What I Learned About Vitamin D and Cholesterol That Blew My Mind
“Your vitamin D is extremely low,” Dr. K said, peering at my bloodwork. “I recommend a high-dose prescription. It’s taken once a week.”
He paused before continuing, “Another thing that really concerns me is your cholesterol level. It looks hereditary, but I’d still recommend considering a statin—a cholesterol-lowering drug.”
I sat there taking it all in… and then a memory surfaced.
“I remember reading something about a relationship between vitamin D and cholesterol,” I said. “Is that a thing?”
Dr. K looked thoughtful. “Hmm… that’s not something I’ve come across in the literature I’ve read. I can look into it and get back to you.”
I’m not against medication. But if there’s a natural approach—like spending more time in the sun, adjusting my diet, or exercise more—I’ll explore that first.
And I did vaguely remember seeing something about vitamin D and cholesterol being linked. Curious, I typed into Google:
“Relationship between vitamin D and cholesterol.”
As someone who geeks out on health and wellness, I dove in—and what I discovered blew my mind.
🧬 Cholesterol is a Precursor to Vitamin D
Wait… what?
Turns out, we need cholesterol in our skin cells to make vitamin D from sunlight. Specifically, a molecule called 7-dehydrocholesterol (a form of cholesterol) converts into vitamin D3 when exposed to UVB rays.
This blew me away:
The chemical formula for cholesterol is C27H46O.
The chemical formula for vitamin D3 is C27H44O.
The only difference? Two hydrogen atoms.
Those two hydrogen atoms are released when our skin is exposed to ultraviolet light.
So yes—the link is real. And closer than I ever imagined.
🌟 Cholesterol Isn’t the Villain We've Been Told It Is
Cholesterol has been demonized in our culture. We seek out “low-cholesterol” or cholesterol lowering foods. We’re taught cholesterol clogs arteries and causes heart attacks. But that’s just one piece of a larger story.
Cholesterol plays a critical role in the body. Blood cholesterol not only helps create vitamin D, it also converts into hormones, supports brain function, helps form blood cells, and protects our nerves.
And did you know your cholesterol level can be too low? In fact, low cholesterol is associated with mortality from stroke, heart disease, and cancer. Source: National Institute of Health
So no—it’s not all bad. Like many things in life, it’s about balance, not elimination.
☀️ Sunlight: Our Primary Source of Vitamin D
Vitamin D is crucial for healthy bones, muscles, immunity—and may help prevent diseases like diabetes, cancer, and autoimmune disorders. Source: MDPI Journal
But here’s the catch:
Diet alone usually isn’t enough to meet our vitamin D needs. The primary source? Sunlight.
Only one specific type of ultraviolet ray—UVB—can trigger vitamin D synthesis in the body. It photolyzes 7-dehydrocholesterol in the skin, starting the transformation into usable vitamin D3.
But here’s what blew my mind even more:
You can be outside and still not get any UVB.
SPF 15 blocks 93% of UVB rays
SPF 30 blocks 97%
Car, home, and office windows block nearly all UVB
So even if you think you’re getting sun, your body might not be making any vitamin D.
⚖️ Finding the Right Balance
UVB rays are a double-edged sword. Too little exposure can lead to deficiency. Too much can increase the risk of skin cancer. Same source—radically different outcomes depending on dosage.
How much is “just right”? That depends on your skin tone, location, and time of year. (This NIH paper helped, but I’m still digging into this.)
Bottom line: we need moderate, intentional sun exposure to support our vitamin D levels—and, by extension, our overall health.
📉 Could More Vitamin D Lower Cholesterol?
I also found studies exploring whether raising vitamin D levels might help lower LDL (the so-called “bad” cholesterol). The evidence is still mixed, but some research shows a possible correlation between higher vitamin D and lower LDL levels.
Source: Nature
More research is needed, but it’s a promising area.
📬 A Follow-Up from Dr. K
Two days later, Dr. K messaged me.
“I did some digging and found that there is a relationship between vitamin D and cholesterol production. UVB is the light that converts 7-dehydrocholestrol to Vitamin D3 in the body…”
💡 So What?
I feel like I just earned a mini-PhD in vitamin D and cholesterol—ha.
But seriously, what struck me most wasn’t the science itself. It was how little I actually knew about basic processes in my own body—despite being “well-educated” by traditional standards.
I had unknowingly formed beliefs based on headlines, ads, and half-truths. That cholesterol is all bad. That the sun rays cause skin cancer. None of it was completely true—or completely false.
Here’s what I learned instead:
Cholesterol is a precursor to vitamin D3
Their chemical formulas are nearly identical
Cholesterol plays essential roles in the body
Sunlight, not diet, is our main source of vitamin D
We may not be producing vitamin D even when we are “in the sun”
The answer lies in balance, not avoidance
🔍 The Bigger Lesson
The truth is often more nuanced than we’re led to believe.
When it comes to our health—and our lives—we owe it to ourselves to ask better questions, challenge surface-level assumptions, and take radical responsibility for our own well-being.
Reflection question:
What’s one “truth” you’ve accepted without questioning—about your health, body, or life—that might be worth a second look?
This is fascinating. Thank you!