An fMRI Investigation into the Effects of Ketogenic Medium-Chain Triglycerides on Cognitive Function in Elderly Adults: A Pilot Study.

Yukihito Yomogida,Kinya Ashida,Miho Ota,Ikki Ishida,Kentaro Nakamura,Junko Matsuo,Hiroshi Kunugi

doi:10.3390/nu13072134

Abstract

Evidence suggests that oral intake of medium-chain triglycerides (MCTs), which promote the production of ketone bodies, may improve cognitive functions in elderly people; however, the underlying brain mechanisms remain elusive. We tested the hypothesis that cognitive improvement accompanies physiological changes in the brain and reflects the use of ketone bodies as an extra energy source. To this end, by using functional magnetic resonance imaging, cerebral blood oxygenation level-dependent (BOLD) signals were measured while 20 healthy elderly subjects (14 females and 6 males; mean age: 65.7 ± 3.9 years) were engaged in executive function tasks (N-back and Go-Nogo) after ingesting a single MCT meal (Ketonformula®) or placebo meal in a randomized, double-blind placebo-controlled design (UMIN000031539). Morphological characteristics of the brain were also examined in relation to the effects of an MCT meal. The MCT meal improved N-back task performance, and this was prominent in subjects who had reduced grey matter volume in the dorsolateral prefrontal cortex (DLPFC), a region known to promote executive functions. When the participants were dichotomized into high/low level groups of global cognitive function at baseline, the high group showed improved N-back task performance, while the low group showed improved Go-Nogo task performance. This was accompanied by decreased BOLD signals in the DLPFC, indicative of the consumption of ketone bodies as an extra energy source.

Highlights

With today’s increasing life expectancy, it is increasingly important for the elderly to preserve and improve their cognitive functions, which are vital for maintaining independent living and quality of life [1,2]
Analysis of the subgroups based on the global level ofofcognitive function (assessed bybythe atatbaseline indicated that different aspects ofofexecutive function (working the baseline indicated that different aspects executive function at baseline indicated that different aspects of executive function were improved by the meal depending on the level memoryororinhibitory inhibitorycontrol) meal depending on the memory were improved byby thethe meal depending on the levellevel of ofofglobal cognitive function
The results show that consuming the medium-chain triglycerides (MCTs) meal was associated with better performance results show that consuming the meal was associated with performance in in some executive functions in our elderly subjects, depending onbetter their baseline cognitive some executive functions in our elderly subjects, depending on their baseline cognitive function

Summary

Introduction

With today’s increasing life expectancy, it is increasingly important for the elderly to preserve and improve their cognitive functions, which are vital for maintaining independent living and quality of life [1,2]. It has been suggested that elderly people can improve their cognitive functions by ingesting specific meals that elevate plasma ketone body levels, and in this context, the oral intake of medium-chain triglycerides (MCTs) has been garnering considerable attention [3,4,5]; its physiological mechanisms in the brain remain elusive. There are three types of ketone bodies: acetone, β-hydroxybutyrate, and acetoacetate. Of these, the latter two are utilized in the brain [7]. Increasing evidence has suggested that ketone bodies are effective for the treatment of other neurological disorders. Longitudinal studies have shown that elevating the plasma ketone body level improved cognitive dysfunction in people suffering from Alzheimer’s disease [9,10,11] and mild cognitive impairment [12,13]

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