Vitamin D is essential for maintaining healthy bones, immune function, and cardiovascular health. The normal range for vitamin D levels in your blood is typically 30–100 ng/mL. If your levels fall between 20–30 ng/mL, you are considered to have insufficient vitamin D, and if it’s below 20 ng/mL, you are deficient.
While it’s important to keep your vitamin D levels within the normal range, it’s also crucial not to exceed 100 ng/mL, as this can lead to toxicity. Most experts agree that maintaining vitamin D levels between 30–50 ng/mL is optimal for overall health, reducing the risk of chronic diseases and improving immune function.
How Much Vitamin D Should You Take?
If you’re wondering how much vitamin D you need to reach these optimal levels, research provides some useful guidelines. According to studies, 1,000 IU of vitamin D per day can raise your blood levels by approximately 10 ng/mL over 2–3 months. However, as the dose increases, the rate of increase slows down, meaning that doubling the dose doesn’t double the effect.
For most people, the Endocrine Society suggests 600–800 IU per day as the baseline for healthy individuals, but those at risk of deficiency may need higher amounts. Experts recommend 1,500–2,000 IU daily for individuals who are at risk or currently deficient.
The Optimal Vitamin D Range: 30 ng/mL vs. 40–50 ng/mL
While the recommended normal range for vitamin D is 30–100 ng/mL, some experts argue that levels closer to 40–50 ng/mL may be more beneficial for reducing the risk of chronic conditions like heart disease, diabetes, and cancer. A study in Nutrients (2020) found that individuals with vitamin D levels between 40 ng/mL and 50 ng/mL had a significantly lower risk of these conditions.
If you’re aiming for a level closer to 40–50 ng/mL, you may need to increase your intake beyond 1,000 IU daily, as this amount might not be sufficient to raise your levels to the higher end of the range.
Vitamin D Side Effects: How Much Is Too Much?
While vitamin D is essential for health, it’s important to avoid taking excessive amounts, as vitamin D is a fat-soluble vitamin. This means it can accumulate in your body if taken in large doses. However, studies have shown that 5,000 IU of vitamin D per day is safe for most people, and doses up to 10,000 IU are considered safe for short-term use.
Toxicity usually occurs when blood levels exceed 200 ng/mL, and can cause symptoms like nausea, vomiting, kidney stones, and in severe cases, kidney damage. Fortunately, vitamin D toxicity is rare and typically occurs only with excessive, long-term supplementation.
The Risk of Excessive Vitamin D: Is It Linked to Increased Mortality?
In 2015, a study from Copenhagen University raised concerns that high levels of vitamin D might be linked to increased mortality. The study found that individuals with blood levels over 40 ng/mL had a higher risk of death due to complications like kidney disease and excessive calcium absorption. However, this study has faced criticism for its methodology, and most experts still recommend maintaining vitamin D levels between 30–50 ng/mL.
A meta-analysis published in The Lancet (2016) concluded that there’s no significant evidence linking vitamin D levels in the range of 30–50 ng/mL to increased mortality risk.
What to Do If You Experience Vitamin D Toxicity?
If you take too much vitamin D and experience symptoms such as nausea, vomiting, or high calcium levels, it’s important to reduce your vitamin D intake and consult with a healthcare provider. In most cases, the symptoms of toxicity can be managed by reducing the dose and increasing hydration.
Individuals with kidney disease or parathyroid disorders should be particularly cautious and monitor their vitamin D levels regularly.
My Recommendations for Vitamin D Daily Intake
To sum up, here’s my personal recommendation for vitamin D intake based on your age and health status:
- For infants (under 12 months): 400–600 IU per day
- For children: 1,000 IU per day
- For adults:
- General health: 1,000–2,000 IU per day
- Deficiency or at risk: 4,000–5,000 IU per day for a few months, then reduce to 1,000–2,000 IU for maintenance.
People with obesity or conditions that affect vitamin D metabolism might need slightly higher doses, so adjusting your intake may be necessary.