Odors and Infections

Many illnesses are associated with distinct odors. Especially those caused by infectious or opportunistic microbes inside the body or on its surfaces.  Body odor of someone infected with C. difficile, for example, can appear "swampy", Rotavirus gives sharply sweet putrid smell that some people associate with wet dogs. H. pylori can create a range of foul odors, and pseudomonas infections can smell like grapes and bitter almonds. 

Infections like C. difficile are usually linked to a general imbalance of the intestinal microbiota, often referred to as dysbiosis. This means that the odors could be coming from several microbial species, hence could be different for different individuals. Does it mean odor-based diagnostics will never be enough specific?

Not according to a 2-year-old beagle from Netherland, named Cliff. After just a little over two months of training, the beagle learned to identify the C. diff toxin by sniffing people or their samples. During one test, he was able to identify 25 out of 30 infected patients and 265 of 270 non-infected individuals. He also correctly identified 50 of 50 C. diff positive stool samples and 47 of 50 samples from people that did not have this infection. That's sensitivity of 100% for samples and 83-93% for sniffing the air around the patients, and a specificity of 94-100%! And it took him less than 10 minutes to accurately perform 300 diagnostic tests.  

Dogs already do the dirty work with detecting molds. They can examine an office building with 200 rooms in just 8 hours, a task that would take us several days of measuring  moisture, probably without any result. Electronic noses would be of great help and many years of research are finally being translated into useful technologies - to be integrated with refrigerators and mobile phones. But until we are able to build smart devices to detect odors without labor-intensive dog training, perhaps we could train our own nozzles. Studies have shown we do get better with practice. 


REFERENCES

Bomers MK, van Agtmael MA, Luik H, van Veen MC, Vandenbroucke-Grauls CM, & Smulders YM (2012). Using a dog's superior olfactory sensitivity to identify Clostridium difficile in stools and patients: proof of principle study. BMJ (Clinical research ed.), 345 PMID: 23241268

Poulton J, Tarlow MJ. (1987) Diagnosis of rotavirus gastroenteritis by smell. Arch Dis Child. 1987 Aug;62(8):851-2. PMID: 3662595

Arnaud Tognetti, Megan N Williams, Nathalie Lybert, Mats Lekander, John Axelsson, Mats J Olsson, Humans can detect axillary odor cues of an acute respiratory infection in others, Evolution, Medicine, and Public Health, Volume 11, Issue 1, 2023, Pages 219–228, https://doi.org/10.1093/emph/eoad016

Come out smelling like a rose

You are what you eat. And you smell like your food. Well, it's actually a bit more complicated - as we emit complex combinations of volatile chemicals produced from food by our own metabolic system as well as microbes that call us home. Same foods can be translated into a wide range of odors, depending on the individual. People exhibit a large variety of smells, much more diverse than animals or plants. Thanks to variations in our digestive enzymes, diets, supplements, medicines, perfumes, detergents, clothes, cars and a lot of other chemicals we are exposed to via different routes. And there are many ways to smell of a rose - for example, by putting a few petals in the pocket, wearing Sa Majeste La Rose or drinking rose oil.

As confirmed by gas-chromatograph mass spectrometry using a thermo desorption system and a selective ion mode (Akiyama et al., 2006), linalool, citronellol and geraniol, which are the main components of rose essential oil, are emitted from our palms after an oral intake of rose oil. The aroma starts to increase 30 minutes after ingestion and reaches its peak within an hour, then slowly decreases, wearing off more than 100 times in the next 6 hours. Citronellol seems to evaporate the fastest, and linalool lingers a little longer than the other two compounds, but, of course, this may very well differ for different individuals.

A new "functional food" - Deo Perfume Candy  - is an attempt to take the sciences of smells and foods to a whole new level by creating a sweet treat intended to make you smell good. The main active ingredient of this candies is Geraniol. It is extracted from rose oil, which in its turn is extracted from real rose petals - one gram of oil per two thousand petals. Small amounts of citric acid and tangerine oil are added for more flavor. An healthy food company Beneo partnered with Bulgarian candy maker, Alpi, to develop this nutricosmetics  treat. At present it is sold exclusively on Amazon and has already collected 5 reviews - ranging from a praise of the observed fresh-just-showered smell to complaints of the need to eat a buck load of candies to see some kind of effect. Does it really work? It might for some of us. With the right chemistry and metabolism, and the right combination of everything else. You can enter it in Aurametrix as Deo Perfume Candy and check back later to see how it worked for others. Or just log what you normally eat and wear to find how your body could react to Geraniol.

You might want to compare it with “Fuwarinka” or Otoko Kaoru's chewing gum - despite a name that translates to "man smell" it also contains rose-flavored geraniol. Although one tester reported to smell like an apple-flavored soap after chewing it.  You can also experiment with the "coming soon" edible perfume from Netherlands, and its mystery ingredient (transformed by the body enzymes and excreted through the skin’s surface through perspiration). There will be more to come.

The possibilities are endless and so are the human odor outcomes.

REFERENCES

AKIYAMA, A., IMAI, K., ISHIDA, S., ITO, K., KOBAYASHI, T., NAKAMURA, H., NOSE, K., & TSUDA, T. (2006). Determination of Aromatic Compounds in Exhalated from Human Skin by Solid-Phase Micro Extraction and GC/MS with Thermo Desorption System BUNSEKI KAGAKU, 55 (10), 787-792 DOI: 10.2116/bunsekikagaku.55.787

Chemicals in food affecting body odor

Volatile compounds (complex organic and simple like hydrogen sulfide and ammonia), together with sugars and acids, are the main chemicals determining the characteristic aroma of food, as well as odors related to human body.

The bad smells are generally the result of a combination of odorous sulfur compounds and ammonia.

Volatile sulfur compounds are produced through bacterial metabolism of sulfur amino acids such as cysteine and methionine. High sulfur content in food is another source.

Choline  - a quaternary saturated amine - can lead to increases in the amount of trimethylamine responsible for sweet and sickly, fish-like smell.

How to estimate the amount of choline, sulfur and sulfur-containing aminoacids in your food?
You can do it easily with Aurametrix.
Watch these videos:

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!

REFERENCES
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.