Wednesday, January 31, 2018

Blended teas and drug/diet interactions

Have begun working on a course for the World Tea Academy on blending flowers, fruits, and more, into teas, including teas from both Camellia sinensis and rooibos. I think I will add hibiscus into the mix as well. 

The course is going to begin with a discussion of the classic English blend, Earl Grey, a combination of black tea with bergamot, so I have been looking into the chemistry of bergamot in more detail.

As you know, bergamot is a member of the citrus family, and its oil contains a host of chemicals that are common to many different kinds of citrus, grapefruit in particular. In fact an important chemical, bergamottin, gets its name from the bergamot, but is more abundant in grapefruit. It is one of a class of compounds called furanocoumarins.

The reason that bergamottin is important is that—together with 6',7' dihydrobergamottin, another chemical in bergamot and grapefruit—it inhibits an essential enzyme family involved in drug metabolism, called cytochrome P450.

The consequences of this inhibition are neither simple and nor predictable. For example, some medications are detoxified by cytochrome P450 enzyme in the gut and possibly the liver, so inhibition of these enzymes by bergamottin and similar compounds will increase the blood levels of the drug you get from a given dose. For some drugs the result is toxicity, which may be serious and even possibly life-threatening. However, for other drugs, inhibition of cytochrome P450 may mean that you could get the desired effect at a lower, less toxic dose.

Bergamot —Image from Wikipedia.
On the other hand, there are drugs that require metabolism by cytochrome P450 enzymes in order to be active. For these drugs, consumption of a cytochrome P450 inhibitor means you would actually have to increase your dosage for the drug to be effective. 

Look up "grapefruit juice effect" in Wikipedia to get an idea of what drugs are involved, as well as more information about the bergamottin/drug interactions.

Incidentally, there are other common additives to teas that may have the same effects, including angelica in particular.*

While I have not found reports associating reasonable amounts of Earl Grey tea with drug metabolism problems, you should be aware that these problems may exist, and not just with Earl Grey, but with other blended teas and herbal teas.** 

And always, consult your doctor about drug/diet interactions! 

* Guo LQ, Yamazoe Y. Inhibition of cytochrome P450 by furanocoumarins in grapefruit juice and herbal medicines. Acta Pharmacol Sin. 2004 Feb;25(2):129-36.

** Rainer Nowack, Barbara Nowak. Herbal teas interfere with cyclosporin levels in renal transplant patients. Nephrology Dialysis Transplantation, Volume 20, Issue 11, 1 November 2005, Pages 2554–2556.

Friday, January 26, 2018

How strong is the smell of new-mown grass to you?

When grass is cut, a chemical called leaf alcohol (chemically speaking 3-cis-hexen-1-ol or (Z)-3-hexenol) is released into the air. It's the plant's way of signaling that it has been injured. Tea leaves do the same thing. You're probably not surprised to find out, then, that the chemical is particularly prominent in green teas, but it's present in most other teas as well.*

According to The Good Scents Company, the taste (= flavor) of this chemical is "Fresh, green, raw, fruity with a pungent depth." In other words, it activates not just your odor receptors but also your cool/cold receptors, hence "fresh," "raw," and "pungent."

Turns out that to some people the smell of leaf alcohol is more intense than it is to others. People who are more sensitive tend to consume cucumbers a little more often, perhaps because for them cucumbers are more flavorful?** Here's the graph:

The difference looks slight, but it turns out that statistically it is quite significant.

The odor receptor for cis-3-hexen-1-ol is named OR2J3. Changes in the structure of this receptor lead to a 25% decrease in the ability to smell this chemical!***

There a single genetic change that is in strong linkage disequilibrium with these changes in OR2J3. Linkage disequilibrium means that if you have a version of the gene change in one place in your DNA, you are very likely to have a gene change in another location in your DNA. You can find this linked genetic change in your raw DNA report from both Ancestry DNA and 23andme, at rs7766902.

I've included rs7766902 in my survey on tea preferences and genetic changes. If you have done either 23andme or Ancestry DNA, would love to have you take the survey so we can find out whether a change in rs7766902 leads to preferences in tea just as it does for cucumbers!

Here's the link to the survey:

Be ready to take a few minutes to find your raw data, but I think finding out why you like what you like will be worth it!

Thanks so much --

* Chi-Tang Ho, Xin Zheng, Shiming Li. Tea aroma formation. Food Science and Human Wellness 4 (2015) 9–27.

