Genetics and environment both play a role in the sense of smell

I saw this article a while back and haven’t had time to post a link until now, but I wanted to include it in our series of posts on the genetic variance in the sense of smell (to find the other posts, search for the tag “genetics” on Perfume in Progress).

I’ve posted links to other research demonstrating that genetics helps determine our sensitivity to various aroma molecules, giving each of us a unique sense of smell. New research indicates that the environment we live in may actually change the structure of the olfactory neurons and therefore change our ability to smell, meaning that both environment and genetics play a role. The research was conducted with mice, but presumably researchers will confirm that it applies to humans as well. Here’s a link to the interesting ScienceDaily article titled “Genetics, environment combine to give everyone a unique sense of smell.”

From the ScienceDaily article:
Dr Darren Logan, the lead author on the study from the Wellcome Trust Sanger Institute, said: “The neurons in the olfactory system are highly connected to the neurons in the brain and studying these can help us understand neuronal development. We have shown that each individual has a very different combination of possible olfactory neurons, driven by genetics. In this study we also show that, with experience of different smells, these combinations of neurons change, so both genetics and environment interplay to give every individual a unique sense of smell.”

More research on the differences in our scent perception

A recent article in Inside Science describes more evidence that people experience scents differently. (Perfume In Progress has followed this research topic for a number of years; you can find a series of posts about it by searching for the #genetics tag on our posts.)

In this experiment, researchers broke the common smell of potato chips into three main aromatic molecules that smell like rotten cabbage, roasted potato, and toast when they are sniffed individually. When the three molecules are combined in the right ratio, they smell like potato chips. The researchers measured each person’s sensitivity to each molecule, which varied widely; people could be “tens of thousands of times” more sensitive to one molecule than to another, and each person had a unique sensitivity profile. Despite these different sensitivities to the individual components, three of four people could identify the mixture as potato chips based on their previous experience with eating potato chips. The article says, “Most of us know a potato chip when we sniff it. But at the chemical level, a new study shows, our noses smell quite different things.”

An article from 2013 described a study that found a 30% difference in people’s scent receptors in their noses, showing that genes play a role in why we have these different sensitivities to aroma molecules. The article says, “The human nose contains 400 different olfactory receptors – and Dr Mainland’s team found that changing a single receptor could dramatically change the way a person perceives a smell.”

Just something to think about when you discuss perfume with your friends! 🙂

Some links: Amber Incense review and more on scent perception

Julie of The Redolent Mermaid blog just posted a review of the new SSS Amber Incense. Her blog, which has a pretty new format, features reviews with gorgeous product photography and fun DIY project tutorials.

I also wanted to post a link to a recent article about scent perception because we’ve been covering that topic here on my blog for quite a few years. I’ve been tagging posts with the tag “genetics” to help identify the topic of the genetic basis for scent perception. If you’re interested in that topic you can search for my posts with the “genetics” tag to find more information. This particular article discusses a way to identify people according to their “olfactory fingerprint” because our scent perception may vary enough from one person to the next to make each one of us identifiably unique. An interesting thought! 🙂

Just editing this to add a link to another online article on this same study about our olfactory fingerprint. This is fascinating, “Researchers then repeated that sniff test on another 130 subjects. But this time they did a blood test, too, to figure out each person’s HLA type—an immune factor that determines whether you’ll reject someone’s organ, for example. They found that people who perceived smells similarly also had similar HLA types.” They suggest that taking sniff tests may become a first line medical screening test someday.

Just adding a link to one more article about the olfactory fingerprint.

Update and some links…

I’m making progress on all fronts here (dishwasher installation is in progress at this moment, I’m researching medical insurance, we’re hosting some family visits etc). I’m working on Amber Incense in my spare moments.

I’m very appreciative to see that Robin included Incense Pure on her fall 2014 incense list yesterday along with some other great incense ideas. I’m hoping people will like the new all-natural Amber Incense too.

Last week Mark posted a nice explanation of supercritical extracts and included a fun video by Mane that explains the process. It might be of interest if you missed it.

I wanted to bookmark/link here to another article I’d noticed about the genetic variation in olfactory perception. It’s a topic we’ve discussed here over the years, so I try to tag the studies I notice on this subject.

One more link of interest: recently U.K. perfumer Pia Long was interviewed by Christine of Perfumer Supply House. Pia has worked for Lush Cosmetics (she’s currently at Equinox Aromas) and is an eloquent speaker and talented writer. The audio interview runs long but is quite worthwhile, especially if you are interested in the perfume ingredient regulations issue.

