{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T20:34:03Z","timestamp":1790886843544,"version":"4.1.0"},"reference-count":53,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,1,15]],"date-time":"2026-01-15T00:00:00Z","timestamp":1768435200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Liverpool John Moores University VC Studentships Faculty Funding"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biology"],"abstract":"<jats:p>Elevated atmospheric CO2 is known to alter plant physiology, yet its specific effects on nutrient-rich leafy vegetables remain insufficiently quantified. This study aimed to examine how eCO2 influences yield and nutritional quality in kale (Brassica oleracea) and spinach (Spinacia oleracea) through the first meta-analysis focused exclusively on these crops. Following the Collaboration for Environmental Evidence (CEE) guidelines, we systematically reviewed eligible studies and conducted a random-effects meta-analysis to evaluate overall and subgroup responses based on CO2 concentration, crop type and exposure duration. Effect sizes were calculated using Hedges\u2019 g with 95% confidence intervals. The analysis showed that eCO2 significantly increased biomass in spinach (g = 1.21) and kale (g = 0.97). However, protein content declined in both crops (spinach: g = \u22120.76; kale: g = \u22120.61), and mineral concentrations, particularly calcium and magnesium, were reduced, with spinach exhibiting stronger nutrient losses overall. The variability in response across different CO2 concentrations and exposure times further underscores the complexity of eCO2 effects. These results highlight a trade-off between productivity and nutritional quality under future CO2 conditions. Addressing this challenge will require strategies such as targeted breeding programmes, biofortification, precision agriculture and improved sustainable agricultural practices to maintain nutrient density. This research provides critical evidence for policymakers and scientists to design sustainable food systems that safeguard public health in a changing climate.<\/jats:p>","DOI":"10.3390\/biology15020152","type":"journal-article","created":{"date-parts":[[2026,1,15]],"date-time":"2026-01-15T11:13:21Z","timestamp":1768475601000},"page":"152","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Effects of Elevated CO2 on Yield and Nutritional Quality of Kale and Spinach: A Meta-Analysis"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0009-0008-8349-5024","authenticated-orcid":false,"given":"Jiata U.","family":"Ekele","sequence":"first","affiliation":[{"name":"School of Biological and Environmental Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-1496-2318","authenticated-orcid":false,"given":"Joseph O.","family":"Obaje","sequence":"additional","affiliation":[{"name":"School of Biological and Environmental Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4676-9950","authenticated-orcid":false,"given":"Susanne R. K.","family":"Zajitschek","sequence":"additional","affiliation":[{"name":"School of Biological and Environmental Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3424-9301","authenticated-orcid":false,"given":"Richard J.","family":"Webster","sequence":"additional","affiliation":[{"name":"School of Biological and Environmental Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2537-3327","authenticated-orcid":false,"given":"Fatima","family":"Perez de Heredia","sequence":"additional","affiliation":[{"name":"School of Biological and Environmental Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"},{"name":"Institute of Health Research, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"},{"name":"Liverpool Centre for Cardiovascular Science, Liverpool L7 8TX, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9092-2927","authenticated-orcid":false,"given":"Katie E.","family":"Lane","sequence":"additional","affiliation":[{"name":"Department of Sports and Exercise Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6042-8939","authenticated-orcid":false,"given":"Abdulmannan","family":"Fadel","sequence":"additional","affiliation":[{"name":"Department of Nutrition and Health, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain P.O. Box 1555, United Arab Emirates"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6838-2904","authenticated-orcid":false,"given":"Rachael C.","family":"Symonds","sequence":"additional","affiliation":[{"name":"School of Biological and Environmental Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,15]]},"reference":[{"key":"ref_1","unstructured":"IPCC (2023). Climate Change 2023: Synthesis Report. Contribution of Working Group I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, IPCC. 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