Tag Archives: amino acid tryptophan

Krebs in the Army?

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This is Krebs. Sir Hans Adolf Krebs to be precise. Who is he you may ask?

Sir Hans Adolf Krebs was a German-born British physician and biochemist. Krebs is well known for his Nobel Prize winning research in the citric acid cycle or what we usually call it, the TCA cycle/ Krebs cycle.

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The Krebs cycle is a series of metabolic chemical reactions used not only by us, but also by all aerobic organisms, to produce energy through the oxidization of acetate into carbon dioxide.

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Yeah, you may have heard of him before but I bet you didn’t know this about him.

Krebs was Jewish and he joined the German army in 1932, and was also appointed to the 13th Mechanized Infantry Division. You’re probably confused. How could a Jew be a part of the German army at that time? Well the Nazi party was not in power as yet so German Jews were welcome in the German army.

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Afterwards, Krebs returned to clinical medicine at the hospital of Altona and then at the medical clinic of the University of Freiburg, where he conducted studies and discovered the urea cycle. Yup, the Krebs cycle wasn’t the only cycle he discovered!

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Unfortunately, because he was Jewish, he was prohibited from practicing medicine in Germany when the Nazis took power, and he emigrated to England in 1933.  He then worked in the biochemistry department under Sir Frederick Gowland Hopkins in Cambridge. So… the guy who discovered the essential amino acid Tryptophan and the guy who discovered the TCA cycle were buddies! Two great minds working together for the love of biochemistry! I love it! 🙂

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References:

http://www.nndb.com/people/619/000129232/

http://en.wikipedia.org/wiki/Citric_acid_cycle

http://www.nobelprize.org/nobel_prizes/medicine/laureates/1953/krebs-bio.html

http://inoxx.net/?tag=citric-acid-cycle

http://pictureshistory.blogspot.com/2009/12/men-of-wehrmacht-german-soldiers-part-1.html

http://www.corbisimages.com/stock-photo/rights-managed/SF8172/chemist-hans-adolf-krebs-and-assistant-in

http://en.wikipedia.org/wiki/Hans_Adolf_Krebs

Turkey Coma?

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I know Christmas may be long gone but it is and will forever be my most favourite holiday. The season brings joy, cheer and a spirit of giving, as well as those chilly nights when you just want to snuggle up in your bed. Although I love all of these things, the highlight of the season is…you guessed right, the food! Ham, pastelles, sorrel, ginger beer, you name it, I love it. Sadly my brother is allergic to pork ham so since mummy doesn’t want him to feel left out, she cooks a whole turkey just for him. He’s so spoiled. But that doesn’t mean I don’t have my fair share of turkey as well 🙂  Have you ever felt like you were in a food induced coma after eating your belly’s full at Christmas lunch? You know, when you’ve just finished eating a plate like this:

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And after you’re just like:

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What if I told you that there just might be an amino acid found in turkey and ham that induces drowsiness in human beings. That amino acid is called Tryptophan.

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In my amino acids and proteins lecture, I learnt that Tryptophan is one of the 20 amino acids and an essential amino acid that is required for a healthy diet. An essential amino acid is one which the body cannot make on its own thus has to be supplied in the diet. Only the L-stereoisomer of tryptophan is used in enzyme proteins. Since tryptophan is not found in the body, we have to consume different food sources and the tryptophan then converts into serotonin in the body. Serotonin, which in turn is the precursor of hormone melatonin, is a chemical found in the brain that maintains calmness and composure in humans.

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Different scientific studies have been done, even by the Oxford University, into the truth of whether or not tryptophan does in fact calm nerves and induce sleep. Interestingly enough, some studies go so far as to show that excessive consumption of the amino acid tryptophan actually affects the human sense of trust.

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Here is an excerpt from an article (Country Facts 2010) which explains how their study was conducted:

A very interesting research was conducted by Oxford University through a two member game titled the “Prisoners Dilemma”. The two options given to the teams were to make moves which would allow a player to earn money by taking it from another player or make moves where both of the players could make money. The idea was for both players to co-operate. Under normal situations, without any tampering, this occurred approximately 75% of the time.

 However in the second stage a chemical serotonin inhibitor was introduced. Before the players began the game half of the group of volunteers was made to drink a concoction which reduced their tryptophan levels thereby reducing the total amount of serotonin in the brain. This group of volunteers was less cooperative than the others who were not given any chemicals and also doubted the trustworthiness of others.

 The study activity reveals that a lack of serotonin or tryptophan in the human body could lead to lack of cooperative behavior in all age groups.

Since mutual cooperation always enhances brain activity and promotes positive reinforcement it is interesting to note that human beings who lack this chemical at optimum levels in the brain suffer from behavioral imbalances.”

You would think that if someone was consuming large numbers of turkey and ham they would have a large amount of tryptophan in the body right? That is not the case because there are many other factors that may contribute to post-meal drowsiness such as:

  • Carbohydrates

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L-tryptophan may be found in turkey and other protein rich foods, but it’s actually a carbohydrate-rich (as opposed to protein-rich) meal that raises the level of this amino acid in the brain and leads to serotonin synthesis. Carbohydrates stimulate the pancreas to secrete insulin. When this occurs, some amino acids that compete with tryptophan leave the bloodstream and enter muscle cells. This causes an increase in the relative concentration of tryptophan in the bloodstream. Serotonin is synthesized and you feel that familiar sleepy feeling.

  • Fats

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Fats slow down the digestive system, giving Christmas dinner plenty of time to take effect. Fats take a good amount of energy in order to digest, so the body will redirect blood to your digestive system to handle the job. Since you have less blood flow elsewhere in your body, you will feel less energetic after eating a meal high in fats.

  • Alcohol

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Alcohol is a central nervous system depressant. If alcoholic beverages are part of the Christmas celebration, then they will add to the sleep-factor.

I had no idea that this topic was an ageless debate with many persons claiming this as either fact or fiction. But nevertheless, I will continue to gobble my turkey and ham with a big smile on my face and then to my bed I will go.

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My apologies if this post made you hungry…or sleepy….or both :p. What do you think? Do you believe that the turkey coma is a myth?

Article Reference:

Country Facts. 2010. “Turkey Enzyme” Accessed March 1, 2013. http://www.kwintessential.co.uk/articles/turkey/Turkey-Enzyme/3446

References:

http://www.tumblr.com/tagged/sleep%20gif

http://circadiana.blogspot.com/2005/11/does-tryptophan-from-turkey-meat-make.html

http://scienceblogs.com/clock/2006/11/22/does-tryptophan-from-turkey-me/

http://en.wikipedia.org/wiki/Tryptophan

http://trinichow.com/2013/01/02/holiday-christmas-food-trinidad-tobago/

http://www.loopbarbados.com/loop-blog/santas-got-sunburn-ponche-de-creme

http://naparimagirls.edu.tt/09/index.php?option=com_content&view=article&id=61&Itemid=66

http://www.uncommoncaribbean.com/2011/12/19/taste-of-the-caribbean-tis-the-season-for-sweet-bread/

http://science.howstuffworks.com/innovation/edible-innovations/question519.htm