|MadSci Network: Microbiology|
What a great question! Body odour is related to bacteria associated with the sweat glands. Bacterial growth around these sweat glands results in production of body odour. The apocrine glands, found mainly in the underarm and genital regions, are most commonly associated with body odour. Bacterial populations in these warm humid areas is relatively high. The bacteria that are commonly found in this environment are: micrococci, staphylococci, aerobic and anaerobic coryneforms as well as pityrosporum species (to find specific information about some of these species click here or consult The Bergy’s Manual of Determinative Bacteriology). How do bacteria cause odour? The groups of bacteria listed above metabolise compounds found in our sweat and certain resulting by-products (mainly volatile fatty acids) are odour causing. Anyone with active apocrine glands, (apocrine glands become active during puberty) will have some degree of body odour. People who produce a lot of sweat will have higher levels of bacterial growth and hence more body odour. Therefore body odour is directly related to the amount a person perspires. Does the composition of bacterial populations vary depending on human populations? Individual species and strains of bacterial will vary greatly amongst individuals, however the genera and general types of bacteria (i.e. micrococci, staphylococci, aerobic and anaerobic coryneforms) will remain the same. I could not find research documenting differences in the microbial populations living on the skin of Asians vs. North American individuals. It is an interesting question, though. Research I did find indicates differences in body odour from different human populations may be the result of differences in diets. Research has shown that diet will affect body odour. This is likely due to compounds found in the sweat that are produced as a result of the individuals diet. These compounds may be metabolised by bacteria to produce unique or strong odours that are not found in people with different eating habits. Some components of diet that can relate to body odour are: garlic, onion, spicy foods, curry, or alcohol. Therefore differences in body odour amongst human populations may be due to differences in microbial populations and can be related to differences in diets. I have listed a reference to an article that I believe may help answer your question in greater detail and should provide you with additional references. You may also want to search the scientific literature using PubMed . Try using key words such as body odour and bacteria in the same search. Hope this helps answer your question, you certainly asked an interesting question. Chris
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