How the Change in Seasons Affects Your Health

As the weather gets cooler, we all know the cold and flu season are sure to follow. In fact, there are seasonal variances in many infectious diseases, gene expressions, and chronic health conditions. Understanding how the factors at play interact with one’s lifestyle are important to maintaining health throughout the year.

Bacterial staph infections, common in hospital settings, occur more often in the summer and fall and can take the form of food poisoning, skin infections, pneumonia, meningitis, and sinusitis. There are other infections that accompany changes in the seasons that not only cause illness but may trigger chronic health conditions. An infection may result in an autoimmune condition when the antibodies created to fight the infection mistakenly attack healthy cells or tissue with proteins similar to the bacteria or virus. Studies have begun to link infections to lupus, cardiovascular disease, stroke, gastrointestinal conditions, psychiatric conditions, and obesity.

Variation in gene expression that accompanies changes in the seasons may influence susceptibility to disease. How genes are expressed as a result of an individual’s environment, lifestyle, and the seasons is what matters most. In a study of 606 healthy individuals, researchers found that seasonal variation is an important environmental regulator of gene expression and blood cell composition. They noted that changes in white blood cell counts and the genes involved in the immune function indicate that immune cell physiology varies throughout the year in healthy individuals. When gene expression is down during certain seasons, it may lead to higher susceptibility to disease.

Using data from different latitudes around the world, including the US, Germany, UK, Australia, Ghana, and Iceland, another study found that 23% of the human genome had different expressions in a seasonal pattern. Further, it was shown that the immune system is more pro-inflammatory during the winter months for those living in temporal climates like the UK. In Ghana, gene expression changes correlated to its rainy season when there are more pathogens.

Temperature changes that accompany seasonal change may play a role in triggering acute and chronic conditions, especially in the elderly, children, and vulnerable populations. The results of one global study using a decade of data found that cold ambient temperatures increased mortality rates. Seasonal temperature changes have other broad effects, such as increasing and decreasing the number of bacteria and viruses that are spread, as well as specific effects, such as the aggravation of multiple sclerosis (MS) in hot conditions. Therefore, it is important to avoid extreme temperatures, especially extreme cold.

Seasonal changes can affect important chemicals and hormones in the body that interact with the immune system, such as vitamin D and melatonin. Deficiencies in vitamin D are associated with infectious diseases, autoimmune conditions, metabolic syndrome, acute stoke, cancer, and weakened bones. As a result of seasonal changes, vitamin D should be monitored throughout the year with particular attention to the winter and spring months when levels are naturally the lowest. To boost vitamin D levels, get 5 to 30 minutes (based on skin type) of sun twice a week without sunscreen on at least an arm and the face, and eat more vitamin D-rich foods such as salmon, fortified orange juice, milk alternatives, and cod liver oil. A vitamin D supplement also may be recommended by your practitioner.

Melatonin levels vary from season to season as the days get longer or shorter and could affect one’s susceptibility to diseases. In addition to regulating the sleep-wake cycle, melatonin serves several key functions, including influencing the immune system and glucose, and providing anti-inflammatory, antioxidant, and anti-hypertensive defenses. Changes in melatonin are linked to autoimmune conditions, Alzheimer’s disease, neurodegenerative disorders, gastrointestinal imbalances, obesity, metabolic syndrome, and MS. To keep melatonin at the right level, especially in the winter, spend time outdoors in the morning, maintain a consistent sleep-wake cycle, consume tryptophan, folate, and vitamin B6, and take supplemental melatonin when recommended by your practitioner.