Prevention of Atherosclerosis by Berries: The Case of Blueberries.

Berry consumption has been associated with cardiovascular disease prevention in recent years. Atherosclerosis is one of the major causes of cardiovascular diseases. However, research on the prevention of atherosclerosis through consuming individual whole berries, specifically direct evidence, remains scarce. Therefore, further elucidating the role that berries play in the prevention of atherosclerosis is warranted. In this perspective, blueberries were selected to articulate research strategies for studying atheroprotective effects of berries. Studies from human subjects and various animal models are summarized. The mechanisms by which blueberries may act, through reducing oxidative stress, decreasing inflammation, improving endothelial dysfunction, regulating cholesterol accumulation and trafficking, along with potentially influencing gut microbiota, are also discussed. Blueberries contain high levels of polyphenolic compounds, which were widely indicated as major bioactive compounds. Nonetheless, the metabolites/catabolites after blueberry consumption, such as simple phenolic acids, rather than original compounds in berries, may be the actual in vivo bioactive compounds. Future research should focus on obtaining more direct evidence, preferably in humans, understanding of the mechanisms of action at the molecular level, and identifying bioactive compounds as well as which compounds act synergistically to convey health benefits. The research strategy discussed here may also be applied to the studies of other fruits and berries.

Urinary excretion of phenolic acids in rats fed cranberry, blueberry, or black raspberry powder.

Dietary polyphenolics can be converted into smaller phenolic acids (PA) by microorganisms in the colon and may contribute to health benefits associated with the parent polyphenolics. Urinary excretion of 18 PA and their conjugates was studied, using HPLC-MS/MS, in rats fed AIN93G-based diets containing 5% (dry weight basis) of either cranberry (CB), blueberry (BB), or black raspberry (BRB). Hippuric, 4-hydroxyphenylacetic, 3-methoxy-4-hydroxyphenylacetic, and 4-hydroxybenzoic acids were excreted in greatest quantity in the urine over a 24 h period in all diets. Primary PA excreted in the berry diets were 4-hydroxycinnamic acid for CB; chlorogenic, ferulic, and 3,4-dihydroxycinnamic acids for BB; and 3-hydroxyphenylpropionic, 3-hydroxybenzoic, and 3-hydroxycinnamic acids for BRB. PA were present in conjugated form with cinnamic acid derivatives being 50-70% and phenylacetic acid derivatives conjugated <10%. Conjugated, and not just the free, PA are significant contributors to total urinary excretion.

Changes in chokeberry (Aronia melanocarpa L.) polyphenols during juice processing and storage.

Chokeberries are an excellent source of polyphenols, but their fate during juice processing and storage is unknown. The stability of anthocyanins, total proanthocyanidins, hydroxycinnamic acids, and flavonols at various stages of juice processing and over 6 months of storage at 25 °C was determined. Flavonols, total proanthocyanidins, and hydroxycinnamic acids were retained in the juice to a greater extent than anthocyanins, with losses mostly due to removal of seeds and skins following pressing. Anthocyanins were extensively degraded by thermal treatments during which time levels of protocatechuic acid and phloroglucinaldehyde increased, and additional losses occurred following pressing. Flavonols, total proanthocyanidins, and hydroxycinnamic acids were well retained in juices stored for 6 months at 25 °C, whereas anthocyanins declined linearly. Anthocyanin losses during storage were paralleled by increased polymeric color values, indicating that the small amounts of anthocyanins remaining were present in large part in polymeric forms.

Suppression of Wnt1-induced mammary tumor growth and lower serum insulin in offspring exposed to maternal blueberry diet suggest early dietary influence on developmental programming.

Despite the well-accepted notion that early maternal influences persist beyond fetal life and may underlie many adult diseases, the risks imposed by the maternal environment on breast cancer development and underlying biological mechanisms remain poorly understood. In this study, we investigated whether early exposure to blueberry (BB) via maternal diet alters oncogene Wnt1-induced mammary tumorigenesis in offspring. Wnt1-transgenic female mice were exposed to maternal Casein (CAS, control) or blueberry-supplemented (CAS + 3%BB) diets throughout pregnancy and lactation. Offspring were weaned to CAS and mammary tumor development was followed until age 8 months. Tumor incidence and latency were similar for both groups; however, tumor weight at killing and tumor volume within 2 weeks of initial detection were lower (by 50 and 60%, respectively) in offspring of BB- versus control-fed dams. Dietary BB exposure beginning at weaning did not alter mammary tumor parameters. Tumors from maternal BB-exposed offspring showed higher tumor suppressor (Pten and Cdh1) and lower proproliferative (Ccnd1), anti-apoptotic (Bcl2) and proangiogenic (Figf, Flt1 and Ephb4) transcript levels, and displayed attenuated microvessel density. Expression of Pten and Cdh1 genes was also higher in mammary tissues of maternal BB-exposed offspring. Mammary tissues and tumors of maternal BB-exposed offspring showed increased chromatin-modifying enzyme Dnmt1 and Ezh2 transcript levels. Body weight, serum insulin and serum leptin/adiponectin ratio were lower for maternal BB-exposed than control tumor-bearing offspring. Tumor weights and serum insulin were positively correlated. Results suggest that dietary influences on the maternal environment contribute to key developmental programs in the mammary gland to modify breast cancer outcome in adult progeny.

