Table 3.
Key findings on the effects of blueberries on gut health in preclinical models
| Animal Model | Study Protocol | Duration of Intervention | Effect of blueberries on gut health |
Ref | |
|---|---|---|---|---|---|
| Primary Outcome | Secondary Outcome | ||||
| Sprague-Dawley rats Male Age: 3 Weeks |
AIN-93 Diet (n=4) AIN93 Diet supplemented with 8% lowbush wild blueberry powder (w/w) (n=5) |
6 Weeks | ↑ Protein families involved with amino acid metabolism, 2,4-dienoyl-CoA reductase, metal ion binding, glutamate synthase, REDOX homeostasis, and aryl transferases. ↓ Protein families involved with integrase/recombinase, reverse transcriptase, and transposon/transposase. |
[26] | |
| Sprague-Dawley rats Male Age: 3 Weeks |
AIN-93 Diet (n=4) AIN93 Diet supplemented with 8% lowbush wild blueberry powder (w/w) (n=5) |
6 Weeks | ↑ Abundance of the phylum Actinobacteria, the order Actinomycetales and family Bifidobacteriaceae and Coriobacteriaceae, ORFs assigned to KEGG category xenobiotics biodegradation and metabolism. ↓ Abundance of the genera Lactobacillus and Enterococcus, number of ORFs assigned to the bacterial invasion of epithelial cells. |
[64] | |
| C57BL/6J mice Male Age: 6 Weeks |
Low fat diet (n=12) High fat diet (n=56) Obese mice were further randomized to control high fat diet (HFD, n=8) or berry-supplemented treatment groups normalized to 400 mg/g total anthocyanins. |
12 Weeks | ↑ Firmicutes, Bacteroidetes, Actinobacteria ↓ Anthocyanin content of the feces |
↑ Lean body and water mass, insulin sensitivity ↓ Body weight, fat body mass ↔ Food intake, blood glucose levels |
[28] |
| Wistar rats Male |
Low fat diet (LF) (n=8) High fat diet (HF) (n=8) High fat diet supplemented with 10% blueberry powder (w/w) (HF_BB) (n=8) |
8 Weeks | ↔ Abundance and ratio of the main phyla Firmicutes and Bacteriodetes (HF vs. LF), IL-1B (ileum), IL-6 (ileum), CD11d (ileum), CD6 (ileum) ↓ Firmicutes and Bacteriodetes abundance (HF_BB vs. HF and LF) ↑ Proteobacteria (HF_BB vs. HF and LF) ↑ Fusobacteria (HF_BB vs. HF and LF) ↑ Bacilli (class) (HF_BB vs. HF and LF) ↑ Porphyromonadaceae (family) (HF_BB vs. HF and LF) ↓ Butyrate (HF_BB vs. LF) ↓ TNF-A (ileum) (HF_BB and LF vs. HF) ↑ Acetate (HF_BB vs. HF and LF) ↑ Propionate (HF_BB vs. LF) ↑ Gpr43 and Defb2 gene expression (HF_BB vs. LF) ↑ Villus length (HF_BB and LF vs. HF) ↑ Goblet cells/crypt (HF_BB vs. HF) ↑ Muc2 gene expression (HF_BB vs. HF) ↑ Glp1 gene expression (LF and HF_BB vs. HF) |
↔ Body weight, mesenteric fat, epididymal fat, AUC, IL-6 (adipose tissue), CD68 (adipose tissue), phosphorylation of NF-κB p65 in adipose tissue ↑ Retroperitoneal fat (HF_BB vs. LF) ↑ Gene expression of PPARD (HF_BB vs. HF) ↑ Gene expression of PPARD (HF_BB and LF vs. HF) ↑ Urine F2-isoprostanes (HF_BB and LF vs. HF) ↑Liver fat droplets (HF_BB and HF vs. LF) ↓ Blood glucose (min. 15) (HF_BB vs. LF) ↓ Serum insulin (min. 30) (HF_BB and LF vs. HF) ↓ TNF-A and IL-1B (adipose tissue) (HF_BB and LF vs. HF) ↓ Hepatic p-IRS1 (Ser307) to IRS1 ratio (HF_BB and LF vs. HF) ↓ CD11D (adipose tissue) (HF_BB vs. LF and HF) ↓ Serum LBP in adipose tissue (HF_BB vs. HF) ↓Liver MDA (HF_BB vs. HF) |