** S.R. Jaeger, B. Pineau, C.M. Bava, K.R. Atkinson, J.F. McRae, L.G. Axten, S.L. Chheang, M.K. Beresfor*d, M. Peng, A.G. Paisley, H.C. Reinbach, S.A. Rouse, M.W. Wohlers, Y Jia, R.D. Newcomb. Investigation of the impact of sensitivity to cis-3-hexen-1-ol (green/grassy) on food acceptability and selection. Food Quality and Preference 24 (2012) 230–242.

*** Jeremy F. McRae, Joel D. Mainland, Sara R. Jaeger, Kaylin A. Adipietro, Hiroaki Matsunami, Richard D. Newcomb; Genetic Variation in the Odorant Receptor OR2J3 Is Associated with the Ability to Detect the “Grassy” Smelling Odor, cis-3-hexen-1-ol. Chemical Senses 37 (2012) 585–593.

Wednesday, January 17, 2018

Hot Tea Month Survey Time!

Is there a genetic basis for hot tea preferences? Have you had your DNA tested? If so, you can help us discover the answer!.

I've chosen three genetic markers—single nucleotide polymorphisms or snps—that may modify how we experience flavors and thus our tea choices.

For example, there is a single snp change that makes you unable to smell beta-ionone, a  floral chemical that's in all Camellia sinensis teas. I have this snp change, so I cannot smell beta-ionone. I've found that the aromas of teas are not quite so flowery to me as they are to other people—this may be why.

The other two snps in the survey are in genes that influence how many taste buds you have on your tongue, so the overall intensity of flavors for you, and how you experience the smell of cut grass—a smell that is typical of green teas. 

(Note that I'm not collecting any identifying information and no IP addresses, so the results I receive will be anonymous.)

==>> The following instructions are for 23andme and AncestryDNA. If you have done one of the other DNA tests, check to see whether they offer results for the snps listed below.

Before starting this survey, go to either 23andme or Ancestry DNA, and write down your results for the following so you can insert them in the survey:

     A. Your ethnicity (areas only—don't need percentages)

     B. The results for the following snps: 

  • rs227433 
  • rs6591536
  • rs7766902

Here's how to find your raw data concerning these snp's:

If you have completed 23andme:

  1. Click on “Tools” in the header of your page. 
  2. Scroll down to “Raw Data” and click on “Browse your data.” 
  3. You will see a box with “Search your data for a specific gene or marker (SNP)
  4. Type in the letter-number combinations (for example rs227433), then scroll down to find the letters entered under “Your genotype” in the table.

If you have completed Ancestry DNA:

  1. Click on “Settings” on the right hand side of your AncestryDNA homepage.
  2. On the right hand side, click on “Download Raw Data.”
  3. Once you have entered your password in the pop-up box, you’ll receive a confirmation email and download instructions at the email address associated with your Ancestry account. You will then be able to search for a specific DNA result (for example rs227433).

Now click here for the survey:

Once you have completed the survey, you will see "instant results" that show you how many people like each kind of tea, etc. 

Once I have collected data from 100 people, I will be able to tell you whether there are any relationships among the results, in other words whether the snps have anything to do with tea preferences, and I'll let you know!

Thank you so much for participating! 

Wednesday, January 10, 2018

Call them tea tables!

We call them coffee tables...but if you are a tea drinker, why not call them tea tables?

Friend of Pairteas and guest blogger Mark, who is a foosball supernerd (see bio below), presents 5 amazing tea tables for your home...As he says:

"When people are designing their homes, they are focused on bedrooms, bathrooms, and kitchen, and somehow, the living room often is left behind. But, there are some tricks you can do to make your living room stand out. For example, a great tea table can make the entire living room shine. A table like that should be a center of the room and it should leave all your guests speechless. So, today I want to show you some of the most amazing tea tables for your home.

Ocean Abyss table
There is something soothing in looking at the ocean and this incredible table represents that perfect feeling. Just imagine drinking tea above marine table which changes its colors depending on where you stand. This calming table is made from wood and colored glass where the glass represents the deep blue sea and the wood represents ocean’s bottom. The only downside of this amazing table is the fact that it doesn’t have any storage, but I think we can get past that.

Ocean Abyss table:
 [My note: this is the table I like best, being a geology buff and loving all things oceanic!]

Foosball tea table
If you want to decorate your man’s room I definitely suggest you do it with this incredibly cool table. Every man is a foosball player and instead of getting him big foosball table you can surprise him with Chicago Gaming table. This table is a combination of foosball table and elegant small table for living room. It looks amazing as a small table and it can provide hours of fun as a foosball table. The table is made from solid wood with tempered glass above the foosball field so you don’t have to worry about spilling on the table or breaking the glass with the ball. Great thing is that you have a shelf below the field for storage.
Foosball tea table:
[My note: I confess I play foosball whenever I get a chance, which is very seldom. If I had this table I'd be playing all the time, and may even forget to keep this blog up! Not to mention that it looks so seriously elegant that people might never guess it is such fun.]

