Article - Effects of a Raisin Supplement on Cognitive Performance, Quality of Life, and Functional Activities in Healthy Older Adults-Randomized Clinical Trial.

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Take home message

The regular intake of polyphenol-rich foods, and especially flavonoids, could mitigate the progression of different neurological conditions, and support general functional activities.

Evidence category

A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)

Summary review

Introduction

This study analysed the effects of 50g of Málaga muscatel raisins supplemented to the usual diet (containing 9.48 mg of polyphenols, of which 6.76 mg were flavanols), on cognitive performance, quality of life, and functional activities (via questionnaires).

Methods

80 participants (average age of 76.7 years), of which 53 participants (66.3%) were women, were equally divided between the intervention group (IG) or the control group (CG). The intervention was provided for 6 months, and was single-blinded.
Cognitive performance used a Montreal Cognitive Assessment (MOCA) test, Mini-Mental State Examination test (MMSE), Rey Auditory Verbal Learning Test (RAVLT), and verbal fluency.
Functional activities measured: Pfeffer Functional Activities Questionnaire (FAQ), quality of life through the EuroQol

Questionnaire and the World Health Organisation Quality of Life Instrument (WHOQOL), an adaptation of WHOQOL-AGE.

Results

MOCA: overall significant improvement in IG (2.81; CI: 1.72 - 3.90) versus CG (−0.46; CI1.70 to 0.77).
Specifically for the IG group: visuospatial-executive capacity significantly improved by 1.36 (0.77 to 1.95) points (p ≤ 0.001), as did language - 0.54 (0.12 to 0.96) points (p = 0.014); and orientation - 0.49 (0.10 to 0.87) points (p = 0.014).
MMSE: overall no differences reported between groups. However for time orientation, a difference of 0.36 points (p = 0.038) between IG and CG was noted. Also for spatial orientation, memory and comprehension, reading, writing, drawing: (IG) general improvement noted at 6 month (0.02, −0.11 to 0.14) but was not significant.

RAVLT: immediate recall - a significant difference of 1.2 (0.51 to 1.89) words (p = 0.01); delayed recall - a non-significant difference of 1.7 (0.46 to 2.94) words (p = 0.08).

WHOQOL: significant changes to quality of life, (IG) - 1.21 (−0.13 to 2.55) points, (CG) −1.39 (−2.93 to 0.15).
FAQ: (IG) positive changes: −0.24 (−0.57 to 0.09), (CG) 0.69 (0.32 to 1.05).

Limitations Blinding of the participants was not possible due to the nature of the intervention. The nutritional composition of the 3-day dietary record did not provide exact data on dietary polyphenols.

Conclusion

Study suggests that the daily addition of 50g of Málaga muscatel raisins slightly improved cognitive performance. However, results should be interpreted with caution based of the study limitations.

Clinical practice applications

This study suggests that nutritional interventions containing bioactive nutrients such as polyphenols (particularly flavanols), such as raisins that have a low to moderate glycemic index and a low insulin index, may prevent age-related cognitive decline.

Considerations for future research

More research is needed to know exactly the mechanism of action of polyphenols on cognitive performance. Also methods involving double-blinding of participants and careful control of polyphenol intake would help clarify specific effects of additional foods/supplements.

Abstract

["The objective of this study was to evaluate the effects of consuming 50 g of raisins on cognitive performance, quality of life, and functional activities in healthy older adults. This is a parallel randomized controlled clinical trial, in which 80 subjects over 70 years of age participated. For 6 months, the intervention group (IG; = 40) consumed 50 g of raisins per day added to their usual diet, whereas the control group (CG; = 40) received no supplement. All variables were measured at baseline and at 6 months. Cognitive performance assessed with the Montreal Cognitive Assessment (MOCA) test shows a difference of 3.27 points (95% CI 1.59 to 4.96), \u2264 0.001, favorable to the IG, after the intervention. Among the cognitive performances, an improvement is observed in the IG in orientation, assessed both with the MOCA test 0.49 (95% CI 0.10 to 0.87), = 0.014, and with the Mini-Mental State Examination (MMSE) test, 0.36 (95% CI 0.02 to 0.70), = 0.038. In visuospatial\/executive capacity and in language, improvements were also observed in the IG, 1.36 (95% CI 0.77 to 1.95), = 0.001, and 0.54 points (95% CI 0.12 to 0.96), = 0.014, respectively. Immediate and delayed recall, assessed with the Rey Auditory Verbal Learning Test, improved in the IG. In addition, the IG showed a better quality of life and greater autonomy in instrumental activities of daily living after 6 months. No significant changes were observed in the rest of the variables analyzed. Therefore, the consumption of 50 g of raisins produces a slight improvement in cognitive performance, quality of life, and functional activities in the elderly."]