SUBSTANTIALITY OF HYGIENE HYPOTHESIS AND THE NATURAL SUSTENANCE OF GUT MICROBIOME
Hygiene is the practice of keeping oneself and the surroundings clean especially in-order-to prevent the spread of disease. In today's world, we have fixed our minds that unhygienic habits pave the way for disease. Man wants to make everything "too clean" with anti- microbial creams, sanitizers and soaps. Even the rate of atopic diseases seems to increase every year. During the olden times, man was not exposed to greater sanitation levels as of now. They lived near animals, drank unpasteurized milk, walked barefoot, slept on floor and toiled in mud. They were also exposed to atopic diseases but compared to the present health conditions, the former had decrease in allergy and death. This led to hygiene hypothesis.
THE HYGIENE HYPOTHESIS - MICROBES OUR FRIENDS FOR SURVIVAL
Hygiene hypothesis was founded in 1989 by epidemiologist Dr. Strachan. Hygiene hypothesis states that, "Reduction or lack of infectious and microbial exposures early in life may be associated with increased risk of allergy, asthma and immune diseases". According to this hypothesis, the developing immune system must have early microbial exposure so that it evokes a response and not over reaction (hyper sensitivity). Tucson Childern's Respiratory Study, done in day care centers in USA, states that children had more frequent colds at age 2 and fewer colds at age 6-11. Observing the immune responses, atopic diseases occur due to an over reactive TH2 1 response but early exposure to microbes cause stimulation of TH1 arm and induces tolerance. Antibiotic drugs do not differentiate between healthy and not healthy bugs. They induce dysbiosis and microbial deprivation of natural flora. Good bacteria are lactobacilli, streptococcus thermophilus, bifidobacteria etc. We should remember that even when a healthy person has a good immune system, there is no complete evacuation of gut bacteria. Therefore gut bacteria is very important for our survival and good health.
Considering the substantiality of hygiene hypothesis in our present day-to-day lives, it is noted that vaginal delivery helps to deliver bacteria of the mother’s birth canal to the baby and breast feeding promotes effective passage of microbes through milk while caesarean sections and artificially fed infants are more prone for allergies. Smaller families results in less transfer of infections from siblings. Sometimes our “too clean” habits cause harmful effect to the good bugs. Research states that Paracetamol tablets taken in early childhood produce constant wheeze in adulthood. Sanitizers should be used only if there is no availability of soap. Make sure that there is 70% alcohol content in the sanitizer. Continuous scrubbing of the hands with soap everyday should be avoided. Stress can stimulate or depress the passage of food through the gut thereby changing the floral integration.
SUSTENANCE OF GUT MICROBIOME
The proper alignment of the gut bacteria is useful to prevent and treat Irritable Bowel Syndrome, peptic ulcer, diarrhoea etc. Natural foods are said to stabilize the microbial levels namely - Prebiotics which are indigestible carbohydrate fibers which act as food for the microbes. Prebiotic fibers are also converted to short chain fatty acids called butyrate which is anti-inflammatory and blocks cancer cells. Prebiotic foods include legumes, beans, onions, oats, peas, asparagus, bananas etc. Prebiotics are live bacteria found in certain foods like yogurt (made from milk that has been fermented by friendly bacteria namely lactic acid bacilli). But processed yogurt does not contain microbes. Kombucha (fermented black or green tea) contains bacteria and yeast. Pickled cucumber, fermented rice gruel has many friendly bacteria, vitamin K, B12 and B6 content. Buttermilk made from leftovers of butter is of two types – traditional buttermilk (grandma’s probiotic) is recommended and cultured buttermilk found in supermarkets contains no probiotics. Further symbiotics which contain both prebiotic and probiotics together can be supplemented. Postbiotics are non living bacteria or the byproducts of probiotic organisms. Fermented foods should not be taken in cases of SIBO (Small Intestine Bacterial Overgrowth), helminthic intolerance and yeast overgrowth.
Hygiene hypothesis taken in a wrong way may discourage hygienic practices which are mandatory. Therefore this hypothesis has not been completely made into practice but there is substantial evidence supporting the hypothesis and Thomson Reuters Web of Science states that, use of the term “Hygiene hypothesis” in scientific literature has increased three fold over the past 10 years. Therefore, let us realize that “too clean” can never be healthy.
1. TH, T : T-Lymphocyte, H-Helper.
Textbook of Medical Physiology, Author : Guyton and Hall, South Asian Edition, P-134, Section III.
MERLIN BIJU., IV BNYS