The effect of orally consumed Lactuca sativa syrup on human milk volume and weight gain in the preterm infant: a randomized controlled clinical trial

Human milk feeding can support premature infants to thrive. Yet those with premature infants can be challenged in human milk production. Considering this, and the use of potentially harmful human milk enhancers, the present study was conducted with the aim of determining the effect of orally consumed Lactuca sativa (L. sativa) syrup (lettuce extract) on human milk volume and subsequent weight gain in the preterm infant. Extracts from lettuce and other plants such as silymarin are already evidenced to be safe for use during lactation and have other therapeutic effects in humans. Yet this is the first study of its kind. This parallel randomized clinical trial included lactating participants with their preterm infants who were born at < 32 weeks' gestation and admitted to an intensive care unit. Convenience sampling was used to recruit participants. Eligible participants were allocated to groups randomly: intervention (n = 47), placebo (n = 46), and control (n = 47). The intervention group received one tablespoon of Lactuca sativa (L. sativa) syrup, and the placebo group received one tablespoon of placebo syrup 3 times a day for 1 week. Those in the control group did not receive any herbal or chemical milk-enhancing compounds. Routine care was provided to all three groups. Participants recorded their milk volume for 7 days in a daily information recorder form. Infant weight was measured prior to the intervention, and on the third, fifth and seventh days of the intervention period. There was a statistically significant difference observed in the adjusted mean volume of milk on the fourth and fifth days between the intervention, placebo, and control groups (P < 0.05). The adjusted mean milk volume of those in the intervention group on the first day was significantly higher than those in the control group and those in the placebo group. On the second day, the adjusted mean milk volume of those in the intervention group was higher than in those from the control group; and on the fourth day it was higher than in those from both the control and placebo groups; on the fifth day it was higher than in those in the placebo group; on the sixth day it was higher than in those in the control group and on the seventh day it was higher than in those in the control group (P < 0.05). There was no statistically significant difference in terms of the mean changes (with or without adjustment) in the weight of preterm infants between any of the groups. Lactuca sativa (L. sativa) syrup increases the volume of human milk production and no specific side effects have been reported in its use. Therefore, Lactuca sativa syrup can be recommended for use as one of the compounds that increase human milk volume.