I’ve written here before about my long and occasionally expensive relationship with my dermatologist — the product, I’m pretty sure, of Irish ancestry combined with years of swim team and summers spent lifeguarding as a kid.
In fact, I have an appointment with him today. These days I’m pretty religious about sunscreen, which he strongly endorses. Apparently, there’s a catch that I think a lot of people might have missed.
It’s that vitamin D — sometimes called the sunshine vitamin because your body produces it when your skin is exposed to sunlight — is one nutrient that my otherwise sensible SPF habits might be denying me.
Block enough sun, and you may also be limiting how much vitamin D your body makes naturally. You can get some from food — fatty fish, egg yolks, and fortified milk. It’s also in most standard multivitamins.
However, sun exposure is the primary natural source for most people, which means those of us slathering on SPF 50 every morning may be quietly running low without knowing it.
Recently, i came across a new study that made me think about vitamin D levels in a way I honestly never had before.
Poetic justice?
Researchers at the University of Galway followed 793 adults with an average age of 39 — none of whom had dementia — and measured their vitamin D levels at the start of the study.
About 16 years later, the same participants underwent brain scans measuring tau protein and amyloid beta, both of which are biomarkers for Alzheimer’s disease.
The study, published in Neurology Open Access, found that those with higher vitamin D levels in midlife had measurably lower tau buildup in brain regions known to be affected earliest in Alzheimer’s, specifically areas tied to memory formation.
The association held up after controlling for age, sex, depression, and other health factors.
“These results suggest that higher vitamin D levels in midlife may offer protection against developing these tau deposits in the brain,” said lead author Martin David Mulligan, “and that low vitamin D levels could potentially be a risk factor that could be modified and treated to reduce the risk of dementia.”
Ironically, the University of Galway is in Ireland, which, given that I’m blaming my Irish ancestry for my dermatologist bills in the first place, feels like a certain kind of poetic justice.
16 years later
The vitamin D measurements were taken when participants were around 39 years old, and the brain scans came 16 years later.
Whatever was happening in those people’s bodies during middle age — the sunscreen habits, the time spent outdoors, whether they thought to take a supplement or whether their multivitamin was doing enough work — showed up in their brains a decade and a half down the road.
Mulligan made the point explicitly: Midlife is when risk factor modification can have the greatest impact on long-term brain health. It’s not in your 70s, when damage may already be accumulating.
The good news is that something as simple as a routine blood test — the kind your doctor can order at your next physical — could tell you whether you’re in the 34 percent with low levels.
If you are, it’s a relatively easy thing to address. A supplement, a multivitamin with adequate D, a conversation with your doctor about the right amount for your situation.
A nudge
The researchers are careful, and you should be too. This is observational research — vitamin D was measured only once, not tracked over time, so there’s no way to know whether levels fluctuated over those 16 years.
Also, the study shows an association, not proof that vitamin D directly prevents Alzheimer’s.
Bottom line: Get your levels checked. Find out where you stand. If you’re low, talk to your doctor about whether it makes sense to do something about it.
Given the alternative — finding out 16 years from now that you probably should have — it all seems like a manageable ask.
Other things worth knowing …
AP: The Trump administration told Congress it plans to admit up to 17,500 white South Africans as refugees through September, up from an earlier cap of 7,500, citing what it called an "emergency refugee situation." Virtually all refugees admitted to the U.S. over the past six months have been from South Africa, even as millions of people displaced by other conflicts remain excluded.
NBC News: Trump endorsed Texas Attorney General Ken Paxton over sitting Sen. John Cornyn ahead of next week's Texas Senate runoff — the latest in a series of moves by the president to reshape the Republican Party in his image.
France 24: Iranian authorities held mass public weddings in Tehran Monday for couples who signed up to a state-sponsored scheme declaring their readiness to sacrifice their lives in the war against the US and Israel.
CNN: The Long Island Rail Road strike — the first in more than 30 years on North America’s largest commuter rail system — ended Monday night after three days, with trains resuming at noon Tuesday.
Reuters: SpaceX is planning to price its IPO as early as June 11 and begin trading on Nasdaq under the ticker SPCX as early as June 12, according to sources familiar with the matter. The company is targeting a valuation of roughly $1.75 trillion and aims to raise approximately $75 billion — which would make it the largest initial public offering in history, nearly double Saudi Aramco’s record.
NPR: More than a quarter of private colleges — 442 of the nation’s 1,700 private, nonprofit four-year schools, with a combined 670,000 students — are at risk of closing or merging within the next ten years, according to a new analysis. Federal funding cuts, demographic shifts, and declining enrollment are all contributing factors.
CBS News: Researchers analyzing blood samples from 85 sharks near a remote island in the Bahamas found that about one in three tested positive for caffeine, cocaine, or painkillers. Caffeine was the most common hit — and the first time it has ever been detected in sharks anywhere. “While the detection of cocaine tends to draw immediate attention,” one researcher said, “the widespread presence of caffeine and pharmaceuticals is equally alarming.”
Thanks for reading. I wrote about some of this at Inc.com. See you in the comments.