AP

Rising food prices are probably a threat to your portfolio. Because they mean slower world growth at a time when the recovery is still patchy.

Through 2010, investors flew on one engine of demand: emerging markets. But now, central banks on those places are slamming on the brakes. And local stock markets are starting to show the pain.

Tonight, India will probably raise interest rates for a seventh time, because wholesale prices are rising at 8.5 percent.

Foreign investors poured $29 billion into Mumbai's stock market last year. This month, they've already yanked $1 billion back. Indian stocks are down 6 percent.

That's not as bad as Indonesia where the loss is 9 percent. With rice prices up 30 percent, its central bank said Friday it too would soon raise interest rates, for the first time in 18 months.

In Latin America, Brazilian stocks are still holding steady, after interest rates were hiked to 11.25 percent last week. Still, today local economists raised their inflation forecasts for the seventh straight week.

What ultimately happens in Brazil will likely be dependent on what happens to its largest trading partner: China.

China is the big one to slow down: unpredictable and potentially destabilizing. The Shanghai Composite's down 5 percent amid talk Beijing will hike rates before February's Lunar New Year.

It's not all bad. Some investors are booking good profits in emerging markets to buy in to new themes for 2012—perhaps American stocks. But less growth in the world can only mean slimmer profits for large cap multinationals. 

And central bank tightening is the last thing investors in the West need right now, in markets artificially buoyed by cheap money from the Fed.