Being in the thick of winter, well not so much winter as I remember in last years filled with frigid temperatures and lots of sun, rather meh temperatures and grey sky. I’m always keeping my radar on the amount of sun and how I feel and my vitamin D consumption.
My family dies in March! March is the month in the northern hemisphere when vitamin D levels have bottomed out. Vitamin D is a fat soluble vitamin, meaning we store it in our fat cells. With our body continually tapping into the stores, AND sun exposure decreases AND sun screen has been applied during sunny days, leading to a situation where vitamin D is about more than just mental health.
People with low levels of vitamin D in their blood have significantly higher rates of virtually every disease and disorder you can think (https://www.outsideonline.com/2380751/sunscreen-sun-exposure-skin-cancer-science) of: cancer, diabetes, obesity, osteoporosis, heart attack, stroke, depression, cognitive impairment, autoimmune conditions, and more.