Once a week.
Subscribe to our weekly newsletter.
Why eating turkey really makes you sleepy
Is everyone's favorite Thanksgiving centerpiece really to blame for the post-dinner doldrums?
- Americans kill around 45 million turkeys every year in preparation for the Thanksgiving meal, only to blame our favorite centerpiece for the following food comas.
- Rumor has it our after-dinner sleepiness results from the tryptophan found in turkey.
- However, it is the meal's overall nutritional imbalance, not just the tryptophan, that make us want to leave the dishes for tomorrow. Or maybe the next day.
The turkey is one of the closest living relatives to avian dinosaurs, but recent evolutionary turns has taken it from peak predator to meek entrée. Americans kill about 45 to 46 million turkeys in preparation for Thanksgiving, and to really rub it in, our nation's leader pardons one every year as a lark.
But ignominy doesn't stop there. Through selective breeding, we've dramatically increased the size of turkeys, particularly in the breast for more of that coveted white meat. This has led to all sorts of health issues, including skeletal problems, cardiac morbidity, and reduced immune response. Thanks to those robust breasts, domestic turkeys can't mate anymore and rely on us for artificial insemination.
If that wasn't bad enough, every year after we've feasted on millions of these birds, we then blame them for making us miserably tired. We've even developed a term for it: the turkey coma, the "inevitable and unavoidable nap that occurs about 45 minutes after gorging one's self on a Thanksgiving Day turkey," as one Urban Dictionary user defined it.
But are turkeys really to blame for the turkey coma? And if so, how do they manage this posthumous revenge?
Jerry and George use a turkey's tryptophan to make Celia fall asleep in the episode "The Merv Griffin Show."
(Photo from NBCUniversal)
As any Seinfeld fan can tell you, that stuff in turkey that makes you sleepy is tryptophan. Specifically, L-tryptophan, an essential amino acid that our livers synthesize into niacin. Niacin, in turn, helps create the neurotransmitter serotonin.
Our brains and bodies use serotonin for many functions. It plays a role in appetite, emotional stability, motor skills, and cognitive processes, but it's most famous for regulating our body's sleep-wake cycles. This common knowledge serves as the basis for the belief that turkey makes you sleepy.
Thing is, a lot of foods contain tryptophan. Nuts, soy, eggs, milk, salmon, chicken, spinach, yogurt, and chocolate are all dietary sources of tryptophan, with many of them containing more tryptophan than our favorite holiday fowl.
According to My Food Data, turkey has 404 milligrams of tryptophan per 100 gram serving. But in the same serving size, pumpkin and squash seeds have 576 milligrams, soybeans have 575, and reduced fat mozzarella has 571. None of these is associated with drowsiness, and nuts are a go-to for an afternoon pick-me-up snack.
Either turkey is being unfairly maligned or something else is weighing down our eyelids after a Thanksgiving meal.
Caloric cat nap
While Seinfeld may have exaggerated the effects of tryptophan, the show did get one thing right. If you want to put your girlfriend to sleep so you can play with her antique toy collection, a calorie-laden meal of turkey, heavy gravy, and a whole box of red wine will do the trick.
Americans consume a lot of calories during a Thanksgiving meal. This isn't news but the numbers, once laid bare, can still be guilt-inducing. The Calorie Control Council estimates that the average Thanksgiving meal weighs in at 3,150 calories, but it's worth noting that their estimate uses sweet tea as a beverage benchmark and not beer, wine, or cocktails.
Dietitian Tanya Zuckerbrot told Fox News that a turkey day dinner ranges between 3,000 and 4,500 calories. Like the Calorie Control Council, her estimate does not include alcoholic drinks, but she also skipped on appetizers.
Obviously, these numbers vary depending on the food available and serving sizes. But any estimate will have one thing in common: a single meal sporting well over the USDA recommended daily caloric intake for all demographics outside of Olympian athletes.
Putting the sleep turkey myth to rest
Two male turkeys named Peas and Carrots sent by the National Turkey Federation (NTF) to the White House are seen before the upcoming annual turkey-pardoning ceremony on November 19, 2018 in Washington, DC.
(Photo by Chen Mengtong/China News Service/VCG via Getty Images)
And this is why the term "food coma" is much more apt — or, if you want to get clinical, "postprandial somnolence."
"We've known for many years that meals with an imbalance of nutrients — that are rich in either fats or carbohydrates — are associated with feeling sleepy," writes Angus Steward, senior lecturer of nutrition and dietetics at Edith Cowan University. "But this is not the case when nutrients are balanced or the meal is rich in protein."
When we start our Thanksgiving meal, our stomachs begin producing a hormone called gastrin. Gastrin kickstarts the digestive process, which reroutes blood to our stomachs to carry away the newly formed nutrients.