[16] |
| C57BL/6J Mice Male Age: 4 Weeks |
Normal fat diet (n=6) High fat diet (HFD) (n=6) HFD supplemented with blueberry polyphenol extract (200 mg/kg body weight/day) (HFD + PPE) (n=6) |
12 Weeks | ↔OTUs and species richness (HFD vs. HFD+PPE) ↓ The Simpson diversity (HFD+PPE vs. HFD) ↑ Bifidobacterium, Desulfovibrio, Adlercreutzia, Helicobacter, and Flexispira (HFD+PPE vs. HFD) ↓ Adlercreutzia and Prevotella (HFD+PPE vs. HFD) ↔ Bacterial taxa |
↓Body weight, weight gain and food intake (HFD+PPE vs. HFD) ↓FER compared to HFD ↔ TG, AST, ALT, and leptin (serum) ↓ LDL-C (HFD+PPE vs. HFD) ↑ HDL-C (HFD+PPE vs. HFD) ↓T-CHO in (HFD+PPE vs. HFD) ↓Hepatic PPARy, FAS, SREBP-1 (HFD+PPE vs. HFD) ↑ Hepatic CPT1 and PPARɑ (HFD+PPE vs. HFD) ↓EWAT PPARy, FAS, SREBP-1, aP2, GAPDH, GLUT4 (HFD+PPE vs. HFD) ↑Hepatic and EWAT p-AMP/total AMPK ratio (HFD+PPE vs. HFD) |
[20] |
|
Study 1: C57BL/6 mice Male Age: 1– 3 Weeks |
Study 1: (n=9–12/group) G1: CHOW 1 (standard chow diet) G2: HFD 1 (high fat diet, 60% fat) G3: CBE (CHOW + 5 gL−1 blueberry extract in drinking water) G4: BE 1 (HFD + 5 gL−1 blueberry extract in drinking water) |
Study 1:
15 Weeks |
Study 1: ↑ mRNA expression of occludin, TJP1, MUC2 levels ↓ mRNA levels TLR4, IL-6, TNF-ɑ in the colon and ileum ↑ Akkermansia and Bifidobacterium ↓ Desulfovibrio and Bilophila genera ↑ Abundance of the significant taxa ↑ Ratio Bacteroidetes to Firmicutes |
Study 1: ↓ Weight gain (BE1 vs. HFD 1) ↔ Energy intake, water intake ↓ Body fat, liver fat induced by HFD ↓ Hepatic and plasmatic TG ↓ ALT and HDL ↑ Energy expenditure, core body temperature ↓ mRNA levels LPS, IL-6, TNFɑ in plasma ↓ Plasma leptin ↑ Glucose tolerance and insulin sensitivity ↓ Expression of CCAAT in the iWAT and mRNA of proteins linked to lipolysis, FXR, SHP, TGR5 ↓ Plasma BAs |
[19] |
|
Study 2:
C57BL/ KsJ db/db mice Male Age: 21 Days |
Study 2: (n=10/group) G1: CHOW 2 (standard chow diet) G2: BE 2 (CHOW + 5 gL−1 blueberry extract in drinking water) |
Study 2:
10 Weeks |
Study 2: ↑ Diversity of the GM ↓ Abundance of Proteobacteria ↑ Ratio Bacteroidetes to Firmicutes |
Study 2: ↓ Weight gain ↔ Energy intake ↓ TG, colesterol, leptin ↑ Energy expenditure ↑ Hepatic steatosis, systemic inflammation, fat deposition ↑ Glucose and lipid metabolism ↓ Plasma BAs |
|
|
Study 3: C57BL/6 mice Male Age: 8 Weeks |
Study 3: (n=10–12/group) G1: CHOW 3 (standard chow diet) G2: HFD 3 (high fat diet, 60% fat) G3: BE 3 (HFD + 5 gL−1 blueberry extract in drinking water) G4: Abx (HFD + 200uL PBS containing antibiotic) G5: ABE (HFD + 5 gL−1 blueberry extract in drinking water + 200uL PBS containing antibiotic) |
