It is well established that regular exercise benefits our bodies, especially in protecting against obesity, but scientists continue to look more closely at why this is happening at the molecular level.
In a new study, scientists put mice on intense workouts on tape and analyzed how the chemicals in the cells of animals began to change over time. They found the appearance of a metabolite called Lac-Phe (N-lactyl-phenylalanine), synthesized from lactate and phenylalanine.
Phenylalanine is an amino acid that is combined to make protein, and you may be familiar with lactate: it is produced by the body after intense exercise and causes a burning sensation after training that is felt in the muscles.
The authors of the study believe that they have found an important biological pathway open to exercise, which then has an impact on the rest of the body, specifically on the level of appetite and the amount of food ingested.
Further testing confirmed these results. The researchers gave high doses of Lac-Phe to mice on a high-fat diet, which caused the mice to eat about half over the next 12 hours compared to a group of control mice. Meanwhile, the movement and energy expenditure of the animals remained unchanged.
Over a 10-day period, doses of Lac-Phe resulted in a decrease in food intake, a resulting drop in body weight, and an improvement in glucose tolerance in mice. These are positive results when thinking about ways to fight obesity and obesity related diseases.
There were some warnings, though. Differences in appetite suppression caused by Lac-Phe were only noticed after exercise and in mice on a high-fat diet. The same effects were not seen in more sedentary mice fed normally.
Scientists also analyzed the effects of exercise on humans and racehorses, finding high levels of Lac-Phe here as well, especially after sprinting in people. However, no side effects were studied and further research is needed to see if these results are fully translated in humans.
By shedding more light on molecular responses to physical activity, the results of the study will help in a number of areas of research, including treatments.
There is likely to be much more to discover. Researchers point out that because Lac-Phe occurs in a variety of cell types in mice, it’s probably not just the muscles in the body that know when we’re training.
“Future work uncovering molecular and cellular mediators downstream of Lac-Phe’s action on the brain may offer new therapeutic opportunities to capture the cardiometabolic benefits of physical activity for human health,” the researchers write. .
The research has been published in Nature.