Here is an excerpt from a relatively unbiased source. The news is not so good if you were counting on acai to solve all your health problems:
“Welcome to the 21st century, where doctors write advertising copy for
fancy fruit juices and open boutiques on Madison Avenue to sell their
branded wares.
Is there any scientific backing for the health claims made for açai
products?
Here are some basic facts. The nutritional content of açai is 1–4 percent
protein, 7–11 percent fats, 25 percent sugar, 0.05 percent calcium, 0.033
percent phosphorous, and 0.0009 percent iron. Açai also has small amounts
of sulphur, vitamin B1 and E and beta carotene. It delivers 88 to 265
calories per 100 grams, depending on the source and preparation method.
A PubMed search for Euterpe oleracea reveals half a dozen relevant
articles, but none clinical in nature. In fact, none has anything to say
about its alleged health-promoting properties, except in the most general
terms. Yes, it has antioxidants and antioxidants are good for you. But it
is a far stretch to claim that this juice or its constituents will cure
any disease.
Simply put, I can discover no scientific basis whatsoever for making
medical or health promoting claims for açai. Nor is its traditional usage
of much help.”