30 percent of adults and 40 percent of children are affected by allergies and the incidence of allergic reactions is on the rise. In fact, allergic disease, such as asthma, is among the most common chronic diseases in Western societies. Allergies are more than a minor annoyance; they can have very serious health consequences, most notably when anaphylaxis occurs. Anaphylaxis is a life-threatening allergic reaction to medicine, food, insect bites, or environmental toxins and is a compelling reason to never take allergies lightly.
The rising incidence of allergies has not gone unnoticed. At first, health researchers noticed rising rates of asthma and allergic rhinitis (commonly known as hay fever) , but the prevalence of all forms of allergy (food and medicine allergies included) is trending similarly. Interestingly, one proposed explanation for this trend is a reduced exposure to allergens because of improved hygiene. We’ll take a closer look at this “hygiene hypothesis” and how probiotics might be a solution to the problem.
The Hygiene Hypothesis
The concept of the hygiene hypothesis applies to industrialized nations, as these countries have become more hygienic through receiving less exposure to environmental microbes. Some actions that contribute to the hypothesis are getting regular vaccination against disease, cleaning our bodies and environments more thoroughly, using antimicrobial medication, and consuming more sterile foods. As a result, we have significantly reduced our exposure to a wide variety of microbes. Historically, humans have evolved in an environment full of bacteria and our immune systems have concurrently evolved to protect us from those bacteria.
Advances in medicine, food processing, and personal hygiene have changed our environment significantly, as we now lack exposure to nearly as many microbes. Ultimately, the hygiene hypothesis implicates the changed environment as a factor in the rising incidence of allergies. In the absence of microbial exposure, our developing immune systems do not learn how to respond to the many different microorganisms that we contact every day. In some cases, this means our immune systems are hyper-sensitive and react to harmless microbes.
Recent research supports the hygiene hypothesis. Avoiding allergens has been shown to reduce the symptoms associated with allergies without actually treating the underlying disease, while exposure to allergens has been linked to improved tolerance. Ethical reasons prohibit the exposure of people to allergens in an attempt to treat their allergies, so health researchers are investigating safe alternatives. One such alternative is probiotic treatment.
Probiotics as an Allergy Solution
A wealth of recent research has been dedicated to understanding the possible link between probiotics and allergy relief. The reasoning behind using probiotics to prevent or treat allergies stems from the role of microflora in the gut in the functioning of our immune systems. Healthy intestinal bacteria have been identified as an important barrier that protects against incoming microbes including various pathogens. Moreover, we know that the intestines contain the most antibody-producing cells in the human body, and recent research suggests probiotics stimulate the immune system and may therefore stimulate antibody production.
Another hint that probiotics may be useful in allergy prevention and treatment stems from research that shows children with allergies have fewer different strains of healthy bacteria in their gut than children with no allergies. There is a difference in the composition of intestinal bacteria of children with less allergies and children with more allergies. While researchers are convinced there is a connection between intestinal bacteria composition, immune functioning, and ultimately allergic responses, the nuances of that connection are still unclear.
Nevertheless, certain probiotics have been demonstrated to reduce the risk of allergies in children. Most notably, researchers have found infants whose mothers were given probiotics before birth and during breastfeeding were less likely to develop eczema than infants who were not exposed to probiotics. However, the mechanism of anti-allergic probiotic action is not clearly understood and more research must be conducted.
 Platts-Mills, T. & Commins, S. (2016, January 19). Increasing prevalence of asthma and allergic rhinitis and the role of environmental factors. Received from http://www.uptodate.com/contents/increasing-prevalence-of-asthma-and-allergic-rhinitis-and-the-role-of-environmental-factors