DIY tea table
There is something special about making your own furniture through DIY projects and this table is a living proof for that. A tea table made of crates is simple to make and it looks great, not to mention the storage space you can get with it. For the table you will have to get 4 identical creates and fix them together. You can also put the wheels on the table for easier movement but that is only an option for living rooms without carpets.
DIY tea table: it is a DIY project so here is the link with the instructions
[My note: the orchid is nice, but imagine this table with a small fountain in the middle!]

Oval Mod Swivel tea table
This specific piece is the perfect addition to light colored living rooms because it is in shiny white. The best feature of this table is the fact that it folds in on itself; actually, it has a rotating top so you can have a table twice the size in a few seconds. Even though the idea originates from the 60’s, this table looks absolutely modern and refreshing.

Oval Mod Swivel:
[My note: my grandchildren would have a great time swinging this table's tops around...perhaps not the best idea for tea, but no doubt fun!]

Paper Table
If you love eco-friendly furniture then you will love this table because it is made from recycled paper.  The entire table is made to leave a positive impression because it looks amazing. When you look at the table you will notice holes in it and they aren’t there by chance. Every hole is actually a book or magazine holder so you can store your papers in the Paper table.

Paper table:
[My note: very cool, indeed! Perhaps a papier mâché tray on top to hold the tea cups?]"

Author bio:
Mark Čop is a former professional now hobby foosball player who has a blog about foosball —he loves to share his knowledge about foosball and that is the reason why he writes about it. From foosball history to foosball table reviews, Mark has covered every foosball topic you can think of [and he knows a lot about tables!].  You can check them out on his blog Foosball Zone. Also, if you have any questions you would like to ask him, you can contact him on his Facebook page.


Friday, January 5, 2018

Sniffing oolong

While I was looking for something else today, an article about aroma interactions caught my attention: "Evaluation of the Synergism among Volatile Compounds in Oolong tea."*

A fundamental problem in understanding the interactions of aromas has been whether a compound present at sub-threshhold concentrations can influence the overall aroma of a tea. By sub-threshold concentrations I mean concentrations at which you cannot smell the chemical by itself in a solution.

What the authors this paper did was to have trained smellers sniff the aroma of a Tie Guan Yin with and without added (E)-2-hexenal at a sub-threshold concentration. (E)-2-hexenal is characteristically abundant in green teas. The smellers graded the aroma according to degree of roast, sulfur, sweet, floral, and green and grassy aroma.

As you can see in the diagram below, the "roast" and "sulfur" quality of the tea aroma decreased and the "green and grassy" quality increased markedly in the tea with (E)-2-hexenal added.

To me, (E)-2-hexenal has a pungent "green and grassy" smell by itself, indicating that it activates the cool/cold TRPM8 and TRPA1. In fact, the authors of the paper say that (E)-2-hexenal is referred to as having a "fresh note," a term applied to compounds that activate these receptors.

Among the compounds in oolongs that give a "roast" quality is 2,5 dimethylpyrazine, that activates the "hot" receptor, TRPV1, while the sulfur quality is conferred by dimethyl sulfide, that activates the warm receptor TRPV3.

What I think is happening here is that by activating the cool/cold receptors, (E)-2-hexenal even at this sub-threshold concentration is turning off to some degree the warm and hot receptors. While the overall impression remains that of a moderately oxidized oolong, the tea's aroma profile shifts towards that of a pouchong.**

When Friend of Pairteas Kristin van Eetvelt and her sister-in-law were with me in December we had fun sniffing some of these chemicals and then sniffing an oolong tea (a Tie Guan Yin if memory serves). We all declared that sniffing (E)-2-hexenal (obviously over threshold), followed by sniffing the tea was quite unpleasant, and that the beautiful aroma of the tea was severely dampened. We quickly went back to sniffing one of the floral compounds characteristic of moderately oxidized oolongs. After that the tea itself smelled good again!

