Vitamin D is an essential nutrient for health. It can be obtained by exposing the skin to sunlight and eating fatty fish, oils, eggs, liver pate, cheese, milk, and butter.
It helps the body absorb calcium, one of the main substances needed for strong bones. Vitamin D, along with this mineral, helps prevent osteoporosis, a disease that causes bones to weaken. Additionally, muscles need it to move and nerves use it to carry messages between the brain and other parts of the body.
On the other hand, it is essential so that the immune system can fight bacteria and viruses that attack it. Two studies, conducted by researchers at the Millennium Institute of Immunology and Immunotherapy (IMII) and academics Susan Bueno and Manuel Álvarez at the Pontifical Catholic University of Chile (UC), are part of this field and suggest that a lack of this vitamin can make people more The human body is susceptible to acute bacterial infections and autoimmune diseases such as inflammatory bowel disease. Therefore, diagnosing a deficiency in this nutrient and initiating appropriate treatment will be a priority in reducing the incidence of this disease.
Infectious diseases are one of the leading causes of death in the world, especially among young children and the elderly. For example, among the first cohort, pneumonia caused the most deaths, with 740,000 deaths in 2019, according to the World Health Organization (WHO). Overall, the death toll is approximately 2.4 million. In addition, approximately 336 million people suffer from lower respiratory tract infections every year. Meanwhile, diarrhea is the second leading cause of death in children under 5: 525,000 people die from it every year, according to the World Health Organization. The agency said cases among children have reached 1.7 billion.
UNICEF estimates that nearly 34 million children died from pneumonia or diarrhea between 2000 and 2016.
Vitamin D in Chile
The 2016 National Health Survey is the first population-based study in Chile to provide vitamin D data, and the sample is representative of the entire country. In this case, the target groups of the study are women of childbearing age between 15 and 49 years old and elderly people over 65 years old. Measurements show that 84% of the Chilean population is deficient in vitamin D to varying degrees. Research shows that among women of childbearing age (under 50 years old), 16% suffer from severe deficiency, while in older age groups, severe conditions are more common, reaching 21.5% of those examined.
On the other hand, a 2019 study of children aged 4 to 14 years in Santiago, Concepción and Antofagasta showed that more than three-quarters of them had low vitamin D levels.
immune response
The UC School of Biological Sciences professor’s research, sponsored by the Fondecyt 2023 regular competition, aimed to determine whether vitamin D affects the response of neutrophils, one of the first immune cells to respond when microorganisms enter the body. Acute bacterial infection.
The microbiologist said vitamin D “has emerged in recent years as a promising immune modulator for different cells involved in innate and adaptive immune responses, including neutrophils. Specifically, this vitamin can Regulates the production of cytokines (small proteins critical for controlling the proliferation and activity of other cells of the immune system and blood cells) in neutrophils and improves their ability to destroy bacteria by enhancing the production of antimicrobial peptides in the cells.
The project states that there are several clinical and epidemiological studies linking vitamin D deficiency to an increased risk of serious infections, but also notes that current data on vitamin D immune modulation in the setting of pneumococcal infection are unclear. Studies have not addressed the potential role of this nutrient in host defense and survival. Additionally, there are reportedly few studies showing the impact of vitamin D deficiency on infections caused by Salmonella.
The aim was to test the hypothesis that vitamin D modulates neutrophil responses in acute bacterial infection, favoring bacterial elimination and preventing damage to infected tissue. Susan Bueno explains that this was accomplished by “evaluating the role of this vitamin in inflammation, host defense, and neutrophil function during pneumococcal and salmonella lung infections.”
Likewise, doctors in Biomedical Sciences said they will evaluate whether taking calcitriol, a drug containing active vitamin D, can improve host defenses against pneumococcal bacteria (the most common cause of pneumonia) and influenza viruses. ability. The bacteria that cause salmonella. It will also be analyzed whether vitamin D directly modulates the antibacterial function and neutrophil inflammatory response to both bacteria.
“Given the emergence of more virulent, multidrug-resistant bacterial pathogens and the vitamin D deficiency in the world’s population, this study is extremely relevant,” stressed the professor at the University of California School of Biological Sciences, as it aimed to identify ways to improve New approaches to immunity against pathogenic microorganisms. “
He noted that this study is “very important because vitamin D deficiency is very common in Chile.”
chronic inflammation
Inflammatory bowel disease (IBD) is a group of diseases that cause chronic inflammation of the mucosa of the small and large intestines, according to a project led by IMII associate researcher Manuel Álvarez. As scholars explain, these pathologies manifest clinically in two main forms: Crohn’s disease and ulcerative colitis.
The characteristic symptoms of inflammatory bowel disease are usually diarrhea, fever, abdominal pain, and blood in the stool, which can occur alone or together, resulting in attacks of varying severity.
Although IBD has been described since the 20th century, its cause remains unclear, and its incidence has increased in recent decades, particularly in Western countries. In 2017, the global IBD prevalence was estimated at 84.3 cases per 100,000 people. “This is a significant increase compared to 1990, when there were 79.5 cases per 100,000 people,” said Manuel Álvarez. Research shows industrialization changes people’s lifestyles , thereby increasing exposure to environmental factors associated with the onset of IBD.
IMII associate researcher noted that IBD is a multifactorial condition in which different genetic and environmental factors are associated with the emergence, progression and severity of these pathologies. He added: “Latest research shows that in addition to the interaction between genetic and environmental factors in the development of IBD, the status of the gut microbiota is also of great relevance. “Therefore, as a multifactorial disease , it is difficult to determine the mechanism of unilateral inflammation in patients. “
Given that the incidence of IBD has increased in Western countries, environmental factors that may influence this increase were investigated. “In general, the lifestyle of people living in Western countries is affected by a variety of environmental factors that may affect IBD, such as stress, diet, lack of sun exposure, etc.,” said the University of California professor. “This last factor affects the levels of vitamin D in the body, and vitamin D deficiency is associated with the severity of IBD symptom attacks,” he added.
In this sense, Alvarez explained, various studies have shown the importance of adequate concentrations of vitamin D for maintaining the integrity of the intestinal epithelium (i.e., the cellular tissue that covers said organ), the endothelium of blood vessels, and the immune system. of correct operation. The gastroenterologist added that vitamin D can influence gene expression and alter important signaling pathways, including the ability and integrity of epithelial cells to mount an immune response.
«In people with inflammatory bowel disease, a disturbance in the intestinal epithelium is observed, which allows increased permeability and the potential for intestinal microorganisms to enter the intestinal wall. Since the cells of this system are present in the intestinal wall, the passage of microorganisms through the intestinal lumen induces their activation and immune responses, which are dysregulated in patients with inflammatory bowel disease. This is why potential problems that may arise for intestinal epithelial cells in establishing an intact and minimally permeable barrier have been studied. This would avoid over-detection of gut microbes and subsequent over-activation of immune cells, thereby preventing a dysregulated inflammatory response in patients. ” said members of the Millennium Institute of Immunology and Immunotherapy.
“Given the nutritional status of our country, understanding the role of this important nutrient in the immune system and how it affects our population is critical to better guide the treatment of diseases that may be related to vitamin D deficiency,” he said. Alexis Kalergis is Director of the Millennium Institute of Immunology and Immunotherapy and Professor at the Pontifical Catholic University of Chile. «At IMII, we support collaborative and multidisciplinary research to address health issues related to the immune system to generate excellent scientific knowledge that contributes to improving the quality of life of the Chilean people. The research conducted by Susan Bueno and Manuel Álvarez can undoubtedly have a huge impact at the national level.