BACKGROUND: Seasonal variation of vitamin C in fresh fruits and vegetables is not reflected in food composition database average values, yet many factors influence content and retention. RESULTS: Fresh fruits and vegetables were sampled on three occasions in each season, from the same local retail outlets, for 1 or 2 years. Vitamin C was significantly higher in winter-sampled spinach (436 mg kg-1 ) compared with spring (298 mg kg-1 ) and summer/fall (180 mg kg-1 ); in potatoes in summer/fall (156 mg kg-1 ) versus winter/spring (106 mg kg-1 ); and in oranges in winter (616 mg kg-1 ), spring (592 mg kg-1 ), and summer (506 mg kg-1 ). Ranges were dramatic among sampling occasions for broccoli, oranges, potatoes, and spinach (700-1210 mg kg-1 , 420-780 mg kg-1 , 70-280 mg kg-1 , and 90-660 mg kg-1 respectively). Mean values for apples, bananas, tomatoes, and potatoes differed from the USDA National Nutrient Database for Standard Reference (SR) average by ≥10% of the daily recommended intake (90 mg). For broccoli, oranges, and spinach, vitamin C was substantially above or below the SR range in 50-100% of the samples. For spinach, the average content did not differ from SR, but vitamin C in winter was 55% higher than SR. CONCLUSION: Database average values for vitamin C in fresh produce can significantly over- or underestimate the content in a specific food supply.
BACKGROUND: Seasonal variation of vitamin C in fresh fruits and vegetables is not reflected in food composition database average values, yet many factors influence content and retention. RESULTS: Fresh fruits and vegetables were sampled on three occasions in each season, from the same local retail outlets, for 1 or 2 years. Vitamin C was significantly higher in winter-sampled spinach (436 mg kg-1 ) compared with spring (298 mg kg-1 ) and summer/fall (180 mg kg-1 ); in potatoes in summer/fall (156 mg kg-1 ) versus winter/spring (106 mg kg-1 ); and in oranges in winter (616 mg kg-1 ), spring (592 mg kg-1 ), and summer (506 mg kg-1 ). Ranges were dramatic among sampling occasions for broccoli, oranges, potatoes, and spinach (700-1210 mg kg-1 , 420-780 mg kg-1 , 70-280 mg kg-1 , and 90-660 mg kg-1 respectively). Mean values for apples, bananas, tomatoes, and potatoes differed from the USDA National Nutrient Database for Standard Reference (SR) average by ≥10% of the daily recommended intake (90 mg). For broccoli, oranges, and spinach, vitamin C was substantially above or below the SR range in 50-100% of the samples. For spinach, the average content did not differ from SR, but vitamin C in winter was 55% higher than SR. CONCLUSION: Database average values for vitamin C in fresh produce can significantly over- or underestimate the content in a specific food supply.
Authors: Katherine M Phillips; Ryan C McGinty; Garret Couture; Pamela R Pehrsson; Kyle McKillop; Naomi K Fukagawa Journal: PLoS One Date: 2021-07-08 Impact factor: 3.240
Authors: Chen Jin; Rui Li; Tuo Deng; Zixia Lin; Haoqi Li; Yan Yang; Qing Su; Jingxian Wang; Yi Yang; Juejin Wang; Gang Chen; Yi Wang Journal: Front Nutr Date: 2022-07-18