Do you ever wonder why stiff joints are more common on winter or why it's more difficult to lose weight during this season? While you can blame the latter on the holidays, science says it's all because of your genes.
A large research conducted by Professor John Todd of Cambridge University and his team discovered that some of the immunity genes tend to be more active in certain seasons such as the winter. There are also times when they tend to be "off."
The basis of the study was a chance discovery. A PhD student under him learned that white blood cells, the type of blood cell that is responsible for fighting infection and building immunity, tend to have more active immunity genes once the season gets a lot colder.
From this, they analyzed more than 20,000 different types of genes from over 15,000 people around the world who provided samples of their tissues and blood. The diversified sample is presumably because of the varying season patterns.
Upon their analyses, the team discovered that those who lived in a region where seasons tend to be more consistent such as Iceland, the degree of changes in their genes is pretty low. However, in countries that experience significant seasonal changes such as the UK, immune genes become more active when it's winter. In areas where seasons are limited, such as in Asia where they have only dry and wet season, there's more gene activity once the rainy season came along. Overall, at least 25% of the studied genes showed response to the changing seasons.
Researchers have no clear explanation why this happens except that it may be related to evolution or the genes simply react to environmental cues like light or temperature. Nevertheless, it's possible that the body increases the body's immunity as a way of preparing it from the possible diseases that can occur within a season.
The increased immunity may also be the reason why inflammatory diseases such as arthritis are more common during winter. As the immune system is increased, there's a good chance it can go into a hyperdrive, attacking instead of protecting the body.
The study is available in Nature Communications.
