ChiroACCESS Article



The Power of Blueberries



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ChiroACCESS Editorial Staff

  

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December 14, 2011

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Although the blueberry is small it has the potential to provide huge health benefits.  The basic science and clinical science published this year underscores their importance.  In summary the research demonstrates the value of blueberries in the prevention and treatment of a wide variety of clinical conditions.  They play a role in lowering blood pressure, improving age related memory loss, preventing atherosclerosis, preventing or impeding cancers, promoting colon health, and reducing oxidative stress and inflammation associated with physical activity. 
 
Research from previous years suggests additional benefits from consuming the fresh or frozen berries as well as blueberry juice.  Some of the underlying mechanisms include increases in anti-inflammatory cytokines, improving human immune markers including natural killer cells, reducing oxidative stress, improving insulin resistance, etc.  As one review article noted, “Recent studies demonstrated the benefit of blueberries to prevent the age-related chronic diseases such as cancer, diabetes, hyperlipidemia, hypertension, neurodegeneration, obesity, and osteoporosis through its apoptosis, antioxidant, anti-inflammation, and antiangiogenesis effects. Blueberries can eradicate microorganisms for the prevention of symptomatic urinary tract infections in women.”  There is not a single drug on the market that can come close to doing all of that. 
 
With each passing year, research provides evidence that many natural foods make profound but previously unknown contributions to prevention, treatment and promoting human health.  The 2010 Practice Analysis of Chiropractic reported that over 94% of chiropractors give dietary or nutritional advice to their patients. In view of the growing body of evidence supporting the therapeutic and preventive properties of blueberries, they should be considered as a dietary recommendation for many chiropractic patients.

Note:  These mini-reviews are designed as updates and direct the reader to the full text of current research.  The abstracts presented here are no substitute for reading and critically reviewing the full text of the original research.  Where permitted we will direct the reader to that full text.

Effect of blueberry ingestion on natural killer cell counts, oxidative stress, and inflammation prior to and after 2.5 h of running.  [Link]

Appl Physiol Nutr Metab. 2011 Dec;36(6):976-84. Epub 2011 Nov 23.

McAnulty LS, Nieman DC, Dumke CL, Shooter LA, Henson DA, Utter AC, Milne G, McAnulty SR.
Department of Nutrition and Health Care Management, Appalachian State University, Boone, NC 28608, USA.

Blueberries are rich in antioxidants known as anthocyanins, which may exhibit significant health benefits. Strenous exercise is known to acutely generate oxidative stress and an inflammatory state, and serves as an on-demand model to test antioxidant and anti-inflammatory compounds. The purpose of this study was to examine whether 250 g of blueberries per day for 6 weeks and 375 g given 1 h prior to 2.5 h of running at ~72% maximal oxygen consumption counters oxidative stress, inflammation, and immune changes. Twenty-five well-trained subjects were recruited and randomized into blueberry (BB) (N = 13) or control (CON) (N = 12) groups. Blood, muscle, and urine samples were obtained pre-exercise and immediately postexercise, and blood and urine 1 h postexercise. Blood was examined for F(2)-isoprostanes for oxidative stress, cortisol, cytokines, homocysteine, leukocytes, T-cell function, natural killer (NK), and lymphocyte cell counts for inflammation and immune system activation, and ferric reducing ability of plasma for antioxidant capacity. Muscle biopsies were examined for glycogen and NFkB expression to evaluate stress and inflammation. Urine was tested for modification of DNA (8-OHDG) and RNA (5-OHMU) as markers of nucleic acid oxidation. A 2 (treatment) × 3 (time) repeated measures ANOVA was used for statistical analysis. Increases in F(2)-isoprostanes and 5-OHMU were significantly less in BB and plasma IL-10 and NK cell counts were significantly greater in BB vs. CON. Changes in all other markers did not differ. This study indicates that daily blueberry consumption for 6 weeks increases NK cell counts, and acute ingestion reduces oxidative stress and increases anti-inflammatory cytokines.