Part of the drowsiness is due to the volume of food you consume. It simply takes longer to digest, requiring your body to take it easy while it diverts blood from other bodily functions. But as Steward explains, it isn't just volume at work here. It's also what we eat.
Thanksgiving meals are heavy in fats and carbohydrates. Carbs release glucose into the bloodstream quickly, causing a spike in insulin production. Insulin helps the body absorb the glucose, but in doing so, it makes it easier for tryptophan to pass the blood-brain barrier. Once tryptophan is in the brain, it begins conversion to serotonin to tell your body it's time to sleep.
With your body and mind at rest, your body can get to work absorbing the massive meal.
That's the bad news if you still have a daunting pile of dishes to clean Thanksgiving evening. The good news, as the National Sleep Foundation points out, is that you can use your newfound understanding as a little bio-hack. Eating small bedtime snack that contains both carbs and tryptophan, such as peanut butter on toast, can help you ease into a restful night's sleep.
Ending the blame game
So, the myth is partially right; turkey does have a role to play. It and many other Thanksgiving favorites provide you with ample tryptophan. When combined with an overall high-calorie meal and enough stuffing to carb-load for a marathon, the result is a mid-afternoon snooze.
But the turkey is hardly the sole cause of anyone's sleepiness. If anything, we only have ourselves to blame and can stop blaming it for those decisions. And even if turkey did make us sleepy, let's face it: it has far more grievances against us than we do against it.
- Does turkey make you sleepy? - The Washington Post ›
- Why Does Turkey Make You Tired? | Mental Floss ›
- Thanksgiving Myth Busted: Eating Turkey Won't Make You Sleepy ›
- Does Turkey Make You Sleepy? - Scientific American ›
- What is in turkey that makes you sleepy? The truth about tryptophan ›
- L-Tryptophan: Does Turkey Really Make You Sleepy? ›
We explore the history of blood types and how they are classified to find out what makes the Rh-null type important to science and dangerous for those who live with it.
- Fewer than 50 people worldwide have 'golden blood' — or Rh-null.
- Blood is considered Rh-null if it lacks all of the 61 possible antigens in the Rh system.
- It's also very dangerous to live with this blood type, as so few people have it.
Golden blood sounds like the latest in medical quackery. As in, get a golden blood transfusion to balance your tantric midichlorians and receive a free charcoal ice cream cleanse. Don't let the New-Agey moniker throw you. Golden blood is actually the nickname for Rh-null, the world's rarest blood type.
As Mosaic reports, the type is so rare that only about 43 people have been reported to have it worldwide, and until 1961, when it was first identified in an Aboriginal Australian woman, doctors assumed embryos with Rh-null blood would simply die in utero.
But what makes Rh-null so rare, and why is it so dangerous to live with? To answer that, we'll first have to explore why hematologists classify blood types the way they do.
A (brief) bloody history
Our ancestors understood little about blood. Even the most basic of blood knowledge — blood inside the body is good, blood outside is not ideal, too much blood outside is cause for concern — escaped humanity's grasp for an embarrassing number of centuries.
Absence this knowledge, our ancestors devised less-than-scientific theories as to what blood was, theories that varied wildly across time and culture. To pick just one, the physicians of Shakespeare's day believed blood to be one of four bodily fluids or "humors" (the others being black bile, yellow bile, and phlegm).
Handed down from ancient Greek physicians, humorism stated that these bodily fluids determined someone's personality. Blood was considered hot and moist, resulting in a sanguine temperament. The more blood people had in their systems, the more passionate, charismatic, and impulsive they would be. Teenagers were considered to have a natural abundance of blood, and men had more than women.
Humorism lead to all sorts of poor medical advice. Most famously, Galen of Pergamum used it as the basis for his prescription of bloodletting. Sporting a "when in doubt, let it out" mentality, Galen declared blood the dominant humor, and bloodletting an excellent way to balance the body. Blood's relation to heat also made it a go-to for fever reduction.
While bloodletting remained common until well into the 19th century, William Harvey's discovery of the circulation of blood in 1628 would put medicine on its path to modern hematology.
Soon after Harvey's discovery, the earliest blood transfusions were attempted, but it wasn't until 1665 that first successful transfusion was performed by British physician Richard Lower. Lower's operation was between dogs, and his success prompted physicians like Jean-Baptiste Denis to try to transfuse blood from animals to humans, a process called xenotransfusion. The death of human patients ultimately led to the practice being outlawed.4
The first successful human-to-human transfusion wouldn't be performed until 1818, when British obstetrician James Blundell managed it to treat postpartum hemorrhage. But even with a proven technique in place, in the following decades many blood-transfusion patients continued to die mysteriously.
Enter Austrian physician Karl Landsteiner. In 1901 he began his work to classify blood groups. Exploring the work of Leonard Landois — the physiologist who showed that when the red blood cells of one animal are introduced to a different animal's, they clump together — Landsteiner thought a similar reaction may occur in intra-human transfusions, which would explain why transfusion success was so spotty. In 1909, he classified the A, B, AB, and O blood groups, and for his work he received the 1930 Nobel Prize for Physiology or Medicine.
What causes blood types?
It took us a while to grasp the intricacies of blood, but today, we know that this life-sustaining substance consists of:
- Red blood cells — cells that carry oxygen and remove carbon dioxide throughout the body;
- White blood cells — immune cells that protect the body against infection and foreign agents;
- Platelets — cells that help blood clot; and
- Plasma — a liquid that carries salts and enzymes.6,7
Each component has a part to play in blood's function, but the red blood cells are responsible for our differing blood types. These cells have proteins* covering their surface called antigens, and the presence or absence of particular antigens determines blood type — type A blood has only A antigens, type B only B, type AB both, and type O neither. Red blood cells sport another antigen called the RhD protein. When it is present, a blood type is said to be positive; when it is absent, it is said to be negative. The typical combinations of A, B, and RhD antigens give us the eight common blood types (A+, A-, B+, B-, AB+, AB-, O+, and O-).
Blood antigen proteins play a variety of cellular roles, but recognizing foreign cells in the blood is the most important for this discussion.
Think of antigens as backstage passes to the bloodstream, while our immune system is the doorman. If the immune system recognizes an antigen, it lets the cell pass. If it does not recognize an antigen, it initiates the body's defense systems and destroys the invader. So, a very aggressive doorman.
While our immune systems are thorough, they are not too bright. If a person with type A blood receives a transfusion of type B blood, the immune system won't recognize the new substance as a life-saving necessity. Instead, it will consider the red blood cells invaders and attack. This is why so many people either grew ill or died during transfusions before Landsteiner's brilliant discovery.
This is also why people with O negative blood are considered "universal donors." Since their red blood cells lack A, B, and RhD antigens, immune systems don't have a way to recognize these cells as foreign and so leaves them well enough alone.
How is Rh-null the rarest blood type?
Let's return to golden blood. In truth, the eight common blood types are an oversimplification of how blood types actually work. As Smithsonian.com points out, "[e]ach of these eight types can be subdivided into many distinct varieties," resulting in millions of different blood types, each classified on a multitude of antigens combinations.
Here is where things get tricky. The RhD protein previously mentioned only refers to one of 61 potential proteins in the Rh system. Blood is considered Rh-null if it lacks all of the 61 possible antigens in the Rh system. This not only makes it rare, but this also means it can be accepted by anyone with a rare blood type within the Rh system.
This is why it is considered "golden blood." It is worth its weight in gold.
As Mosaic reports, golden blood is incredibly important to medicine, but also very dangerous to live with. If a Rh-null carrier needs a blood transfusion, they can find it difficult to locate a donor, and blood is notoriously difficult to transport internationally. Rh-null carriers are encouraged to donate blood as insurance for themselves, but with so few donors spread out over the world and limits on how often they can donate, this can also put an altruistic burden on those select few who agree to donate for others.
Some bloody good questions about blood types
A nurse takes blood samples from a pregnant woman at the North Hospital (Hopital Nord) in Marseille, southern France.
Photo by BERTRAND LANGLOIS / AFP
There remain many mysteries regarding blood types. For example, we still don't know why humans evolved the A and B antigens. Some theories point to these antigens as a byproduct of the diseases various populations contacted throughout history. But we can't say for sure.
In this absence of knowledge, various myths and questions have grown around the concept of blood types in the popular consciousness. Here are some of the most common and their answers.
Do blood types affect personality?
Japan's blood type personality theory is a contemporary resurrection of humorism. The idea states that your blood type directly affects your personality, so type A blood carriers are kind and fastidious, while type B carriers are optimistic and do their own thing. However, a 2003 study sampling 180 men and 180 women found no relationship between blood type and personality.
The theory makes for a fun question on a Cosmopolitan quiz, but that's as accurate as it gets.
Should you alter your diet based on your blood type?
Remember Galen of Pergamon? In addition to bloodletting, he also prescribed his patients to eat certain foods depending on which humors needed to be balanced. Wine, for example, was considered a hot and dry drink, so it would be prescribed to treat a cold. In other words, belief that your diet should complement your blood type is yet another holdover of humorism theory.
Created by Peter J. D'Adamo, the Blood Type Diet argues that one's diet should match one's blood type. Type A carriers should eat a meat-free diet of whole grains, legumes, fruits, and vegetables; type B carriers should eat green vegetables, certain meats, and low-fat dairy; and so on.
