Editorial: The Nutritional and Health Benefits of Vaccinium Berries

Paulina Malgorzata Nowaczyk ^1* Patrick Turck ² Małgorzata Jamka ^3*

• ¹ Department of Sports Dietetics, Faculty of Health Sciences, Poznan University of Physical Education, Poznań, Poland
• ² Department of Physiology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil, Porto Alegre, Rio de Janeiro, Brazil
• ³ Department of Pediatric Gastroenterology and Metabolic Diseases, Poznan University of Medical Sciences, Poznan, Poland

Previous research on the pro-health properties of Vaccinium berries (with blueberries being at the forefront) and their bioactive compounds has focused on cardiovascular health, prediabetes and type 2 diabetes, or brain health and cognitive function (1). The perspective literature review by Stull et al. (1) indicated that consuming ≥1-3 servings/week of blueberry may result in reduced risk of myocardial infarction, hypertension, or coronary heart disease (incidence and mortality), effectively lowering total and low-density lipoprotein cholesterol, selected inflammatory markers (i.e., C-reactive protein), and improving vascular function (i.e., endothelial function and arterial stiffness). It is strongly suggested that anthocyanins and their metabolites are key mediators of blueberries' vascular-protective effects. Meanwhile, habitual blueberry intake of ≥2 servings/week may be associated with a lower risk of type 2 diabetes (1). Nonetheless, the current body of evidence on blueberry consumption and glucose regulation and insulin resistance in adults yields mixed results, with individuals with normal or nearnormal blood glucose concentration only experiencing marginal or negligible improvements in glycemia after blueberry consumption (1). Higher berries intake has been associated with a slower rate of cognitive decline, a higher probability of healthy aging with the absence of major chronic diseases and physical and cognitive disability, and a lower risk of Parkinson's disease (1). Thus, according to Stull et al. (1), ≥1-2 servings/week of blueberry is recommended to enhance cognitive performance in the contexts of aging and cognitive impairment resulting from brain injury or metabolic and vascular disturbances.Less-known and less obvious pro-health properties of berries are related to the risk and treatment of urinary tract disorders (2) or chronic pain (3). Two articles (2,3) 4) revealed that 18 weeks of feeding C57Bl/6J male mice with high-fat (HF) diet (60% energy from fat) enriched with a mix of freeze-dried powder (20% dry weight basis) of a Nordic berries (lingonberries, bilberries) and red grape juice resulted in improved indicators of spatial memory, increased concentration of the inflammation modifying interleukine-10 cytokine in hippocampal extracts, as well as in significantly greater cecal microbial diversity, as measured by the Shannon diversity index and total operational taxonomic unit (OTU) richness. The HF diet supplemented with berries resulted in a strong trend of higher total OTU richness and significantly increased the relative abundance of Akkermansia muciniphila associated with protective effects on cognitive decline (4).Despite the natural and specific abundance of bioactive compounds in Vaccinium berries, food science, and the food industry are seeking to further improve the pro-health properties of these fruits. Tian et al. (5) investigated the effect of solid-state fermentation (SSF) of blueberry pomace utilizing three fungi strains and three lactic acid bacterial strains on polyphenol profiles, antioxidant capacities, and bioaccessibility. Ten phenolic acids and six flavonoids were increased in blueberry pomace fermented by Lactobacillus acidophilus. A similar tendency was observed after fermentation by Aspergillus niger (AN) and Lactobacillus plantarum, where the concentration of eight phenolic acids and five flavonoids was enhanced.The anthocyanin decreased after fermentation (apart from fermentation by AN). However, all the evaluated antioxidant activity markers increased, and the bioaccessibility of polyphenolic compounds assessed via simulated gastrointestinal digestion increased (5). Thus, the polyphenolic compounds and their bioaccessibility in blueberry pomace could be further improved by SSF utilizing appropriate microbial strains.Despite the promising results on the multidirectional pro-health properties of Vaccinium berries and their selected phenolic compounds, numerous research gaps remain to be resolved.First, there is too little evidence from long-term randomized controlled trials on humans, covering various population groups and health domains/conditions. The mechanisms of the in vivo action of Vaccinium berries have not been elucidated and little is known about the actual bioavailability of phenolic compounds and the factors affecting bioavailability. Furthermore, the effective and safe doses and standardized recommended servings of Vaccinium berries (fresh fruit, freeze-dried powders, supplements) or their bioactive compounds (supplements) must be established.