Tired of diets with no weight loss? Scientists say cutting cysteine may help

Tried all the diets under the sun, and yet the weighing scale refuses to move? Calorie-restrictive diets, avoiding certain foods and eating specific ones, cutting back on sugar, weight loss strategies come in all shapes and sizes. Despite putting themselves through all these, some people find it hard to lose weight. Why? Scientists have found a key factor that may have a role to play in this. A new study led by Pennington Biomedical researchers found that a specific sulfur-containing amino acid cysteine, is a key component in weight loss. The findings of the study are published in Nature Metabolism. Cysteine’s role in weight lossThough consuming fewer calories has been associated with improved health and weight loss, recent research found the key role of cysteine in metabolism. The researchers found that participants who were on a calorie-restrictive diet had reduced levels of cysteine in white fat.Pennington Biomedical researchers Dr. Eric Ravussin and Dr. Krisztian Stadler, along with other scientists, studied the amino acid cysteine and found that it plays a huge role in how our body handles fat. Normally, we have white fat cells that store energy, but when cysteine levels drop, these cells can turn into brown fat cells. Brown fat is more active because it burns energy to create heat and maintain body temperature. When the researchers restricted cysteine in animal models entirely, the test subjects exhibited high levels of weight loss and increased fat burning and browning of fat cells, further demonstrating cysteine’s importance in metabolism.“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. These results suggest future weight management strategies that might not rely exclusively on reducing caloric intake,” Dr. Stadler, who directs the Oxidative Stress and Disease laboratory at Pennington Biomedical, said in a statement.The study The study involved human and animal trials. The human trial involved healthy young and middle-aged men and women. They were instructed to be on a calorie deficit diet, by an average of 14% over two years. In the human trials, the researchers examined fat tissue samples taken from trial participants who had actively restricted calorie intake over a year. When the fat tissue samples were examined, the researchedlooked for changes in the thousands of metabolites, which are compounds formed when the body breaks down food and stores energy. The exploration of these metabolites indicated a reduced level of cysteine. They also noticed that the participants had subsequent weight loss, improved muscle health, and reduced inflammation.“Reverse translation of a human caloric restriction trial identified a new player in energy metabolism. Systemic cysteine depletion in mice causes weight loss with increased fat utilization and browning of adipocytes,” Dr. Ravussin, who holds the Douglas L. Gordon Chair in Diabetes and Metabolism at Pennington Biomedical and oversees its Human Translation Physiology Lab, added. For animal trial, the calorie restrictive meals were provided. They found that it lead to a 40% drop in body temperature, but regardless of the cellular stress, the animal models did not exhibit tissue damage, suggesting that protective systems may kick in when cysteine is low.The results are a remarkable discovery which confirms that cysteine regulates the transition from white to brown fat cells, and could open new therapeutic avenues for treating obesity. The new findings explporing important metabolic mechanism could eventually transform how we approach weight management interventions.