Over the last sixty years, the nutrient content in our fruits and vegetables has been on the decline, onions included. From 1950 to 1999, onions saw a 46% decline in iron, 33% decline in riboflavin, 24% decline in calcium, 14% decline in vitamin C, and a 9% decline in phosphorus. Though these onion-specific results are not statistically significant and are based on a small number of data points, the overall trend toward nutrient decline is significant. To learn more about the trend and what you can do, read more about it here.
Onions: Change in Nutrient Data
In the table presented here we include the nutrient content of onions from 1950 and 1999. The 1950 values for onions are adjusted for water content so that the 1999 and 1950 data points have the same amount of dry matter. These nutrient indicators are based on a very small number of data points and not one of the apparent differences are statistically significant, however taken together, they suggest a decline in nutrient content in small garden produce.
Nutrient Change In Onions
*The 1950 data is adjusted for water content.
Creative Commons License: Share the Knowledge
The figures used to display decline in nutrients in garden produce here are Traditional Foods, including change in onions, can be reposted and redistributed for noncommercial use with a linked attribution to this onions page or to our more general article here: nutrient decline.
Nutrient Data Source
The historical values on the nutrient content of garden crops has been published and made available by the U.S. Department of Agriculture. It was also examined by Davis, Epp, and Riordan whose work we describe on this site. Following the lead of the authors, we adjusted the 1950 onion nutrient measures so that the 1950 and 1999 food samples had the same water content.
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