Showing posts with label IBS. Show all posts
Showing posts with label IBS. Show all posts

Tuesday, January 10, 2012

Studying body odor: one step at a time

Unpleasant body odors could be a sign of a disease. But even when the cause of the disease is known - an example is trimethylaminuria or TMAU - there are no one-size-fits-all solutions. Elimination of choline and other essential nutrients from diet can be harmful and unhelpful.  Everyone has their own unique needs, with individual combinations of foods, activities and optimal environmental conditions.

An earlier survey of about 100 body odor and halitosis sufferers indicated stress (34%), food (25%) and environment, including the weather and perfumed products (15%) as main triggers of odors. 23% of sufferers did not know what the trigger was.

Our study seems to have less unknowns. As you see from the picture, 60% of participants have both body odor and halitosis. Only 22% of participants were diagnosed with TMAU, one third has IBS, one third has environmental sensitivities (mostly pollen and mold allergies, but some have dust mite and pet allergies and chemical sensitivities). Over 60% of participants reported sensitivities to specific foods. Most frequent was lactose sensitivity.

It is known that a specific diet, infections and diseases have major impact on variations in human body odor.  Some of our early results on fatty and ammonia types of odors identified a few food ingredients and their maldigestion as potential causes. Our next posts on musty and smoky odors, as well as unpleasant odors in general will tell more.

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And stay tuned for results!

Jan Havlicek, & Pavlina Lenochova (2008). Environmental effects on human body odour Chemical Signals in Vertebrates DOI: 10.1007/978-0-387-73945-8_19

Havlicek, J., & Lenochova, P. (2006). The Effect of Meat Consumption on Body Odor Attractiveness Chemical Senses, 31 (8), 747-752 DOI: 10.1093/chemse/bjl017

Moshkin M, Litvinova N, Litvinova EA, Bedareva A, Lutsyuk A, Gerlinskaya L. Scent Recognition of Infected Status in Humans. J Sex Med. 2011 Dec 6. doi: 10.1111/j.1743-6109.2011.02562.x.

Wednesday, February 2, 2011

Colonoscopy for everyone! ..or Gonna Buy Me A Dog

New research from Japan brings good news: dogs can be almost as accurate as a colonoscopy exam.
In patients with colorectal cancer (CRC) and controls, the sensitivity of canine scent detection of breath samples compared with conventional diagnosis by colonoscopy was 0.91 and the specificity was 0.99.
The sensitivity of canine scent detection of watery stool samples was 0.97 and the specificity was 0.99.
The accuracy of canine scent detection was high even for early cancer. Canine scent detection was not confounded by current smoking, benign colorectal disease or inflammatory disease.  
As simple as that: exhaling 100-200 ml into a breath sampling bag and storing it in a Ziploc bag at 4°C until a trained dog has a change to sniff it can be enough for diagnostics. Just one breath sample! And it was almost as good as a watery stool sample obtained during colonoscopy or this joyous examination itself.

There have been many research studies that dogs, rats and even moth can detect scents pertaining to human disease. Ordinary household dogs can be trained to distinguish breath odors (McCulloch et al 2006). For some cancers, sensitivity can be as high as 100% (Horvath et al 2008).

Unfortunately, sophisticated mass-spectrometry, gas chromatography and software tools interpreting the signals are still not as good as our four-legged friends that are never getting lost in the noise of disease-unrelated flavors.
But we are getting better in identifying specific chemicals responsible for various conditions - from alkanes  - such as pentane in breath of IBD patients and polystyrene foam or aromatic components of petroleum in cancer breath to blends of fatty acids like oleic and linoleic acids forming the smell of death.

Perhaps pet rats will find their use as pocket doctors before men-made sensors are developed to cope with infections, medical conditions, even fear and anxiety that also have a distinctive odor signature. In any case, Dr. Sonoda and his colleagues bring us a reassuring word that not every frequent visitor to the GI doctor's office will have to experience the joys of a colonoscopy.

Sonoda H, Kohnoe S, Yamazato T, Satoh Y, Morizono G, Shikata K, Morita M, Watanabe A, Morita M, Kakeji Y, Inoue F, & Maehara Y (2011). Colorectal cancer screening with odour material by canine scent detection. Gut PMID: 21282130

Other published literature on olfactory signatures in gastrointestinal disease:

Cheu HW, Brown DR, Rowe MI (1989) Breath hydrogen excretion as a screening test for the early diagnosis of necrotizing enterocolitis. Am J Dis Child 1989;143:156–9.

Pelli MA, Trovarelli G,, Capodicasa E, Breath alkanes determination in ulcerative colitis and Crohn's disease. Dis Colon Rectum 1999;42:71–6.

Pelton NS, Tivey DR, Howarth GS, A novel breath test for the non-invasive assessment of small intestinal mucosal injury following methotrexate administration in the rat. Scand J Gastroenterol 2004;9:1015–16.

Tibble JA, Sigthorsson G, Foster R, Use of surrogate markers of inflammation and Rome criteria to distinguish organic from nonorganic intestinal disease. Gastroenterology 2002;123:450–60.