Author(s): YUUKI, I.W., DORA, K.1,2, MATSUMURA, T.1, FUKUZAWA, K.1, MURAKAMI, Y.1, HASHIMOTO, K.1, HASHIMOTO, T.1, TSUKAMOTO, H.3, Institution: RITSUMEIKAN UNIVERSITY, Country: JAPAN, Abstract-ID: 2506

INTRODUCTION:
Cognitive function can be improved by the antioxidative effects of some oil consumption habits (1-3). Among them, compared to regular long-chain triglycerides (LCT; e.g., olive oil) consumption, medium-chain triglycerides (MCT; e.g., coconut oil) are quickly absorbed and promote the production of ketone bodies which are an important energy substrate for the brain (4). Indeed, the positive MCT impact on cognitive function has been observed in various populations (1,5). Along with the aforementioned advantages, it is possible that the positive MCT impact on cognitive function is greater than the LCT impact but there is a lack of research directly comparing the long-term effects of LCT and MCT on cognitive function in healthy young individuals. Meanwhile, it is well known that long-term aerobic exercise (AE) improves cognitive function (6). Given the additive effect of AE to dietary intervention on cognitive improvement (7), it is assumed that compared with MCT alone, a combination of MCT and AE (MCT-AE) further improves cognitive function. Here, we compared the long-term effect of LCT, MCT, and MCT-AE on working memory (WM) which is one of the major cognitive functions.
METHODS:
Thirty healthy young men were randomly allocated into the LCT [n = 10, age 21 ± 1], MCT [n = 10, age 21 ± 1], and MCT-AE [n = 10, age 21 ± 1] groups. All participants took the 16.3 ml oil (LCT: Olive oil; MCT and MCT-AE: MCT oil, containing 12 g MCT) every morning for four weeks in a single-blind manner. During four weeks of oil intervention, participants in the MCT-AE group performed moderate-intensity cycling AE (30 min/time, 3 times/week). Exercise intensity was determined using heart rate reserve (HRR), and moderate intensity at the onset of AE was defined at 50%HRR (but the workload was decreased if HR during AE exceeded 70%HRR due to cardiac drift). WM was assessed before and after the intervention using the face n-back task. The number of errors (ERR) and reaction time (RT) of the face n-back task were measured. The changes in ERR and RT from pre- to post-intervention were compared using the Kruskal-Wallis test and Mann-Whitney U test for post-hoc. The statistical significance level was defined at P < 0.050 and the Bonferroni correction was applied for post-hoc analysis.
RESULTS:
The changes in ERR were similar between all groups (P > 0.050). Compared with the LCT group (22 [-5 – 42] ms; median [IQR]), the changes in RT were shorter in the MCT-AE group (-63 [-91 – -31] ms, P = 0.044) and MCT group (-29 [-50 – -6] ms; P = 0.035). However, regarding the changes in RT, there were no significant differences between the MCT-AE and MCT groups (P = 0.371).
CONCLUSION:
Compared with LCT intervention, four weeks of MCT advances WM improvement in healthy young individuals. On the other hand, AE during MCT intervention did not cause further WM improvement.
1) Ashton et al. 2021
2) Espina et al. 2023
3) Fazlollahi et al. 2023
4) Page et al. 2009
5) Juby et al. 2022
6) Kelly et al. 2014
7) Blumenthal et al. 2019