4.3. Strengths and Limitations
BLIND
This trial has a larger number of participants compared to other studies looking at the effect of polyphenols on cognitive performance [Regarding the limitations of this study, it should be noted that it was not possible to blind the participants due to the nature of the intervention, although blinding of the investigators was ensured in the measurements and in the statistical analyses. Furthermore, the tool used to assess the nutritional composition of the habitual diet, the 3-day dietary record, does not provide exact data on dietary polyphenols. Despite this, we can assume that randomization would have balanced the groups with respect to dietary intake. However, it should be taken into account in future trials. Another limitation of our study is that the amount of polyphenols administered in the IG contains a low concentration of polyphenols, compared to other studies. On the other hand, we must bear in mind that repeating the same tests 6 months after the baseline visit may have a learning component for both groups, despite the fact that this is the recommended period of time to avoid the learning effect.