I remember reading it having to do with diet. But as trends such as "super foods" grow and the obesity epidemic expands into south america, these trends likely aren't going to last. As staple foods in latin american countries see the price of their foods increase. And the shifting diets towards unhealthy alternatives that are priced cheaper than said goods.
I'd hypotize that it's got to do with social networks (the real life one), Latin Americans seem to have closer-knit family and friends, and social bonds have been shown to be very helpful for longevity.
But it's just my hunch without concrete numbers (in regards to e.g. percentage of old people reporting being lonely, classified by race)
