MCT oil may boost brain power in young adults, study suggests

A new study published in Physiology & Behavior has found that medium‑chain triglyceride oil can sharpen certain aspects of thinking in young adults, both immediately after a single dose and after a month of daily use.

Medium‑chain triglyceride oil has long been studied for its potential to support brain health in older adults and people with neurological conditions. However, the cognitive enhancing capabilities in healthy young people have remained an open question.

The brain relies heavily on energy, and medium‑chain triglycerides are known for their ability to quickly increase ketone bodies, an alternative fuel source that the brain can use when glucose is low. This metabolic advantage has made medium‑chain triglycerides a popular topic in nutrition and neuroscience research.

Led by I Wayan Yuuki from Ritsumeikan University in Japan, the researchers sought to discover whether the benefits of medium‑chain triglyceride oil extend to young adults who do not have cognitive impairments.

To investigate, Yuuki and colleagues conducted a randomized controlled trial involving 36 healthy young adults (20 males, 16 females), with an average age of 21 years old. Participants were assigned to consume either 12 grams of medium‑chain triglyceride oil or olive oil, which served as the long‑chain triglyceride comparison. The study included two phases: an acute test and a 4‑week daily supplementation period.

In the acute phase, participants completed a series of cognitive tests, consumed their assigned oil mixed with oatmeal, and repeated the tests 75 minutes later.

The researchers found that medium‑chain triglyceride oil did not improve short‑term memory or working memory in the immediate timeframe. However, it did significantly enhance inhibitory control compared to the long-chain triglyceride oil, the mental process that helps people resist distractions and suppress automatic responses. This improvement was measured using the reverse-Stroop task, a classic test of cognitive control whereby individuals must name the word rather than the color that the word is printed in.

“The mechanisms underlying the acute effect of medium‑chain triglyceride on the inhibitory control process remain unknown,” Yuuki and colleagues noted. They hypothesized that “increased ketone body metabolism [in the brain] via increased circulating levels of ketone bodies” may play a role.

The long‑term phase told a different story. After four weeks of daily medium‑chain triglyceride intake, participants showed no improvement in memory or inhibitory control compared to the olive‑oil group.

However, the participants did perform better on a demanding working‑memory task compared to the long-chain triglyceride oil, responding more quickly and consistently during the 2‑back test. The 2-back test involves participants watching a series of images appear one by one and pressing a button whenever the current image matched the one shown two steps earlier. This suggests that regular medium‑chain triglyceride consumption may strengthen the brain’s ability to hold and manipulate information, even if it does not produce immediate changes in this area.

Yuuki’s team concluded, “to the best of our knowledge, this study is the first to demonstrate that, compared to long-chain triglyceride intervention with the same macronutrients, a 4-week daily medium‑chain triglyceride regimen is an effective strategy for improving information processing speed and performance stability in complex working memory, though not in easy working memory, among young adults.”

However, the researchers note that the study has limitations. For instance, participants were told to maintain their usual lifestyle habits, including usual diet, physical activity levels, and sleep quality, during the testing period—but these factors were not measured.

The study, “Both a single dose and a 4-week daily regimen of medium-chain triglycerides boost certain aspects of cognitive function in young adults: A randomized controlled trial,” was authored by I Wayan Yuuki, Kento Dora, Teppei Matsumura, Kazushi Fukuzawa, Yoshino Murakami, Kaito Hashimoto, Hayato Tsukamoto, and Takeshi Hashimoto.