Influence of dietary blueberry and broccoli on cecal microbiota activity and colon morphology in mdr1a(-/-) mice, a model of inflammatory bowel diseases.  [Link]

Nutrition. 2011 Nov 22. [Epub ahead of print]

Paturi G, Mandimika T, Butts CA, Zhu S, Roy NC, McNabb WC, Ansell J.
The New Zealand Institute for Plant and Food Research Limited, Private Bag 92169, Auckland 1142, New Zealand.

OBJECTIVE: Enteric microbiota has been shown to be associated with various pathological conditions such as inflammatory bowel disease (IBD). This study aimed to determine the anti-inflammatory colonic effects of blueberries and broccoli in mdr1a(-/-) mice (IBD mouse model) through modification of microbiota composition in the gastrointestinal tract.

METHODS: The mdr1a(-/-) mice were fed either a control diet or the control diet supplemented with either 10% blueberry or broccoli for 21 wk. We investigated the influence of these diets on cecal microbiota and organic acids, colon morphology, and bacterial translocation to mesenteric lymph nodes.

RESULTS: In comparison to mice fed the control diet, blueberry and broccoli supplementation altered cecum microbiota similarly with the exception of Faecalibacterium prausnitzii, which was found to be significantly lower in broccoli-fed mice. High concentrations of butyric acid and low concentrations of succinic acid were observed in the cecum of broccoli-fed mice. Blueberry- and broccoli-supplemented diets increased colon crypt size and the number of goblet cells per crypt. Only the broccoli-supplemented diet significantly lowered colonic inflammation compared to mice fed the control diet. Translocation of total microbes to mesenteric lymph nodes was lower in broccoli-fed mice compared to blueberry and control diet groups.

CONCLUSION: Dietary blueberries and/or broccoli altered the composition and metabolism of the cecal microbiota and colon morphology. Overall, these results warrant further investigation through clinical studies to establish whether the consumption of blueberries and/or broccoli is able to alter the composition and metabolism of large intestine microbiota and promote colon health in humans.


Strawberries, Blueberries, and Cranberries in the Metabolic Syndrome: Clinical Perspectives.  [Link]

J Agric Food Chem. 2011 Nov 29. [Epub ahead of print]

Basu A, Lyons TJ.
Nutritional Sciences, 301 Human Sciences, Oklahoma State University , Stillwater, Oklahoma 74078-6141, United States.

Emerging science supports therapeutic roles of strawberries, blueberries, and cranberries in metabolic syndrome, a prediabetic state characterized by several cardiovascular risk factors. Interventional studies reported by our group and others have demonstrated the following effects: strawberries lowering total and LDL-cholesterol, but not triglycerides, and decreasing surrogate biomarkers of atherosclerosis (malondialdehyde and adhesion molecules); blueberries lowering systolic and diastolic blood pressure and lipid oxidation and improving insulin resistance; and low-calorie cranberry juice selectively decreasing biomarkers of lipid oxidation (oxidized LDL) and inflammation (adhesion molecules) in metabolic syndrome. Mechanistic studies further explain these observations as up-regulation of endothelial nitric oxide synthase activity, reduction in renal oxidative damage, and inhibition of the activity of carbohydrate digestive enzymes or angiotensin-converting enzyme by these berries. These findings need confirmation in future studies with a focus on the effects of strawberry, blueberry, or cranberry intervention in clinical biomarkers and molecular mechanisms underlying the metabolic syndrome.


Berries: emerging impact on cardiovascular health.  [Link]

Nutr Rev. 2010 Mar;68(3):168-77.

