This Sugar Substitute May Not Be So Sweet After All

Did you make the switch to artificial sweeteners, but are still having trouble taking off the pounds?

Researchers at Massachusetts General Hospital may have identified a reason why the artificial sweetener aspartame could actually be an obstacle to weight loss.

In a new study, the team demonstrated that an amino acid produced as a byproduct of aspartame digestion blocks the functioning of a digestive enzyme that has been shown to prevent obesity.

In a series of experiments, the team demonstrated that the activity of this enzyme was reduced once it was added to a solution containing aspartame. The enzyme’s activity was not reduced when added to a solution with sugar, however.

In a second experiment, the team showed that mice on a high fat diet who received aspartame in their drinking water gained more weight than mice that were fed a similar diet, but drank only water.

More research is now needed to confirm the results in humans and to identify any other mechanisms that might contribute to the weight gain.

Richard Hodin, MD, of the MGH Department of Surgery, is the study’s senior author.

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A Groundbreaking Imaging Tool Turns 25

This month, the Martinos Center for Biomedical Imaging at Mass General is celebrating the 25th anniversary of functional Magnetic Resonance Imaging, or fMRI, a groundbreaking technique that was first described in papers submitted by two Martinos Center researchers in 1991 and 1992.

fMRI was the first technology that was able to show both the structure of the brain and how different regions are activated in response to activity or stimuli. The technology works by measuring an increase in blood flow in the activated regions.

Today, fMRI is used in several clinical areas, including presurgical planning for brain tumors, where it helps surgeons differentiate the tumor from the normal functioning brain tissue.

It has also helped psychiatric researchers better understand which parts of the brain are affected by conditions such as post-traumatic stress disorder, obsessive compulsive disorder and schizophrenia.

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Blood Test May Not Accurately Measure Intestinal Healing in Pediatric Celiac Disease Patients

In a surprising new finding, researchers from the MassGeneral Hospital for Children (MGHfC) and Boston Children’s Hospital discovered that 20 percent of children with celiac disease still show intestinal damage even with strict adherence to a gluten-free diet.

The study examined 103 children with celiac disease who had been on gluten free diets for a year and had been determined to comply well with the dietary restrictions. In repeated biopsies, approximately 20 percent of these patients continued to show intestinal damage, even though the patients reported feeling better and were no longer testing high in blood screenings for celiac disease.

Findings from this study have already been translated into clinical practice at MGHfC, where most pediatric patients over the age of 10 will now be tested with both and endoscopy and a blood test after a year on a gluten-free diet.

The previous guidelines had called for endoscopy only at diagnosis, with subsequent monitoring by blood test after a year.

Although the long-term risks for children with persistent intestinal damage are not clear, such damage in adults has been linked to an increased risk of lymphoma (a cancer that affects the immune system), low bone density and more frequent bone fractures.

Maureen Leonard, MD, MSSc, and Alessio Fasano, MD, were co-senior authors of the study.

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