With food and oil prices setting new record highs, many investors find it hard to resist the lure of commodity investments nowadays.

The asset class that only a decade ago seemed to require specific knowledge has now become much easier to access via a broad range of indices and exchange-traded vehicles, to the delight of investors seeking diversification and protection against inflation.

According to one provider, assets under management of commodity exchange-traded products (ETPs) rose to a new all-time high in the first quarter of 2011, with a 58% year-on-year increase.

While oil futures often hog the limelight when it comes to commodity investments, investing in their agricultural counterparts has grown more significant. After all they are just as easily linked to a basic human need.

But with unrests in large parts of North Africa and the Middle East continuing and the initial tensions being blamed on soaring food prices, a cloud continues to hang over investments in agricultural commodity futures.

The never-ending debate is about the ethics of investing in such futures. Different studies have come to different conclusions. A paper by the International Food Policy Research Institute suggests that the prices of futures do affect spot prices. But proponents of commodities futures highlight their vital services to the producers and ultimately to the end-consumer. Opponents are not happy with the out-of-control volatility of futures and spot prices, advocating investments that boost the production of food instead.

In between, are the pension funds and asset managers with both commodity investments and responsible investment policies in place. Having been faced with criticism on the matter, it seems many experience a bitter aftertaste as a result of their investments in sugar, grains and cocoa beans.

But the term commodity has become more encompassing. Water funds have spread and investments in this liquid commodity have made it onto the agenda of several institutional investors. One of the newest kids on the commodity block is shale gas. Again, controversy surrounds this fossil fuel, particularly with regard to emissions and climate change targets. In the world of commodities it seems controversy is not uncommon.