Basu A, Rhone M, Lyons TJ.
Department of Nutritional Sciences, Oklahoma State University (OSU), Stillwater, Oklahoma 74078-6141, USA. arpita.basu@okstate.edu

Berries are a good source of polyphenols, especially anthocyanins, micronutrients, and fiber. In epidemiological and clinical studies, these constituents have been associated with improved cardiovascular risk profiles. Human intervention studies using chokeberries, cranberries, blueberries, and strawberries (either fresh, or as juice, or freeze-dried), or purified anthocyanin extracts have demonstrated significant improvements in LDL oxidation, lipid peroxidation, total plasma antioxidant capacity, dyslipidemia, and glucose metabolism. Benefits were seen in healthy subjects and in those with existing metabolic risk factors. Underlying mechanisms for these beneficial effects are believed to include upregulation of endothelial nitric oxide synthase, decreased activities of carbohydrate digestive enzymes, decreased oxidative stress, and inhibition of inflammatory gene expression and foam cell formation. Though limited, these data support the recommendation of berries as an essential fruit group in a heart-healthy diet.


Whole blueberry powder modulates the growth and metastasis of MDA-MB-231 triple negative breast tumors in nude mice.  [Link]

J Nutr. 2011 Oct;141(10):1805-12. Epub 2011 Aug 31.

Adams LS, Kanaya N, Phung S, Liu Z, Chen S.
Adams LS, Kanaya N, Phung S, Liu Z, Chen S.

Previous studies in our laboratory demonstrated that blueberry (BB) extract exhibited antitumor activity against MDA-MB-231 triple negative breast cancer (TNBC) cells and decreased metastatic potential in vitro. The current study tested 2 doses of whole BB powder, 5 and 10% (wt:wt) in the diet, against MDA-MB-231 tumor growth in female nude mice. In this study, tumor volume was 75% lower in mice fed the 5% BB diet and 60% lower in mice fed the 10% BB diet than in control mice (P = 0.05). Tumor cell proliferation (Ki-67) was lower in the 5 and 10% BB-fed mice and cell death (Caspase 3) was greater in the 10% BB-fed mice compared to control mice (P = 0.05). Gene analysis of tumor tissues from the 5% BB-fed mice revealed significantly altered expression of genes important to inflammation, cancer, and metastasis, specifically, Wnt signaling, thrombospondin-2, IL-13, and IFN?. To confirm effects on Wnt signaling, analysis of tumor tissues from 5% BB-fed mice revealed lower ß-catenin expression and glycogen synthase kinase-3ß phosphorylation with greater expression of the ß-catenin inhibitory protein adenomatous polyposis coli compared to controls. A second study tested the ability of the 5% BB diet to inhibit MDA-MB-231-luc-D3H2LN metastasis in vivo. In this study, 5% BB-fed mice developed 70% fewer liver metastases (P = 0.04) and 25% fewer lymph node metastases (P = 0.09) compared to control mice. This study demonstrates the oral antitumor and metastasis activity of whole BB powder against TNBC in mice.


A blueberry-enriched diet attenuates nephropathy in a rat model of hypertension via reduction in oxidative stress.  [Link]

PLoS One. 2011;6(9):e24028. Epub 2011 Sep 15.

Elks CM, Reed SD, Mariappan N, Shukitt-Hale B, Joseph JA, Ingram DK, Francis J.
Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, Louisiana, United States of America.

OBJECTIVE AND BACKGROUND: To assess renoprotective effects of a blueberry-enriched diet in a rat model of hypertension. Oxidative stress (OS) appears to be involved in the development of hypertension and related renal injury. Pharmacological antioxidants can attenuate hypertension and hypertension-induced renal injury; however, attention has shifted recently to the therapeutic potential of natural products as antioxidants. Blueberries (BB) have among the highest antioxidant capacities of fruits and vegetables.

