Sunlight brings us joy. It helps us wake up in the morning, keeps us warm, and makes being outdoors pleasant. But it also has a nifty way of making vitamin D from cholesterol.
That’s why vitamin D is called the “sunshine vitamin.” It is crucial for health and well-being, drawing the attention of healthcare providers and supplement manufacturers alike.
But did you know that vitamin D is not a vitamin at all? In fact, it is a secosteroid hormone. This powerful compound is essential for various bodily functions, yet its supplementation can be a double-edged sword.
Join us as we uncover the ins and outs of vitamin D and the potential dangers behind those seemingly innocent supplements.
The Secosteroid nature of Vitamin D.
Everyone’s heard of steroids and can probably even list a few such as cortisol or testosterone. But have you heard of secosteroids? Vitamin D is one of these unique class of compounds. Basically, they are steroids with a slightly different molecular structure—a “broken” ring. Because of this broken ring structure, a secosteroid has the ability to transform into a variety of shapes and perform many functions within the body.
Vitamin D comes in several forms. The most common ones in humans are:
- Vitamin D3 (cholecalciferol). It is found in certain animal-based foods and synthesized in the skin from cholesterol in the presence of sunlight.
- Vitamin D2 (ergocalciferol). This form of the vitamin is usually pharmaceutically manufactured and added to food or sold as supplements.
Both are transformed in the liver and kidneys to become the active hormone calcitriol, a molecule with potent health benefits.
The focus today is on the outrageous vitamin D recommendations circulating on social media. There are videos on YouTube right now suggesting 10,000 IU, and even 50,000 IU of vitamin D are beneficial. And as a research biochemist, I find that advice hard to accept.
The biggest risk with high doses of vitamin D is hypercalcemia, or high levels of calcium levels in the blood. This can cause nausea and vomiting, weakness, and frequent urination. Hypercalcemia can lead to bone pain, kidney stones and stenosis as well.
How much vitamin D??
Vitamin D wears many hats in the body, including:
- Bone Health: Vitamin D is crucial for calcium absorption and maintaining strong bones.
- Immune System: It helps regulate immune responses and may protect against infections.
- Muscle Function: It plays a role in muscle strength and reducing falls in older adults.
- Mood Regulation: Some studies suggest a link between vitamin D levels and mood disorders.
The widespread nature of vitamin D’s benefits is because vitamin D receptors are found in tissues throughout the body. Without these receptors, vitamin D cannot do its job.
In my opinion, the current RDA daily recommendation of 600-800 IU for adults is too high. But it certainly doesn’t present the dangerous risks that a megadose of 10,000-50,000 IU does. Optimal levels of vitamin D do more than protect bone health, such as reducing inflammation, stabilizing glucose metabolism, and improving neuromuscular and immune function. But TOO much can cause serious problems.
Where do we get vitamin D
There’s a reason vitamin D is called the sunshine vitamin. Most of our vitamin D is produced when the sun’s UVB rays hit our skin. They trigger a chemical reaction that converts cholesterol to vitamin D3. That’s why sunlight exposure is considered the best source of vitamin D.
You also get vitamin D from your diet. Foods containing this secosteroid include fatty fish like salmon, trout and sardines, egg yolks, mushrooms, and fortified foods. Did you know that giving your mushrooms a suntan by placing them in the sun for 10-15 minutes increases their vitamin D levels?
Sun exposure and diet are by far the best ways to get your daily vitamin D requirement. At a UV level of 3, it takes about 2-3 hours per week of sun exposure to maintain adequate D levels. At higher UV levels, that time drops to a few minutes per day. If you’re struggling to meet your needs through sunlight and diet alone, supplements are available—but as we’ll see, they come with their own risks.
The Dark Side of Vitamin D Supplements
While vitamin D is essential for health, too much of a good thing is bad. Excessive intake through supplements can lead to vitamin D toxicity, or hypervitaminosis D. This condition is rare but potentially serious.
Overdoing it is unlikely if your vitamin D comes from the sun or your food. Your body stops the synthesis of the secosteroid when enough has been produced. So even if you spend the whole day in the sun, your vitamin D levels will remain constant.
Symptoms of vitamin D toxicity include:
- Nausea and vomiting
- Weakness
- Frequent urination
- Kidney problems
- Calcification of soft tissues
Remember, vitamin D is a fat-soluble vitamin and is stored in the body’s fatty tissue. This increases the risk of toxicity when you take high-dose vitamin D supplements.
Moreover, these supplements can interact with certain medications, including steroids, weight-loss drugs, and cholesterol-lowering statins. People with conditions like hyperparathyroidism or sarcoidosis should be particularly cautious with vitamin D supplementation.
Filling the gaps in the vitamin D puzzle.
Vitamin supplementation requires balance: Vitamin D needs the appropriate level of a few other fat-soluble vitamins to be effective. You must pay attention to your vitamin K, vitamin A and vitamin E levels as well.
You should also know how your kidneys produce the bioactive form of D: efficiently or poorly? A study by the Grassroots Health Nutrient Research Institute shows a 10-fold variance in supplementation levels in people taking the same dose of vitamin D. Unless you’re testing yourself, you don’t know how efficient you are storing those fat-soluble vitamins.
Conclusion: Striking a Balance
One of the simplest ways to elevate your vitamin D levels is to get some time outside without sunscreen. Your body uses UVB photons to break down 7-dehydrocholesterol into pre vitamin D, and ultimately into a bioavailable version of vitamin D.1
Natural food sources are eggs, salmon, liver, mushrooms, and fish liver oils. Consider a little sun exposure. Yes, I suggest the benefits of being outside for a short time to allow your body to make vitamin D outweigh the risks of sun damage. The key here is moderation. A little daily exposure, and then protection.
By understanding both the benefits and risks of vitamin D, we can harness its power safely and effectively. So step out into the sunshine, enjoy some fatty fish, and consult your doctor before popping those supplement pills.
Meehan Formulations wants to keep you safe. You might like to read about other topics in our library, such as the the dangers of vitamin C. If you have any questions and want to talk to me about vitamin D or any other topic, please send me an email at support@meehanformulations.com or comment below.
Thanks for reading today!
1 Holick, Michael F. “Sunlight, ultraviolet radiation, vitamin D and skin cancer: how much sunlight do we need?.” Advances in experimental medicine and biology vol. 810 (2014): 1-16.
