With age, fat accumulates in the abdominal area in many people - even if they are otherwise slim. This is not without danger, because belly fat is considered a risk factor for many diseases such as diabetes, high blood pressure, gout and coronary artery disease. Researchers at the University of Yale and the University of Bonn have now found a possible explanation for why fat loss no longer works properly in old age. According to the scientists, the study currently published in the "Nature" magazine could also open up new therapy options.
Thicker bellies even for slim people
Older people usually have more fat in the abdomen, even if they are otherwise normal weight. The reason for the increasing "hip gold" is an impaired fat loss in old age, informs the University of Bonn. As a result, the body only taps into the fat stores on the abdomen and hips to a very limited extent when it needs energy. Until now it was unknown why fat loss works poorly in old age. Scientists from the University of Yale and the University of Bonn have now been able to provide valuable explanatory approaches through a study with mice.
Researchers examine belly fat from mice
In order to understand what causes the breakdown of fat loss, the researchers examined the adipose tissue of laboratory mice - because these also only insufficiently break down fat in old age, the University of Bonn informed in a current report. The Yale group assumed that the cause of the age-related changes was a certain cell type in the rodent's belly fat, more precisely a new type of so-called macrophages. These large phagocytes are white blood cells (leukocytes), which among other things play a crucial role in the defense against pathogens.
Phagocytes sit next to nerve cells
The researchers led by Prof. Dr. Vishwa Deep Dixit from Yale University had previously recognized that these types of phagocytes are also located in adipose tissue, always close to nerve cells. Once the mice go hungry, the nerve cells would produce messenger substances that stimulate fat burning, the report said. The researchers therefore assumed that the macrophages could be the cause of the fat metabolism disorder.
Bonn scientists analyze transcriptome data
For their investigation, the scientists isolated all active genes (transcriptome) from the macrophages in the belly fat of the mice - both in the young and in the old animals. All rodents had been put on a diet before this step. They then sent the data to the Life & Medical Sciences Institute (LIMES) at the University of Bonn for further investigation.
The analysis of the Bonn colleagues brought the first insights: “We were able to find out which genes differ in their activity in old and young animals. This included the hereditary systems that are responsible for the slower fat metabolism in old age, ”said Prof. Joachim Schultze from the LIMES Institute, according to the announcement.
Enzymes destroy noradrenaline
After limiting the genes in question, the US researchers were finally able to demonstrate the mechanism of the impaired fat loss. Accordingly, the nerve cells in abdominal fat release the neurotransmitter noradrenaline in hunger mode, which stimulates fat loss. In the older animals, however, the macrophages constantly switched to a kind of inflammation mode, whereby the phagocytes increasingly produced the enzyme monoamine oxidase-A (MAOA). MAOA in turn destroys the norepinephrine, which prevents the rodents from breaking down the accumulated fat.
Transferability of the results to people is being examined
According to the communication, this proof has so far only applied to mice. But the researchers assume that an analogous mechanism is responsible for the increase in belly fat in old age. This theory is currently being tested and could open the door for new therapy options if there is sufficient evidence. For example, it is known that the enzyme monoamine oxidase-A can be inhibited by certain antidepressants. "In theory, these drugs could be used to improve the metabolism of older people," said study leader Vishwa Deep Dixit.
Tips: This is how you can reduce belly fat
Small changes in everyday life are often a good start to reduce belly fat and thereby reduce the risk of cardiovascular diseases. For example, a regular breakfast is important to avoid cravings for sweets and fats. In addition to fiber and minerals, a healthy and balanced breakfast should also include vitamins and complex carbohydrates e.g. included in the form of whole grain bread. Generally, be sure to drink plenty of cold water regularly throughout the day to fill your stomach and avoid sudden starvation attacks.
If you want to reduce belly fat, you should pay attention to a low-calorie diet with lots of fruits and vegetables, healthy olive oil, fish and protein-rich foods. Finished products, chips, fast food, soft drinks and sugar should be avoided.
Move as much as possible
Exercise is just as important as proper nutrition in order to melt the fat on the stomach and hips. Use every opportunity for activity, e.g. by to drive to work by bike. Strength training is particularly effective. Avoid negative stress, because this is often the trigger for cravings for sweets or greasy snacks. (No)