Precision Nutrition and the Gut Microbiome: The Impact of Blueberries
Nutrition research funding is increasingly focused on precision nutrition, which has recently gained significant interest. The consumption of fruits and vegetables is related to a lower risk of developing chronic diseases such as obesity, cardiovascular disease, diabetes and neurocognitive diseases.
Berries, tea and cocoa contain (poly)phenolic compounds identified with potential health benefits among thousands of phytochemicals studied.
Epidemiological studies have prompted further research investigating the health benefits of blueberries and blueberry-rich foods. More research is needed to discover the mechanisms of action behind these health benefits.
About the Studio
In the present study, the researchers showed the variety of polyphenol profiles found in blueberries, examined the bioavailability of anthocyanins in blueberries in various forms, and explored their impact on the gut microbiome.
Anthocyanin profiles of 267 blueberry genotypes were analyzed at the North Carolina State University Piedmont Research Station in Salisbury, North Carolina. The genotypes included both commercial varieties and breeding selections.
Principal component analysis (PCA) was performed on 17 anthocyanins tested in each genotype using a multivariate statistical method. Blueberry genotypes with various anthocyanin profiles were chosen based on their different PCA profiles.
These genotypes were then analyzed to determine their polyphenolic profiles. The bioavailability of flavonoids was further tested in ovariectomized rats, which serve as a model for postmenopausal bone loss in women.
Six genotypes were chosen for the study, including three rabbit eye genotypes ( Vaccinium virgatum ) including Montgomery, Ira, and Onslow, along with three southern tallshrub genotypes ( V. corybosum ) such as Sampson, Legacy and SHF2B1-21:3.
Plasma was subjected to solid phase extraction (SPE) to extract flavonol, anthocyanin and flavan-3-ol metabolites, which were subsequently analysed.
The impact of blueberries on bone calcium retention was studied in four-month-old ovariectomized female Sprague Dawley rats through microbiome analysis. The team extracted deoxyribonucleic acid (DNA) from fecal samples and sequenced the resulting amplicons.
The study involved 20 rats and 160 fecal samples collected at various stages, including baseline, 10-day cranberry treatments, and wash phases for microbiota analysis.
Anthocyanins identified from plants belonging to the same genotype included cyanidin 3-O-galactoside, cyanidin 3-O-arabinisido, cyanidin 6-O-glucoside, cyanidin 3-O-glucoside, delphinidin 3-O-arabinisido, delphinidin 3-O - galactoside, delphinidin 6-O-glucoside, delphinidin 3-O-glucoside, malvidin 3-O-galactoside, malvidin 3-O-arabinisido, malvidin 3-O-glucoside, malvidin 6-O-galactoside, peonidin 3-O-galactoside , malvidin 6-O-glucoside, petunidin 3-O-glucoside, petunidin 6-O-glucoside and petunidin 3-O-arabinisido.
The study analyzed six blueberry genotypes and four members of the genus Vaccinium to determine their total phenolic content (TP) and monomeric anthocyanins.
The results showed that blueberry and Lowbush Blueberry (LB) composite had higher levels of phenolic and total monomeric anthocyanins compared to their highbush counterparts.
The content of total phenols was between 1.951 and 4.627 mg/100 g of berry, while the total of monomeric anthocyanins was between 369 and 1.722 mg/100 g.
About 50% of all phenols found in blueberries were anthocyanins, the most abundant phenolic class in Vaccinium species. The ten genotypes examined showed significant differences in the levels and proportions of various anthocyanins.
The blueberry and compound LB genotypes had the highest levels of anthocyanins, which is consistent with their higher levels of total monomeric and total phenolic anthocyanins.
Blueberries exhibited the most significant amounts of cyanidin and delphinidin species, while the LB compound exhibited the highest levels of malvidin and acylated anthocyanin. Blueberries had a distinct anthocyanin profile compared to other berries, exhibiting elevated levels of peonidin but reduced levels of malvidin, delphinidin, and petunidin.
The tested genotypes showed variable levels of glycosylation, and most had significant content of arabinoside and galactoside derivatives. Specific genotypes, such as Legacy, Ira, and Sampson, had remarkably low amounts of glycosidic derivatives. In contrast, other genotypes, including Onslow, Wild Blueberry (WBB), Bilberry, SHF2B1-21:3, and Composite LB, exhibited amounts of glycosidic derivatives equal to or greater than their arabinoside and galactoside derivatives.
Plasma samples from OVX rats showed the presence of various anthocyanin metabolites such as delphinidin-3-O-glucosides, cyanidin-3-O-glucosides, peonidin-3-O-glucosides, malvidin-3-O-glucosides, and petunidin3- O -glycosides after an acute dose.
Cyanidin-3-O-glucosides and malvidin-3-O-glucosides had higher bioavailability in Montgomery cranberries than in other berries.
The study found that the dose of blueberries significantly affected the Firmicutes-Bacteroidota ratio, which decreased as the dose increased. The proportions were highest in samples without blueberry diets and gradually decreased in samples with increasing concentrations of blueberries.
Furthermore, comparisons of diversity in the gut microbiome in each sample exhibited considerably greater variety among samples that had higher blueberry treatments.
In addition, the team observed that two taxa from the Actinobacteria phylum, one from the Bacteroidota phylum, family Prevotellaceae_UCG-001, and one from the Firmicutes family, Anaerovoracaceae XIII_UCG-001, had higher ratios after blueberry treatments.
The study findings showed that the phenolic profiles of blueberries vary depending on their genetic background, which affects their bioavailability and the metabolism of their polyphenols. The team also found evidence of a gut microbiome response to the blueberry dose.
The diversity found in farming systems, from growth to consumption to the gut microbiome, can be used to improve crop selection, breeding methods, and identification of critical genotypes. This information can help understand functional responses to health and develop precision nutrition practices.