RIO DE JANEIRO — Rising U.S. sales of acai, a purple Amazon berry promoted as a "superfood" on Oprah Winfrey's Web site, are depriving Brazilian jungle dwellers of a protein-rich nutrient they've relied on for generations.

U.S. consumers are turning a "a typical poor people's food into something like a delicacy," said Oscar Nogueira, who specializes in the fruit at Embrapa, Brazil's agricultural research company.

Spending on acai-based products by Americans seeking to lose weight, gain energy or slow aging doubled to $104 million last year, according to SPINS, a Schaumburg, Ill.-based market research firm. Since U.S. demand took off early this decade, the fruit's wholesale price in Brazil has jumped about 60-fold, Embrapa data show.

In 2008, exports from Para, the South American country's main producing state, climbed 53 percent to account for about a quarter of output, according to the local government. Production, though, has increased little in the past five years.

Winfrey, 55, discussed the berry with Mehmet Oz on her TV talk show in February 2008, when the New York cardiologist presented his "anti-aging checklist." It includes acai, blueberries and tomatoes.

"It has twice the antioxidant content of a blueberry," said Oz, 48.

Winfrey's site publishes dermatologist Nicholas Perricone's "10 Superfoods List," which includes the Brazilian fruit.

WINFREY DISCLAIMER

Perricone's list on Winfrey's site includes a link to a statement saying she isn't associated with any acai product.

"We are pursuing unauthorized uses of Ms. Winfrey's name associated to acai-based products, none of which she has endorsed," said Don Halcombe, a spokesman for Harpo Inc., Winfrey's production company. Chicago-based Harpo is turning over complaints about such items to the Illinois Attorney General's office, Halcombe said.

In Igarape-Miri, an Amazon village 1,100 miles north of Brasilia, Francisca Neves, who sells manioc flour — also known as tapioca — to neighbors and restaurants, says the bitter pulp she used to eat twice a day is now a luxury.

"Our granddaughter is turning 3 and we're going to have family coming to our house," said Neves, 68, as she paid 20 reais ($9.40), or about 7 percent of her monthly household income, for 2 quarts of the thick mush at a local street market.

HEAVY ON PROTEIN

Acai grows on palm trees and looks like a blueberry. In the Amazon, it is beaten, diluted in water and eaten with manioc, meat, fish or shrimp.

The pulp provides more protein in relation to its weight than eggs and milk, and has high levels of anthocyanin, an antioxidant, as well as vitamins E and B1, potassium, iron and calcium, according to Embrapa.

The Para government recommends its consumption. The berry is popularly associated with bone and muscular strength, longevity and a healthy immune system, said Lucival Cardoso, the state's chief health inspector.

"We encourage families to give acai to children as young as 6 months," Cardoso said. "It's also very filling; that's why it's traditionally associated with low-income family diets."

Neves says she and her fellow villagers are paying the price of the berry's international fame.

"We are happy that people on the other side of the world are able to enjoy our acai, but we don't want to have to go without it," Neves said. "Why should we suffer so people who don't even know anything about the fruit can have their acai pills?"