For instance, they could recall stories that they have heard and point out changes seen on a screen quicker than those who did not consume the supplement.
Such benefits persisted even two weeks after the supplementation had stopped.
The tablet supplement used for the trial was ProBeptigen, which is made of hydrolysed peptides extracted from the essence of chicken.
It comprises 91.4% protein, of which, 4.2% are free amino acids and 7.6% are cyclic dipeptides. It also contains carbohydrate, lipid, and moisture.
Published in Nutrients, the researchers said that the trial funded by BRAND’S Suntory Asia provided incremental evidence to a pilot study conducted earlier on.
A total of 90 healthy subjects aged 35 to 65 with perceived stress had completed the trial.
The experiment group took two tablets of ProBeptigen (355mg/tablet) per day after their breakfast while the control group took the placebo. To track the changes in their memory function, they will need to visit the researchers on five occasions.
Their verbal working memory was assessed via the use of the ‘logical memory’ subtest, where they would need to recall narrative stories presented orally.
Their spatial working memory was assessed via the use of CANTAB battery test, which will track their eye movement when they look at the screen.
Results showed that the experiment group showed a greater improvement in their verbal working test, with the mean score improving by 6.49 ± 0.51 from the start to two weeks after the supplementation ended.
In the placebo group, there was also improvements in their verbal working score, but to a lower extent, where the mean score improved by 5.28 ± 0.37.
As for the spatial working memory, the differences in the performance between the experiment and placebo group was statistically significant, with a p-value of 0.045.
On the other hand, the amount of inflammation also declined in the experiment group and remained low two weeks after the supplementation had stopped.
For instance, the level of the inflammation indicator hs-CRP saw a mean difference of −0.08 ± 0.05 from the second to the fifth visit, while that of the placebo was 0.04 ± 0.05.
The difference seen between the two groups was a statistically significant result, with the p value = 0.042.
The anti-inflammatory effects could have contributed to the improvement in cognitive function, said the researchers, adding that the results were largely in line with previous studies.
They concluded that the “daily ProBeptigen 670 mg consumption for two months was suggested to improve verbal short- and long-term memory, as well as spatial working memory in middle-aged healthy individuals with perceived stress.”
There were several areas which require further investigation, one of which was the mechanisms behind the effects of ProBeptigen and the nature of the potential bioactives, said the researchers.
On the other hand, there was scope to further examine the other benefits of ProBeptigen, such as improved psychomotor speed and lasting cognitive benefits even two weeks after supplementation has stopped.
Other areas requiring further research include whether the improvement in spatial working memory was a standalone phenomenon, or was it linked to an improved memory, or executive function, or processing speed.
The above was not examined as it was beyond the scope of the trial to assess the differentiation, said the researchers.
In contrary to previous studies, the trial found that the experiment group had elevated levels of mean fasting glucose after the supplementation stopped.
The difference in plasma fasting glucose levels in the two groups post-supplementation was statistically significant, with p value = 0.008.
As such, they said it would be prudent to monitor fasting blood sugar regularly in future clinical trials to confirm the product’s safety.
Hydrolyzed Chicken Extract (ProBeptigen®) on Cognitive Function in Healthy Middle-Aged People: A Randomized Double-Blind Trial
Authors: Hsieh, Hu, and et al