'Superfood' is a marketing term with no scientific or legal definition. Overall eating pattern matters far more than any single food.
Evidence & sources
In the EU, a health claim such as 'superfood' can only be used with an authorized, specific health claim. Evidence: regulatory. Known: EU regulation on nutrition and health claims. Unknown: — Source: European Union, Regulation (EC) No 1924/2006 on nutrition and health claims (2006).