Effect of dietary blueberry pomace on selected metabolic factors associated with high fructose feeding in growing Sprague-Dawley rats.

An experiment was conducted to study the protective effect of feeding extruded and unextruded blueberry pomace (BBP) on selected metabolic parameters associated with metabolic syndrome in a model of high fructose (HF)-fed growing Sprague-Dawley rats. Treatments were as follows: (1) control (modified AIN-based diet); (2) HF diet (AIN diet with 58% fructose); (3) HF diet with 1.5% unextruded BBP; (4) HF diet with 1.5% extruded BBP; (5) HF diet with 3% unextruded BBP; and (6) HF diet with 3% extruded BBP. Compared with the control, HF feeding increased fasting plasma insulin and fasting and postprandial plasma triglycerides as well as homeostatic scores of insulin resistance and ß-cell function, but not weight gain, diet intake and efficiency, abdominal fat, oral glucose tolerance, and fasting and postprandial plasma glucose, cholesterol, and leptin levels. Inclusion of unextruded or extruded BBP was effective in minimizing or ameliorating the fructose-induced metabolic anomalies, except postprandial plasma triglycerides, especially at 3% of the diet. In addition, unextruded or extruded BBP at 3% of the diet was also able to reduce plasma cholesterol and abdominal fat relative to the HF control, which may impart additional health benefits. Compared with the control, inclusion of unextruded or extruded BBP at both 1.5% and 3% resulted in lower total fat weight, and animals fed a diet supplemented with 3% unextruded BBP in fasting state or 3% unextruded BBP in fed state had lower leptin levels than the control. This is the first study demonstrating the beneficial effects of feeding blueberry pomace on health.

Repression of mammosphere formation of human breast cancer cells by soy isoflavone genistein and blueberry polyphenolic acids suggests diet-mediated targeting of cancer stem-like/progenitor cells.

Mammary stem cells are undifferentiated epithelial cells, which initiate mammary tumors and render them resistant to anticancer therapies, when deregulated. Diets rich in fruits and vegetables are implicated in breast cancer risk reduction, yet underlying mechanisms are poorly understood. Here, we addressed whether dietary factors selectively target mammary epithelial cells that display stem-like/progenitor subpopulations with previously recognized tumor-initiating potential. Using estrogen receptor-positive MCF-7 and estrogen receptor-negative MDA-MB-231 human breast cancer cell lines and freshly isolated epithelial cells from MMTV-Wnt-1 transgenic mouse mammary tumors, we demonstrate that sera of adult mice consuming soy isoflavone genistein (GEN) or blueberry (BB) polyphenol-containing diets alter the population of stem-like/progenitor cells, as measured by their functional ability to self-renew and form anchorage-independent spheroid cultures in vitro at low frequency (1-2%). Serum effects on mammosphere formation were dose-dependently replicated by GEN (40 nM >2 µM) and targeted the basal stem-like CD44+/CD24-/ESA+ and the luminal progenitor CD24+ subpopulations in MDA-MB-231 and MCF-7 cells. GEN inhibition of mammosphere formation was mimicked by the Akt inhibitor perifosine and was associated with enhanced tumor suppressor phosphatase and tensin homologue deleted on chromosome ten (PTEN) expression. In contrast, a selected mixture of BB phenolic acids was only active in MDA-MD-231 cells and its CD44+/CD24-/ESA+ subpopulation, and this activity was independent of induction of PTEN expression. These findings delineate a novel and selective function of distinct dietary factors in targeting stem/progenitor cell populations in estrogen receptor-dependent and -independent breast cancers.

Effect of feeding grape pomace on selected metabolic parameters associated with high fructose feeding in growing Sprague-Dawley rats.

The effect of feeding grape pomace on certain metabolic parameters associated with high fructose (HF) feeding was studied. Forty male growing Sprague-Dawley rats were randomly assigned into groups: (1) control; (2) HF; (3) HF with low-level (1.5% of diet) grape pomace (HF+LP), and (4) HF with high-level (5.0% of diet) grape pomace (HF+HP). The HF+LP and HF+HP diets provided 115 and 218 mg of procyanidins/kg, respectively. Compared with the controls, HF-fed animals consumed less and were smaller, whereas animals in the HF+LP and HF+HP groups were in between. A similar trend was observed for abdominal fat and abdominal fat as a percentage of body weight. No change in heart or kidney weight occurred. Liver weight as a percentage of body weight was higher for animals when fructose was included in the diet compared with those on control diet, and inclusion of grape pomace had no effect. Fasting plasma glucose, insulin, and triglyceride levels tended to be higher in animals fed HF diet, and grape pomace reduced their levels to values similar to the control animals. Compared with control animals, HF-fed animals had higher weekly postprandial plasma triglycerides, which were reduced by feeding grape pomace, but no change in plasma cholesterol was observed. Glucose intolerance was observed in animals fed HF diet and was accompanied by a 25% increase in homeostatic model assessment (HOMA) of insulin resistance. Inclusion of grape pomace increased glucose tolerance and insulin sensitivity. No significant change (P>.1) in HOMA of ß-cell function or Quantitative Insulin-Sensitivity Check Index was observed. Overall, HF diet did not produce as strong a response of metabolic syndrome as has been shown in the literature. The inclusion of grape pomace in the diet was effective in modulating some aspects of metabolic parameters associated with metabolic syndrome, and the higher level of grape pomace in the diet produced a slightly better response than the lower level.

