Exchange-traded funds offer a convenient way to invest in sectors or niches that interest you. If you expect the world's consumer products industry to thrive as the global economy recovers and develops and rising incomes permit more purchases, the iShares S&P Global Consumer Staples ETF (NYSE: KXI) could save you a lot of trouble. Instead of trying to figure out which companies will perform best, you can use this ETF to invest in lots of them simultaneously.

The basics
ETFs often sport lower expense ratios than their mutual fund cousins. The iShares ETF's expense ratio -- its annual fee -- is a relatively low 0.48%.

This ETF has performed reasonably, beating the S&P 500 handily over the past three years. As with most investments, of course, we can't expect outstanding performances in every quarter or year. Investors with conviction need to wait for their holdings to deliver.

With an ultra-low turnover rate of 4%, this fund isn't frantically and frequently rejiggering its holdings, as many funds do.

What's in it?
Several of this ETF's components made strong contributions to its performance over the past year. Domestic tobacco giant Altria (NYSE: MO) gained about 26% over the past year, though its future might not be as awesome as its incredibly profitable past because of rising taxes on cigarettes and fewer Americans smoking. Still, Marlboro and other powerful brands do have pricing power. Those who are attracted by the reliability of tobacco revenues might also want to look at Philip Morris International (NYSE: PM), up 36% in the past year, as it's likely to grow more briskly.

Drugstore giant Walgreen (NYSE: WAG), meanwhile, gained about 28% as it continues a strong stock buyback program and hefty dividend increases. The company has recently gotten out of the pharmacy benefits management business, breaking off its relationship with Express Scripts and leading some to wonder if competitor CVS Caremark (NYSE: CVS) will do the same.

Other companies didn't add as much to the ETF's returns last year but could have an effect in the years to come. PepsiCo (NYSE: PEP), for example, gained only 2%, but it has strong growth potential in developing economies and has been aggressively developing "good for you" offerings. Food price inflation has been putting pressure on its profitability lately. Procter & Gamble (NYSE: PG), up 9%, has been shrinking some of its packaging in order to boost profits and remains a juggernaut in many product categories around the world.

The big picture
Demand for consumer staples, by definition, isn't going away anytime soon. A well-chosen ETF can grant you instant diversification across any industry or group of companies -- and make investing in and profiting from it that much easier.

ETFs can help you find the way to better investing results. To find some great ETF investing ideas, take a look at The Motley Fool's special free report, " 3 ETFs Set to Soar During the Recovery ."