Further research needed on phytochemicals.

The promise of functional foods continues to evolve. Consumer interest in diet and health is at an all-time high. Functional foods, food products and supplements that deliver possible benefits in the management or prevention of disease represent an opportunity for future product growth in the food and beverage industries.

Researchers are examining these foods, isolating and characterizing chemical components, structures and physiologic function. The number of physiologically active food components has increased dramatically in the last 10 years. As you're probably aware, possible naturally occurring protective agents include the carotenoids, vitamins C and E, the flavonoids and other phenolic compounds, phytoestrogens, indoles and fiber.

But additional research is needed on a number of fronts to thoroughly characterize physiologically active phytochemicals. Investigators must identify the specific types of phytochemicals that provide health benefits and determine the strength and characterize the sources of phytochemicals that are beneficial or harmful. In addition, they must characterize the factors that affect absorption and bioavailability of phytochemicals; determine the metabolic fate of absorbed phytochemicals; establish the levels of phytochemicals identified with specific tissues; determine specific functions of the phytochemicals in these tissues; and identify and characterize metabolites of phytochemical metabolism, determining the physiologic activities of metabolic products.

On another front, scientists should establish safety of use by determining the concentrations at which pharmacological doses become a toxicological problem; determining the type of phytochemical and the effective dose that protect against disease; defining the saturation point of phytochemicals that provide protection against cancer; identifying new mechanisms by which phytochemicals produce protective effects; and characterizing the effects of phytochemicals at various concentrations.

Beyond this, investigators still have to determine optimal phytochemical mixtures: determine the composition, duration of feeding and amounts to be fed; identify the proportion of the population likely to respond positively to phytochemicals; establish the pharmacokinetics of a delivered dose by evaluating single and combined doses with and without food sources present; and more closely examine the dietary components associated with health and disease prevention from the diet as a whole.

Further information. Wayne Bidlack, California State Polytechnic University, College of Agriculture, 3801 W. Temple Ave., Pomona, CA 91768; phone: [phone]; fax: [phone]; URL: www.csupomona.edu.