METHODS AND RESULTS: Male spontaneously hypertensive rats received a BB-enriched diet (2% w/w) or an isocaloric control diet for 6 or 12 weeks or 2 days. Compared to controls, rats fed BB-enriched diet for 6 or 12 weeks exhibited lower blood pressure, improved glomerular filtration rate, and decreased renovascular resistance. As measured by electron paramagnetic resonance spectroscopy, significant decreases in total reactive oxygen species (ROS), peroxynitrite, and superoxide production rates were observed in kidney tissues in rats on long-term dietary treatment, consistent with reduced pathology and improved function. Additionally, measures of antioxidant status improved; specifically, renal glutathione and catalase activities increased markedly. Contrasted to these observations indicating reduced OS in the BB group after long-term feeding, similar measurements made in rats fed the same diet for only 2 days yielded evidence of increased OS; specifically, significant increases in total ROS, peroxynitrite, and superoxide production rates in all tissues (kidney, brain, and liver) assayed in BB-fed rats. These results were evidence of "hormesis" during brief exposure, which dissipated with time as indicated by enhanced levels of catalase in heart and liver of BB group.

CONCLUSION: Long-term feeding of BB-enriched diet lowered blood pressure, preserved renal hemodynamics, and improved redox status in kidneys of hypertensive rats and concomitantly demonstrated the potential to delay or attenuate development of hypertension-induced renal injury, and these effects appear to be mediated by a short-term hormetic response.


How can food extracts consumed in the Mediterranean and East Asia suppress prostate cancer proliferation?  [Link]

Br J Nutr. 2011 Nov 9:1-7. [Epub ahead of print]

Yao M, Xie C, Constantine M, Hua S, Hambly BD, Jardine G, Sved P, Dong Q.
Department of Endocrinology, Central Clinical School and Bosch Institute, Room 394, Blackburn Building, D06, Royal Prince Alfred Hospital, The University of Sydney, Sydney, NSW 2006, Australia.

We have developed a blend of food extracts commonly consumed in the Mediterranean and East Asia, named blueberry punch (BBP), with the ultimate aim to formulate a chemoprevention strategy to inhibit prostate cancer progression in men on active surveillance protocol. We demonstrated previously that BBP inhibited prostate cancer cell proliferation in vitro and in vivo. The purpose of this study was to determine the molecular mechanism responsible for the suppression of prostate cancer cell proliferation by BBP. Treatment of lymph node-metastasised prostate cancer cells (LNCaP) and bone-metastasised prostate cancer cells (PC-3 and MDA-PCa-2b) with BBP (up to 0•8 %) for 72 h increased the percentage of cells at the G0/G1 phase and decreased those at the S and G2/M phases. The finding was supported by the reduction in the percentage of Ki-67-positive cells and of DNA synthesis measured by the incorporation of 5-ethynyl-2'-deoxyuridine. Concomitantly, BBP treatment decreased the protein levels of phosphorylated retinoblastoma, cyclin D1 and E, cyclin-dependent kinase (CDK) 4 and 2, and pre-replication complex (CDC6 and MCM7) in LNCaP and PC-3 cells, whereas CDK inhibitor p27 was elevated in these cell lines. In conclusion, BBP exerts its anti-proliferative effect on prostate cancer cells by modulating the expression and phosphorylation of multiple regulatory proteins essential for cell proliferation.


Phenolic acids are in vivo atheroprotective compounds appearing in the serum of rats after blueberry consumption.  [Link]

J Agric Food Chem. 2011 Sep 28;59(18):10381-7. Epub 2011 Sep 1.

Xie C, Kang J, Chen JR, Nagarajan S, Badger TM, Wu X.
USDA Arkansas Children's Nutrition Center, Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, 15 Children's Way, Little Rock, Arkansas 72202, United States.

