How Do Different Seasons Impact Your Immune System?

Scientists have a new explanation for why people tend to be healthier in the summertime: According to a new study, it seems that your immune system may fluctuate with the seasons.

The study was recently published in the journal Nature Communications. The study notes the first time medical experts have shown a direct connection between the change in climate and our genes, including genes that affect immunity.

Previous research has indicated that certain diseases, such as cardiovascular disease, autoimmune diseases like rheumatoid arthritis and Type 1 diabetes, and psychiatric disorders, are linked to seasonal variation. With the change of seasons comes a change in the way our immune system functions, as well as changes in the make-up of our blood and fat tissue.

More than 16,000 blood and fatty tissue samples were analyzed from people living around the globe in both the northern and southern hemispheres. The study experts discovered that thousands of genes were expressed differently, meaning when they became active in a cell or tissue, during certain seasons.

The types of cells found in the blood also changed according to the season. The analysis concluded that nearly 25% of our genes (5,136 out of 22,822 genes tested) alter depending on the time of year.

Scientists were especially focused on two different findings. The first was the gene ARNTL, which was shown to be more active in the summer months. Since prior research in mice indicates that this gene suppresses inflammation, the body’s way of protecting itself, the new finding most likely means that inflammation in humans is higher during the winter, ultimately increasing our odds for developing a host of diseases.

It is my personal opinion that this may all be tied into the fact that many of us spend a significant amount of time during the winter indoors.

The relative humidity indoors during the winter in significantly lower as compared to the summer. This lower relative humidity tends to dry out our skin and our mucus membranes, which decreases their efficiency to protect us against bacterial and viral infections as well as inflammation.

Another factor related to spending more time indoors is that we are exposed to less sunlight during the winter and therefore have lower serum vitamin D3 levels. Higher vitamin D3 levels are associated with turning on good genes and turning off bad ones, as well as a number of other significant health benefits.

The bottom line here is that more research is needed to determine what exactly is causing this seasonal flux in the immune system. Once those factors are identified, we can attempt to do more things during the winter to help boost our immunity!

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