Written by Jessica Patella, ND. This study demonstrated that consuming a mixture of flavonoid rich berries maintained or improved cognitive performance up to six hours post consumption.

fruits and vegetables - berriesThere is growing research on the effects of diet on mood, brain development and brain functioning 1.  Flavonoids have shown to be protective against cognitive decline 1-3 and dementia 4 and therefore interest has grown on how flavonoids may support brain functioning 1.  Recent research showed consuming mixed berries, high in flavonoids, resulted in maintaining or improving cognitive performance across the 6-hour day 1.

Flavonoids are a class of nutrients in the polyphenol group that are found in berries, tea, cocoa, citrus fruit and green leafy spices 1.  Berries are a rich source of the flavonoid anthocyanidins, which have shown improved cognitive performance and testing in both young and aging rodents 1,5,6.

To test these previous findings from the animal models, the recent research included 40 healthy young adults, 20-30 years of age (mean 22.8 years), that were randomized to a single-blind, placebo-controlled, parallel group trial to assess the effects of mixed berries on thinking and mood.  The berry intervention was a 400 mL “smoothie” containing 75 grams of whole strawberries, blueberries, blackberries and raspberries blended with 100 mL of water (total polyphenols 14.3 g based on USDA database).  The placebo was matched for carbohydrates and vitamin C and contained 341 mL water, 11.6 g fructose, 10.0 g glucose, 37.4 g vitamin C.  Both drinks were contained in opaque flasks and black opaque straws were used to consume the drink 1. Cognition was tested through tasks that lasted 30 minutes and were measured via the Modified Attention Network Task (MANT).  In this test, attention is put under various levels of cognitive demands based on varying levels of difficulty and distracting noises while the participant’s response time and accuracy is measured.  The Task Switch Test (TST) was also used to measure mental flexibility, again with accuracy and response time measured 1.  Mood regulation was measured via the Positive and Negative Affect Schedule (PANAS-NOW) which measures positive and negative mood states.  In this test participants rated 20 different motions on a 5-point scale, half of which related to a negative affect and the other which relate to a positive effect.  All tests occurred at baseline, then 2, 4, and 6 hours post “smoothie.”  The following results were observed:

  • Following the berry intervention participants maintained accuracy on cognitive tests up to and including 6 hours post-consumption (p=0.003)
  • Following the berry intervention there was a quicker response time on the MANT at 2-hours (p<0.01) and 4 hours (p<0.01) and TST at 6 hours (p<0.001).
  • Following the placebo, performance decreased across the day as participants become cognitively fatigued.
  • There were no significant difference noted between the groups in mood. Although, positive affect was higher for the berry intervention compared to placebo at 2 hours, it did not reach statistical significance.

In conclusion, consuming mixed berries, a rich source of flavonoids, improved cognitive brain functions.  Even though the placebo was matched for sugar content and sweetness, it was not matched for texture or flavor; in the future this should be considered, if possible, to reduce possible placebo-effect 1.

Source: Whyte, Adrian R., Nancy Cheng, Laurie T. Butler, Daniel J. Lamport, and Claire M. Williams. “Flavonoid-Rich Mixed Berries Maintain and Improve Cognitive Function Over a 6 h Period in Young Healthy Adults.” Nutrients 11, no. 11 (2019): 2685.

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

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Posted September 28, 2020.

Jessica Patella, ND, is a naturopathic physician specializing in nutrition and homeopathic medicine and offers a holistic approach to health. She earned her ND from Southwest College of Naturopathic Medicine in Tempe, AZ, and is a member of the North Carolina Association of Naturopathic Physicians. Visit her website at www.awarenesswellness.com.

References:

  1. Whyte AR, Cheng N, Butler LT, Lamport DJ, Williams CM. Flavonoid-Rich Mixed Berries Maintain and Improve Cognitive Function Over a 6 h Period in Young Healthy Adults. Nutrients. 2019;11(11).
  2. Devore EE, Kang JH, Breteler MM, Grodstein F. Dietary intakes of berries and flavonoids in relation to cognitive decline. Annals of neurology. 2012;72(1):135-143.
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  4. Beking K, Vieira A. Flavonoid intake and disability-adjusted life years due to Alzheimer’s and related dementias: a population-based study involving twenty-three developed countries. Public Health Nutr. 2010;13(9):1403-1409.
  5. Joseph JA, Shukitt-Hale B, Denisova NA, et al. Reversals of age-related declines in neuronal signal transduction, cognitive, and motor behavioral deficits with blueberry, spinach, or strawberry dietary supplementation. The Journal of neuroscience : the official journal of the Society for Neuroscience. 1999;19(18):8114-8121.
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