Weekend Update

First I wanted to say thank you to Ida for her lovely review of Ambre Noir on Fragrantica yesterday! I’ve heard from a number of people over the years that they like to use Ambre Noir as a layering fragrance, which makes sense to me.

I’m still testing the new floral scent and tinkering a little bit with the formula. I’ve not had much time to spend on it but am getting close.

A few interesting links that you may have missed recently:

I love natural perfumery ingredients and prefer fragrances that contain high percentages of them, but this post caught my eye because, even though I am a fan of naturals, I still dislike the misuse of the word “chemical.” An Australian chemistry teacher created illustrations of natural foods with accompanying ingredient lists to illustrate that even things like natural raw fruits contain chemicals and that “chemistry is everywhere.” When people say that they want a perfume without chemicals, they really mean that they want a perfume without synthetic chemicals. Or, they may mean that they want a perfume without toxic substances. There are synthetic and natural chemicals, and there are synthetic and natural toxic substances. I don’t want to get into the natural/synthetic debate, but the chemistry teacher’s illustrations do help make his point about the word “chemical.”

Here’s an article about taking the study of the genetic influence on scent perception one step further by trying to understand how some smells (like rotting meat) are genetically hard-coded from birth to be distasteful (at least to most humans!).

Jordan of The Fragrant Man is posting a series on oud on Fragrantica; his series on sandalwood on basenotes was excellent so I look forward to reading the oud series too.

Checking in…

Things are settling down here after the holidays, though I’m trying to tackle the year-end paperwork. I’m also test sniffing the latest ylang/tuberose/jasmine mod. I enjoy white florals in winter because they bring a little bit of summer when the days are short.

I noticed a 60-second Science Talk audio about the genetic influence on how we smell aroma molecules. This topic seems to be getting widespread press lately. I was interested to see that one example they used was beta ionone, saying it smells to some like flowers and to others like sour vinegar. I like beta ionone and use it in a number of scents. It is woodsier and less sweet and powdery than alpha ionone or methyl ionone gamma. All of these ionones have varying amounts of sweet/powdery floral violet notes, fruity notes, orris notes, and woodsy aspects. Some people have told me that ISO E Super smells like vinegar to them, and it sounds like beta ionone can seem that way to some people too. I’ve realized that any component of a blend can be problematic to some while being great to others. It’s also interesting to note that beta ionone is a natural aroma chemical found in things like violets, osmanthus, wine, tobacco, grapes, almonds, peaches, plums, tea, and beer, so both natural and synthetic ingredients can be problematic to some people.

I’ll be away from email for most of Tuesday the 7th but will be back in the afternoon.

Study Finds 30% Difference in People’s Scent Receptors

I’ve been talking about this for years on my blog based on my experiences with testers during the process of creating scents, and the studies keep coming in to support what we perfumistas have suspected for ages: our different sets of scent receptors in our noses make us smell scents differently. A study by Monell Chemical Senses Centre in Philadelphia (published in the Nature Neuroscience Journal) found that 30% of scent receptors can vary from one person to the next. That’s a surprisingly big difference.

We tend to be quick to say that a scent doesn’t smell good on our skin when we dislike something and don’t want to hurt the feelings of fans of the scent, but it can be both our skin and our noses that are different. Sometimes you can put the same scent on two different people and the same nose will smell it differently on those people. But if many different people smell the same scent on a paper strip, taking skin out of the equation, they will experience it differently. Their receptors will pick up different aroma molecules in the scent to different degrees, changing the scent experience.

This is partly why it is impossible to create a universal scent that everyone loves and why we need options to choose from (though maybe not as many options as the crazy explosion of new scent offerings in recent years!). It’s also why you’ll see different people online describe the same scent so differently, and why it’s important to try samples for yourself rather than going by what others say. And of course, personal preferences based on experiences and upbringing are added on top of genetic scent receptor differences, which further complicates the scent experience.

If you are interested in this topic, the article at the link is worth a quick read. You can find other posts on my blog on this topic by clicking on the tag “genetics” below this post.

Checking in, and some perfume industry links

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I’m sorry I’ve been scarce lately. I’ve been busy getting ready for next week’s event at Jessup Cellars in Napa as well as keeping up with orders. The photo above shows the making of carded sample sets for the Jessup event (before sorting into sets of five).

I’ve seen a few interesting reads in the perfume world lately and wanted to post links for those who may have missed them. First, The Washington Post ran an article about a study into how genetics determines our perception of smells. We’ve discussed this topic here on the blog a number of times because I find it fascinating.

