and Poor-Arm-Control

associated with

Drink Additives & Preservatives

A story starting with left-thumb twitches.

Including some web links to data,
case reports, & web searches.

Note the rather unusual drink
ingredient - 'quillaia extract'.

And note 'sodium benzoate

See story below.

(2021 Jun blog post)

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Text or web-links or images may be added
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On 2021 March 21, while on an out-of-town trip to visit relatives, I went to a grocery store and bought a liter bottle of Diet A&W Root Beer.

    I was used to drinking Diet Dr Pepper, but this grocery store did not have liter bottles of Diet Dr Pepper, so I decided to use Diet A&W Root Beer as a substitute.

When I got back to the place we were staying, I poured a glass of the Diet A&W Root Beer and drank it in about an hour.

Several hours later, that night, I went to bed --- but found I could not get to sleep --- because my left thumb was twitching --- and I could not stop the twitching.

I tried 'shaking out' my left hand. That did not work.

I tried 'windmill rotating' my left arm. That did not work.

I tried doing push ups - hoping that getting the blood circulation flowing rapidly might change the situation. That did not work.

I ended up finally getting so tired that I fell asleep.

The next morning, fortunately, the thumb was no longer twitching constantly.

In 'casting about' for a cause of the twitching, I realized that the only unusual thing that I had to eat or drink the previous day was the glass of A&W root beer.

I looked at the 'ingredients list' on the bottle of Diet A&W root beer and saw a label like the following.

Ingredients in Diet A&W Root Beer

The item that stood out to me was QUILLAIA EXTRACT (Wikipedia link).

Most of the other ingredients are found in other carbonated drinks -- such as Diet Dr Pepper, which I had been drinking almost daily for many weeks, with no twitching-of-the-left-thumb.

So my prime suspect was the 'Quillaia extract' --- although I was not prone to leave items like 'sodium benzoate' and 'acesulfame potassium' and 'malic acid' off the hook. (These are Wikipedia links.)

    I did not find reason to suspect 'aspartame' of causing the thumb twitches because for many months I had been drinking Diet Dr Pepper almost every day, with no instances of left-thumb twitching, even though it contains 'aspartame'.

Note that the label says 'caffeine free', so I could not blame the twitching thumb on caffeine.

The Wikipedia page for 'Quillaia' points out that

  • Quillaia is the milled inner bark/stems/branches of the soapbark tree, and

  • Quillaia contains a high concentration of saponins.

Some statements on the Wikipedia pages for 'Quillaia' and for Saponin (Wikipedia link) that stood out to me were

    "extract of quillaia is used ... as a foaming agent in soft drinks"


    "it is listed as an ingredient in root beer and cream soda"


    "highly purified quillaia is used to enhance vaccines"

    "In particular, saponins from Quillaia saponaria are used in veterinary vaccines as adjuvant" where

    adjuvant means "a substance or combination of substances that is used to increase the efficacy or potency of certain drugs."

In other words, Quillaia is a 'potentiator' of substances and could be 'potentiating' the action of other substances in the Diet A&W root beer, such as the 'sodium benzoate' (Wikipedia link).

Sodium benzoate is used in many soft drinks, and is usually touted as a 'preservative', as in the Diet A&W root beer label above.

Note that 'sodium benzoate' has certain 'side effects'. For example, it has been linked to 'hyperactive behavior'.

This leads me to believe it could be a combination of the 'quillaia extract' and the 'sodium benzoate' that led to my thumb twitches --- and that I should be wary of either of those substances.

    Since 'potassium benzoate' is sometimes used as a substitute for 'sodium benzoate', I am now wary of that substance also.

The LEFT Thumb Twitches:
(Why the left?)

Another interesting thing I found:

When I did WEB SEARCHES on keywords like

I found that it was common that when people (not doctors, but actual 'victims' of the thumb twitches) spoke of twitches, they often spoke of twitches in their LEFT thumb --- NOT their RIGHT thumb or BOTH thumbs.

For example, one web page was titled
"What Does It Mean When Your Left Thumb Twitches?"

