According to an upcoming paper published on the British Journal of Nutrition website, consuming papaya will give you a higher level of β-carotene and lycopene in your blood than carrots or tomatoes respectively.
The researchers recruited 16 people for the study and gave them test meals containing a set amount of β-carotene and lycopene in the form of carrot, tomato or papaya. Blood samples were taken during the 10 hours after eating and the level of carotenes measured.
People who got their β-carotene from papaya had 3 times the level in their blood compared to those that had eaten carrot. For lycopene is was 2.6 times the level compared to those that had eaten tomato. The authors suggest the difference in bio-availability could be due to the way the carotenes are stored in the tissue of papaya and that this fruit could help to reduce the incidence of vitamin A deficiency in the tropics.
It also makes a great addition to the fruit bowl here.