Is freeze-dried superfood kale supplementation healthier than common green peas? Outcomes of a cross-over trial

Front Nutr. 2024 Jul 24:11:1370677. doi: 10.3389/fnut.2024.1370677. eCollection 2024.

Abstract

Kale (Brassica oleracea species) is considered a functional food whose macronutrient and phytochemical contents are considered beneficial and widely considered as a superfood. In the present 6-week cross-over trial with a 2-week washout period, we compared the beneficial effects of freeze-dried kale over peas among Arab women with obesity. A total of 124 Saudi women with obesity were allocated to receive either freeze-dried kale (n = 62) or freeze-dried peas (n = 62) given in the form of 3-gram sachets thrice daily for 2 weeks, followed by a 2-week washout period and a cross-over of 4 weeks. Anthropometric measurements, glucose, lipids and markers of gut barrier function were assessed at baseline and post-intervention. Participants who took kale supplementation first resulted in significant weight reduction (p = 0.02) which was not observed among those who took peas first. Participants receiving pea supplementation first experienced a significant decline in Hba1c (p = 0.005) and CD14 (p = 0.03), but C-peptide increased (p = 0.05). Crossover analysis revealed significant carryover effects in most variables with non-significant combined treatment effects. Among the variables with no carryover effect with significant combined treatment effect include HbA1c which was in favor of the pea group (p = 0.005) and C-peptide which was modestly in favor of the kale group (p = 0.05). While both freeze dried kale and pea supplementation appear beneficial, supplementation of freeze-dried pea appears to be more effective in terms of acute glycemic control than kale. The study suggests that common but less-hyped vegetables such as pea maybe equally, if not more beneficial than the more expensive promoted superfoods such as kale. Longer clinical trials using a parallel design instead of cross-over are recommended to strengthen present findings.

Keywords: crossover trial; green peas; kale; obesity; superfood.

Grants and funding

The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. The present study was funded by the National Plan for Science, Technology and Innovation (MAARIFAH), King Abdulaziz City for Science and Technology, Kingdom of Saudi Arabia (Award No: 2-17-03-001-0031). The authors are grateful to Ishaana Nutraceuticals in Dehradun, Uttarakhand, India for the provision of sachets needed for the crossover trial. The funder nor “Ishaana Nutraceuticals” had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the result.