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© 2012 Biology Roots (Vanessa Jason) www.biology-roots.com
Name: ________________________________ Date: _____________________
GOBBLE GOBBLE ZZZz
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zz
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or years now, many people have claimed that after eating your Thanksgiving meal,
the sleepy feeling that overcomes you isn’t just in your head; ; many folks claim that
it is related to a chemical in turkey called tryptophan.
Tryptophan is an amino acid Amino acids are the building blocks of proteins and are
required for life. Tryptophan is an "essential" amino acid because the body cannot make
it. Instead, you have to eat foods that contain tryptophan to get enough. You can also find
tryptophan in oats, bananas, milk, eggs, peanuts and sunflower seeds. It
is almost sure to be found in all common livestock and poultry.
Besides making thousands of proteins, the body uses tryptophan to make
serotonin, a key brain transmitter. Serotonin plays a role in the regulation
of mood. Tryptophan’s sedative effects could be related to its role in the
synthesis of serotonin. Serotonin also plays a small role in promoting
sleep. Tryptophan is also necessary for making a form of vitamin B called
niacin, which is important for the function of skin, nerves and the digestive tract.
1. What is tryptophan? ____________________________________________________.
2. Why is tryptophan “essential”? ____________________________________________
3. Which foods contain tryptophan? __________________________________________
_____________________________________________________________________.
4. What is one theory as to why you get so tired after eating your Thanksgiving meal?
_______________________________________________________________________
____________________________________________________________________.
5. Name two things that the body uses tryptophan for.
_______________________________________________________________________
______________________________________________________.
6. What is one possible explanation as to why tryptophan makes you sleepy?
____________________________________________________________________.
Tryptophan supplements can be taken for insomnia (trouble sleeping). These
supplements usually come in doses that range from 500 milligrams to 3,000
milligrams daily. However, a 3 ounce serving of turkey contains about 200 mg
of tryptophan — about the same as chicken or beef contains and significantly
less than peanuts or cheddar cheese contain.
F
© 2012 Biology Roots (Vanessa Jason) www.biology-roots.com
Additionally, your body strictly regulates the synthesis of serotonin, so ingesting extra
tryptophan will probably not cause increased serotonin levels in the brain (recall that the
sleepiness tryptophan may cause might linked to serotonin synthesis).
Another thing to think about is the Thanksgiving meal as a whole. How much people eat
(not just of turkey, but the other dishes, as well), and what time of day they eat. When
digesting food, blood flow increases to the small intestines to absorb nutrients. This may
mean a temporary decrease of blood flow to other parts of the body, including the
muscles and brain.
Review the chart below. Graph the data by creating a bar graph. Be sure to clearly
label your axes.
Tryptophan mg per 3 oz serving
Turkey
190
Chicken
160
Beef
180
Peanuts
210
Cheddar Cheese
220
Banana
20
Oats
60
Tryptophan Levels among Different Foods
© 2012 Biology Roots (Vanessa Jason) www.biology-roots.com
ANALYSIS & CONCLUSION
1. According to the data, which food would make you the sleepiest?
2. According to the data, which food would hypothetically make you the least sleepy?
3. Do you think that the tryptophan in turkey is primarily responsible for making you
sleepy after your Thanksgiving meals? Why or why not? (Does not necessarily
need to be a yes or no answer!)
Your Answer: __________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
___________________________________________________________.
You are a recent Harvard Medical Grad who is specializing in nutrition.
You have finally received your big break- a guest seat on the hit television
show “The Doctors”. You are there for their Thanksgiving Special all
about the nutrition behind the holiday. The big questions they want to
know are: Does turkey make you sleepy? Why or why not? Are there
other factors that could contribute to the post-Thanksgiving-meal-coma?
Use all you know to give them a solid, scientific answer!
© 2012 Biology Roots (Vanessa Jason) www.biology-roots.com
Answer Key
GOBBLE GOBBLE ZZZz
z
zz
z
or years now, many people have claimed that after eating your Thanksgiving meal,
the sleepy feeling that overcomes you isn’t just in your head; many folks claim that
it is related to a chemical in turkey called tryptophan.
Tryptophan is an amino acid. Amino acids are the building blocks of proteins and are
required for life. Tryptophan is an "essential" amino acid because the body cannot make
it. Instead, you have to eat foods that contain tryptophan to get enough. You can also find
tryptophan in oats, bananas, milk, eggs, peanuts and sunflower seeds. It
is almost sure to be found in all common livestock and poultry.