Study 3:
15 Weeks |
Study 3: ↓ Fecal anthocyanin content (BE vs. ABE) |
Study 3: ↔ Weight gain ↔ TG, hepatic fat, cholesterol ↔ Metabolic disease, systemic inflammation and glucose metabolism ↔ Plasma BA pool size and composition, FXR, TGR5 |
|
| C57BL/6J mice Male Age: 6 Weeks |
(n=12/ Group) Standard chow diet (n=12) High-fat high-sucrose diet (HFHS) (n=12) HFHS diet supplemented with wild blueberry extract (200 mg/kg/day equivalent to 17 mg polyphenols) (WBE) HFHS diet supplemented with anthocyanins and phenolic acids (32 mg/kg) (F1) HFHS diet supplemented with anthocyanins and phenolic acids (32 mg/kg) (F1) G5: F2 (PACs oligomers, phenolic acids and flavonols, 53mg/kg) + HFHS G6: F3 (PACs polymers, 37mg/kg) + HFHS oligomeric proanthocyanidins (PACs) |
8 Weeks | ↑ Mucus layer thickness (colon) (WBE and BPFs) ↔ Crypt’s depth (WBE, BPF) and total goblet cells (WBE, F1 and F2) ↔ Firmicutes/ Bacteroidetes ratio ↑ Number of total goblet cells (GC) (at F3 group) ↑ Adlercreutzia equolifacens (WBE e F2) ↑ Mix of neutral and acidic mucins (BPFs) ↑ Neutral mucin-filled GC proportion (WBE) ↓ Proportion of mucin-unfilled GC (WBE and BPFs) ↔ mRNA of ZO-1 and occludin ↔ α-diversity index, species abundance and Shannon’s diversity index, β-diversity of the gut microbiota ↑ Family Coriobacteriaceae, S24–7, Verrucomicrobia and the order Clostridiales (WBE and BPFs) ↓ Unassigned genus of the family S24–7 (WBE) ↑ A. muciniphila at feces (F2 group) ↑ A. equolifaciens at feces (F2, WBE) |
↔ Total energy intake ↔ Visceral mass, fasting glycemia, HOMA-IR index ↓ AUC of the OGTT (WBE e F3) |
[30] |
| C57BL/6 mice Male Age: 5 weeks |
(n=7/ Group) G1: C (control) G2: CL (C with 4% fermented blueberry pomace (FBP) supplementation) G3: CH (C with 8% FBP-supplementation) G4: HFD (high fat diet) G5: HFDL (HFD with 4% FBP-supplementation) G6: HFDH (HFD with 8% FBP-supplementation) |
5 Weeks | ↑ Villus length (HFDL and HFDH vs. HFD) ↑ Ratio of villus length to crypt depth (HFDL and HFDH vs. HFD) ↑ Claudin-4 mRNA level (HFDL and HFDH vs. HFD) ↑ Occludin mRNA level (HFDL and HFDH vs. HFD) ↑ Goblet cells (HFDL and HFDH vs. HFD) ↑ mRNA expression of ZO-1 (HFDL and HFDH vs. HFD) ↑ Claudin-1 mRNA level (HFDH vs. HFDL and HFD) ↑E-cadherin mRNA level (HFDH vs. HFDL vs. HFD) ↑ Muc 2 mRNA level (HFDH vs. HFDL vs. HFD) ↓ Crypt depth (CL vs. C) ↑ T-AOC (ileum) (HFDH vs. HFD) ↑ CAT (ileum) (HFDH vs. HFDL vs. HFD) ↑ SOD (ileum) (HFDH vs. HFDL) ↓ MDA (ileum) (HFDH vs. HFD) |
↓ TNF-α (serum) (HFDL vs. HFD) ↑ IL-10 level (serum) (HFDH vs. HFDL vs. HFD) ↓NF-κB mRNA level (HFDH vs. HFDL and HFD) ↓ protein level of NF-κB p-P65 (HFDH vs. HFD and HFDL) ↓ MPO activity in small intestine tissue (HFDL and HFDH vs. HFD) ↓ MLCK mRNA level (HFDH vs. HFDL and HFD) ↓Protein level of p-MLC (HFDH vs. HFDL vs. HFD) ↓ Final body weight (HFDL and HFDH vs. HFD) ↓ Abdominal fat index (HFDL and HFDH vs. HFD) ↑ GSH (liver) (HFDH vs. HFD and HFDL) ↑ T-AOC (liver) (HFDH and HFDL vs. HFD) ↑ CAT (liver) (HFDH vs. HFDL and HFD) ↑ SOD (liver) (HFDH and HFDL vs. HFD) |
