Hello friends, here’s a fun question for you. How many oranges do you need to eat to get the same amount of vitamin C as a 1000mg vitamin C tablet?

A quick Google search suggests that a single orange has about 70mg of vitamin C. So by using pure math alone, we will approximately need to eat 14 oranges to get the same amount of vitamin C as the tablet… However, we have yet to factor in the concept of bioavailability, or the proportion of a drug or other substance that enters the circulation when introduced into the body and so can have an active effect.

This paper by Blanchard J et al. (PMID: 9356534), illustrates nicely how vitamin C has dose dependent bioavailability.

This means that the higher the dose, the lower the amount of vitamin C that can be absorbed into the body. This suggests a 1000mg dose of vitamin C will give you only about 200mg of bioavailable vitamin C in actuality. This is much less than what we initially started with.

As a pharmacometrician, I could suggest you split the 1000 mg dose of vitamin C over 4 or more times throughout the day to improve the bioavailability and thus absorption. However, as the general vitamin C intake guidance is 90mg for men and 75mg for women, it might not be as worthwhile to go through the trouble. 🙂

Fun fact, as Lunar New Year is coming up soon, I found that tangerines (aka mandarin oranges) contain less vitamin C, with about 32mg of vitamin C for a large tangerine, compared to 70mg in an orange. I like tangerines because they are sweeter though, so I will be eating lots soon 🙂

Hope you enjoyed the read and learnt some PK!