Tongue Taste Map is a LIE!

As children, we all learned about the 4 different taste qualities the human tongue can appreciate: salty, sugar, bitter, and sour. Savory or umami was added in 1985. "Calcium" has been proposed in 2008 as well as more recently, "fatty" taste.

Along with the 5 (and possibly more) taste qualities we all had to memorize at some point, we also had to memorize the taste map of the tongue (yes... I know umami is missing):

Well... what a waste of time to memorize the tongue taste map because it is wrong!!! This tongue taste map was originally sketched by Edwin Boring in 1942 and has since been frequently reproduced in textbooks, wine classes, and biology courses.

The tongue taste map delineates specific areas where certain taste qualities are perceived better than in other areas like the state of Texas is distinctly a different region than Montana.

However, reality is a mish-mash patchwork spread unevenly throughout the tongue that is different for each person.

Each of the ~5000 taste buds found on the surface of the tongue contain clusters of over 100 taste cells with receptors that have different degrees of sensitivity to molecules carrying MORE than one basic taste and that these clusters are distributed across the entire surface of the tongue.

Bottom line?

Tongue taste map is a lie.


Reference:
The cell biology of taste. JCB vol. 190 no. 3 285-296, doi: 10.1083/jcb.201003144

Receptor seeks ligand: on the way to cloning the molecular receptors for sweet and bitter taste. Nat. Med. 5:381–382. doi:10.1038/7377

A Map of Taste. NYT 3/19/12

Allergy Shots in the Leg? Abdomen?

It is not uncommon that we have patients that ask if allergy shots can be administered in the leg (or other part of the body) rather than the usual behind the upper arm.

Before we answer that question, let's ask why we given it in the upper arm in the first place!

1) Easy to access
2) Easy to monitor for any adverse reaction
3) All the good studies done are based on injections administered to the upper arm
4) No good studies performed determining whether injections done at other body sites has equal efficacy to the arm.
5) If anaphylaxis occurs, a tourniquet can be easily applied to the arm proximal to the injection site which theoretically would decrease allergen traveling systemically

Given these answers, is it possible to give allergy shots in other body locations other than the arm?

Yes... BUT...

1) No good studies performed determining whether injections done at other body sites has equal efficacy to the arm.

2) If anaphylaxis occurs, may not be possible to apply a tourniquet easily (if given in the abdomen for example)

3) May not be as easy to monitor for a reaction (if given in the buttocks for example)

SO...

It is recommended that allergy shots be given in the upper arm and not other locations.

Reference:

Ask the expert. AAAAI 2/6/12

Google Flu Shot Finder

The brainy folks at Google has been at it again... Not only did they produce a map showing the flu trends in the US... but now they have produced a Flu Shot finder based on zip code for both seasonal as well as H1N1 vaccines. The locations are displayed on their Google Maps page.

Check it out here!