US sales of functional foods reached US$18.5bn in 2001, or 3.7% of the total food market of US$503bn.

The 1990s saw virtually every major food corporation launch functional food initiatives - some successful and some not, according to a report published by the Nutrition Business Journal (NBJ).

Patrick Rea, NBJ's research director and author of the report, commented: "In the highly competitive US$503bn US food market, even minor product differences can translate into market share gains, and functional foods provide corporations with one of their most powerful opportunities for brand differentiation.

"Functional foods [have developed] over the last several years from a marketing catch phrase into a trend that is truly quantifiable and meaningful to consumers," noted Rea. 

Annual growth in the functional foods arena is forecast at 5-7% in the US over the next four years, slowing gradually thereafter to reach sales of US$31bn in 2010.