Data published in Nutrition Research indicated that the isomaltulose drink was associated with increases in beneficial slow wave sleep and improved overnight retention of neutral story content compared to a high-glycemic index (HGI) drink but only when the LGI drink was consumed on the second test night.
The study on 20 males is reportedly the first to show the influence of a pre-bed drink on memory consolidation, “a finding particularly significant for populations who would benefit from improved episodic memory such as older adults and school children if replicated,” wrote the researchers from Swansea University, Nottingham Trent University and the Centre for Clinical Brain Sciences in Edinburgh, UK.
“These findings are significant, as deep or slow-wave sleep is important for physical recovery and cognitive health,” Dr. Stephan Theis, head of nutrition science and communication at Beneo, said in a press release.
“By supporting balanced blood sugar levels and prolonging the deep sleep phase, Palatinose may improve restful sleep and a person’s overall well-being” he added. “Its ability to sustain blood sugar levels overnight may also have far-reaching implications for dietary interventions, targeting sleep disorders and cognitive decline.”
Isomaltulose is a slow-releasing carbohydrate
The LGI drink used in the study was supplied by German ingredients company Beneo, which funded the study. It markets the drink as a “smart carbohydrate” under the brand name Palatinose.
Beneo notes on its website that isomaltulose is a disaccharide carbohydrate that occurs naturally in honey and sugar cane juice and is derived from sucrose by enzymatic conversion.
As a slow-releasing carbohydrate, it helps to balance blood glucose levels and insulin release, maintaining a more steady energy supply and potentially supporting sleep cycles.
Previous research suggests that carbohydrates and macronutrient ratios in the diet may affect different stages of sleep, possibly by influencing glucose-sensing neurons in the hypothalamus, although the exact mechanisms are not yet identified.
Study details
The double-blind crossover study involved 20 healthy males between the ages of 19 and 33 with normal sleep schedules who attended the laboratory on three occasions one week apart. The first visit was an acclimatization night in the laboratory setting.
At the second visit, they consumed a pre-bedtime drink containing either glucose (HGI) or isomaltulose (LGI) supplied by Beneo after eating a standardized evening meal. After a one-week washout period, they consumed the alternative drink.
Researchers used polysomnography to monitor sleep phases. They assessed memory using a story recall task based on neutral, negative and positive stories that participants were tested on the following morning. They also used a device to monitor glucose levels.
The results revealed a nonsignificant effect of the drink but a significant interaction between drink type and order.
“Consuming a LGI drink containing isomaltulose 15 minutes before bedtime was associated with a higher percentage of [slow wave] sleep (28.71% vs. 23.99%, respectively) and better overnight retention of neutral words (0.63 words vs. -10.13 words, respectively) compared to a HGI drink containing glucose but only when consumed on the second test night,” the researchers wrote.
The GI of the drinks did not affect the overnight retention of positive or negative words and stories.
An exploratory analysis also suggested that the LGI drink “was associated with a significantly lower percentage of wake (4.3%) earlier in the night compared to the HGI drink.”
The study noted that more research is needed to make firm conclusions.
Source: Nutrition Research, Volume 134, 2025, Pages 49-59, ISSN 0271-5317. doi: 10.1016/j.nutres.2024.11.012. “Low and high glycemic index drinks differentially affect sleep polysomnography and memory consolidation: A randomized controlled trial”. Authors: C.M. Gaylor et al.