Courtesy Lord JimWhat makes human beings so special? How did we evolve into an agriculture-developing, city-building, history-making, world-changing species that can live on every continent and even in outer space?
Scientists have been asking questions about our evolutionary trajectory and human "uniqueness" for as long as there's been science - and guess what? We still don't know the answer! Some of our best theories are explored by anthropologists in the PBS television series The Human Spark, airing throughout the month and also online at the PBS website. If you're curious, you might want to watch, but don't do it on an empty stomach! Many of the theories that anthropologists have developed to explain how we became human involve food.
That food and evolution would go hand in hand is not really surprising, since food is necessary to survival and an important and dynamic part of our environment. Did a search for nutritious plants and animals lead our ancestors to new environments, causing our species to adapt and change? Did hunting and eating meat mean the evolution of new physical characteristics? How has agriculture changed our environment and species over time? How will present and future foods change what it means to be human in the future?
Some evolutionary theories involving food look not just at what we ate, but how we ate it - namely the invention of fire and the use of heat to cook food. Think about it: our Hominid ancestors needed calories in order to develop into the big-brained humans we all know and love. How did they do it? And what did this mean for human evolution?
Sure, eating meat was an important dietary step, but cooking root vegetables can transform hard-to-chew or even poisonous plant parts into nutritious food that can be consumed out of season. With cooking, environments that would otherwise provide few nutritious options suddenly become bountiful. This change in diet may also have led to changes in body size and shape - even social structures! Large teeth and jaws were less desirable once food could be more easily chewed, and delaying the gratification of food until it could be cooked may also have meant that our species had to develop new social skills.
Those social skills - the same ones that mean you and I can now share a burger or beer without fighting each other for scraps - may be one of many "sparks" that makes us human.
If you live in the Twin Cities, you can meet an anthropologist and here how he thinks food impacted human evolution by attending tonight's Cafe Scientifique program in Minneapolis.
if you don't drink water you wil die
Courtesy José Miguel SerranoA few years ago, some close friends called with the grim and heartbreaking news that their 21 year-old daughter had committed suicide. My first reaction was anger. Why would she do something like that? How could she cause such heartache for her family and friends? I knew she had been battling with the eating disorder known as anorexia nervosa since high school, but as it turns out I was totally oblivious to the magnitude of her disease. I knew nothing of the agony she had suffered or the struggle her family had gone through dealing with it. But it all became clear once she gave up hope and decided not to fight it anymore. At her funeral, memorial posters included shocking photographs of her decimated person wasting away in the throes of her disease. And in the weeks following, when my friends would relate stories of their desperate efforts to get their daughter to take in nourishment, or their exasperating attempts to get her back into treatment, or the hardships of just taking care of her in their own home, it became all too obvious that in her last years their poor daughter had led a very tortured and depressing struggle against herself.
But that’s how devastating anorexia nervosa can be. It’s an extremely puzzling and potentially deadly eating disorder characterized by a distorted body image, self-starvation, and excessive weight loss. One researcher described it as the body digesting its own nervous system. Nine out of ten of those diagnosed with the disease are female, and while it’s long been considered a white, suburban disorder, it’s now recognized that it can occur across all social and economic barriers. Incidents of the disease have risen since the 1950s, and some researchers blame the rise on the heavy cultural emphasis of beauty defined by flawless and very thin models.
But new research ties the troubling disorder to prenatal genetics and disrupted brain chemistry.
In the first study, it appears sex steroid hormones released by the mother into the womb during pregnancy could set up the female fetus for anorexia later in life. Researchers reached this conclusion after studying data from thousands of twins born in Sweden between 1935 and 1958. When comparing sets of female twins against sets of male twins, the females were statistically more likely to develop anorexia than the males, just as expected. However, with mixed-sex twins, the male was as likely to become anorexic as the female. This signaled to scientists that more than likely the triggering mechanism had to do with something taking place during pregnancy.
The second study, which was done by University of Pittsburg researchers, tested both anorexic and healthy patients while monitoring their brains with a magnetic resonance imaging device, Those subjects suffering from anorexia – and even those who were recovering from it - displayed unusual patterns of activity in regions of the brain associated with anxiety and perfectionism. Test questions were given and correct answers were rewarded. In the healthy women, the activity in the brain’s emotion-response center showed distinct differences when they won compared to when they lost. But the women with a history of anorexia showed very little emotional response no matter which way they answered.
Dr. Walter Kaye, the study’s head author, thinks this could affect how a person suffering from anorexia experiences the normally positive responses derived from eating food.
“For anorexics, then, perhaps it is difficult to appreciate immediate pleasure if it does not feel much different from a negative experience”, he said.
The study’s findings appeared in the American Journal of Psychiatry and could lead to new developments in fighting the disorder.
Since their daughter’s death, my friends have worked tirelessly to raise awareness of anorexia nervosa and other eating disorders, including establishing a treatment center in their daughter's name. And as that awareness grows, a tremendous amount of information has become available for anyone looking for answers and help.
Finally, the National Eating Disorders Awareness Week takes place from February 24 - March 1, 2008. If interested in participating you can learn more about it and register here.
Eating Disorder and Referral Information Center
National Association of Anorexia Nervosa and Associated Disorders
More Anorexia info
Anna Westin Foundation
More Links on Squidoo Health
Karen Carpenter's struggle with Anorexia
A perfect post for a Monday morning...