[21] |
| C57BL/6J mice Male Age: 8 weeks |
G1: Chow (n=14); G2: HFHS: High-fat,high-sucrose diet (n=13); G3: BB-HFHS: High-fat, high-sucrose + whole blueberry powder (n=14); G4: ANT-HFHS: High-fat, high-sucrose diet + blueberry anthocyanin-rich fraction (n=14); G5: PAC-HFHS: High-fat, high-sucrose diet + proanthocyanidin-rich fraction (n =13) |
20 Weeks | ↓ Lachnospiraceae bacterium Choco86, Ruminococcus, Blautia hansenii and Blautia sp. N6H1–15 (BB-HFHS and ANT-HFHS vs. HFHS). ↑Turicibacter sp. H121 abundance (BB-HFHS vs. HFHS) ↑ Muribaculum intestinale abundance (PAC-HFHS vs. HFSH) ↓Acetic and propionic acids (BB-HFHS vs. HFHS) ↓Valeric acid (BB-HFHS and ANT-HFHS vs. HFHS) ↓ Isobutyric and isovaleric acid BB-HFHS, ANT-HFHS and PAC vs. HFHS) ↔ Fecal Butyric Acid |
↓ Weight gain (PAC-HFHS VC HFHS) ↔ Food intake, IWAT, MWAT, lean mass, energy expenditure, glycaemia, insulinemia 6h fasting, C-Peptide, liver weight, TBARS, liver TG, liver cholesterol, AST, ALT ↔ IL-2, IL-6, TNF-a, MCP-1, INFy ↓HOMA-IR (PAC-HFHS vs. HFHS) ↓ Insulin (ANT-HFHS and PAC-HFHS vs. HFHS) |
[29] |
| C57BL/6J Male mice Age: 6 weeks |
(n=12/ Group) G1: CT (standard chow diet) G2: HFHS (high-fat high-sucrose diet) G3: HFHS + BP (high-fat high-sucrose diet + blueberry powder) G4: HFHS + BF (high-fat high-sucrose diet + blueberry fibrous residue) |
8 Weeks | ↑ Mucus thickness (BP vs. HFHS) ↔ Crypt depth, number of Goblet cells, types of mucin ↑ Microbial richness relative ↑ Gut microbiota diversity ↑ Verrucomicrobia (BP group) ↓ Firmicutes (BP group) ↔ Abundance of pathobionts, taxa at the family level (BP group) ↑ Akkermansiaceae (BP group) ↑ Eggerthellaceae and Coriobacteriales_Incertae_Sedis (BP group) ↑ A. muciniphila (BP group) ↓ Romboutsia, Ruminiclostridium, and Oscillibacter ↑ Raxa Lachnospiraceae_NK4A136_group e Acetatifactor ↑ Polysaccharide-degrading taxa such as Clostridium_senso_stricto1, Muribaculaceae, and Roseburia ↑ Pathways of metabolism of cofactors and vitamins, lipid metabolism and DNA replication and repair (BP group) |
↔ Body weight ↑ EWAT (BF group) ↑ TG (BF vs. HFHS) ↔ Glycemia, HOMA-IR ↑ Fasting insulin (BF vs. HFHS) ↔ Cecum weight |
[31] |
| Sprague-Dawley rats Age: 21 days |
(n=48/Group) G1: Standard diet (AIN-93G) G2: Standard diet + 200 mg/kg blueberry polyphenol extract |
2 Weeks | ↑SOD jejunal, CAT ileal, T-AOC jejunal and ileal ↓MDA jejunal ↔ SOD and MDA ileum, CAT jejunum ↓IL-1 and IFN-y (jejunum and ileum) ↔ IL-6 and TNF-a (jejunum and ileum) ↓ Keap1 jejunal and ileal ↑ Nrf2 jejunal and ileal ↑mRNA of mTOR, S6K1, 4EBP1 jejunal and ileal ↔HO-1 jejunal and ileal |
↔ Growth performance | [24] |
