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Newsletter: Issue #28
by Salynn Boyles - Web MD News Hormone Linked to Appetite Increases When Calories Restricted
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You gain, you lose, you gain, you lose. It is a sad fact that most people who lose weight through dieting end up gaining the pounds back, and then some. Now science may be closer to figuring out why. |
According to the CDC, 35% of Americans are overweight and 27% are considered obese. But the track record for people who try to lose significant amounts of weight by modifying their diet is dismal, with the vast majority gaining lost weight back over time. This is not true, however, for obese patients who lose weight after receiving gastric bypass surgery -- an operation in which food is rerouted to avoid most of the stomach and parts of the small intestine. Studies have shown that most of these patients not only lose significant amounts of weight, but they keep the weight off for many years.
Because ghrelin is produced primarily in the stomach, researcher David E. Cummings and colleagues at the University of Washington hypothesized that impaired secretion of the hormone might help explain sustained weight loss among gastric surgery patients. Since its discovery two years ago, studies in rats have shown ghrelin to be a powerful appetite stimulant. And hormone levels have also been shown to rise in humans shortly before meals and decrease shortly afterward.
Adaptive Response
The researchers measured plasma ghrelin levels in 13 obese patients who lost weight during a six-month diet program and compared them to five patients who lost weight after gastric bypass surgery and 10 normal-weight people. Their findings were reported May 23 in The New England Journal of Medicine. They found that a 17% decrease in body weight among patients who dieted was associated with a 24% increase in 24-hour plasma ghrelin levels. But the surgery patients, who lost an average of 36% of their body weight during the study period, had ghrelin levels that were 77% lower than the normal-weight people.
The researchers suggest that the rise in ghrelin levels among patients who diet may represent the body's evolutionary response to restricting calories, and why people who lose weight through dieting often experience an increase in appetite. "This study is consistent with a potential role for ghrelin in what we refer to as the adaptive response to weight loss," Cummings tells WebMD. "This is a well-described series of physiological responses that come into play to restrict weight loss when it is attempted. We have shown that weight loss through dieting triggers an increase of ghrelin, and gastric bypass triggers suppression. This could explain why gastric bypass works as well as it does."
Though effective, the surgery is also considered major and only intended for patients who are severely or morbidly obese. Doctors often use a number called the body mass index (BMI) to measure obesity. Severe morbid obesity is a BMI over 40. A BMI of 30-40 is obesity, and normal is less than 25.
"A Big Leap"
Ghrelin research offers hope, but no guarantees, for a more effective therapeutic option in people who need to lose less weight. Pharmaceutical researchers are now working to come up with a drug that will act as a ghrelin blocker, in the hopes that suppressing the hormone will mean suppressing the appetite. "If suppressing this hormone is directly involved in suppressing appetite, then we might be able to achieve some of the benefits of gastric surgery without the surgery," says endocrinologist and obesity expert Jeffrey S. Flier, MD, of Boston's Beth Israel Deaconess Medical Center. "But that is a
big leap from where we are right now."
Flier wrote an editorial accompanying the ghrelin study in which he called for interventional studies to clarify the role of ghrelin in appetite control. One possible study, he tells WebMD, would be to give infusions of ghrelin to patients who have had gastric bypass surgery. "If they become ravenously hungry, that would be a good indication that ghrelin is controlling appetite," he says. Cummings adds that while a ghrelin-blocking drug might prove to be an effective weight-loss aid, he sees more potential for the hormone's pharmaceutical use as an appetite stimulant.
"Patients with cancer, AIDS, and any number of wasting diseases are in a constant battle to keep weight on, and the treatment options for this are dismal," he says. "Ghrelin blockers may prove to have a role in weight loss,but it is more obvious to me that [ghrelin] could be useful as a promoter of
weight gain."
The Rose
The first day of class our professor introduced himself and challenged us to get to know someone we didn't already know. I stood up to look around when a gentle hand touched my shoulder. I turned around to find a wrinkled, little old lady beaming up at me with a smile that lit up her entire being. She said, "Hi handsome. My name is Rose. I'm eighty-seven ears old. Can I give you a hug"? I laughed and enthusiastically responded,
"Of course you may"!
And she gave me a giant squeeze. "Why are you in college at such a young, innocent age"? I asked. She jokingly replied, "I'm here to meet a rich husband, get married, have a couple of children, and then retire and travel". "No seriously", I asked. I was curious what may have motivated her to be taking on this challenge at her age. "I always dreamed of having a college
education and now I'm getting one"! she told me.
After class we walked to the student union building and shared a chocolate milkshake. We became instant friends. Everyday for the next three months we would leave class together and talk nonstop. I was always mesmerized listening to this "time machine" as she shared her wisdom and experience with me. Over the course of the year, Rose became a campus icon and she easily made friends wherever she went. She loved to dress up and she reveled in the attention bestowed upon her from the other students. She was living it up. At the end of the semester we invited Rose to speak at our football banquet. I'll never forget what she taught us.
She was introduced and stepped up to the podium. As she began to deliver her prepared speech, she dropped all of her 3 x 5 note cards. Frustrated and a little embarrassed, she leaned into the microphone and simply said, "I'm sorry I'm so jittery. I gave up beer for Lent and this whiskey is killing me! I'll never get my speech back in order, so let me just tell you what I know".
As we laughed she cleared her throat and began, "We do not stop playing because we are old; we grow old because we stop playing. There are only four secrets to staying young, being happy, and achieving success. You have to laugh and find humor everyday. You've got to have a dream. When you lose your dreams, you die. We have so many people walking around who are dead and don't even know it! There is a huge difference between growing older and growing up.
If you are nineteen years old and lie in bed for one full year and don't do one productive thing, you will turn twenty years old. If I am eighty-seven years old and stay in bed for a year and never do anything I will turn eighty-eight. Anybody can grow older. That doesn't take any talent or ability. The idea is to grow up by always finding the opportunity in change. Have no regrets. The elderly rarely have regrets for the things we did, but rather for things we did not do. The only people who fear death are those with regrets.
The concluded her speech by courageously singing "The Rose". She challenged each of us to study the lyrics. At the years end Rose finished the college degree she had begun all those years ago. One week after graduation, Rose died peacefully in her sleep. Over two thousand college students attended her funeral in tribute to the wonderful woman who taught by example that it's never too late to be all you can possibly be.