Even with daylight savings in effect, your friend still spends the majority of his time indoors. His job—which starts early and lets out late—requires full-body armor (aka a suit) that blocks all of his limbs from the sun. He slathers on the Kiehl’s SPF his girlfriend gifted him to protect his Irish mug in the rare case he does commute post-sunrise, blocking any rays from his pale cheeks. And when the weekend hits, your pal prefers to decompress with video games and Netflix marathons versus, say, riverfront half-marathons. When he’s finally regrouped enough to socialize on Saturdays, it’s usually past dark—and naturally, he’s looking for a dark bar.
The majority of Americans (especially those who live in Northern climates) don’t get enough sun, says physician Joel Fuhrman, president of the Nutritional Research Foundation and faculty member of the Health Sciences Division at Northern Arizona University. In fact, research shows a whopping 42 percent of adults are deficient in Vitamin D, the sunshine vitamin that the body can’t produce naturally and has a tough time getting enough of through food alone.
What’s Likely to Happen
Your friend’s sleep habits and emotional health might be the first to take a hit: Sun exposure during the day helps regulate the body’s production of melatonin, the sleep hormone, stabilizing the natural sleep-wake cycle to ward off insomnia and ensure a deep snooze, Fuhrman says. And because sunlight triggers the release of serotonin (the "happy hormone" that's important for feeling alert and stable), life in the dark puts your buddy at an increased risk of depression and seasonal affective disorder.
After two to four months of little or next to no sunlight, his Vitamin D levels could drop low enough that they might start messing with his body’s absorption of calcium (a process enabled by Vitamin D), Fuhrman says. A common result: fatigue, aches and pains in his limbs and joints, and muscle spasms that can even occur in the GI tract, triggering indigestion. Because a solid dose of Vitamin D has been linked to a healthy immune system, your friend may also be more prone to getting, or take longer to recover from, viruses like the common cold, Fuhrman says.
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The Worst That Could Happen
If your friend continues to live a vampire-like lifestyle and stays low on Vitamin D over a number of years, he could be looking at an increased risk of hair loss—or even cancer—down the road, Fuhrman says. Some studies have linked chronic levels of low Vitamin D to diseases like Alzheimer’s, cardiovascular disease, and diabetes, but more research is needed before we can point to a solid cause and effect of any of these long term consequences.
What to Tell Your Friend
If he can find a way to get a little ambient light exposure during the day, even if it's just through an office window for a few minutes at a time, that could help regulate his melatonin production to make sleep more restful, and ward off the depressing effects of missing out on natural sunshine, says Alex Korb, a neuroscientist at UCLA and author of The Upward Spiral: Using Neuroscience to Reverse the Course of Depression, One Small Change at a Time. Investing in a sunlamp or lightbox is an option, too.
Window time won't help the Vitamin D problem, though, because glass blocks UVB rays, which are needed to make D. (Note that you can still get sunburned through glass, though, because UVA rays pass through it.) Going outside to soak up some rays would potentially help, but sunscreen blocks UVB rays, so your friend will make less D with it on. Plus, the sun is a known carcinogen, so it's hard to ensure that he gets enough outdoor sun exposure to raise his D levels but not so much that he raises his risk of skin cancer.
A daily D supplement will cover your friend’s bases until he can check in with his doctor. The National Academy of Medicine recommends most adults get 600 IU of D a day, but Furhman says most adults need to supplement with closer to 1,000 to 2,000 daily IU. Most D supplements are considered safe as long as you don’t take more than 4,000 IU. Your friend can get more D through fortified dairy products and breakfast cereals, along with some fatty fish like salmon (3 oz may pack around 400 IU).
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