When puzzling this one out, I came to suspect that, because the heart is located toward the left side of the human body, it may be the case that a little more of the 'twitch-causing-substance(s)' are delivered to the left arm than to the right --- especially when sleeping on one's left side.

As they say at the end of most research journal articles, "this is a subject for further investigation".

Other Root Beers:

I was curious as to whether other root beers use 'quillaia extract' in their root beer.

Following are the ingredients lists of a few non-A&W root beers.

Ingredients in Diet Barq's Root Beer
(no 'quillaia extract' but other junk
such as preservatives, benzoates & sorbates)

Ingredients in Barq's Root Beer
(no 'quillaia extract' but other junk
such as preservatives, benzoates &
'artifical flavors' & 'natural flavors',
which are not what most people would call 'natural')

Ingredients in Virgil's Zero Root Beer
(no 'quillaia extract' and 'Zero Preservatives',
but other junk
such as 'natural flavors', which are not
what most people would call 'natural' ---
but, unfortunately, it is hard to find
a drink without added 'natural flavors'.)

Note that these root beers do not contain 'quillaia extract', but many root beers do contain 'benzoates'.

See the following 'Tennis Effects' section, for more on benzoates.


Not surprisingly, the day after I had the 'left-thumb-twitch' experience while out-of-town at a relative's home, I poured the remaining part of the liter of Diet A&W root beer down their kitchen drain.

When I got home, I was now much more aware of what I might be putting in my body when I drank 'soft drinks'.

I am a tennis fan and so is my wife. Almost every week, several times per week, she is good about getting us out on the tennis court for some practice.

Each time we practice, we start out near the net hitting short balls to each other.

I used to be able to start the ball easily, hitting the ball gently and under-control to her --- BUT, starting several months previous to this time (in March 2021), I had been having a heck of a time starting the ball properly.

My right arm seemed to tense up each time I started the ball (no matter how much I tried to relax), and the ball would often go quickly to the left and down into the net.

And when I would try to compensate, I would almost always over-compensate and hit the ball wildly, high in the air, to the right or left of my practice partner --- and often over her head.

After the left-thumb-twitching experience, I was now motivated to think about what I may be drinking (or eating) that might explain why this 'tenseness' started happening in the past few months.

I realized almost immediately, that in the past several months, I had been increasing the number of glasses of Diet Dr. Pepper that I had been consuming each day.

We have a bottled water dispenser in our kitchen. I keep it filled with distilled water. But distilled water is rather 'blah' --- so in the past year I had been filling a glass about half to 2/3 full of Diet Dr Pepper and filling the rest of the glass with distilled water.

About a year earlier, I was drinking the equivalent of about one full glass of Diet Dr Pepper per day.

BUT ... in the past several months, I had been doing that glass-filling routine about 6 times per day --- so I was drinking the equivalent of about 4 full glasses of Diet Dr Pepper per day.

Based on the Diet A&W Root Beer experience (which involved 'sodium benzoate'), I decided to quit Diet Dr Pepper 'cold-turkey'.

Ingredients in Diet Dr Pepper

I did web searches on keywords such as

I found that there are quite a few soft drink manufacturers who are catering to people who have concerns about all the additives and preservatives in soft drinks.

I also prowled the aisles of local grocery stores looking at ingredient labels on a wide variety of soft drinks --- sparkling and non-sparkling.

I found a few that seemed to be good candidates, and I started using a couple of those as replacements for all the Diet Dr Pepper that I was drinking.

    (I love the taste of Dr Pepper. So I miss it. I would 'come back'if Dr Pepper would offer a Dr Pepper without all the additives and preservatives.)

    (I should point out that most of the 'no additives and preservatives' soft drinks still use 'natural flavors', which are not so natural. You can do web searches on keywords such as natural flavors side effects to get a start on investigating that topic further. Some day, I may provide a web page on the subject of finding an 'ideal' soft drink. Later.)

Ingredients of some
Highly-Consumed Soft Drinks:

To compare with the ingredients of Diet Dr Pepper, I provide here images of the ingredient labels of a few soft drinks that are consumed in huge quantities by U.S. citizens --- and by people world-wide.

