Thursday, January 31, 2013

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. 


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

Thursday, November 29, 2012

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.
Come out smelling like a rose
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. There will be more to come.

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


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

Wednesday, May 9, 2012

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:

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.

e-mail to
 for more information

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.

Saturday, December 24, 2011

The smell of Christmas

How does Christmas smell like? 

Like cinnamon! So say studies by European scientists  [1-3]. And even though the smell of cinnamon is described as "pungent" (besides "warm", 'sweet", and "spicy"), it fires up our brains, evoking a joyful Christmas mood and making us more generous. 

Cinnamon is classified as a stimulant. Smelling and tasting cinnamon could enhance attention and virtual recognition memory [4], at least in comparison to smells of peppermint, jasmine or cherries. In addition to its many healthy properties - like fighting E.coli in unpasteurized juices, lowering concentration of  fasting glucose, triglycerides, and total cholesterol - Cinnamon can make you feel fuller for longer [5]. So for those of us hoping to lose some weight - a cinnamon-flavored floss would be a good replacement for a Christmas desert.

Aggregate correlations - aka experience of the crowds analyzed in Aurametrix - tell many good things about Cinnamon. For example, that it led to less severe joint pain and helped with bad breath. Although - in higher concentrations - it was the reason of a yellowish skin.

Unfortunately for those with digestive problems, other Christmas-flavored foods seemed to have more side effects. Aurametrix correlations for Apple told that exceeding sensitivity thresholds could lead to gas, fecal and musty smell (was this why an apple a day kept the doctor away?). Too much orange was associated with bloating, indigestion and yellow stool. Pumpkin, on the other hand, lead to slightly better flavored gas!

With more daily observations entered by the users, Aurametrix will make more correlations between wellbeing and food flavors. But for now -

Merry Christmas! And let's smell some cinnamon!


1. Seo HS, Buschhüter D, & Hummel T (2009). Odor attributes change in relation to the time of the year. Cinnamon odor is more familiar and pleasant during Christmas season than summertime. Appetite, 53 (2), 222-5 PMID: 19576937

2. Martin Lindström, Philip Kotler. Brand Sense: Sensory Secrets Behind the Stuff We Buy. Simon and Schuster, Feb 2, 2010

3. Idle JR. Christmas gingerbread (Lebkuchen) and Christmas cheer--review of the potential role of mood elevating amphetamine-like compounds formed in vivo and in furno. Prague.Med Rep. 2005;106(1):27-38.

4. Phillip Zoladz.  2003-2004 Allyn & Bacon Award Abstracts. Impact of the Chemical Senses on Augmenting Memory, Attention, Reaction Time, Problem Solving, and Response Variability: The Differential Role of Retronasal Versus Orthonasal Odorant Administration

5. Hlebowicz, J., Hlebowicz, A., Lindstedt, S., Bjorgell, O., Hoglund, P., Holst, J., Darwiche, G., & Almer, L. (2009). Effects of 1 and 3 g cinnamon on gastric emptying, satiety, and postprandial blood glucose, insulin, glucose-dependent insulinotropic polypeptide, glucagon-like peptide 1, and ghrelin concentrations in healthy subjects American Journal of Clinical Nutrition, 89 (3), 815-821 DOI: 10.3945/ajcn.2008.26807

6. Khan A, Safdar M, Ali Khan MM, Khattak KN, Anderson RA. Cinnamon improves glucose and lipids of people with type 2 diabetes. Diabetes Care 2003;26:3215–8.

7. Catherine Ulbricht, Erica Seamon, Regina C. Windsor, Nicole Armbruester, J. Kathryn Bryan, Dawn Costa, Nicole Giese, Joerg Gruenwald, Ramon Iovin, Richard Isaac, Jill M. Grimes Serrano, Shaina Tanguay-Colucci, Wendy Weissner, Heeja Yoon, and Jie Zhang. An Evidence-Based Systematic Review of Cinnamon (Cinnamomum spp.) by the Natural Standard Research Collaboration.  Journal of Dietary Supplements, December 2011, Vol. 8, No. 4 : Pages 378-454 (doi: 10.3109/19390211.2011.627783)

Monday, December 5, 2011

The Road to Ammonia

Why do I smell like Ammonia? This question, in thousands of variations, has been asked over and over again at every major question/answer site, especially teen, bodybuilding and athletic forums.

