Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2008
Publication Date: 5/1/2008
Citation: 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.
Interpretive Summary: Many of the red, blue, and purple colors of fruits and vegetables result from healthful phytonutrients called anthocyanins. Consumption of foods containing these pigments can provide protection against cancer, improve brain function, and promote cardiovascular health. Strawberries are rich in anthocyanins, and it is these healthful pigments that give strawberries their color. Moreover, strawberries are a popular commodity and are the fifth highest consumed fresh fruit in the United States, with strawberry consumption doubling during the past decade. We conducted a clinical nutrition study to determine if consuming increasing doses of strawberries delivers increasing amounts of anthocyanin to body tissues or if absorption is saturated at low doses. We showed that the body’s ability to absorb anthocyanin pigments from strawberries is not saturated by large serving sizes (at or below about 14 ounces), thus the body can assimulate more healthful pigments with increasing dose. These results will be used by nutrition scientists to evaluate the healthful properties of individual anthocyanins and by plant scientists to develop strawberry cultivars with optimal anthocyanin content. Health professionals will use these results to make dietary recommendations based on the beneficial health properties of strawberries.
Technical Abstract: A clinical study was conducted to investigate the dose response and metabolism of strawberry anthocyanins. In a crossover study design, twelve healthy adults consumed each of three strawberry treatments. The treatments were 100 g, 200 g, and 400 g of pureed strawberries, delivering 15 micromol, 30 micromol, and 60 micromol anthocyanin, respectively. Urine samples were collected for 24 hours after each dose, and samples were analyzed by HPLC(high performance liquid chromatography) with DAD(drode array detector) and ion trap mass spectrometry. Pelargonidin-3-glucoside (Pg-3-glu) was the major anthocyanin form in the treatments, and Pg-3-glu and three metabolites of Pg-3-glu (detected as monoglucuronides) were observed in urine after the strawberry ingestion. One predominant monoglucuronide form was detected in urine in masses 10-fold higher than the other two monoglucuronide forms. Increasing dose resulted in increasing appearance of anthocyanins in urine, and mass of each pelargonidin monoglucuronide increased in urine with increasing dose. These results suggest that pelargonidin-3-glucoside absorption and metabolism are not saturated at masses less than or equal to 60 micromol, thus showing that more strawberry anthocyanin can be absorbed with increasing dose.