The role of fruits and vegetables in health promotion and disease prevention




Dr. Cynthia Thomson’s dietary intervention trials research group at the University of Arizona, Department of Nutritional Sciences focuses on translational clinical science, wherein we design and implement human feeding trials using crops rich in bioactive compounds in order to gain a greater understanding of the role of fruits and vegetables in health promotion and disease prevention.
Previous research from our group has demonstrated an inverse relationship between plasma carotenoid levels and breast cancer recurrence, and carrots represent an ideal carotenoid-rich food for increasing carotenoid concentrations in the blood. Furthermore, carrots are highly palatable and available at a reasonable cost to consumers year-round.  The Carrot Study, completed in 2008-2009, enrolled 68 overweight breast cancer survivors.   Participants consumed 8 fl oz of fresh purple carrot juice or orange carrot juice daily for 3 weeks, with a primary endpoint of increasing plasma carotenoids and decreasing inflammation and oxidative stress.  Consumption of carrot juice significantly reduced the oxidative stress biomarker, 8-epi-PGF2-alpha, and significantly increased plasma carotenoid levels, though the types of cultivars showed no significant differences in outcomes.

                     A                      B                       C                         D

Clinical research has a significant role in agricultural and nutritional sciences, as it provides a logical step in translating what we learn from animal models and cell culture studies to humans. A) The Carrot study, conducted in 2008-2009, aimed to determine the role of a diet high in carotenoids in increasing circulating carotenoids in overweight breast cancer survivors. B) Amy Butalla, M.S., coordinator of the Carrot Study, demonstrates how to make carrot juice for a study participant. C and D) Caitlin Dow, coordinator of the Grapefruit Study, enrolled overweight and obese men and women to a randomized feeding study to test the hypothesis that regular consumption of ruby red grapefruit would promote weight and lipid control, as well as reduce obesity-associated inflammation

Folklore has also suggested that consuming grapefruit may promote weight control.  Sparse data exist to support this, though there is some evidence of health promotional effects on blood pressure and lipid profiles.  Seventy-one healthy, overweight and obese adults completed the Ruby Red Grapefruit Trial in the winters of 2009-2010 and 2010-2011.  Participants randomized to the intervention arm consumed a diet low in fruits and vegetables supplemented with one half of a Rio Red grapefruit before each meal (3x daily) for 6 weeks.  Analysis from this study shows a non-significant decrease in weight, systolic blood pressure, and a significant decrease in total and LDL cholesterol following regular consumption of grapefruit.  Analysis of the effects of grapefruit consumption on oxidative stress and inflammation will be completed in Summer 2011.

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