(Adds details throughout on stocks and sectors, updates prices)
* TSX down 50.83 points, or 0.35 percent, to 14,634.02
* Seven of the TSX's 10 main groups were lower
TORONTO, Aug 31 (Reuters) - Canada's main stock index fell on Wednesday as lower oil and gold prices weighed on energy and mining stocks.
Still, the index was on course to rise 0.4 percent for the month of August.
The most influential movers on the index included Suncor Energy Inc, which fell 1.9 percent to C$35.73, and TransCanada Corp, which declined 1.2 percent to C$59.14.
U.S. crude prices were down 2.2 percent to $45.34 a barrel, extending losses as data showed a bigger-than-expected increase in U.S. stockpiles.
The energy group retreated 1 percent, while the materials group, which includes precious and base metals miners and fertilizer companies, lost 0.7 percent.
Barrick Gold Corp fell 2.1 percent to C$22.33, pressured by lower gold prices.
Gold slid to a two-month low after forecast-beating U.S. jobs data stoked speculation that the Federal Reserve would move ahead with plans to raise interest rates.
At 10:40 a.m. EDT (1440 GMT), the Toronto Stock Exchange's S&P/TSX composite index fell 50.83 points, or 0.35 percent, to 14,634.02.
Seven of the index's 10 main groups were lower.
National Bank of Canada reported a 6-percent increase in quarterly profit, benefiting from a recent acquisition that enabled it to beat market expectations.
Still, its shares fell 2.4 percent to C$46.45, while the overall financials group dipped 0.1 percent.
Canada's economy shrank in the second quarter in its worst showing in seven years, hurt by a drop in exports and a disruption to oil production caused by wildfires in northern Alberta, data from Statistics Canada showed. (Reporting by Fergal Smith; Editing by Nick Zieminski)