Posted by Brigham and Women's Hospital May 10, 2012
Gastric bypass, Lap-Band, and hot sauce. One of these things is not like the others – or is it?
The first two are weight-loss surgeries, but hot sauce? The ingredient that gives the peppery liquid its heat could play a role in the future of weight loss, according to BWH researchers.
As the rate of obesity continues to rise throughout the U.S., so does the number of patients choosing weight-loss surgery. Yet, while most common weight-loss surgeries prove successful, they also involve significant recovery time and notable side effects. Not surprisingly, patients and doctors alike are on the lookout for less invasive surgical alternatives for weight loss.
That’s where Dr. Ali Tavakkoli, Department of Surgery, his research team, and capsaicin – the component responsible for the burning sensation in hot sauce – come in. Dr. Tavakkoli is investigating whether two surgeries – vagal de-afferentation, which uses capsaicin, and vagotomy – can achieve weight loss and reduce the risk of obesity-related diseases, such as diabetes, with fewer side effects than today’s surgical options.
Snipping and ‘Chili’-ing Out Nerves
Vagotomy involves removing the vagus nerve, which sends information between the gut and the brain. Vagotomy, typically used to treat ulcers, was promoted by surgeons in the 1980s as a weight-loss procedure, since it led to the feeling of fullness in patients who had the surgery.
However, it eventually lost its appeal due to undesirable side effects and the growing popularity of other weight-loss surgeries. But with today’s high prevalence of obesity and diabetes, researchers are revisiting vagotomy as a possible alternative.
Vagal de-afferentation, like vagotomy, also involves the vagus nerve. But rather than removing the nerve completely, surgeons use capsaicin to destroy only certain nerve fibers. Capsaicin destroys the nerve fibers that take signals from the gut to the brain, leaving intact the nerve fibers that send signals in the opposite direction, from the brain to the gut.
In other words, with the help of capsaicin (and its ability to selectively destroy and preserve certain fibers), doctors may be able to achieve weight loss without affecting gut muscle functions – “thus eliminating some of the side effects associated with a complete vagotomy,” says Dr. Tavakkoli.
So What Works?
After testing the two surgeries in his lab, Dr. Tavakkoli found that vagotomy significantly reduced total body fat, as well as visceral abdominal fat – the “beer belly” fat that pads the spaces between abdominal organs. Vagal de-afferentation also reduced these fats, but to a lesser degree. Dr. Tavakkoli believes, however, that the reduction was still remarkable.
“The reduction in visceral fat is particularly important,” says Dr. Tavakkoli. “High visceral fat volume is a marker of obesity and obesity-related diseases.”
Dr. Tavakkoli notes that there is still a lot of work to be done before determining whether vagal de-afferentation or vagotomy can actually be used more widely, and whether capsaicin could be applied directly to human vagal fibers. The study results, however, provide some promise of what the future can hold.
“As demand for surgeries that reduce weight and obesity-related diseases increases, procedures that can achieve success in a less invasive fashion will become increasingly important,” says Dr. Tavakkoli. “This is an important and developing surgical discipline, especially as diabetes rates soar worldwide, and people try to find effective therapies to fight this epidemic.”
– MMQ, Linda W