Should You Take Vitamin D with Fat?
Yes, you should take vitamin D with a meal containing fat to optimize absorption and achieve higher blood levels.
The Evidence for Fat-Enhanced Absorption
Vitamin D is a fat-soluble vitamin, meaning its absorption is significantly enhanced when consumed with dietary fat 1. This is not merely theoretical—clinical studies demonstrate substantial real-world benefits:
Taking vitamin D with a fat-containing meal increases absorption by approximately 32% compared to a fat-free meal 2. This translates to meaningfully higher blood levels of the vitamin.
When vitamin D is taken with the largest meal of the day (which typically contains more fat), serum 25-hydroxyvitamin D levels increase by an average of 50-57% 3. This effect was consistent across a wide range of vitamin D doses (1,000 to 50,000 IU daily) and was particularly important for patients who were not responding adequately to supplementation 3.
The mechanism involves both passive diffusion and active transport through cholesterol carriers in the intestinal membrane 4. Since fat facilitates this process, absorption occurs more efficiently when fat is present 4.
Practical Recommendations
Take your vitamin D supplement with your largest meal of the day, as this meal typically contains the most dietary fat and will maximize absorption 3. You don't need excessive amounts of fat—a meal with approximately 30% of calories from fat is sufficient 2.
What Counts as "Something Fatty"
Suitable options include:
- Meals containing fatty fish, eggs, or dairy products 5
- Foods with nuts, avocado, or olive oil
- Any regular meal that includes some fat content
The type of fat (monounsaturated vs. polyunsaturated) does not significantly affect vitamin D absorption, so you don't need to worry about the specific fat composition 2. What matters is that some fat is present.
Important Context
While vitamin D absorption can occur without fat, the enhancement provided by fat is clinically significant 4. For individuals who are vitamin D deficient or not responding adequately to supplementation, this simple dietary modification can make the difference between achieving adequate levels and remaining deficient 3.
The recommended daily intake is 600 IU (15 μg) for most adults and 800 IU (20 μg) for those over 70 years 1. However, these recommendations assume optimal absorption conditions—taking vitamin D with fat helps ensure you actually absorb what you're taking.