Upcycled Romaine Lettuce Powder as a Dietary Supplement for Control of Metabolic Syndrome

Abstract

Romaine lettuce outer leaves are discarded in the field during harvesting, presenting an opportunity for upcycling. We previously developed a romaine lettuce powder (RLP) from discarded outer leaves with high antioxidant capacity, high levels of fiber, and high concentration of total soluble phenolics. In this study, we evaluated the health benefits and preventive effects of RLP in metabolic syndrome (MS) induced by a high-fat diet fed to mice for 12 weeks. Supplementation with 10% RLP in a high-fat diet lowered glucose and insulin levels and prevented the development of insulin resistance in mice. Moreover, adipose tissue weight was lower in mice fed with a high-fat diet supplemented with 10% RLP compared to mice fed with a control high-fat diet. Liver weight was also lower in mice fed with a high-fat diet supplemented with 10% RLP compared to those fed with low-fat and high-fat diet groups, suggesting a positive effect of lettuce powder on liver health. Here, we show that RLP has a preventive effect on MS by regulating body weight, lowering lipid levels, and improving glucose metabolism. Our results indicate that incorporating RLP into mice’s diet has potential health benefits.