A fructan is a polymer of fructose molecules. They occur in foods such as artichokes, asparagus, green beans, leeks, onions (including spring onion), yacon, and wheat. In animal fodder, fructans also appear in grass, with dietary implications for horses and other equidae. Plants storing their food as fructans are able to thrive at low temperatures since fructans confer tolerance to freezing. They bind to membranes, thereby helping to keep cells intact.