Blueberries (BB) have recently been shown to have cardioprotective effects and to prevent atherosclerosis in rodent models. However, the bioactive compounds in BB responsible for these effects have not yet been characterized. Seven phenolic acids (7PA) were identified as metabolites in the serum of rats fed diets supplemented with 10% freeze-dried BB. In this study, 7PA were evaluated for their potential atheroprotective effects in murine macrophage cell line RAW 264.7. 7PA were found to inhibit LPS-induced mRNA expression and protein levels of pro-inflammatory cytokine TNF-a and IL-6 by reducing MAPK JNK, p38, and Erk1/2 phosphorylation. After treatment with 7PA for 2 weeks, mRNA expression and protein levels of scavenger receptor CD36 were decreased (P<0.05), whereas type A scavenger receptor (SR-A) remained unchanged. Moreover, foam cell formation induced by oxLDL and oxLDL binding to macrophages was also inhibited by 7PA. In addition, 7PA increased (P<0.05) expression and protein levels of ATP-binding cassette transporter A1 (ABCA1), which facilitates cholesterol efflux and reduces cholesterol accumulation in macrophages. In summary, the present study demonstrates that certain phenolic acids are potential in vivo atheroprotective compounds following BB consumption in the rodent model. Because BB contain many phytochemicals, other as yet unidentified bioactive compounds may also be important in preventing atherosclerosis in this model and, possibly, in humans.


Blueberry Intake Alters Skeletal Muscle and Adipose Tissue Peroxisome Proliferator-Activated Receptor Activity and Reduces Insulin Resistance in Obese Rats.  [Link]

J Med Food. 2011 Aug 23. [Epub ahead of print]

Seymour EM, Tanone II, Urcuyo-Llanes DE, Lewis SK, Kirakosyan A, Kondoleon MG, Kaufman PB, Bolling SF.
Cardiovascular Center and the Michigan Integrative Medicine Program, University of Michigan Health System , Ann Arbor, Michigan, USA.

Metabolic syndrome can precede the development of type 2 diabetes and cardiovascular disease and includes phenotypes such as obesity, systemic inflammation, insulin resistance, and hyperlipidemia. A recent epidemiological study indicated that blueberry intake reduced cardiovascular mortality in humans, but the possible genetic mechanisms of this effect are unknown. Blueberries are a rich source of anthocyanins, and anthocyanins can alter the activity of peroxisome proliferator-activated receptors (PPARs), which affect energy substrate metabolism. The effect of blueberry intake was assessed in obesity-prone rats. Zucker Fatty and Zucker Lean rats were fed a higher-fat diet (45% of kcal) or a lower-fat diet (10% of kcal) containing 2% (wt/wt) freeze-dried whole highbush blueberry powder or added sugars to match macronutrient and calorie content. In Zucker Fatty rats fed a high-fat diet, the addition of blueberry reduced triglycerides, fasting insulin, homeostasis model index of insulin resistance, and glucose area under the curve. Blueberry intake also reduced abdominal fat mass, increased adipose and skeletal muscle PPAR activity, and affected PPAR transcripts involved in fat oxidation and glucose uptake/oxidation. In Zucker Fatty rats fed a low-fat diet, the addition of blueberry also significantly reduced liver weight, body weight, and total fat mass. Finally, Zucker Lean rats fed blueberry had higher body weight and reduced triglycerides, but all other measures were unaffected. In conclusion, whole blueberry intake reduced phenotypes of metabolic syndrome in obesity-prone rats and affected PPAR gene transcripts in adipose and muscle tissue involved in fat and glucose metabolism.


Antioxidant and neuroprotective properties of blueberry polyphenols: a critical review.  [Link]

Nutr Neurosci. 2011 May;14(3):119-25.

Giacalone M, Di Sacco F, Traupe I, Topini R, Forfori F, Giunta F.
Intensive Care Unit, Department of Surgery, University of Pisa, Pisa, Italy.

OBJECTIVE: The aim of this work was to highlight the effects and the possible mechanisms of the action of blueberry polyphenols on the central nervous system (CNS).

METHODS: An analysis was carried out, in a temporal order, of the most important literature about this topic and the results have been correlated with the beneficial and protective effects, mainly concerning the CNS.

DISCUSSION: Over the last 10 years an increasing scientific interest has developed about polyphenols, which are very abundant in blueberries, as they have been seen to produce favourable effects related to neuroprotection and linked to a possible decrease of age-related cognitive and motor decline, as shown by the improvement of such functions in animal models with a supplemented diet. Such effects could not only be explained through a purely antioxidant action but also through more complex mechanisms related to inflammation, genic expression, and regulation of cell survival.