Also, a link to a video discussing the state of affairs in the EU with more upcoming restrictions on allergenic ingredients. It says, “European negotiations are ongoing. An initial proposal restricting coumarin and twelve other allergenic substances to 0.01 per cent of a product looks like it has been dropped. This would signal a partial success for the perfume lobby. However, it looks like at least three ingredients will definitely be banned.” And, “It’s a breathtaking battle between well-organized business lobbies and patient groups, between scientific researchers and political powers. The new law will be on the table next year: will it signal the end of Europe’s perfume-makers? Only time will tell.” I wonder how all of this will eventually play out.

More Discussion About Individual Scent Perception

I’ve been talking about the topic of scent perception for several years on this blog, and here’s another interesting, though limited, study showing that we each smell things a little differently. Thanks to Robin at Now Smell This for the link.

This investigation found that almost everyone was anosmic to some ingredient in the study, and those anosmias of course influence the way people smell fragrance blends that include the ingredients they can’t smell. The author said she discovered that she can’t smell galaxolide, which is a common musk (it’s a polycyclic musk very common in laundry products but on the decline in fine fragrance now that we are moving to biodegradable macrocyclic musks instead). I’ve found people are commonly anosmic to things besides musks, like ISO E super, ambroxan, other synthetic ambers, and salicylates. They are less commonly anosmic to naturals since traditional botanical natural extracts are composed of many chemicals, but they can be anosmic to natural isolates that are a single chemical. Sometimes people can also be nearly anosmic to more complex naturals like ambrette seed, being only able to smell them a little bit.

Once again this poll found everyone liked the scent of vanilla; we’ve seen that in previous studies. The author also found that Asians rated the scent of rose higher than other ethnic groups did, and that’s interesting to me because Velvet Rose is very popular with my customers in Japan. I’ve wondered if Velvet Rose received some word of mouth recommendation in that market circle or if there is a cultural preference for rose soliflores too — I’d love to know if rose scents are popular in Japan.

The author also mentions the way people describe scents using different terminology, but you have to be careful there because often people really do smell the same thing but just describe it differently. People who don’t study perfume or scent don’t have the vocabulary that we perfume lovers take for granted, so terms like “green” to describe a smell can seem foreign to them at first, and terms like “aldehydic” won’t be used at all by someone not familiar with fragrance. She mentions isoeugenol, which is an aroma chemical that smells like clove and is used in carnation accords as well as many other types of scents. People can smell isoeugenol and describe it as floral or spicy since it may remind them of clove or of carnation/dianthus flowers. Isoeugenyl acetate is more floral (to my nose anyway), and is gentler.

I have found it interesting to watch these studies continue to trickle in over the years, given that this variation in scent perception is an issue that perfumers have long grappled with. It’s good to see smell research continue; I hope we’ll come to understand how we smell as we research it more.

Here are some of the other posts I’ve made on this topic:
More On The Sense of Smell
Every Human May Have A Unique Nose
Possible Reasons For Why We Differ In Our Perception Of Scents
Our Own Scent Truth

More on the sense of smell

Now Smell This linked to an interesting article today on Yahoo News titled Super Sense of Smell Not Innate (by Marlowe Hood on Wed March 9). The article discusses how perfumers gain much of their ability to detect and identify scents through years of training and experience rather than being born with these skills. It also mentions the ongoing theme we’ve discussed here before concerning the differences in the way people experience the same scents (for example this post and this post and this post).

An excerpt from the Yahoo News article:

“Patrick MacLeod, former head of the Laboratory for Sensorial Neurobiology, near Versailles, says that olfactory thresholds vary dramatically.

“No two people will ever smell the same thing in the same way,” he noted. “When we perceive an odour the exact nature of the sensation that is produced depends as much on the observer as the object.”

In experiments, he has shown that a small quantity of a given molecule may be imperceptible for one person and easily detected by another. For a different chemical, it may be the reverse.

These thresholds can easily vary from one person to the next by a factor of a thousand.

Mac Leod also points out that the human genome contains nearly 350 olfactory genes — far more than for vision or hearing — resulting in highly individualised odour detection.”

When I send samples out to testers, I do see these differences in sensitivities to ingredients. I try to distinguish between people’s preferences and the way they smell a scent because both will determine whether a scent works for them, and differences in people’s skin will add yet another variable. Several questions become relevant. Does the tester like the smell of some ingredient like ambroxan or cosmone musk or jasmine sambac, etc? How strongly does the tester smell it, from being very sensitive to being average to being anosmic to it? And how does it do on the tester’s skin? Of course interactions between ingredients affect the outcome too, so I need to think about both the parts and the whole. It’s a fascinating topic to me.