Although they're tightening their spending due to economic concerns, nearly three-quarters (73 percent) of U.S. families are purchasing organic products -- at least occasionally -- for health reasons, according to a new national study by the Organic Trade Association, Greenfield, Mass., and KIWI Magazine.

Based on interviews with 1,200 families nationwide, the survey also suggests that three in 10 families (31 percent) actually are buying more organic foods compared to a year ago. Moreover, 17 percent of U.S. families said their largest spending increases during the past year involved organic products.