Exchange traded fund (ETF) investors have the most simple and diversified tool to access commodities at their disposal.

The commodity expansion taking place is evidenced by people passed out from sticker shock in the bread aisle at your local grocery store, food riots and rationing in certain countries (including here) and barren tractor showrooms in the midwestern United States, reports Dow Jones Newswires.

ETFs are one quick and diversified way to get in, and commodity funds come in various shapes and sizes. Some hold futures, others hold stock for companies involved in the making of commodities and others are exchange traded notes (ETNs).

Demand for the agricultural items are exceeding supply leading many investors to opportunity. ETFs such as PowerShares DB Agriculture (DBA), which holds futures, is up 11.4% year-to-date. Market Vectors Global Agribusiness (MOO) holds the stock of some of the world’s biggest agriculture companies.

Among the agriculture ETNs available are Elements Rogers International Commodity Agriculture (RJA) and the Opta Lehman Brothers Commodity Agriculture (EOH).

One analyst prefers a broad-based ETF focusing on energy, metals and agriculture. Diversification of this nature are found in PowerShares DB Commodity Index Tracking Fund (DBC) and the note, iPath Dow Jones-AIG Commodity Index (DJP).

A list of all commodity ETFs and ETNs can be found on Seeking Alpha.

When it comes to energy ETFs, exercise caution.

Always knowing the risks is key, though. The more specialized an ETF is, the harder it can fall when the momentum is over. Commodities are volatile, and there’s been talk that he sector is in a bubble. Having your exit strategy will protect you.

Tags: Agriculture, Commodity ETFs, DBA, Energy, ETNs, Sector ETFs