From the Research
For optimal absorption, take vitamin D supplements with a meal containing some fat, ideally during your largest meal of the day (often lunch or dinner), as this can increase serum levels of 25-hydroxyvitamin D by about 50% 1. When considering the optimal timing for taking vitamin D and calcium supplements in relation to meals, several factors come into play to maximize absorption and minimize side effects.
- Vitamin D is fat-soluble, meaning it requires dietary fat for proper absorption into the bloodstream.
- Taking calcium with food helps reduce gastrointestinal discomfort and improves absorption.
- Calcium supplements should be split into doses of 500mg or less to minimize side effects like gas and constipation, as indicated by studies on calcium absorption and supplementation 2, 3.
- If taking both supplements, it is recommended to separate them by at least 2 hours since calcium can interfere with vitamin D absorption.
- For calcium specifically, taking it in the evening may be beneficial as calcium levels naturally drop during sleep.
- Additionally, if you're also taking medications like antibiotics or thyroid medications, maintain at least a 2-hour gap between these and your calcium supplements to prevent interference with medication absorption. The most recent and highest quality study on this topic, published in 2016, focused on the side effects of vitamin D supplementation, including hypercalcemia, hypercalciuria, and kidney stones, but did not directly address the timing of supplement intake in relation to meals 4. However, a 2010 study specifically addressed the issue of timing and found that taking vitamin D with the largest meal of the day improves absorption and results in higher serum levels of 25-hydroxyvitamin D 1. Considering the need to balance absorption, minimize side effects, and adhere to the most recent evidence, the recommendation is to take vitamin D with a meal containing fat and to split calcium doses, taking them with food, while being mindful of potential interactions with other medications. Most adults need about 600-800 IU of vitamin D daily and 1000-1200mg of calcium, though individual needs may vary based on age, health conditions, and current blood levels, as suggested by various studies on vitamin D and calcium supplementation 2, 3, 5.