Gettysburg Medical News
The Clinical View
by P.E. Hoffsten, M.D.
5 June 2002

WHAT IS GHRELIN?

    An article appeared in the New England Journal of Medicine this week that was a blockbuster of importance to our society, 63% of whom are overweight.  What the scourge of cigarettes was to the 1900's, obesity promises to be in the century of 2000.  As our labor saving devices and sedentary lifestyle in front of computers continues, the average weight of the American citizen continues to increase and the percentage overweight individuals continue, to increase.  The epidemic of heart disease, hypertension, high blood cholesterols and diabetes is coming at us like a tidal wave.

     Anyone who has ever tried the diet and exercise program that we all "should" adhere to knows that it is very difficult, if not impossible, to institute and maintain.  We are continuously bombarded with admonitions, advice, and then loads of guilt because the overweight individual somehow continues to struggle.

     The article mentioned above clarifies the problem of our overweight society yearning to be thin. All those people who came to the doctor and said that there was something wrong with their hormones turned out to be absolutely right.  Until the last two years, we just did not know that which hormones we were talking about and probably still don't know them all, but we have found a new one which promises to be very helpful in producing weight loss.

     It turns out that the stomach makes a hormone called ghrelin.  This hormone increases hunger, decreases the burning of fat and decreases the basic metabolic rate.  Anyone who has ever dieted knows that the first few pounds come off relatively easy but then the basic metabolic rate drops, appetite becomes unbearable and further weight loss by voluntary efforts becomes very difficult. These effects are all mediated by a hormone called ghrelin which was discovered in the last two years.   It has been seen that when a person eats, the amount of his hormone drops and when the person doesn't eat, the amount of the hormone increases.  It has a substantial drop after each meal and then rises between meals until the person eats again.  Studies have now been done in both animals and humans showing that this hormone is a potent regulator of eating behavior.

    The obvious question arising from above is, "How do you turn ghrelin off so that hunger ceases, the metabolic rate is maintained and fat is burned?"  To this time, there is no medicine that specifically inhibits ghrelin secretion but, accidentally, it has been found that there is a surgical procedure that turns it off completely.

    That surgically procedure is called gastric bypass surgery that has become more frequently performed in the past several years.  Various types of surgery to treat the individual who is massively obese have been tried for more than 40 years.  In the last several years, a procedure called gastric bypass surgery has provided a novel approach.  Instead of simply slowing the rate at which material moves through the stomach, gastric bypass surgery actually bypasses the stomach completely except for a small pouch at the top.  Thus, the ghrelin- producing cells in the stomach somehow get turned off and the person undergoing the gastric bypass surgery ceases to be hungry.  Their metabolic rate does not drop and they burn fat at very substantial rates.  There are several individuals in central South Dakota who have undergone this type of surgery and each has commented, that in spite of losing as much as 100 pounds in the course of a year, they are not hungry.

    At the University of Washington in Seattle where this recent study on ghrelin was done, it was demonstrated that individuals who had undergone gastric bypass surgery had very low levels of ghrelin that did not rise between meals and cause hunger.  It is now highly probable that the real benefits of gastric bypass surgery are hormonal in suppressing the hormone ghrelin and not really a mechanical interruption of normal food progression through the bowel.

    While this research is in its infancy, the future will undoubtedly find inhibitors of ghrelin and other methods to suppress its secretion besides the drastic step of gastric bypass surgery.  I mentioned, in a previous column, a hormone called leptin which suppresses appetite and now we have found one that is called ghrelin that increases appetite.  Those overweight individuals who have claimed all along that there is something wrong with their hormones are now vindicated.  There is not yet a prescription that can help with this hormonal problem but I promise you help is on the way.  For those who can't wait, gastric bypass surgery still provides a definitive and life saving step for those who are very substantially overweight and willing to consider a surgical intervention.