Taking steps to guard against inflation now feels a bit like shuttering your windows on a sunny day. But when planning for retirement, investors need to have all bets covered, and that includes the possibility that even mild inflation could erode purchasing power. There are abundant choices in commodity land to help you hedge against inflation, from gold ETFs to futures contracts on everything from hogs to natural gas. But for a big basket of assets that are pretty inflation-proof, it's tough to beat the diversity and easy entry of real-asset mutual funds. These funds reach far and wide for investments that will offer real-inflation-adjusted returns. But their strategies can differ markedly. Pimco's Commodity Real Return fund, for example, is a blend of derivatives linked to commodity indexes, plus some Treasury inflation-protected securities. In contrast, the Principal Diversified Real Asset fund owns TIPS but also owns master limited partnerships and REITS as well as natural-resource-related stocks and bonds. Either way, if you're planning for a long retirement, it's a fund category that should be on your short list.