However, when combined with brain training activities, the improvement in cognitive performance was not enhanced.
Findings of the study were recently published in Nutrients. The study was conducted during July 2018 to July 2019 by the fruit and vegetable juice manufacturer and Tohoku University.
A total of 144 adults with an average age of 67.71 completed the study.
They were randomised to four groups: 1) brain training with sulforaphane supplementation 2) brain training with placebo 3) active control game and sulforaphane supplementation and 4) active control game with placebo.
The SFN supplement contains 30mg of its precursor glucoraphanin.
The brain training activity used was Brain Age – games that include mathematical calculations to train the cognitive function, while the active control game used was Tetris.
The participants were asked to play either Brain Age or Tetris at home for 15 minutes every day for 12 weeks. This is accompanied by the intake of three capsules of the supplement or placebo each day.
After playing the games, the participants also needed to note down their game scores. Their scores for processing speed, attention, working memory, short-term memory were assessed.
Compared with the placebo, the groups which took the supplement recorded significant improvements in the processing speed and working memory performance, where the p-values were below 0.05.
“We found a significant main effect of nutrition on processing speed and working memory performances,” the researchers said.
They added that the result was in line with previous evidence. For example, a 2010 study by Nurk showed that there was a positive correlation between the amount of cruciferous vegetable intake and processing speed.
The improvement could be due to the antioxidant and anti-inflammatory properties of sulforaphane.
Nonetheless, they said that further studies should be conducted to measure its antioxidant and anti-inflammatory properties.
No enhanced results
Combining brain training and SFN supplementation, however, did not lead to additional improvements in cognitive performance, as compared to taking the two interventions separately.
“However, we did not find any significant main effects or interaction effects of cognitive training or nutrition on cognitive performance or emotional state,” they said.
They explained that this could be due to the short intervention period of only 12 weeks, and thus, was not sufficient to detect the beneficial impacts.
The paper concluded: “Although we did not find any evidence to support the intervention’s beneficial effects on cognitive functions, we found that the brain training and SFN intake separately led to improvements in cognitive functions.
“The brain training group showed a significant improvement in processing speed compared to the active intervention group.
Further, the SFN intake groups revealed significant improvements in processing and working memory performance.”
Brain Training and Sulforaphane Intake Interventions Separately Improve Cognitive Performance in Healthy Older Adults, Whereas a Combination of These Interventions Does Not Have More Beneficial Effects: Evidence from a Randomized Controlled Trial
Authors: Rui Nouchi and et al