| C57BL/6 mice Male Age: 4 weeks |
(n=6/ Group) G1: ND (normal diet) G2: HFD (high fat diet, 53.8% basic feed, 21% lard oil, 20% saccharose, 5% cholesterol, and 0.2% sodium cholate) G3: BAE100 (HFD and 100 mg/kg body weight of blueberry anthocyanin-rich extract) G4: BAE200 (HFD and 200 mg/kg body weight of blueberry anthocyanin-rich extract) |
8 Weeks |
↓Staphylococcus (BAE100 and BAE200) ↑Ruminiclostridium (BAE100 and BAE200) ↑Bacteroidetes/Firmicutes (BAE100) ↑ Bifidobacterium (BAE200) ↑ Lactobacillus (BAE200) ↑ Roseburia (BAE200) ↑ Faecalibaculum (BAE200) ↑ Parabacteroides (BAE200) ↑ Acetate (BAE200 vs. BAE100 vs. HFD) ↑ Butyrate (BAE200 vs. BAE100 vs. HFD) ↑ Propionate (BAE200 vs. BAE100 vs. HFD) |
↓ Serum concentrations of phospholipids with PUFA (BAE100 and BAE200 vs. HFD) ↑ Liver T-AOC (BAE200 vs. BAE100 vs. HFD) ↑ Liver SOD activity (BAE200 vs. BAE100 vs. HFD) ↑Liver GSH-Px (BAE200 vs. BAE100 vs. HFD) ↑ USFA/SFA (BAE200 vs. BAE100 vs. HFD) |
[23] |
| Outbred laboratory rats Male and female Age: 22–24 months |
(n=12/ Group) G2: blueberry juice; G9: control group (standard vivarium diet food) |
12 Weeks | ↓ Klebsiella pneumoniae, Morganella morganii, E. coli, Actinomyces naeslundii, and Bacteroides ↔ B. subitillis ↓ Streptococcus parvulus ↑ E. faecalis and staphylococci |
↓ Body weight, total lipid, cholesterol, glucose, calcium levels ↔ LDL, triglycerides, blood urea |
[32] |
| C57BL/6J mice Male Age: 5 weeks |
(n= 9/ Group) G1: LFD (Low fat diet - 10% kcal FAT) G2: HFD (High fat diet - 60% kcal FAT) G3: HFD + BL (High fat + 1% blueberry extract) G4: HFD + BH (High fat + 2% blueberry extract) |
24 Weeks | ↑ SCFA (BL and BH vs. HFD) ↔ Firmicutes/Bacteroidetes ratio ↑ Bacteroidetes (BH group) ↓ Abundance of Rikenellaceae (BL and BH vs. HFD) ↓ Abundance of Streptococcaceae (BH group) ↓ Relative abundance of Allobaculum, Anaerotruncus, Intestinimonas, Oscillibacter, Ruminiclostridium, and norank_f_Bacteroidales_S24–7_group ↓ Abundance of Rikenella ↑ Abundance of Peptoclostridium ↑ Functions such as general function prediction only, lipid transport and metabolism, cell motility, RNA processing and modification ↑ Abundance of metabolic pathways related of basic metabolism (BH group) |
↓ Weight gain induced by HFD ↔ energy intake ↓ Accumulation of white adipose tissue ↓ Plasmatic TC ↑ HDL/TC ratio (BL group) ↓ Plasma LPS (BH group) ↔TNFɑ, MCP-1, IL-1β ↓ Liver weight, hepatic total lipids ↔ Hepatic cholesterol |
[22] |
| Male mice Age: 6 weeks |
(n=7/ Group) G1: CON (distilled water) G4: BLUB (blueberry) |
2 Weeks | ↑ SOD activity e AOC (colon) ↔ MDA e GSH content, CAT e GSH-Px activity (colon) ↑ Prevotella, Clostridium_III, Clostridium_XVIII, Intestinimonas, Ruminococcus and Barnesiella ↓ Escherichia, Klebsiella, Proteus, Blautia, Enterococcus, Staphylococcus, Mucispirillum, Acinetobacter and Clostridium_XIVa |