The Internet provides plenty of opinions.

Medical sites talk about diseases like chronic kidney failure, hepatic cirrhosis or H. pylori infection. Fitness sites recommend drinking more water, reevaluating protein sources and eating more carbohydrates.
What are these diet-odor links? And what's the Science? Ammonia may be formed during the alkaline hydrolysis and deamidation of proteins - by our own metabolism and the metabolism of microbes that call us home. If our kidneys can't handle the load of nitrogen, it's excreted as ammonia in sweat. Excretion increases 10 times as temperature goes from 70 to 100 Fahrenheit.

Aurametrix is a breakthrough analysis tool that correlates users' actions and reactions based on what information they enter into the system. Preliminary correlations in the Aurametrix knowledge base show exactly what's expected: excess protein does lead to ammonia-like odor.

But wait a minute - does it say the same about excess fat?

An  example provided by one of our users is very interesting. The user logged a few foods he thought were contributing to odor. These were different odors according to the user - ranging from "Ammonia-like" to "Fishy", sharp, cloying and stale. Aurametrix, however, recognized that all these odors described by the user may be related to nitrogen-containing compounds.  When these three data points were analyzed along with four foods that the user did not associate with any odors, Aurametrix displayed only one result:

Based on your Aura entries, the following may be contributing to "Ammoniacal odor" in a 3 hour timeframe:

Hexadecanoic acid  - commonly known as Palmitic acid - is one of the most common saturated fatty acids in the Western diet. Palm oil and coconut oil contain especially high levels of this acid. What effect does this acid have on metabolism? It down-regulates glycose metabolism and protein metabolism, affecting Calcium or mRNA binding proteins [1]. So there may very well be a connection!

Want to connect the dots to your own health and wellbeing and see what you have in common with others?

Write to:


Hovsepyan, M., Sargsyan, E., & Bergsten, P. (2010). Palmitate-induced changes in protein expression of insulin secreting INS-1E cells Journal of Proteomics, 73 (6), 1148-1155 DOI: 10.1016/j.jprot.2010.01.012

Trabue S, Kerr B, Bearson B, Ziemer C. Swine odor analyzed by odor panels and chemical techniques. J Environ Qual. 2011 Sep-Oct;40(5):1510-20.

Ito, Shigeji; Kohli, Yoshihiro; Kato, Takuji; Abe, Yoshimichi; Ueda, Takashi
Significance of ammonia produced by Helicobacter pylori. European Journal of Gastroenterology & Hepatology. 6(2):167-174, February 1994.

Qiu, Y.T., Smallegange, R.C., Van Loon, J.J.A., Takken, W. 2011 Behavioural responses of Anopheles gambiae sensu stricto to components of human breath, sweat and urine depend on mixture composition and concentration. Medical and Veterinary Entomology 25 (3), pp. 247-255

Enrique Wolpert, M.D., Sidney F. Phillips, M.D., and W. H. J. Summerskill, D.M. Ammonia Production in the Human Colon — Effects of Cleansing, Neomycin and Acetohydroxamic Acid N Engl J Med 1970; 283:159-164

V Bhatia, R Singh, S K Acharya Liver: Predictive value of arterial ammonia for complications and outcome in acute liver failure. Gut 2006;55:98-104 Published Online First: 15 July 2005 doi:10.1136/gut.2004.061754

Consolazio, C.F., Nelson, R.A., Matoush, L.O., Canham, J.E. Nitrogen excretion in sweat and its relation to nitrogen balance requirements. J Nutr. 1963 Apr; 79:399-406.

Ammonia in personal care products:
After Bite ointments
Hair dyes

Ammonia in household products:
Ammonia Removing Products
Glass Cleaners
Kitchen Cleaners

Saturday, November 5, 2011

What's that fatty odor?

