05/12/2025
Your Guide to Vitamin D: 🌞California Sunshine, Supplements, and Salmon:
Hi Friends,
It's easy to assume that those living in the sun-kissed Napa Valley are all basking in sufficient Vitamin D. Yet, surprisingly, Vitamin D deficiency remains prevalent—even here. This aligns with statistics showing that 50% of the world’s population has insufficient Vitamin D, and 35% of U.S. adults are Vitamin D deficient.
As we exit the overcast April showers and move toward May flowers, let's delve into why Vitamin D deficiency happens and how to ensure you're getting enough of this essential nutrient.
🌤️ Why Vitamin D Matters
Vitamin D plays a pivotal role in:
✅ Bone Health – Helps the body absorb calcium, crucial for strong bones
✅ Immune Function – Enhances our body's defense mechanisms
✅ Mood Regulation – Low levels have been linked to mood disorders
🌫️ How do we get Vitamin D?
Your body makes most of its vitamin D when your skin is exposed to sunlight—specifically UVB rays.
In fact, about 80% of vitamin D is produced through the skin, not diet.
A vitamin D precursor in the skin travels to your liver and kidneys, where it's converted into its active form.
🥗 You can also get vitamin D from foods like fatty fish, mushrooms, eggs, and fortified milk or cereal—but sunlight is still the best source for most people.
🌞The Challenge:
Getting vitamin D from sunlight is a balancing act between getting enough sun for vitamin D production and protecting your skin from damage. Generally, the UV index must be above 3 for your skin to produce vitamin D. However, as shown in the graph below, the higher the UV index, the greater the potential for skin damage. In Northern California, the sweet spot for sun exposure is likely between 8 a.m. and 1 p.m., as well as the late evening.
💊 Supplements: When Diet and Sunlight Aren't Enough
For nearly half the world with insufficient vitamin D, supplementation can help.
Dosage: The recommended daily amount varies by age, health, and sun exposure. For most non-severe cases, 400–1,000 IUs daily is common—but always consult your personal healthcare provider first.
🧪 Testing and Monitoring
Vitamin D is a fat-soluble vitamin, meaning it’s stored in your body’s fat for months. If you take too much, you don’t just p*e it out like some other vitamins—excess can lead to toxicity.
Consider testing your vitamin D levels to:
1️⃣ Ensure you're not deficient
2️⃣ Determine the correct dose if you are
All that said, try not to over think it. Get your steps in while enjoying the sun and eat healthy wholesome, nutrient-dense foods!
Rooting for you,
Dr. Eric Lee