CONCLUSIONS: Despite the wealth of data from animal studies, there is a relative lack of data concerning human beings, even if some positive results are beginning to emerge. Therefore, blueberry polyphenols could become useful pharmacological agents for various conditions including neurological diseases, but further studies are still necessary to attain this objective.


Synaptic failure and adenosine triphosphate imbalance induced by amyloid-ß aggregates are prevented by blueberry-enriched polyphenols extract.  [Link]

J Neurosci Res. 2011 Sep;89(9):1499-508. doi: 10.1002/jnr.22679. Epub 2011 Jun 6.

Fuentealba J, Dibarrart AJ, Fuentes-Fuentes MC, Saez-Orellana F, Quiñones K, Guzmán L, Perez C, Becerra J, Aguayo LG.
Neuroactive Drugs Screening Unit, Department of Physiology, Faculty of Biological Sciences, University of Concepción, Concepcion, Chile. jorgefuentealba@udec.cl

The potential neuroprotective properties of fruits have been widely recognized. In this study, we evaluated the protective properties of a blueberry extract (BB-4), rich in polyphenols, in a neurodegenerative model induced by amyloid-ß peptide (Aß). Chronic treatment with Aß drastically reduced synaptic transmission and the extent of secretory vesicles, which were recovered partially with BB-4. Also, the extract recovered Ca(2+) transients in hippocampal neurons preincubated with Aß (0.5 and 5 µM) by about 25% ± 3% and 30% ± 2, respectively. In this work, we demonstrate a novel effect of the BB-4 extract on Aß-induced ATP leakage, in which this extract was able to antagonize the acute ATP leakage but not chronic ATP depletion. On the other hand, BB-4 prevented the uncoupling of mitochondrial function induced by FCCP by about 85%, but it was unable to modify the uncoupling induced by Aß. The present results strongly indicate that BB-4 plays a role in the process of Aß aggregation by reducing the toxic species (i.e., 40 kDa). These findings suggest that a blueberry extract can protect neuronal tissue from Aß toxicity mainly through its antiaggregation property, and its antioxidant properties and mitochondrial membrane potential capacities are secondary mechanisms important in chronic stages. Our work suggests that BB-4 could be an important nutritional complement to neuronal health as well as a potential nutraceutical formulation useful as a dietary supplement in the elderly.


Short-term blueberry-enriched diet prevents and reverses object recognition memory loss in aging rats.  [Link]

Nutrition. 2011 Mar;27(3):338-42. Epub 2010 Dec 18.

Malin DH, Lee DR, Goyarzu P, Chang YH, Ennis LJ, Beckett E, Shukitt-Hale B, Joseph JA.
University of Houston-Clear Lake, Houston, Texas, USA. malin@uhcl.edu

OBJECTIVE: Previously, 4 mo of a blueberry-enriched (BB) antioxidant diet prevented impaired object recognition memory in aging rats. Experiment 1 determined whether 1- and 2-mo BB diets would have a similar effect and whether the benefits would disappear promptly after terminating the diets. Experiment 2 determined whether a 1-mo BB diet could subsequently reverse existing object memory impairment in aging rats.

METHODS: In experiment 1, Fischer-344 rats were maintained on an appropriate control diet or on 1 or 2 mo of the BB diet before testing object memory at 19 mo postnatally. In experiment 2, rats were tested for object recognition memory at 19 mo and again at 20 mo after 1 mo of maintenance on a 2% BB or control diet.

RESULTS: In experiment 1, the control group performed no better than chance, whereas the 1- and 2-mo BB diet groups performed similarly and significantly better than controls. The 2-mo BB-diet group, but not the 1-mo group, maintained its performance over a subsequent month on a standard laboratory diet. In experiment 2, the 19-mo-old rats performed near chance. At 20 mo of age, the rats subsequently maintained on the BB diet significantly increased their object memory scores, whereas the control diet group exhibited a non-significant decline. The change in object memory scores differed significantly between the two diet groups.

