I ate a large amount of red papaya when we were in Costa Rica a few years ago.

I understand the concern with foods containing vitamin K, but what about foods that may have a blood thinning effect? For example: I ate a large amount of red papaya when we were in Costa Rica a few years ago. When I returned home and had a protime test, my INR was extremely high. I was told it was because of the papaya. Is it OK to eat it occasionally but not everyday as I did there? Are there other foods that have a blood thinning effect?

The Health meets Food Team Says...

There are about 3 micrograms of Vitamin K in 4 ounces of papaya. It may be that by eating a lot of papaya you consumed too much Vitamin K and that is what caused an elevation of your INR.

There has been one case report in the literature that indicates a possible reaction between papain and Coumadin (warfarin). Papain is an enzyme found in papayas that has digestive properties in humans. This could be a potential cause of the change in your INR levels. I have found no other evidence to support an interaction between the fruit itself and Coumadin, however.

Since you did have an issue, one approach would be to speak with your doctor and discuss your trying to introduce papaya into your diet a few days before your labs are drawn and see if there is any variation.

Thanks for writing.