However, a study from the University of Toronto analyzed the data from 1,455 participants and found no evidence to support the theory. While people can lose weight and become healthier on the diet, it probably has more to do with eating all those leafy greens than blood type.
Are there links between blood types and certain diseases?
There is evidence to suggest that different blood types may increase the risk of certain diseases. One analysis suggested that type O blood decreases the risk of having a stroke or heart attack, while AB blood appears to increase it. With that said, type O carriers have a greater chance of developing peptic ulcers and skin cancer.
None of this is to say that your blood type will foredoom your medical future. Many factors, such as diet and exercise, hold influence over your health and likely to a greater extent than blood type.
What is the most common blood type?
In the United States, the most common blood type is O+. Roughly one in three people sports this type of blood. Of the eight well-known blood types, the least common is AB-. Only one in 167 people in the U.S. have it.
Do animals have blood types?
They most certainly do, but they are not the same as ours. This difference is why those 17th-century patients who thought, "Animal blood, now that's the ticket!" ultimately had their tickets punched. In fact, blood types are distinct between species. Unhelpfully, scientists sometimes use the same nomenclature to describe these different types. Cats, for example, have A and B antigens, but these are not the same A and B antigens found in humans.
Interestingly, xenotransfusion is making a comeback. Scientists are working to genetically engineer the blood of pigs to potentially produce human compatible blood.
Scientists are also looking into creating synthetic blood. If they succeed, they may be able to ease the current blood shortage, while also devising a way to create blood for rare blood type carriers. While this may make golden blood less golden, it would certainly make it easier to live with.* While antigens are typically proteins, they can be other molecules as well, such as polysaccharides.
China has reached a new record for nuclear fusion at 120 million degrees Celsius.
This article was originally published on our sister site, Freethink.
China wants to build a mini-star on Earth and house it in a reactor. Many teams across the globe have this same bold goal --- which would create unlimited clean energy via nuclear fusion.
But according to Chinese state media, New Atlas reports, the team at the Experimental Advanced Superconducting Tokamak (EAST) has set a new world record: temperatures of 120 million degrees Celsius for 101 seconds.
Yeah, that's hot. So what? Nuclear fusion reactions require an insane amount of heat and pressure --- a temperature environment similar to the sun, which is approximately 150 million degrees C.
If scientists can essentially build a sun on Earth, they can create endless energy by mimicking how the sun does it.
If scientists can essentially build a sun on Earth, they can create endless energy by mimicking how the sun does it. In nuclear fusion, the extreme heat and pressure create a plasma. Then, within that plasma, two or more hydrogen nuclei crash together, merge into a heavier atom, and release a ton of energy in the process.
Nuclear fusion milestones: The team at EAST built a giant metal torus (similar in shape to a giant donut) with a series of magnetic coils. The coils hold hot plasma where the reactions occur. They've reached many milestones along the way.
According to New Atlas, in 2016, the scientists at EAST could heat hydrogen plasma to roughly 50 million degrees C for 102 seconds. Two years later, they reached 100 million degrees for 10 seconds.
The temperatures are impressive, but the short reaction times, and lack of pressure are another obstacle. Fusion is simple for the sun, because stars are massive and gravity provides even pressure all over the surface. The pressure squeezes hydrogen gas in the sun's core so immensely that several nuclei combine to form one atom, releasing energy.
But on Earth, we have to supply all of the pressure to keep the reaction going, and it has to be perfectly even. It's hard to do this for any length of time, and it uses a ton of energy. So the reactions usually fizzle out in minutes or seconds.
Still, the latest record of 120 million degrees and 101 seconds is one more step toward sustaining longer and hotter reactions.
Why does this matter? No one denies that humankind needs a clean, unlimited source of energy.
We all recognize that oil and gas are limited resources. But even wind and solar power --- renewable energies --- are fundamentally limited. They are dependent upon a breezy day or a cloudless sky, which we can't always count on.
Nuclear fusion is clean, safe, and environmentally sustainable --- its fuel is a nearly limitless resource since it is simply hydrogen (which can be easily made from water).
With each new milestone, we are creeping closer and closer to a breakthrough for unlimited, clean energy.
The symbol for love is the heart, but the brain may be more accurate.
- How love makes us feel can only be defined on an individual basis, but what it does to the body, specifically the brain, is now less abstract thanks to science.
- One of the problems with early-stage attraction, according to anthropologist Helen Fisher, is that it activates parts of the brain that are linked to drive, craving, obsession, and motivation, while other regions that deal with decision-making shut down.
- Dr. Fisher, professor Ted Fischer, and psychiatrist Gail Saltz explain the different types of love, explore the neuroscience of love and attraction, and share tips for sustaining relationships that are healthy and mutually beneficial.