Besides making thousands of proteins, the body uses tryptophan to make
serotonin, a key brain transmitter. Serotonin plays a role in the regulation
of mood. Tryptophan’s sedative effects could be related to its role in the
synthesis of serotonin. Serotonin also plays a small role in promoting
sleep. Tryptophan is also necessary for making a form of vitamin B called
niacin, which is important for the function of skin, nerves and the digestive tract.
What is tryptophan? Tryptophan is an amino acid, which can be used to promote sleep.
Why is tryptophan “essential”? Tryptophan is essential because it can not be made by the
body.
Which foods contain tryptophan? Food that contains tryptophan includes oats, bananas,
milk, eggs, peanuts, sunflower seeds, livestock and poultry.
What is one theory as to why you get so tired after eating your Thanksgiving meal? One
theory as to why you get tired after eating a Thanksgiving meal is because turkey
contains tryptophan, which can be used to promote sleep.
Name two things that the body uses tryptophan for. The body uses tryptophan to make
serotonin and niacin.
What is one possible explanation as to why tryptophan makes you sleepy? Tryptophan
can be used to build serotonin, which is a neurotransmitter that plays a role in promoting
sleep.
Tryptophan supplements can be taken for insomnia (trouble sleeping). These
supplements usually come in doses that range from 500 milligrams to 3,000
milligrams daily. However, a 3 ounce serving of turkey contains about 200 mg
of tryptophan — about the same as chicken or beef contains and significantly
less than peanuts or cheddar cheese contain.
Additionally, your body strictly regulates the synthesis of serotonin, so ingesting
F
© 2012 Biology Roots (Vanessa Jason) www.biology-roots.com
extra tryptophan will probably not cause increased serotonin levels in the brain (recall that
the sleepiness tryptophan may cause might linked to serotonin synthesis).
Another thing to think about is the Thanksgiving meal as a whole. How much people eat
(not just of turkey, but the other dishes, as well), and what time of day they eat. When
digesting food, blood flow increases to the small intestines to absorb nutrients. This may
mean a temporary decrease of blood flow to other parts of the body, including the
muscles and brain.
Review the chart below. Graph the data by creating a bar graph. Be sure to clearly
label your axes.
Tryptophan mg per 3 oz serving
Turkey
190
Chicken
160
Beef
180
Peanuts
210
Cheddar Cheese
220
Banana
20
Oats
60
Tryptophan Levels among Different Foods
© 2012 Biology Roots (Vanessa Jason) www.biology-roots.com
ANALYSIS & CONCLUSION
1. According to the data, which food would make you the sleepiest?
According to the data, cheddar cheese would make you the sleepiest if the
tryptophan theory were true.
2. According to the data, which food would hypothetically make you the least sleepy?
According to the data, a banana would make you the least sleepy.
3. Do you think that the tryptophan in turkey is primarily responsible for making you
sleepy after your Thanksgiving meals? Why or why not? (Does not necessarily
need to be a yes or no answer!)
No right or wrong answer as long as the answer is reasonable, however, students
should gather from the information provided that the sleepiness after a
Thanksgiving meal is most likely linked to increased blood flow to the intestines
after eating, which causes sleepiness.
Your Answer: Answers may vary, but students should realize that given the graph and
information, tryptophan most likely does not play a large role in sleepiness, particularly
since it is mentioned that the body strictly regulates serotonin, so eating food with
tryptophan does not necessarily mean the body produces extra serotonin. Most likely, the
sleepiness acquired after a Thanksgiving meal is because many people eat more at their
Thanksgiving meal, which results in an increased blood flow to the digestive system and a
decreased blood flow to the muscles and brain. Students may also mention that
Thanksgiving meals tend to be a little later in the day, as well.
You are a recent Harvard Medical Grad who is specializing in nutrition.
You have finally received your big break- a guest seat on the hit television
show “The Doctors”. You are there for their Thanksgiving Special all
about the nutrition behind the holiday. The big questions they want to
know are: Does turkey make you sleepy? Why or why not? Are there
other factors that could contribute to the post-Thanksgiving-meal-coma?
Use all you know to give them a solid, scientific answer!
