Thursday 13 May 2021

Grapefruit and Warfarin

Basically people either like Grapefruit or don't. I'm firmly in the bank of "why would I drink something that I have to ply with so much sugar to even make it acceptable to the taste. The lovers of Grapefruit will say how its good for you, but really there is nothing in it that's not easily (and more palatably) got from somewhere else. 

Some time back I wrote a blog post which identified that taking Grapefruit interfered with most medications, warfarin being one of then. As it happens this was the first blog post I did in the INR series.


The purpose of todays blog post is to add a little more clarity to that post and explain some of what was in that podcast interview.

In that podcast Dr David Bailey mentioned in his discussion talked about enzymes in the gut and the changes of bioavailability. If you just listened to that you may be a bit confused about what's actually going on with this bitter "fruit" and warfarin because you may think to yourself

"but wait, warfarin is highly bioavailable, so how does this influence me"

and that's because there is another issue which Dr Bailey did not cover and that's enzymes in the liver. Specifically thats Cytochrome P450; which as I've discussed elsewhere essentially clears toxins out of the blood (and warfarin is actually a toxin). So the active ingredient in this nasty bitter fruit is furanocoumarins (which you can read about here) that interfere with P450. This is important because if you think about it if you put something into your body where does it go? Does it stay there or go away? Some things are used to build you (like calcium in your bones) and some things are used to fuel you (like sugars) and others are deemed bad for you by the body and are disposed of.

P450 is one of the things doing the disposing. If that disposal is blocked then the toxins build up ... 

If you're actually on any medications its pretty simple : just avoid this nasty tasting "food" because it essentially brings nothing to your table.

No comments: