Background: Blueberries are dietary sources of polyphenols, specifically anthocyanins. Anthocyanins have been identified as having a strong association with type 2 diabetes risk reduction; however, to date few human clinical trials have evaluated the potential beneficial health effects of blueberries in populations with type 2 diabetes. Objectives: We investigated the effects of blueberry consumption for 8 wk on cardiometabolic parameters in men with type 2 diabetes. Methods: In a double-blind, parallel-arm, randomized controlled trial, 52 men who are US veterans [mean baseline characteristics: age, 67 y (range: 51-75 y); weight, 102 kg (range: 80-130 kg); BMI (in kg/m(2)), 34 (range: 26-45)] were randomly assigned to 1 of 2 intervention groups. The interventions were either 22 g freeze-dried blueberries or 22 g placebo. The study participants were asked to consume 11 g freeze-dried blueberries or placebo with each of their morning and evening meals along with their typical diet. Results: Mean +/- SE hemoglobin A1c (7.1% +/- 0.1% compared with 7.5% +/- 0.2%; P = 0.03), fructosamine (275.5 +/- 4.1 compared with 292.4 +/- 7.9 mu mol/L; P = 0.04), triglycerides (179.6 +/- 10.1 compared with 199.6 +/- 19.9 mg/dL; P = 0.03), aspartate transaminase (23.2 +/- 1.4 compared with 30.5 +/- 2.7 units/L; P = 0.02), and alanine transaminase (35.6 +/- 1.5 compared with 48.3 +/- 2.9 units/L; P = 0.0003) were significantly lower for those consuming blueberries for 8 wk than for those consuming the placebo. Fasting plasma glucose concentrations; serum insulin, total cholesterol, LDL-cholesterol, HDL-cholesterol, and C-reactive protein concentrations; blood pressure; and body weight were not significantly different after 8 wk consumption of blueberries compared with the placebo. Conclusions: Consumption of 22 g freeze-dried blueberries for 8 wk may beneficially affect cardiometabolic health parameters in men with type 2 diabetes.

The consumption of blueberries, as well as the phenolic compounds they contain, may alter metabolic processes related to type 2 diabetes. The study investigated the effects of adding 140 g of blueberries to a higher-carbohydrate breakfast meal on postprandial glucose metabolism, gastrointestinal hormone response, and perceived appetite. As part of a randomized crossover design study, 17 healthy adults consumed a standardized higher-carbohydrate breakfast along with 2 treatments: (1) 140 g (1 cup) of whole blueberries and (2) a placebo gel (matched for calories, sugars, and fiber of the whole blueberries). Each subject participated in two 2-h meal tests on separate visits ≥8 days apart. Venous blood samples and perceived appetite ratings using visual analog scales were obtained prior to and at 30, 60, 90, and 120 min after consuming the breakfast meals. Results show that glucose metabolism, several gastrointestinal hormones, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), peptide YY (PYY) concentrations and perceived appetite did not change significantly with blueberry consumption. However, pancreatic polypeptide (PP) concentrations were statistically significantly higher (p = 0.0367), and the concentrations were higher during 30, 60, 90, and 120 min after consumption of the blueberry breakfast meal than the placebo breakfast meal. Additional research is needed to determine whether blueberries and other flavonoid-rich foods reduce type 2 diabetes risk by modifying gastrointestinal hormones and perceived appetite.

The U.S. Highbush Blueberry Council; the study is the result of work supported with resources and the use of facilities at the Stratton VA Medical Center, Albany, NY, USA.

Wild blueberries have a high content of polyphenols, but there is limited data evaluating their health benefits in adults at risk for type 2 diabetes. The objective of the study was to investigate whether consumption of 100% wild blueberry juice improves cardiometabolic biomarkers associated with type 2 diabetes risk.

Variability in blood pressure (BP) is a risk factor for cardiovascular events independent of mean BP. Recently we showed that feeding polyphenol‐rich wild blueberries (BB) or probiotics (PRO) to hypertensive rats reduced the characteristic rise in BP over time. Here we report the effect of these diets on BP variability. Groups (n=8 each) of male spontaneously hypertensive rats were fed one of four AIN93G‐based diets for 8 weeks: Control; 3% freeze‐dried wild BB; 1% probiotic bacteria (PRO); or 3% BB + 1% PRO. BP was measured biweekly by the tail‐cuff method. The standard deviation (SD) and coefficient of variation (CV) of diastolic and systolic BP were compared across groups using 2‐way ANOVA with repeated measures. Results Separate diet enrichment with BB or PRO did not have a significant effect on BP variability (p>0.10). However, the interaction of enrichment with BB and PRO had a significant effect on diastolic BP SD (p=0.016) and CV (p=0.007), with post‐hoc comparisons showing lower variability in the BB+PRO vs. BB group (p<0.05). BP variability was not different from control for any enriched diet. Conclusion Diet enrichment with separate or combined BB and PRO does not affect BP variability compared to control diet in hypertensive rats. Adding PRO to BB‐enriched diets might alter BP variability. Support or Funding Information Wild Blueberry Association of North America

Previously we showed that feeding polyphenol-rich wild blueberries to hypertensive rats lowered systolic blood pressure. Since probiotic bacteria produce bioactive metabolites from berry polyphenols that enhance the health benefits of berry consumption, we hypothesized that adding probiotics to a blueberry-enriched diet would augment the anti-hypertensive effects of blueberry consumption. Groups (n = 8) of male spontaneously hypertensive rats were fed one of four AIN ‘93G-based diets for 8 weeks: Control (CON); 3% freeze-dried wild blueberry (BB); 1% probiotic bacteria (PRO); or 3% BB + 1% PRO (BB+PRO). Blood pressure was measured at weeks 0, 2, 4, 6, and 8 by the tail-cuff method, and urine was collected at weeks 4 and 8 to determine markers of oxidative stress (F2-isoprostanes), nitric oxide synthesis (nitrites), and polyphenol metabolism (hippuric acid). Data were analyzed using mixed models ANOVA with repeated measures. Diet had a significant main effect on diastolic blood pressure (p = 0.046), with significantly lower measurements in the BB- vs. CON-fed rats (p = 0.035). Systolic blood pressure showed a similar but less pronounced response to diet (p = 0.220), again with the largest difference between the BB and CON groups. Absolute increase in blood pressure between weeks 0 and 8 tended to be smaller in the BB and PRO vs. CON and BB+PRO groups (systolic increase, p = 0.074; diastolic increase, p = 0.185). Diet had a significant main effect on hippuric acid excretion (p<0.0001), with 2- and ~1.5-fold higher levels at weeks 4 and 8, respectively, in the BB and BB+PRO vs. PRO and CON groups. Diet did not have a significant main effect on F2-isoprostane (p = 0.159) or nitrite excretion (p = 0.670). Our findings show that adding probiotics to a blueberry-enriched diet does not enhance and actually may impair the anti-hypertensive effect of blueberry consumption. However, probiotic bacteria are not interfering with blueberry polyphenol metabolism into hippuric acid.

Oxidative stress has come to the forefront as a contributor to a number of diseases, including cancer, neurodegenerative and cardiovascular diseases (CVD). High‐fat diets (HFD) are thought to increase LDL, which can contribute to oxidative stress by becoming oxidized in artery walls, leading to atherosclerotic plaques that promote CVD. Blueberry (BB) polyphenolics are thought to act as antioxidants, which can potentially mitigate oxidative stress and improve CVD outcomes. The objective of our study was to evaluate the effect of a HFD supplemented with BB puree on serum lipids and biomarkers of oxidative stress. Male Wistar‐Kyoto rats (n=7) were fed either a control diet (CON), CON with 5mL/kg BB (CON+BB), 20% lard diet (HFD) or HFD with BB (HFD+BB) for eight weeks. A serum lipid panel was measured in a clinical laboratory analyzer and urinary 8‐isoprostane, a marker of lipid peroxidation, and urinary nitrite, a product of free‐radical reactivity, were measured using Cayman and Promega kits, respectively. HDL in CON group was 0.747±0.014mM and was increased by 10% in CON+BB to 0.822±0.019mM (p=0.002, ANOVA). All other serum lipids, urinary 8‐isoprostane and urinary nitrite were not significantly changed by either HFD or BB enrichment. We have shown that feeding BB with a normal, healthy diet can improve serum HDL, which could potentially improve excretion of cholesterol from artery walls, improving CVD. Funding support provided by NSERC, UPEI internal grants and WBANA.

Background and Objectives: Apple peel is a rich source of biological active phytochemicals such as flavonoids.The present study investigated the antihypertensive effect of flavonoid-rich Apple Peel Extract (APE) on Spontaneously Hypertensive Rats (SHR).Methodology: Three groups of animals: Control, captopril (20 mg kgG 1 of body weight/day) and APE (25 mg kgG 1 of body weight/day) were fed standard rat chow and their corresponding treatment in sugar-free gelatin, daily for a period of eight weeks.Blood Pressure (BP) was monitored weekly using the tail cuff method.Blood and tissue samples were collected after the eighth week.Results: As expected, treatment with captopril consistently reduced BP (p<0.05).APE treatment reduced both systolic and diastolic BP by 15 and 11 mg Hg, respectively, after 5 weeks of treatment, However, statistical significance was only achieved in systolic BP after eight weeks when compared with control (p<0.05).There were no significant differences in serum and lung ACE activity at week eight.Treatment with APE increased liver superoxide dismutase (SOD) activity by 78% and total reduced Glutathione (GSH) concentrations by 42% when compared to control (p<0.05) but had no effect on the activity of glutathione reductase or peroxidase.Conclusion: Long term intake of APE reduces high blood pressure in SHR possibly through endogenous antioxidant pathways.This preclinical trial suggests that APE as a dietary supplement could be effective in managing early stages of hypertension.

Wild blueberries have a high content of polyphenols, but there is limited data evaluating their health benefits in people at risk for type 2 diabetes. The objective of the study was to investigate whether 100% wild blueberry juice (WBJ) consumption causes biomarker changes in glucoregulatory control or in those that reflect protection against oxidative stress, inflammation or vascular status, all of which are associated with diabetes risk. A single‐blind randomized cross‐over design study was conducted in which women (n = 19, ages 39‐64 y) at risk for type 2 diabetes consumed 240 ml WBJ or 240 ml of a control beverage as part of their free‐living diet for 7 days. Outcome variables included biomarkers of glucose regulation, oxidative stress, and inflammation. Vascular status, assessed by EndoPat, and blood pressure were also evaluated. WBJ consumption produced no significant changes in biomarkers of glucose regulation and surrogate markers of insulin resistance (glucose, insulin, HOMA‐IR and QUICKI); oxidative stress (total 8‐isoprostanes and LDL‐oxidation); inflammation (IL‐6, IL‐10, CRP, TNF‐alpha, ICAM, VCAM, SAA); and vascular status. However, WBJ consumption showed a trend for lowering systolic blood pressure when compared to the control beverage: 120.8 ± 2.2 mmHg in the placebo group vs 116.0 ± 2.2 mmHg in the WBJ group (P = 0.088). Short term intake of WBJ consumption did not have harmful effects on biomarkers of glucose regulation, oxidative stress, inflammation and vascular status in women at risk for type 2 diabetes. In addition, WBJ may improve systolic blood pressure.

Beneficial health effects of cranberries (CBs) and wild blueberries (BBs), such as reduced levels of oxidative stress, have been demonstrated in feeding studies. These Vaccinium berries contain high levels of flavonoids; however, the bioavailability of flavonoids is generally low. We investigated the in vitro effects of these berries on intestinal cells, focusing on mitigating oxidative stress and associated reactive oxygen species (ROS). First, we simulated the passage of CB and BB through the gastrointestinal (GI) tract by treating berry homogenates to a battery of digestive enzymes. Then, Caco-2 cells, a model of small intestine epithelial uptake, were exposed to these homogenates for 60 min. Using a cell-free assay, we found that the antioxidant activity in CB homogenates was not affected by these enzymes, but that BB homogenates treated with gut enzymes had 43% lower free-radical quenching activity (P < 0.05). However, both of the enzyme-treated homogenates were still able to counteract the ROS-generating ability of H2O2 added exogenously to Caco-2 cells. Berry homogenates also increased mitochondrial metabolic rates at 60 min posttreatment, as measured by MTT assays. Enzyme-treated CB (but not BB) homogenates increased the levels of reduced glutathione (GSH) relative to oxidized glutathione (GSSG), a critical indicator of the cellular redox state (P < 0.05). Our data suggest that CBs do not lose their antioxidant ability when passing through the GI tract, and specifically, digested CB may serve to enhance cytoprotective effects in intestinal cells by reducing potential damage caused by free radicals and ROS derived from other food sources.

Prostate cancer is one of the most common cancers in the world, and its prevalence is expected to increase appreciably in the coming decades. As such, more research is necessary to understand the etiology, progression and possible preventative measures to delay or to stop the development of this disease. Recently, there has been interest in examining the effects of whole extracts from commonly harvested crops on the behaviour and progression of cancer. Here, we describe the effects of whole cranberry extract (WCE) on the behaviour of DU145 human prostate cancer cells in vitro. Following treatment of DU145 human prostate cancer cells with 10, 25 and 50 μg ml⁻¹ of WCE, respectively for 6 h, WCE significantly decreased the cellular viability of DU145 cells. WCE also decreased the proportion of cells in the G2-M phase of the cell cycle and increased the proportion of cells in the G1 phase of the cell cycle following treatment of cells with 25 and 50 μg ml⁻¹ treatment of WCE for 6 h. These alterations in cell cycle were associated with changes in cell cycle regulatory proteins and other cell cycle associated proteins. WCE decreased the expression of CDK4, cyclin A, cyclin B1, cyclin D1 and cyclin E, and increased the expression of p27. Changes in p16(INK4a) and pRBp107 protein expression levels also were evident, however, the changes noted in p16(INK4a) and pRBp107 protein expression levels were not statistically significant. These findings demonstrate that phytochemical extracts from the American cranberry (Vaccinium macrocarpon) can affect the behaviour of human prostate cancer cells in vitro and further support the potential health benefits associated with cranberries.

Feeding flavonoid-rich blueberries to spontaneously hypertensive stroke-prone rats (SHRSP) lowers blood pressure. To determine whether this is due to inhibition of angiotensin-converting enzyme (ACE) activity, as seen with other flavanoid-rich foods, we fed blueberries to SHRSP and normotensive rats and analyzed ACE activity in blood and tissues. After 2 weeks on a control diet, the hypertensive rats showed 56% higher levels of ACE activity in blood as compared with the normotensive rats (p < 0.05). Feeding a 3% blueberry diet for 2 weeks lowered ACE activity in the SHRSP (p < 0.05) but not the normotensive rats. ACE activity in plasma of SHRSP was no longer elevated at weeks 4 and 6, but blueberry feeding inhibited ACE in SHRSP after 6 weeks. Blueberry diets had no effect on ACE activity in lung, testis, kidney, or aorta. Our results suggest that dietary blueberries may be effective in managing early stages of hypertension, partially due to an inhibition of soluble ACE activity.

This study examined the effects of a proanthocyanidin‐enriched fraction (PAC) from cranberry (Vaccinium macrocarpon) on matrix metalloproteinase (MMP) activity in DU145 human prostate cancer cells in vitro. MMP‐2/−9 activity was inhibited by PAC in a dose/time dependent manner. PAC (25 ug/mL) decreased cellular viability 30% post 6 h.of treatment and had no significant effect on cellular viability post 3 h. Treatment of DU145 cells with PAC for 3 h. resulted in increased expression of p‐p38, pERK‐1, pERK‐2 protein levels. Increased JNK1 and decreased JNK2 protein expression occurred in response to PAC with corresponding alterations in p‐JNK1 and p‐JNK2. PAC treatment decreased protein expression levels of AKT, p‐AKT, P‐I‐3 kinase p85/p110 proteins. Treatment of DU145 cells with PAC resulted in inhibition of translocation of NF‐kB as suggested by decreased protein expression of p65 in the nuclear fraction. No apparent change in IkB alpha protein levels were noted. Decreased protein levels of p‐IkB alpha were observed. PAC fraction has the ability to inhibit MMP‐2/−9 activity at a concentration which is not cytotoxic to these cells suggesting that PACs inhibit MMP activity levels in DU145 cells in a targeted manner independent of cellular cytotoxicity effects. (N.C.I.C.‐ Canadian Cancer Society, P.E.I. Health Research Program, The Cranberry Institute (Wisconsin Board) funded)

Prostate cancer is one of the most common cancers in the Western world, and it is believed that an individual's diet affects his risk of developing cancer. There has been an interest in examining phytochemicals, the secondary metabolites of plants, in order to determine their potential anti‐cancer activities in vitro and in vivo. In this study we document the effects of proanthocyanidins (PACs) from the American Cranberry (Vaccinium macrocarpon) on matrix metalloproteinase (MMP) activity in DU145 human prostate cancer cells. Cranberry PACs decreased cellular viability of DU145 cells at a concentration of 25 µg/ml by 30% after 6 h of treatment. Treatment of DU145 cells with PACs resulted in an inhibition of both MMPs 2 and 9 activity. PACs increased the expression of TIMP‐2, a known inhibitor of MMP activity, and decreased the expression of EMMPRIN, an inducer of MMP expression. PACs decreased the expression of PI‐3 kinase and AKT proteins, and increased the phosphorylation of both p38 and ERK1/2. Cranberry PACs also decreased the translocation of the NF‐κB p65 protein to the nucleus. Cranberry PACs increased c‐jun and decreased c‐fos protein levels. These results suggest that cranberry PACs decreases MMP activity through the induction and/or inhibition of specific temporal MMP regulators, and by affecting either the phosphorylation status and/or expression of MAP kinase, PI‐3 kinase, NF‐κB and AP‐1 pathway proteins. This study further demonstrates that cranberry PACs are a strong candidate for further research as novel anti‐cancer agents. J. Cell. Biochem. 111: 742–754, 2010. © 2010 Wiley‐Liss, Inc.

Diets rich in fruits and vegetables have been shown to improve patient prognosis in a variety of cancers, a benefit partly derived from phytochemicals, many of which target cell death pathways in tumor cells. Cranberries (Vaccinium macrocarpon) are a phytochemical-rich fruit containing a variety of polyphenolic compounds. As flavonoids have been shown to induce apoptosis in human tumor cells, this study investigated the hypothesis that cranberry-mediated cytotoxicity in DU145 human prostate adenocarcinoma cells involves apoptosis. The results showed that induction of apoptosis in these cells occurred in response to treatment with whole cranberry extract and occurred through caspase-8 mediated cleavage of Bid protein to truncated Bid resulting in cytochrome-C release from the mitochondria. Subsequent activation of caspase-9 ultimately resulted in cell death as characterized by DNA fragmentation. Increased Par-4 protein expression was observed, and this is suggested to be at least partly responsible for caspase-8 activation. Proanthocyanidin-enriched and flavonol-enriched fractions of cranberry also increased caspase-8 and caspase-9 activity, suggesting that these compounds play a possible role in apoptosis induction. These findings indicate that cranberry phytochemicals can induce apoptosis in prostate cancer cells in vitro, and these findings further establish the potential value of cranberry phytochemicals as possible agents against prostate cancer.

Cranberry can slow the growth of DU145 cells by inhibiting cell proliferation and also by apoptosis induction. Apoptosis may occur either via the mitochondrial‐mediated intrinsic pathway or death‐receptor mediated extrinsic pathway. This study investigated how a proanthocyanidin‐enriched fraction (PAC) from cranberry may regulate this complex process. PAC contained proanthocyanidin oligomers (major ones appear to be dimers, trimers & tetramers) (with 2–8 epicatechin units, with at least one A‐type linkage between units). PAC treatment resulted in a dose dependent inhibition of Bcl‐2, Bax, and Bid protein levels coupled with an induction of tBid protein. PAC also inhibits Smac/DIABLO levels. PAR‐4 protein levels increased in response to PAC. PAC resulted in a dose dependent induction of cytochrome ‐C in total cellular extract and cytochrome‐C protein expression also increased in mitochondrial extracts. Increased PARP protein expression occurred in response to PAC (25 ug/mL). PAC inhibited Fas‐L, FADD, and TRAIL protein expression levels whereas Fas protein levels were not affected by PAC. These results suggest that PAC is inducing apoptosis in DU145 cells via the intrinsic pathway and ensures this occurs by specifically inhibiting the extrinsic pathway of apoptosis.(N.C.I.C‐ Canadian Cancer Society, P.E.I. Heath Research Program, Cranberry Institute (Wisconsin Board) funded)

We have shown that feeding cranberries (Vaccinium. macrocarpon, CB) prolongs survival in spontaneously hypertensive stroke‐prone rats (SHRSP). Here, we evaluated the effect of feeding blueberries (V. angustifolium, BB) on survival and evaluated possible mechanisms. SHRSP were fed control diet or a diet enriched with 3% CB or 3% BB until the onset of stroke. Weight, feed intake, and systolic blood pressure (BP) were monitored weekly; urinary F2‐isoprostanes, a marker of oxidative stress, were measured at the end of the study. BB lowered BP by 6‐10% at weeks 5‐7, whereas CB lowered BP by 10% only at week 5. BB did not prolong survival, whereas CB increased survival by 40%. Rats with high BP at wks 4 and 5 were more likely to demonstrate early stroke symptoms (p<0.01). Feed efficiency over the first 5 wks also was positively correlated with days to stroke onset (p=0.018, control; p=0.052, CB). Weight at wk 5 was positively correlated with days to stroke in CB (p=0.038), but not in control‐fed SHRSP (p=0.41). In CB‐fed SHRSP, but not control rats, F2 isoprostanes were negatively correlated with BP at wk 5 (p=0.034), and positively correlated with days to stroke (p=0.027). These results suggest that effects on BP and weight/ feed efficiency can contribute to prolongation of stroke onset in SHRSP. Since F2‐isoprostanes are markers of lipid peroxidation, it is surprisingly that their levels promote survival. (Funded by AIF and NSERC).

Oxidative stress in the vasculature and kidneys contributes to hypertension, a major risk factor for cardiovascular disease. Blueberries (BB) are rich in antioxidants, and so we hypothesized that feeding diets enriched with BB would slow the development of hypertension in spontaneously hypertensive stroke-prone rats (SHRSP). Eight-week-old normotensive rats and SHRSP were fed either a control diet (Con) or a diet enriched with 3% freeze-dried BB for 8 weeks. Systolic blood pressure (SBP) was measured at weeks 2, 4, 6, 7, and 8 by the tail cuff method, and urine was collected at weeks 4 and 8. The SBP was elevated in SHRSP relative to normotensive rats over the entire 8-week feeding period. In SHRSP consuming BB, SBP was 19% lower at week 4 and 30% lower at week 6, relative to SHRSP on Con. Maximum SBP was 216 +/- 11 mm Hg in SHRSP consuming Con vs 178 +/- 15 mm Hg in the BB-fed group (P = .036). Spontaneously hypertensive stroke-prone rats had elevated levels of urine F2-isoprostanes/creatinine relative to normotensive rats, indicating systemic oxidative stress in this strain. Blueberry feeding had no effect on urinary excretion of F2-isoprostanes; therefore, it is unlikely that a systemic antioxidant effect of BB is responsible for the antihypertensive effects at weeks 4 and 6. Blueberry-fed rats had reduced markers of renal oxidative stress, such as proteinuria and kidney nitrites. Thus, a 3% BB diet may be capable of protecting the kidneys from oxidative damage in SHRSP, thereby reducing the magnitude of hypertension.