Do Calcium and Vitamin D Need to be Taken Together?
I’ve received this question twice in the past week, so thought I’d turn it into a post in case other people are wondering the same thing:
“Do you have any view on whether calcium and Vitamin D supplements should be taken at the same time to ensure they are absorbed properly? This seems to be the reason that calcium and Vitamin D are often sold in the same pill. Alternatively, if you aim to get Vitamin D from sunshine, should you wait to take the calcium supplement at that point of the day?”
There is no need to take vitamin D (or get sun) at the same time as you eat calcium. The vitamin D that you eat needs to be absorbed into your blood and then taken to the liver to be modified into a circulating, storage form of vitamin D known as 25(OH)D. Then, when your body senses that you need to absorb more calcium, the kidney further modifies the 25(OH)D into the hormone calcitriol. Calcitriol then increases calcium absorption. Vitamin D ingestion at a single meal will not have an effect on calcium absorption at that meal.