Diet for cells
The amount of calories consumed by a person has a direct impact on the functionality of various cells. Brazilian researchers from the University of Sao Paulo, working under the guidance of Professor Alicia Kowaltowski, have demonstrated that a low-calorie diet protects the body from a number of diseases.
The results of one of the experiments conducted by the group clarified the mechanism by which a low-calorie diet can prevent the death of neurons in the brain associated with diseases such as Alzheimer's disease, Parkinson's disease, epilepsy and acute cerebrovascular accident.
During one of the experiments, the authors divided the mice into two groups and calculated the average number of calories that the control group mice would consume without food restrictions. The animals of the experimental group were kept on a diet whose caloric content was 40% lower than the value obtained. After 14 weeks, the animals of both groups were injected with a compound that causes seizures, nerve tissue damage and neuronal death.
As a result, seizures developed only in animals of the control group that were not limited in calories consumed. To study the changes occurring at the cellular level, the researchers isolated the organelles of the brain cells of mice of both groups and placed them in a nutrient medium. When calcium ions were added to this medium, they were more actively absorbed by the mitochondria of animals of the experimental group.
The main role of mitochondria in the cell is to produce energy. The results of an earlier study showed that in conditions of a low-calorie diet, mitochondria activate the process of absorption of calcium ions with a pathological increase in their concentration.
Insulin
The results of a series of experiments on cultures of insulin-producing beta cells of the islets of Langerhans of the pancreas have shown that a low-calorie diet improves the response of cells of this organ to an increase in the concentration of glucose in the blood.
Blood serum from mice kept on different diets was added to the culture medium of these cells. When the blood serum of animals that consumed a reduced amount of calories was injected into the medium, beta cells produced insulin in a normal mode: in a small amount with a low concentration of glucose and in large quantities with an increase in its concentration. This did not happen when the serum of obese animals was added to the medium, which developed as a result of consuming a large number of calories. The results of the experiment indicated the existence of some kind of circulating factor in the blood that modifies the functions of beta cells.
The researchers again hypothesized that this phenomenon is related to mitochondria, since insulin secretion depends on the availability of ATP (adenosine triphosphate, an energy carrier molecule) in the cell.
When measuring the level of oxygen uptake by two cell cultures, it was found that this value was higher for cells whose culture medium was supplemented with blood serum from animals kept on a low-calorie diet. Since cellular respiration (oxygen uptake) is a key condition for the release of insulin by beta cells in conditions of increased glucose levels, this observation indicated an increase in ATP production when the blood serum of animals of the low-calorie diet group was added to the medium.
Other experiments also demonstrated that the mitochondria of cells, in the culture medium of which blood serum of animals kept on a low-calorie diet was added, more actively exchanged material with each other, which increased their efficiency.
Healthy aging
Professor Kowaltowski emphasizes that understanding the mechanisms underlying the maintenance of normal metabolism is necessary for the prevention and treatment of metabolic diseases such as obesity. It is well known that obesity is one of the prognostic factors of pathological aging.
Obese people are much more likely to develop age-related diseases, including neurodegenerative diseases such as Alzheimer's disease, proliferative diseases such as cancer, metabolic diseases such as type 2 diabetes mellitus and hyperlipidemia, as well as heart failure and acute cerebrovascular accident.
Preventing the development of obesity will prevent the development of all these diseases. However, even constant warnings about the exceptional importance of a balanced diet and physical activity do not affect the epidemic on a global scale.
Therefore, understanding the mechanisms by which obesity increases the risk of developing all of these diseases will provide us with more tools for their prevention.
The results are presented at the FAPESP Week symposium, held in London on February 11-12 as part of the Anglo-Brazilian Year of Science and Innovation program. http://ukbryearofscience.com/en/
Evgenia Ryabtseva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of Agencia FAPESP: Diets consisting of fewer calories improve cell performance.