It’s not just your imagination--gloomy weather can make you sick, or at least prolong your illness. A Norwegian study found that winter flu epidemics are 20 to 600 times more deadly than summer flu epidemics partly because sunlight is in short supply during the winter months. According to the findings, vitamin D gives the body’s immune system an added boost. When a flu virus, or any virus, attacks a body with enough vitamin D in its system, the immune system is better able to battle the virus,
During the winter months, however, sunlight can be in short supply and many people are to, some degree, vitamin D deficient. So, when the annual winter flu season hits, the body’s’ immune system is not as prepared to fight the virus, resulting in prolonged illnesses and higher death rates.
Sourced from: Medical News Today, Vitamin D Deficiency Likely Responsible For Flu Epidemic