"Caloric restriction" leads to longer life: helps the thymus produce T cells and reduces the inflammasome
Is the super simple longevity method effective by limiting caloric intake?
In the past few decades, scientists have found in a large number of animal experiments on flies and mice that restricting caloric intake can help extend the life span of organisms. However, there is still no large-scale experimental data to directly prove whether the human body can obtain the same benefits.
The Yale University research team published the results in the journal Science using subjects from the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE). The research team claimed that caloric restriction affects a protein “PLA2G7” related to extending healthy lifespan, which can indeed reduce chronic inflammation and increase the number of T cells.
The Yale University team divided more than 200 participants into two groups. One group reduced their caloric intake by 14%, and the other group ate according to the caloric intake standards. They regularly monitored the physical changes of the two groups and analyzed the health effects of caloric restriction. And observe whether it also causes changes in inflammatory mechanisms and immune responses.
Professor Vishwa Deep Dixit, the lead author and director of the Yale University Aging Research Center, said that the body’s long-term state of chronic inflammation is the cause of many chronic diseases and obviously has a negative impact on life span. This trial mainly explores the impact of “caloric restriction” on the immune and metabolic systems. If it is really beneficial, through which endogenous pathway is the effect achieved?
Caloric restriction changes the microenvironment to allow the thymus to produce more T cells
The main target of analysis by Professor Dixit’s team is the changes in the “thymus” of the two groups of subjects. The thymus is located above the heart and under the collarbone. It is an important gland that promotes T cells in immune cells. T cells, also known as killer cells, can help identify foreign sources of infection and eliminate infected cells. They are an important component of the human immune system. .
The thymus ages faster than other organs. In healthy adults, by the age of 40, 70% of the thymus tissue has been blocked by fat. As we age, the number of new T cells decreases. The lack of newly manufactured T cells makes the body less good at fighting new pathogens. This is one of the reasons why the elderly have a greater risk of morbidity and severe illness.
Experimental results found that subjects who reduced caloric intake by 14% had less fat and larger functional volume in their thymus tissue after 2 years, indicating that the thymus produced more T cells than at the beginning of the study. In contrast, there was no change in the functional volume of the thymus in subjects who did not restrict calories.
“The results of reviving the thymus are quite exciting, because there is no similar research evidence that this happens in humans!” Professor Dixit said that it was originally expected that caloric restriction would cause changes in T cell genes, but in the end Tests found no changes in gene expression. It is speculated that the effects of caloric restriction occur in the microenvironment rather than in T cells in the blood.
Fat affects gene expression, reducing calories can reduce inflammation
The research team also claims that caloric restriction helps reduce fat, and fat tissue changes the body’s metabolic and anti-inflammatory systems, as well as the expression of genes in animals that affect lifespan.
Professor Dixit’s research team stated that in subjects who adopted caloric restriction, the “PLA2G7” (platelet activating factor acetyl hydrolase) gene was significantly inhibited in the body, and PLA2G7 is a protein produced by macrophages. Animal experiments found that the amount of PLA2G7 When reduced, the thymus can maintain its function for a longer period of time and can also reduce weight gain and inflammation problems caused by aging.
Another important mechanism is that “PLA2G7” is related to the “NLRP3” inflammasome. Once NLRP3 is overactivated, it may promote the development of inflammatory diseases such as cardiovascular disease, type 2 diabetes, cancer, kidney disease, and neurodegenerative diseases. In experiments on mice, it was found that reducing PLA2G7 can reduce chronic inflammation in old animals. Various evidences show that there is an interaction between the metabolic system and the immune system.
Professor Dixit claimed that perhaps by controlling the gene expression of PLA2G7, benefits similar to caloric restriction can be obtained, allowing people who are not suitable for low-calorie diets to have a healthier body.
“As for which diet is the best? Is it low-carb, low-fat, high-protein, or intermittent fasting? There is still a lot of controversy over various methods. Time will tell which things are important!” Professor Dixit pointed out , “CALERIE” is a well-controlled large-scale study that proves that as long as calories are reduced, immune and metabolic benefits can occur without a specific dietary pattern. From a public health perspective, it does bring more hope.
Source:
Caloric restriction in humans reveals immunometabolic regulators of health span
Calorie restriction trial reveals key factors in enhancing human health
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