A research study, published in the Journal of Immunology, has demonstrated that vitamin E regulates the immune system and combats the bacterial infection that can lead to pneumonia. A recent report on antibiotic resistance threats from the Centers for Disease Control and Prevention identified infections from Streptococcus pneumoniae as a serious concern that requires “prompt and sustained action.” The bacterium causes 1.2 million drug-resistant infections, 19,000 excess hospitalizations, 7,000 deaths, and $96 million in excess medical costs per year. Older adults and young children are at most risk for developing these drug-resistant infections.
The research was conducted on mice but translates to humans especially older adults who are at risk for developing pneumonia. The most common type of pneumonia that occurs in this age group is caused by Streptococcus pneumoniae bacteria. As a person ages, the immune system becomes weak, making them vulnerable to lung infection. The body fights this infection using specific white blood cells, known as neutrophils, that enter the lungs and kill the bacteria. If the numbers of neutrophils in the lungs are not well regulated, however, they can cause inflammation and damage. Aging can disrupt the ability of the body to regulate neutrophils.
“Earlier studies have shown that vitamin E can help regulate the aging body’s immune system, but our present research is the first study to demonstrate that dietary vitamin E regulates neutrophil entry into the lungs in mice, and so dramatically reduces inflammation, and helps fight off infection by this common type of bacteria,” said first author Elsa N. Bou Ghanem, Ph.D., postdoctoral scholar in the department of molecular biology and microbiology at Tufts University School of Medicine (TUSM).
Mice were compared before and after they were infected with the pneumonia-causing bacteria. Before these mice acquired the infection, they were fed different levels of vitamin E, specifically alpha-tocopherol, over a period of four weeks. One group of mice was fed the recommended amounts of vitamin E (the control group), while another group was fed elevated amounts of vitamin E (the experimental group).
The older mice who were fed a diet containing extra amounts of vitamin E, the equivalent to about 200 IU/day consumed by humans, about 10 times the Recommended Daily Allowance were far more resistant to the bacteria than the older mice that had a normal amount of vitamin E in their diet.
“A growing body of research suggests vitamin E could make up for the loss of immune response caused by aging,” said co-senior author Simin Nikbin Meydani, D.V.M., Ph.D., director of the Jean Mayer USDA Human Nutrition Research Center on Aging, professor of Nutrition and immunology at the Friedman School of Nutrition Science and Policy, and member of the immunology program faculty at the Sackler School of Graduate Biomedical Sciences. “Whether vitamin E can help protect people against this type of pneumonia affecting older adults requires more research.”
“Approximately 900,000 Americans get pneumonia each year; as many as 400,000 patients are hospitalized; and approximately 50,000 die. Vaccines are available but cannot protect everyone, and antibiotic resistance is a problem, particularly for older adults with pneumonia. Our work provides a better understanding of how nutrition can play a role in modulating how the immune system responds to infection,” said co-senior author John M. Leong, M.D., Ph.D., professor and chair of the department of molecular biology and Microbiology at TUSM and member of both the immunology and molecular microbiology program faculties at the Sackler School.
Bou Ghanem, E.N., Clark, S., Du, X., Wu, D., Camilli, A., Leong, J.M., Meydani, S.N. The α-Tocopherol Form of Vitamin E Reverses Age-Associated Susceptibility to Streptococcus pneumoniae Lung Infection by Modulating Pulmonary Neutrophil Recruitment. The Journal of Immunology, December 2014 DOI: 10.4049/jimmunol.140240