* JianCai Zhu, Feng Chen, LingYing Wang, YunWei Niu, ZuoBing Xiao, Evaluation of the synergism among volatile compounds in Oolong tea infusion by odour threshold with sensory analysis and E-nose, In Food Chemistry, Volume 221, 2017, Pages 1484-1490, ISSN 0308-8146,

** Worth noting for you food chemists or just curious people out there: the researchers also subjected the samples to analysis by "electronic nose," which showed that the oolong sample with and without added (E)-2-hexenal had different profiles. These results raise the question to me of whether the addition of (E)-2-hexenal actually altered the content in aroma chemicals in the air above the samples by preventing certain compounds from becoming volatile. However electronic noses using metal oxide systems (such as the one used by the authors of this article) cannot identify specific compounds, because compounds (and especially aldehydes such as (E)-2-hexenal) activate more than one of the electronic nose sensors. Electronic noses of this type are good at determining whether two or more products, say ripe and green tomatoes, are different, but cannot say what exactly those differences are. The question remains in my mind, but I still think the explanation above of the aroma change with (E)-2-hexenal can simultaneously be correct.

Thursday, January 4, 2018

Heat, spice, itching and the "hot" receptor

Here in Massachusetts today, am watching a "bombogenesis" snow episode from the comfort of my apartment, a mug of hot black tea by my computer (BTW, it's Hot Tea Month!). One of the consequences of the cold is dry skin. My dry skin itches like crazy, and after I scratch it feels boiling hot. So I thought I needed to know more about what an itch is and why I get that hot sensation after scratching enough that the itch goes away.*

Turns out that there are (at least) four types of itch. The one I'm experiencing right now is pruritogenic—you can find out about the other kinds at

The diagram below, from that article, shows the mechanism for pruritogenic itch. What fascinated me was that our old friend TRPV1, the "hot" receptor that responds to chili peppers for example, lies right smack-dab in the middle of the pathway that itch sensations follow from skin nerve ending to brain!

Caption from the article: Molecular anatomy of itch. Channels and receptors on the surface of keratinocytes and nerve fibers respond to various mediators. Several examples are provided. The mechanisms by which keratinocytes and neurons communicate with each other are under investigation. DRG, dorsal root ganglia; IL-31, dorsal root ganglia; GPCR, G-protein coupled receptor; TRP, transient receptor potential [TRPV1]. 

The theory about itch is that once you apply pain through scratching, the nerves that communicate pain somehow turn off the signal to the brain coming from the nerves that communicate itch, so you are left with pain (the milder the better of course). 

I think that the reason I feel heat as well as pain after scratching an itch is that the TRPV1 receptors that are activated by the itch either stay activated and now send a "hot" message, or that the itch TRPV1 receptors also turn on the heat TRPV1 receptors, which in my case happen to be very sensitive.

Why very sensitive? I am unfortunate enough to be homozygous for a single nucleotide polymorphisms in my TRPV1 genes that increase the function of TRPV1. It's called rs161364, and I am the relatively rare person who carries two copies of this gain-of-function mutation.** The result is that I am highly sensitive to the burn of pepper, chilis, and alcohol, and apparently also the burn of an itch. (Many of the compounds in black tea also activate TRPV1, though not to the extent of causing pain).

If you are curious about your status and have done 23andme, you can look up the snp rs161364   in your raw data. A "C" gives you normal function of TRPV1, and a "T" gives you a gain-of-function. I happen to have two "T"'s. If you have one "T" your sensitivity is intermediate.

Incidentally, J. Craig Venter, whose whole genome was the first human genome to be completed, also has two copies of "T."

* Of course I don't recommend scratching—that leads to real skin problems. Better to moisturize your skin.

** 10% of Europeans like me, 5% of East Asians, and 0% of Subsaharan Africans carry 2 "T"'s.


Tuesday, January 2, 2018

Rosewater and tea

According to a blog from the National Restaurant Association that I follow, rose water is going to become more and more appreciated in 2018.*

Here's the results of a fun piece of research that I did at Book Expo America several years back. Had the participants in my survey sniff rose water and tell me whether they liked it or not. Here are there results for regular coffee versus regular tea drinkers:

The number of persons participating in the study was small, but I think the data are quite striking. They line up well with other survey data (no sniffing) that Friend of Pairteas Tim Hanni MW(Master of Wine) collected and I analyzed.

As it turns out the rose smell is considered a fault in coffee, whereas it it is an intrinsic element of the aroma of tea. In fact you might want to consider using rosewater in your cakes, as suggested by the author of the post, Mike Kostyo**. I think rosewater would go best with either green or black teas—oolongs have a more jasmine-related compounds.

I'll be testing recipes shortly (once I have my new kitchen organized), but meanwhile, let me know what you find!


** Mike Kostyo is the senior publications manager of Datassential, a supplier of trends, analysis and concept testing for the food industry. For more information about Datassential’s 2018 Trend Report, contact Kostyo at