Medical Bulletin 09/Jul/2025

Here are the top medical news for the day:

Cutting Cysteine May Activate Fat Loss Pathways

A study published in Nature Metabolism has revealed that a specific sulfur-containing amino acid, cysteine, plays a crucial role in weight loss and fat metabolism. Conducted by researchers including Dr. Eric Ravussin and Dr. Krisztian Stadler from Pennington Biomedical Research Center, the highlights a novel approach to obesity treatment.

Cysteine, an amino acid known for its role in redox balance and cellular metabolism, was found to drop significantly in participants who practiced long-term calorie restriction. This reduction was closely linked to the transformation of white fat cells into brown fat cells a more metabolically active type that burns energy to generate heat.

To understand this relationship, researchers studied both human participants and animal models. Human fat tissue samples were collected from participants in the CALERIE clinical trial, which involved healthy young and middle-aged adults reducing their caloric intake by an average of 14% over two years. Through extensive metabolic profiling, scientists observed that lowered cysteine levels were associated with weight loss, reduced inflammation, and improved muscle health.

Animal studies reinforced these findings. When cysteine was restricted entirely, animals showed marked weight loss, increased fat burning, and significant browning of white fat. Despite a 40% drop in body temperature, a sign of cellular stress there was no observed tissue damage. “Systemic cysteine depletion in mice causes weight loss with increased fat utilization and browning of adipocytes,” said Dr. Ravussin.

Dr. Stadler added, “In addition to the dramatic weight loss and increase in fat burning resulting from the removal of cysteine, the amino acid is also central to redox balance and redox pathways in biology.”

With its dual benefits on fat metabolism and inflammation, cysteine depletion could represent a future cornerstone in combating obesity.

Reference: Lee, A.H., Orliaguet, L., Youm, YH. et al. Cysteine depletion triggers adipose tissue thermogenesis and weight loss. Nat Metab 7, 1204–1222 (2025). https://doi.org/10.1038/s42255-025-01297-8

PCOS Patients Feel Dismissed and Underserved: Study

A new study published in F&S Reports sheds light on the challenges faced by individuals living with Polycystic Ovary Syndrome (PCOS), revealing that many feel ignored, misunderstood, and underserved by the healthcare system. The research emphasizes a need for more empathetic, patient-centered approaches to PCOS care.

PCOS is a common hormonal disorder affecting up to 1 in 10 individuals with ovaries.

The study was conducted by researchers from the Departments of Obstetrics and Gynecology and Psychiatry, who held virtual focus groups with 24 participants. These discussions focused on patient experiences with the diagnosis and treatment of PCOS. Across all groups, participants consistently reported feeling dismissed when they initially voiced concerns about symptoms often in adolescence. Many described waiting years for a formal diagnosis, leading to frustration and emotional distress.

“Patients told us their concerns, such as missed periods, acne or hair loss, were frequently minimized. They often felt that their voices were not heard, and that led to a delay in both diagnosis and effective treatment,” said Dr. Phoutdavone “Noy” Phimphasone-Brady, co-senior author of the study.

Participants said the healthcare system often focused narrowly on weight loss and fertility, while they struggled more with daily symptoms and emotional impacts. “One woman in the study said her doctor seemed to care only about her fertility down the line, when, as a teenager, what she really needed help with was anxiety and persistent acne,” said Dr. Kathryn McKenney, co-director of the PCOS Multi-Disciplinary Program and senior author of the study.

With little support, many turned to online resources for information. “This kind of self-navigation creates unnecessary stress,” added Phimphasone-Brady. “It also increases the risk of misinformation, which can further delay appropriate treatment.”

“Individuals with PCOS deserve comprehensive, personalized care that attends to both their physical and emotional well-being. That care must begin with truly listening to their experiences,” said McKenney.

Reference: Gaps and opportunities in polycystic ovary syndrome care a qualitative study, Zhang, Alexander Z. et al.F&S Reports, Volume 0, Issue 0.

These Diets May Help Prevent Chronic Constipation

A new study published in Gastroenterology by researchers at Mass General Brigham reveals that middle- and older-age adults who follow Mediterranean diet or plant-based diets are significantly less likely to develop chronic constipation. The large-scale study, which followed over 96,000 adults for several years, is among the first to demonstrate that specific dietary patterns can help prevent the onset of this common gastrointestinal condition.

Chronic constipation becomes increasingly prevalent with age and can severely affect quality of life.

“Our findings suggest that as we age, certain healthy diets may provide benefits to our gut beyond the known cardiovascular benefits.” said Dr. Kyle Staller, senior author of the study and a gastroenterologist at Massachusetts General Hospital.

The researchers used long-term data from the Nurses’ Health Study, Nurses’ Health Study II, and the Health Professionals Follow-Up Study to investigate how five popular diets influence the risk of developing chronic constipation. These included the Mediterranean diet, plant-based diet, low-carb diet, Western diet, and inflammatory diet. Participants’ symptoms were tracked, with chronic constipation defined as symptoms lasting at least 12 weeks in a year.

While it has long been believed that dietary fiber plays a central role in alleviating constipation, this study found that the protective effects of the Mediterranean and plant-based diets occurred independently of fiber intake.

Conversely, those adhering to Western and inflammatory diets were more likely to develop constipation. Low-carb diets did not appear to have a significant effect. “Our findings suggest a diet rich in vegetables, nuts and healthy fats may help prevent chronic constipation in middle- and older-age adults,” added Staller.

These findings could pave the way for dietary recommendations aimed not only at treating but also preventing gastrointestinal issues as people age, providing a valuable tool for improving long-term digestive health.

Reference: Dietary Patterns and Incident Chronic Constipation in Three Prospective Cohorts of Middle- and Older-aged Adults, Wang, Yiqing et al. Gastroenterology, Volume 0, Issue 0.