2008 Annual Report
1a.Objectives (from AD-416)
The broad objective of this project is to elucidate details of bioavailability and metabolism of phytochemicals and other micronutrients. Specific nutrients of interest are carotenoids and polyphenols, with special emphasis on anthocyanins. Issues under study will include phytonutrient content of foods, comparison of foods as sources of phytonutrients, dose responses of phytonutrients, kinetics of metabolism of phytonutrients and micronutrients, and development of methodologies to label nutrients in plants for subsequent isolation and use in feeding trials.
1b.Approach (from AD-416)
This research will be conducted through plant growth/nutrient accumulation studies, human feeding trials, quantitative chemistry, and kinetic mathematical modeling techniques. Plant growth/nutrient accumulation studies will be used to improve plant isotopic labeling, human feeding trials will be conducted to gather information about nutrient levels in biological samples after nutrient ingestion, gas chromatography, liquid chromatography, and mass spectrometry will be used to quantitate nutrient levels in biological samples; and compartmental modeling techniques will be used to delineate parameters of absorption and metabolism of nutrients.
This project has made notable progress in delineating absorption, distribution, biological action, and elimination of nutrients and phytochemicals in humans. Research in 2008 focused predominantly on anthocyanins, which are red, purple, and blue pigments found in fruits, vegetables, and ornamental crops. Dietary intake of anthocyanins has been associated with reduction of chronic disease risk. Anthocyanins in red cabbage were tagged with a special isotope of carbon to allow tracing of their metabolism in the body. This was accomplished by growing the red cabbage under tightly controlled conditions in an environmental growth chamber. The tagged products will be used in human feeding studies to provide new insights into anthocyanin absorption, metabolism, and distribution. In another line of research, absorption and biological action of a potent class of vegetables called Brassicas was examined. Brassica vegetables are particularly promising with respect to cancer prevention. A human feeding trial using cabbage and mustard, two foods from the Brassica family that provide a purported cancer preventative agent called allyl isothiocyanate, was conducted. An association was noted between the induction by cabbage and mustard consumption of an important detoxification enzyme with the genotype of an individual. Cabbage and mustard induced the detoxification enzyme more effectively in some genotypes than others. This is exciting groundwork for the future of personalized nutrition. Specific information includes efficiency of absorption and metabolism of plant phytochemicals, their mode of action, and new methodologies to assess these issues.This work falls under National Program 107, Component 2: Bioavailability of Nutrients and Food Components.
Cabbage and mustard intake, genotype, and cancer risk. Studies have associated Brassica vegetables with reduced cancer risk, and genotype appears to be important in this risk reduction, though the dependence of physiologic response on genotype is unknown. A human feeding study showed not only that the Brassica vegetables cabbage and mustard increased concentration of a key detoxification enzyme called glutathione S-transferase, but also that the increase in concentration was dependent on the genotype of an individual. These results clarify the influence of this potent class of vegetables on cancer risk and represent early stages of the thrust toward personalized nutrition. These results will benefit consumers and health professionals as diets are planned. This work falls under National Program 107, Component 5: Health Promoting Properties of Plant and Animal Foods.
Labeling of anthocyanins from red cabbage. Anthocyanins, which are bright pigments in fruits and vegetables, have a variety of health benefits, but the absorption and metabolism of anthocyanins has been difficult to track in the human body. Anthocyanins in red cabbage were tagged with a stable isotope by using specialty plant science techniques so that anthocyanin metabolites could be traced after consumption. Since these compounds are otherwise unavailable in tagged form, the generation of these compounds provides new scientific opportunities for understanding anthocyanin metabolism. The future use of these compounds in human feeding trials will delineate anthocyanin metabolism to a much greater depth that previously possible. These results will benefit consumers and health professionals as diets are planned. This work falls under National Program 107, Component 2: Bioavailability of Nutrients and Food Components.
5.Significant Activities that Support Special Target Populations
Charron, C.S., Britz, S.J., Mirecki, R.M., Harrison, D.J., Clevidence, B.A., Novotny, J. 2008. Isotopic labeling of red cabbage anthocyanins with atmospheric 13-CO2. J. Amer. Soc. Hort. Sci. 133(3):351-359.
Carkeet, C., Clevidence, B.A., Novotny, J. 2008. Anthocyanin excretion by humans increases linearly with increasing strawberry dose. Journal of Nutrition. 138(5):897-902.