↓ Weight gain, food intake and liver index ↓ CAT activity (serum) ↔ AOC, MDA and GSH content (serum) ↔ SOD (liver) ↑ SOD activity (serum) |
[25] |
| C57BL/6J mice Male Age: 22 weeks |
(n= 15/Group) G1: LFD (Low fat diet - 10% kcal FAT) G2: HFD (High fat diet - 60% kcal FAT) G3: HFD + Blueberry (High fat + 6% blueberry powder) |
16 Weeks | ↑ Shannon diversity (G3 vs. G2) ↑ Total OTUs richness (G3 vs. G2) ↑ Firmicutes (G3 vs. G2) ↓ Proteobacteria (G3 vs. G2) ↑ Unclassified genus from Clostridiales, Lachnospiraceae (G3 vs. G2) ↓ Unclassified genus from Ruminococcaceae, Desulfovibrionaceae (G3 vs. G2) ↔ Akkermansia muciniphila |
↔ Body weight, energy intake, fat pad weight | [33] |
4EBP1: eukaryotic initiation factor 4E-binding protein 1; AIN93: nutritional standard; ALT: alanine aminotransferase; AMP: adenosine mono phosphate; AMPK: AMP-activated protein kinase; aP2: adipocyte-specific acid binding protein; AST: aspartate transaminase; AUC: area under curve; CAT: catalase; iWAT; FXR and SHP; CPT1: Carnitine palmitoyl transferase I; Defb2: defensin beta 2; eWAT: epididymal white adipose tissue; FAS: fatty acid synthase; FER: food efficiency ratio; GAPDH: Glyceraldehyde-3-Phosphate Dehydrogenase; Glp1: Glucagon-like peptide-1; GLUT4: glucose transporter 4; Gpr43: G-protein-coupled receptor 43; GSH-Px: liver glutathione peroxidase; HDL-C: high-density lipoprotein cholesterol; HFD: high fat diet; HO-1: heme oxygenase-1; HOMA-IR: Homeostasis Model Assessment-Insulin Resistance; IFN-γ: interferon-γ; IL-1: interleukin-1; IL-10: interleukin-10; IL-2: interleukin-2; IL-6: interleukin-6; iWAT: inguinal white adipose tissue; Keap1: Kelch-like ECH-associated protein 1; KEGG: Kyoto Encyclopaedia of Gene and Genome; LBP: Adipocyte lipopolysaccharide-binding protein; LDH: lactate dehydrogenase; BA: bile acids; LDL-C: low-density lipoprotein cholesterol; LWB: lowbush wild blueberry; MCP-1: monocyte chemoattractant protein-1; MDA: malondialdehyde; MLCK: myosin light chain kinase; MPO: myeloperoxidase; mTOR: mammalian target of rapamycin; Muc2: mucin 2; mWAT: mesenteric white adipose tissue; NFκB: nuclear factor kappa B; Nrf2: nuclear factor-E2-related factor 2; ORFs: open reading frames; OTUs: operational taxonomic units; p-IRS1: Phospho-insulin receptor substrate 1; p-MLC: phospho-myosin light chain 2; PPAR-d: peroxisome proliferator-activated receptor delta; PPARɑ: Peroxisome proliferator-activated receptor ɑ; PPARy: peroxisome proliferator-activated receptor y; PUFA: Polyunsaturated fatty acids; S6K1: ribosomal p70 S6 kinase; SFA: saturated fatty acids; SOD: superoxide dismutase; SREBP-1: sterol regulatory element-binding protein 1; T-AOC: total antioxidant capacity; T-CHO: serum total cholesterol; TBARS: thiobarbituric acid reactive substances; TG: triglycerides; TNF-α: tumor necrosis factor-α; USFA: unsaturated fatty acid; ZO-1: Zonula occludens-1.