No, but it's a useful metaphor:
Slaves in the colonial era created a complex folklore about the southern master class, worrying that slave traders were cannibals. My research uncovered at least one case in Louisiana which newly imported slaves became convinced that the masters were witches and vampires (after watching them drink red wine). These tales of terror illuminate rather than obscure important truths. Slavery did represent a kind of dark magic in which legal fictions transmogrified the bodies of human beings into property. The institution of slavery did become a kind of cannibalism, swallowing millions from the African continent, digesting them in the rice and cotton fields in the relentless pursuit of wealth that characterized the alleged southern "aristocrats." America needed a vampire hunter in 1860.
Jesse Walker adds:
When a piece of conspiracy folklore is this popular, it says something true about the anxieties and experiences of the people who believe and repeat the tale, even if it says nothing true about the objects of the theory itself. The slave traders really were conspiring against their prisoners; it was just the nature of the conspiracy that was misunderstood. The captives were to be consumed by the white economy, not by white mouths.
Sadly, the movie itself sounds terrible.
The Dish 