Looking to hedge against a spike in inflation? Equities may not be much help.

Neither, for that matter, will you do all that well over the longer haul with bonds, cash or even commodities, at least on the historical evidence. In short, when it comes to investing, inflation is a real drag.

It’s impossible to know if, much less when, the current very stimulative monetary policy in the developed world will spur inflation, but increasingly indicators are raising concerns. Emerging market economies show signs of overheating, while prices of food and many other commodities are surging.

The traditional view has been that equities are an effective hedge against inflation, in least over the long term, because companies will, all things being equal, eventually pass on inflation to their clients as higher prices.

That’s the theory, but the practice may prove to be much different, according to a study by IMF economists Alexander Attie and Shaun Roache, who examined the performance of a range of traditional asset classes in the aftermath of inflation shocks.

“Among traditional asset classes, inflation hedges are imperfect at best and unlikely to work at worst,” according to Attie and Roache.