Nutritional analysis of cold-climate perennial vegetables

Fourteen species of perennial vegetables were tested for levels of nine nutrients needed to address common deficiencies. Composition was compared to a set of widely grown and marketed reference vegetables. For eight of the nine nutrients, at least one species had higher content than any reference vegetable, and in the case of Zn, ten species did so. Ten species had more than one nutrient concentration higher than the reference vegetables, with the leaves of Urtica dioica, Morus alba x M. rubra, Chenopodium bonus-henricus, and Rumex patientia especially nutrient-rich. Based on their high content of key nutrients, perennial vegetables are worthy additions to gardens and cuisine, and warrant further exploration for commercial production. Perennial and biennial kale varieties were compared, and despite some variation were found to have identical nutrient concentration rank profiles.

What is the context of this research?

Perennial vegetables are valuable in the transition towards healthier diets and sustainable regenerative agriculture, as well as storing of carbon in the soil. Currently, perennial vegetables are mostly grown in home gardens but there is an increased interest in growing them commercially. Great potential exists for market gardeners to sell many of the perennial vegetables directly to consumers as well as restaurants. They can become nutritious ingredients added to foods such as falafels, burgers etc. Gaining and sharing knowledge about their nutritional value is key to increasing interest in the cultivation and use of these vegetables. We are convinced that finding comparable research results of nutrients will give the perennial movement momentum to grow.

What is the significance of this project?

An important benefit of perennial vegetables is that they are nutritious. Like wild herbaceous plants and unlike annual vegetables, they haven’t been selected for sweet flavors. Our recent scientific paper (Toensmeier), analyzed data of over 300 species of annual and perennial vegetables to determine nutrient levels needed to address nutrient deficiencies, including those missing from the “industrial diet” common in Europe. The study found that many perennial vegetables are much higher in these nutrients than common annual vegetables. However, several gaps were identified — for almost all perennial vegetables, data on many nutrients were missing. Other important perennial vegetables had no data available at all. This project aims to fill in identified gaps and encourage more research.

What are the goals of the project?

If we reach the goal of this fundraiser we will be able to test three of the following: hosta (Hosta sieboldii), linden (Tilia cordata), caucasian spinach (Hablitzia tamnoides) and scorzonera (Scorzonera hispanica). In order to compare results, the same analyses will also be done for a common species with well-known nutrition values (e.g. stinging nettle Urtica dioica). An accredited lab will analyze leaves and buds using standard nutritional analysis methods. We will compare our results with studies of perennial and annual vegetables.

Perennial vegetables are edible plants that regrow in the same place every year. They are a key component of sustainable regenerative food systems and previous research indicates that they are very nutritious and can contribute to healthier diets. However, there is a lack of comprehensive research regarding plant nutrient content. Our aim is to fill the knowledge gaps about the nutrients found in perennial vegetables, with a focus on varieties grown in colder climates.