The Monkey Puzzler

Nutrients in perennial vegetables

I’m pleased to kick off this new blog with results from a new report on testing perennial vegetables for nutrients …..

New results for nutrient levels in some common perennial vegetables

Following his joint paper on nutritional levels in perennial vegetables in 2020, Eric Toensmeier has led a joint crowdfunded project (which we contributed to) to test more common perennials for nutrient levels.

This study classifies perennial vegetable nutrient concentrations using a scale developed by Toensmeier, Mehra and Ferguson. That study compared perennial vegetables to a group of “reference vegetables” (mostly common annual vegetables) which are globally marketed. The reported range for reference vegetables was broken into thirds: “low” for the lowest third, “medium” for the intermediate concentrations, and “high” (H) for the highest. In addition a “very low” category includes results lower than the lowest reported for reference vegetables, “very high” (VH) for those higher than the highest reference vegetables, and “extremely high” (XH) for those more than twice as high as the highest reference vegetables.

This study also compared the nutrition of perennial and biennial kale grown in the same soils. While there was some variation, the overall proportion of nutrients in different concentration classes is the same. Folate was notably higher in the perennial kale, and calcium higher in the biennial.

Rudbeckia laciniata

For all but one of the nine nutrients studied, at least one perennial vegetable had nutrient concentrations higher than the reference vegetables (ranked very or extremely high). In the case of Zinc, ten perennial vegetables were ranked very or extremely high.

Many perennial vegetables are high in the nutrients needed to address nutrient deficiencies. Ten out of the 12 species tested ranked high or higher in multiple nutrients. The leaves of Urtica dioica, Chenopodium bonus-henricus, Morus alba x M. rubra, and Rumex patienta are especially notable in this regard.

References

Eric Toensmeier and others: Testing the Nutrient Composition of Perennial Vegetables in Denmark, Sweden, and the United States.  2023.

Toensmeier, E, Ferguson, R, and Mehra, M. "Perennial vegetables: A neglected resource for biodiversity, carbon sequestration, and nutrition." Plos one 15, no. 7 (2020): e0234611.