Ingredients in Coca Cola (sugared)
( too much sucrose sugar for me)

    By the way, often when a malady such as 'shaking hands' is reported, the solution offered by medical sites is to ADD something to your diet, such as a vitamin or mineral or drug.

    I have found that the solution is often to REMOVE something from your diet.

Ingredients in Diet Pepsi
Note the 'Potassium Benzoate (Preserves Freshness)'.
I will seek drinks with no benzoates.

Ingredients DIFFERENCE
between Pepsi and Coke

Citric Acid in Pepsi, not Coke.
Since citric acid is in lemons,
limes, oranges, it is not likely
to be a problem.

I avoid drinks with lots of sugars (such as the ubiquitous 'High Fructose Corn Syrup', a.k.a. HFCS).

    This HFCS article is one of those Wikipedia articles where it looks like an industry --- in this case, the corn processing industry --- went through this article and inserted many sentences that absolve HFCS of any involvment in obesity and other possible negative effects of HFCS.

    It looks like persons related to the corn processing industry inserted postive-leaning sentences in front of negative-leaning sentences. (At least they left a few negative references in the article --- or they were re-inserted.)

    I find that Wikipedia articles on 'neutral' subjects --- such as technical details in mathematics, physics, and chemistry --- are quite reliable.

    BUT, Wikipedia articles on 'controversial' subjects --- such as politics or the environment --- are subject to insertions and deletions of text, by persons apparently dedicated to protecting the income of industries with 'skeletons in their closets'.

After my twitching-left-thumb experience, I am certainly going to avoid any of these 'colas' that have 'suspicious' (poorly studied & evaluated) preservatives and additives --- like benzoates and/or quillaia.

MY-BOTTOM-LINE (a summary):

I am glad to report that within a week after replacing all the Diet Dr Pepper I was drinking, by drinking soft drinks without preservatives --- and without additives, other than 'natural flavors' --- the 'tenseness' in my arm seems to be gone.

I can once again initiate 'near-the-net short ball practice' (with control) when warming up in tennis practice.

I also seem to have better control of my 'deep' forehand strokes --- something I have been struggling with for years.

I have to wonder if there are some tennis professionals who are drinking too many preservative-laden soft drinks --- and who could improve their tennis game by avoiding the preservatives.

In any case, to avoid the 'left-thumb-twitching' problem, I am avoiding Diet A&W root beer --- with its 'quillaia extract' and 'sodium benzoate'.

There might be those who would benefit from my becoming a human guinea pig by consuming all different kinds of root beers and cream sodas and other soft drinks --- and then reporting the results --- such as thumb-twitching or poor control of tennis strokes.

But, for now, I am not going to do that. I will leave that for others.

Actually, the FDA or NIH should be doing that sort of research --- and DOING IT THEMSELVES --- not farming it out to food-and-drink companies and pharmaceutical companies.

For further information :

Here are some keyword WEB SEARCHES that you can use to look for more information (especially emerging new information) on the relation of

  • thumb twitches
  • shaking hands
  • poor arm control (tightness)


  • additives (such as 'quillaia extract')


  • preservatives (such as benzoates,
    'to protect taste' or 'preserve freshness').

You can try the following keywords --- then change them to zero-in on better information.

For further information, you can try the following Wikipedia pages, and follow links on those pages for even more information.

Ingredients label for powdered A&W Root Beer
(Do they really need all the 'artificial & natural flavors'
and 'acesulfame potassium' and
'Red 40', 'Yellow 5', and 'Blue 1' ??)

Ingredients label for powdered A&W Cream Soda
(Do they really need all the 'artificial & natural flavors'
and 'magnesium oxide' and 'monocalcium phosphate'
and 'Red 40', 'Yellow 5', and 'Blue 1' ??)

Ingredients label for powdered IBC Cherry Cola
(Do they really need all the 'artificial & natural flavors'
and 'sodium acid sulfate' and 'acesulfame potassium'
and 'Red 40', 'Yellow 5', and 'Blue 1' ??)

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Thumb-twitches & Poor-arm-control
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Page history:

Page was created 2021 Jun 13.

Page was changed 2021 Jul 01.
(Fixed a few 'typos' and reworded-or-added a few text areas.)