(Reuters) - Brazil, Latin America's biggest economy and diplomatic power, has toned down its support for Venezuelan President Nicolas Maduro because of disappointment over how he is handling mounting economic problems and opposition-led street protests.

The shift, while subtle, has deprived Maduro of some of the regional backing he wants at a time of food shortages, high inflation and political uncertainty in the OPEC nation....Rousseff has been increasingly disappointed by some of Maduro's actions and has reined in the more enthusiastic support that characterized Brazil-Venezuela relations under his predecessor, the late Hugo Chavez, according to two officials close to Rousseff's government.

Rousseff is worried the Venezuelan government's repression of recent street protests, and Maduro's refusal to hold genuine dialogue with opposition leaders, may make the political crisis worse over time, the officials said.

Worsening turmoil could, in turn, endanger the sizeable interests of Brazilian companies in Venezuela. They include conglomerate Odebrecht SA..... Venezuelan public-sector companies already owe Brazilian companies as much as $2.5 billion in debt....