The new book Sex Sleep Eat Drink Dream by Jennifer Ackerman explores a wide range of new findings in human physiology. According to a review in the NY Times,
A host of new hormones have been discovered to govern appetite and satiety, and while the doldrums that follow lunch are still not completely understood, recent research strongly supports a brief nap to treat them.
So the next time the boss catches me napping at my desk, I’ll have bona-fide scientific research to back me up – all the way to the unemployment line.
Or, I think… I think the world wins, actually.
At any rate, the American Joey Chestnut has finally toppled the Godzilla of Gluttony, Takeru Kobayashi of Japan, from the greasy throne of the world-champion competitive hot dog eater.
Kobayashi has dominated this sport of kings since 2001, until a qualifying match last month, when San Jose native Joey Chestnut downed 59.5 hot dogs and buns in 12 minutes, solidly topping Kobayashi’s previous record of 53.75.
After several weeks during which Kobayashi’s website claimed that the athlete was suffering from a recently-extracted wisdom tooth, the contenders have now met at “Nathan’s Famous Hot Dog Eating Contest” in Coney Island. While Chestnut pulled out to an early lead, he was never more than three hot dogs ahead of Kobayashi, and in the last several minutes of the race Kobayashi made a valiant effort to finish in a tie. After 12 minutes, both contestants appeared to have eaten 63 hot dogs, but after comparing scraps left on the plate, and food still in the mouth (and able to be swallowed) at the buzzer, it was determined that Joey Chestnut had eaten… 66 hot dogs. Whoa.
Here’s some perspective on 66 hot dogs:
And, again, this is all without the buns. The buns (66) alone could have been used to construct a very awesome fort. Now that fort is in Joey Chestnut’s tummy. I would live in that fort.
Takeru Kobayashi began his career in sports as a 5’ 7”, 110-pounder. He is currently hovering around 196 pounds (although his height has remained the same), and claims to be under 10 percent body fat. According to some, slender men and women often make excellent competitive eaters due to a lack of a “fat belt,” which restricts the elasticity of the stomach. Joey Chestnut is 6’ 3” tall, and around 220 pounds, and apparently controls the elasticity of his stomach through pure will power.
Stomach elasticity is credited as the key to dominance in competitive eating, and “competitors commonly train by drinking large amounts of water over a short time to stretch out the stomach.” The International Federation of Competitive Eating - and I - strongly discourage this method. Because it can kill you. In fact, the International Federation of Competitive Eating discourages training of any sorts.
Like many of our more glorious sports (e.g. NASCAR, lawn darts, snake-handling, etc.), competitive eating is certainly not without its risks. Obesity and diabetes are, of course, associated with chronic overeating (although restricting caloric intake while not competing may allow competitors to remain healthy in this respect). Also, many physicians worry that stretching the stomach can reduce its ability to function. Vomiting –a disqualifying action, which it, you know, sometimes just happens – can lead to esophageal tearing and infection, and, obviously, simple choking is a serious consideration.
So, people, always remember to eat safely and responsibly. And, this Fourth of July weekend, take a moment to think of one of our country’s newest heroes: Joey Chestnut.
PS – Civilizations of the future are going to think we were so cool.
If the Venus fly trap doesn't have any muscles, how can it snap closed on its prey in less than 1/10 of a second? Harvard mathematician Lakshminarayanan Mahadevan might have the answer. He discovered that a Venus fly trap uses water pressure to keep its leaves on the brink of slamming shut. When a fly or something else lands inside the plant, tiny hairs trigger an electrochemical reaction. This moves water between the cells of the Venus fly trap's leaves. In the blink of an eye, the plant's bent leaves become unstable and slam shut.
Mahadevan compared this to a bent contact lens or a halved tennis ball. The slightest tap will cause the lens or tennis ball to quickly snap back into shape. Researchers still don't fully understand how the plant triggers the water pressure change.
You're wondering why a mathematician was studying a plant? A student gave Mahadevan a Venus fly trap as a gift. Curious about how the plant's behavior, he used a high-speed camera to watch it eating its prey. From these videos, he developed a mathematical model of the plant's movements. (A mathematical model is a very realistic simulation of the real world using measurements and many mathematical calculations.) His model unraveled the mystery of this carnivorous plant.
Scientists have long wondered about the reason for the star nosed mole's unusual schnozz. There have been many theories. Some thought the star was a souped-up smell organ that helped the moles sniff their way around underground. Some thought it was an extra "hand" for grasping prey. And some thought it was an antenna to detect electric fields as moles swim through muddy marsh water. A 1995 study finally proved that the stars are super-sensitive touch organs. And a study just published in Nature advances a theory about why the stars are so big.
The 22 "fingers" of the star have a surface area eight times greater than the nose of the mole's close cousin, the eastern mole. The fingers also allow the mole to quickly tap on objects it comes across—13 times a second, compared to the eastern mole's eight times a second. That means the star-nosed mole can find 14 times the number of food items than the eastern mole can in a given amount of time. The advantage really pays off where there are lots of small prey animals, as in the marshy homes of star-nosed moles.
Be sure to check out the videos of the mole eating, in real time and slow motion, on the linked website. They're amazing!