Identification of Nordic Berries with Beneficial Effects on Cognitive Outcomes and Gut Microbiota in High-Fat-Fed Middle-Aged C57BL/6J Mice

Abstract

High-fat diets are associated with neuronal and memory dysfunction. Berries may be useful in improving age-related memory deficits in humans, as well as in mice receiving high-fat diets. Emerging research has also demonstrated that brain health and cognitive function may be related to the dynamic changes in the gut microbiota. In this study, the impact of Nordic berries on the brain and the gut microbiota was investigated in middle-aged C57BL/6J mice. The mice were fed high-fat diets (60%E fat) supplemented with freeze-dried powder (6% dwb) of bilberry, lingonberry, cloudberry, blueberry, blackcurrant, and sea buckthorn for 4 months. The results suggest that supplementation with bilberry, blackcurrant, blueberry, lingonberry, and (to some extent) cloudberry has beneficial effects on spatial cognition, as seen by the enhanced performance following the T-maze alternation test, as well as a greater proportion of DCX-expressing cells with prolongation in hippocampus. Furthermore, the proportion of the mucosa-associated symbiotic bacteria Akkermansia muciniphila increased by 4–14 times in the cecal microbiota of mice fed diets supplemented with lingonberry, bilberry, sea buckthorn, and blueberry. These findings demonstrate the potential of Nordic berries to preserve memory and cognitive function, and to induce alterations of the gut microbiota composition.

Scientific Evidence for the Beneficial Effects of Dietary Blueberries on Gut Health: A Systematic Review

“…The studies included in this article [ n = 16] were performed in four different countries that include China [ n = 7], [ 19–25 ] USA [ n = 4], [ 16,26–28 ] Canada [ n = 3], [ 29–31 ] Ukraine [ n = 1], [ 32 ] and Sweden [ n = 1]. [ 33 ] Regarding the animal model used in the studies, 11 of them were performed with mice [ 19–23,25,28–31,33 ] and five were performed with rats. [ 16,24,26,27,32 ] Most studies used male animals [ n = 14] [ 16,19–33 ] and two used both male and female animals.…”

“…[33] Regarding the animal model used in the studies, 11 of them were performed with mice [19][20][21][22][23]25,[28][29][30][31]33] and five were performed with rats. [16,24,26,27,32] Most studies used male animals [n = 14] [16,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] and two used both male and female animals. [24,32] The initial age of the animals ranged from 1 week to 24 months old, although one study did not mention this information.…”

“…[n = 4], [16,[26][27][28] Canada [n = 3], [29][30][31] Ukraine [n = 1], [32] and Sweden [n = 1]. [33] Regarding the animal model used in the studies, 11 of them were performed with mice [19][20][21][22][23]25,[28][29][30][31]33] and five were performed with rats. [16,24,26,27,32] Most studies used male animals [n = 14] [16,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] and two used both male and female animals.…”

Dried Bilberry (Vaccinium myrtillus L.) Alleviates the Inflammation and Adverse Metabolic Effects Caused by a High-Fat Diet in a Mouse Model of Obesity

“…These direct effects of bilberry anthocyanins may well contribute to the effects observed in the current study. In addition, bilberry polyphenols may alter the gut microbiome and thus secondarily influence the response to obesity-inducing diets [ 32 , 56 , 57 , 58 ]. Further studies are needed to understand the effective constituents of bilberry and their detailed mechanisms of action.…”

A mixture of Nordic berries improves cognitive function, metabolic function and alters the gut microbiota in C57Bl/6J male mice

“…Nonetheless, several of these Nordic berries remain largely unexplored for their potential health benefits, especially in relation to memory and cognitive function. There are studies on lingonberry ( Vaccinium vitis-idea ) and bilberry (aka European blueberry, Vaccinium myrtillus ) which show beneficial effects associated with reduced inflammation ( 35 , 36 ), reduced blood pressure ( 37 ) as well as improvement of brain function in mouse models ( 38 , 39 ). In our recent study including a screening of lesser-known wild berries from the Nordic countries, we found for the first time that several Nordic berry species mediate positive effects on spatial memory in middle-aged mice ( 39 ).…”