Body odor is closely associated with diet. Deciphering the chemistry of human odor is not an easy task - only about 5% of odorous molecules are usually recovered from collection containers, and not all of the molecules are identified in complex spectra. Volatile fatty acids, alcohols, and aromatic ring compounds comprise a substantial fraction of smelly molecules, yet very little is known about the origin and factors controlling their production in humans. Fortunately for some (and not so fortunately for others), the human nose can capture and discriminate many smell signatures. Could this discrimination be used to connect the dots between diet and body odor? MEBO Research has just started an anonymous study using the Aurametrix health analysis tool to find out.

Aurametrix's knowledge base provides a wide selection of foods and symptoms, including different types of odors recognizable by the human nose. Participants in the study have been recording some of their food intake and activities on days when their symptoms are better or worse than average, entering items they suspect might be contributing to or alleviating their body odor on those days. The tool's analysis engine then lets them explore all the possible cause-effect relationships. In addition, Aurametrix performs automated analyses across the entire user community and displays cumulative results as "aggregate correlations." The figure on the right is an excerpt from these results.

Although the study has only just begun, the preliminary results already look very interesting. One example is fatty odor. Aurametrix linked several dietary chemicals to unpleasant "fatty odor" emanating from skin based on Aura entries of several participants. The top chemicals so far are:  Vitamin K1 (phylloquinone), Octadecanoic acid, FODMAPs, Beta-carotene,  Carbohydrates and Monosaccharides. Another interesting result (although there were fewer observations) is that Vitamin B12 obtained from diet seemed to help prevent fatty body odor.
  • Could Vitamin K1 really contribute to "fatty" odor?  Could 6 observations derived from different users' Auras be just a coincidence? Vitamin K is proposed to increase production of alkaline phosphatase in intestines. This enzyme produces a number of different substances, some of which have a peculiar sweetish smell.  Chlorophyll, usually recommended to combat body odor and supposedly makes odor "sweeter," is an excellent source of vitamin K1. And so is Asparagus that gives urine a disagreeable odor.
  • Octadecanoic (Stearic) acid was also linked to fatty odor in 6 observations. This saturated fatty acid is most abundant in animal fats and cocoa butter, and also in nuts and seeds (peanuts, flax), cheese, cookies and candies. Its smell is fairly mild, yet can be detected by the human nose (Bolton and Halpern, 2010). Besides, it slowly converts in the liver to heart-healthy oleic acid which has a faintly fatty odor with a hint of dead insects. It could also metabolize into other compounds and incorporate into liver lipids or follow alternative routes.
  • FODMAPs, highly fermentable but poorly absorbed short-chain carbohydrates and polyols, were found to be an important dietary factor contributing to gastrointestinal symptoms. Perhaps FODMAPs, carbohydrates and monosacharides in particular could also contribute to odor in the absence of GI discomfort?
  • Beta-carotene is another heart-healthy chemical with anticancerous properties important in human nutrition as a source of Vitamin A. Tobacco, tea, many spices and flowers owe their flavors to chemicals metabolized from beta-carotene. One of such chemicals is warm and woody beta-Ionone that smells of blackberry at lower concentrations and fatty-cheesy at higher concentrations.

The chemistry of odors and their origins is undoubtedly very complex. Yet, these preliminary results show that together we may find the answers to many health-related questions. With more participants, we'll soon connect the dots between diet and body odor. Want to participate? Write to:


Bolton B, & Halpern BP (2010). Orthonasal and retronasal but not oral-cavity-only discrimination of vapor-phase fatty acids. Chemical senses, 35 (3), 229-38 PMID: 20100787

Dunkel M, Schmidt U, Struck S, Berger L, Gruening B, Hossbach J, Jaeger IS, Effmert U, Piechulla B, Eriksson R, Knudsen J, & Preissner R (2009). SuperScent--a database of flavors and scents. Nucleic acids research, 37 (Database issue) PMID: 18931377