in those with a genetic predisposition, but quite how they achieve this is unclear. Researchers led by Emma Marschan at the University of Helsinki in Finland recently conducted research to address this issue in a placebo-controlled trial.
The team selected 1,223 women with a history of allergies or a partner who suffered from them and gave them either a probiotic or placebo daily starting when they were eight months pregnant. They also gave the same doses to the 925 children of the women who stayed in the study every day for six months.
The children were followed up to the age of two and given regularly medical assessments to look for signs of allergies.
The results showed that children given the probiotic were 30% less likely than their untreated counterparts to develop the itchy skin condition atopic eczema, which is often an early sign of vulnerability to allergies. Atopy is a general allergic hypersensitivity that usually manifests as eczema, allergic rhinitis (hayfever), and asthma. An individual may have only one of these or in some cases all three. There is a strong inherited component to atopic illness with the risk of a child developing the condition increasing dramitically if one or both parents have it.
Marschan and colleagues also tested the blood of 98 of the infants selected at random and found that key proteins which stimulate the immune system and the inflammatory response were 50% higher on average in the blood of probiotic-treated infants than in placebo-treated infants.
Researcher Errki Savilahti commented: "It seems clear that we need to stimulate the infant's immune system as early and as vigorously as is safe, for inflammation seems to go hand in hand with allergy prevention."
The results seem to support the 'Hygiene Hypothesis' which suggests that the increasing incidence of allergies in modern times are the result of a lack of exposure to microbes in early life when our immune systems are developing. With the widespread use of anti-bacterial cleaning products, sterilized foods and kids spending more time indoors playing video games and watching TV and less time outdoors playing in the dirt they simply aren't exposed to as many microbes as kids only a generation or two ago would have been.
It's suggested that this lack of exposure to pathogens in early life results in the immune system not learning how to recognise and respond to threats as it should and increases the chances of it directing its defences against harmless substances such as pollen, dust, and foods. In other words allergic reactions.
Immunologist Anthony Horner, from the University of California in San Diego, said that in the past people ate food loaded with bacteria and developed immunity to cope with it.
He said: "These probiotics are probably closely mimicking the effects of regularly eating unpasteurised and unsterilised food."
The research suggests that even when allergies run in the family, probiotic products taken during pregnancy and early in the child's life may reduce the risk of them going on to develop allergies.