This cacti fruit is touted as a superfood, but the science says otherwise. It has almost no antioxidant content. Even the bright pink pitaya has a dismal ORAC score.
To add insult to injury, these fruits are crazy expensive and that's assuming you can find one for sale. In a nutshell, dragon fruit is a superfood scam that isn't worth buying for health purposes. If you love the taste though and don't mind paying for it, then knock yourself out.
Research Support, Non-U.S. Gov't: Mahattanatawee K, Manthey JA, Luzio G, Talcott ST, Goodner K, Baldwin EA. Total antioxidant activity and fiber content of select Florida-grown tropical fruits. J Agric Food Chem. 2006;54(19):7355-63. NIH 2006