CONCLUSION: These results suggest that a considerable degree of age-related object memory decline can be prevented and reversed by brief maintenance on BB diets.


Bioactives in blueberries improve insulin sensitivity in obese, insulin-resistant men and women.  [Link]

J Nutr. 2010 Oct;140(10):1764-8. Epub 2010 Aug 19.

Stull AJ, Cash KC, Johnson WD, Champagne CM, Cefalu WT.
Center for the Study of Botanicals and Metabolic Syndrome, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA.

Dietary supplementation with whole blueberries in a preclinical study resulted in a reduction in glucose concentrations over time. We sought to evaluate the effect of daily dietary supplementation with bioactives from blueberries on whole-body insulin sensitivity in men and women. A double-blinded, randomized, and placebo-controlled clinical study design was used. After screening to resolve study eligibility, baseline (wk 0) insulin sensitivity was measured on 32 obese, nondiabetic, and insulin-resistant subjects using a high-dose hyperinsulinemic-euglycemic clamp (insulin infusion of 120 mU(861 pmol)·m(-2)·min(-1)). Serum inflammatory biomarkers and adiposity were measured at baseline. At the end of the study, insulin sensitivity, inflammatory biomarkers, and adiposity were reassessed. Participants were randomized to consume either a smoothie containing 22.5 g blueberry bioactives (blueberry group, n = 15) or a smoothie of equal nutritional value without added blueberry bioactives (placebo group, n = 17) twice daily for 6 wk. Both groups were instructed to maintain their body weight by reducing ad libitum intake by an amount equal to the energy intake of the smoothies. Participants' body weights were evaluated weekly and 3-d food records were collected at baseline, the middle, and end of the study. The mean change in insulin sensitivity improved more in the blueberry group (1.7 ± 0.5 mg·kg FFM(-1)·min(-1)) than in the placebo group (0.4 ± 0.4 mg·kg FFM(-1)·min(-1)) (P = 0.04). Insulin sensitivity was enhanced in the blueberry group at the end of the study without significant changes in adiposity, energy intake, and inflammatory biomarkers. In conclusion, daily dietary supplementation with bioactives from whole blueberries improved insulin sensitivity in obese, nondiabetic, and insulin-resistant participants.


Blueberry supplementation improves memory in older adults.  [Link]

J Agric Food Chem. 2010 Apr 14;58(7):3996-4000.

Krikorian R, Shidler MD, Nash TA, Kalt W, Vinqvist-Tymchuk MR, Shukitt-Hale B, Joseph JA.
Department of Psychiatry, University of Cincinnati Academic Health Center, Cincinnati, Ohio 45267-0559, USA. robert.krikorian@uc.edu

The prevalence of dementia is increasing with expansion of the older adult population. In the absence of effective therapy, preventive approaches are essential to address this public health problem. Blueberries contain polyphenolic compounds, most prominently anthocyanins, which have antioxidant and anti-inflammatory effects. In addition, anthocyanins have been associated with increased neuronal signaling in brain centers, mediating memory function as well as improved glucose disposal, benefits that would be expected to mitigate neurodegeneration. This study investigated the effects of daily consumption of wild blueberry juice in a sample of nine older adults with early memory changes. At 12 weeks, improved paired associate learning (p = 0.009) and word list recall (p = 0.04) were observed. In addition, there were trends suggesting reduced depressive symptoms (p = 0.08) and lower glucose levels (p = 0.10). We also compared the memory performances of the blueberry subjects with a demographically matched sample who consumed a berry placebo beverage in a companion trial of identical design and observed comparable results for paired associate learning. The findings of this preliminary study suggest that moderate-term blueberry supplementation can confer neurocognitive benefit and establish a basis for more comprehensive human trials to study preventive potential and neuronal mechanisms.
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