Impact of different stages of juice processing on the anthocyanin, flavonol, and procyanidin contents of cranberries.

Juice is the most common form in which cranberries are consumed; however there is limited information on the changes of polyphenolic content of the berries during juice processing. This study investigated the effects of three different pretreatments (grinding plus blanching; only grinding; only blanching) for cranberry juice processing on the concentrations of anthocyanins, flavonols, and procyanidins throughout processing. Flavonols and procyanidins were retained in the juice to a greater extent than anthocyanins, and pressing resulted in the most significant losses in polyphenolics due to removal of the seeds and skins. Flavonol aglycones were formed during processing as a result of heat treatment. Drying of cranberry pomace resulted in increased extraction of flavonols and procyanidin oligomers but lower extraction of polymeric procyanidins. The results indicate that cranberry polyphenolics are relatively stable during processing compared to other berries; however, more work is needed to determine their fate during storage of juices.

Processing and storage effects on the ellagitannin composition of processed blackberry products.

Changes in blackberry ellagitannin composition in response to juicing (clarified and nonclarified), pureeing, canning (in water or syrup), and freezing as well as changes in processed products during 6 months of storage were investigated. Canning, pureeing, and freezing had little effect on ellagitannins, but processing berries into nonclarified and clarified juices resulted in total ellagitannin losses of 70 and 82%, respectively, due to removal of ellagitannin-rich seeds in the presscake. Minimal changes in total ellagitannin content were observed during storage of thermally processed products, but compositional changes indicative of ellagitannin depolymerization were apparent. The ellagitannin content and composition of frozen berries remained stable over 6 months of storage. Ellagitannins are well retained in canned, pureed, and frozen blackberries, but methods are needed to prevent losses during juice processing and/or exploit the ellagitannin-rich coproducts.

Urinary excretion of (Epi)catechins in rats fed different berries or berry products.

(Epi)catechins are associated with many health benefits in humans. However, their bioavailability, excretory pattern, and extent of conjugation in animals fed different sources or levels in the diet are not well documented. Two experiments were conducted to investigate the urinary excretion of (epi)catechins after feeding of different types of berries or different levels of the same berry source to rats. Experiment 1 investigated the effects of feeding a commercially available concentrated cranberry powder (CCP) at three different levels, 3.3, 6.6, and 33 g/kg of diet, whereas experiment 2 investigated the effect of feeding freeze-dried whole cranberry (CB), blueberry (BB), or black raspberry (BRB) powder at 50 g/kg of diet. Both experiments had an AIN-93-based control and a high-fructose diet (53-65% of the diet) to which was added three levels of CCP in experiment 1 and CB, BB, and BRB in experiment 2. (Epi)catechins were excreted as free and conjugated in both intact and methylated forms. Excretion of conjugated (epi)catechins was as high as 60% of the total consumed in some cases. A majority of both catechins and epicatechins excreted in the urine was in a methylated form. Excretion of epicatechins, including their methylated forms, ranged from 30 to 47% of the ingested amount, whereas that of catechins, including their methylated forms, ranged from 9 to 31%. Urinary excretion of (epi)catechins was dose dependent and increased with the amount of (epi)catechins present in the diet. On the basis of the excretory pattern of (epi)catechins in the urine, data suggested that the bioavailability of epicatechins may be higher than that of catechins and that (epi)catechins may be more available from blueberries compared to cranberries.

Release of bound procyanidins from cranberry pomace by alkaline hydrolysis.

Procyanidins in plant products are present as extractable or unextractable/bound forms. We optimized alkaline hydrolysis conditions to liberate procyanidins and depolymerize polymers from dried cranberry pomace. Alkaline extracts were neutralized (pH 6-7) and then procyanidins were extracted with ethyl acetate and analyzed by normal phase high performance liquid chromatography. Alkaline hydrolysis resulted in an increase in low molecular weight procyanidins, and the increase was greater at higher temperature, short time combinations. The most procyanidins (DP1-DP3) were extracted at 60 degrees C for 15 min with each concentration of NaOH. When compared to conventional extraction using homogenization with acetone/water/acetic acid (70:29.5:0.5 v/v/v), treatment with NaOH increased procyanidin oligomer extraction by 3.8-14.9-fold, with the greatest increase being DP1 (14.9x) and A-type DP2 (8.4x) procyanidins. Alkaline treatment of the residue remaining after conventional extraction resulted in further procyanidin extraction, indicating that procyanidins are not fully extracted by conventional extraction methods.

Multi-laboratory validation of a standard method for quantifying proanthocyanidins in cranberry powders.

BACKGROUND: The objective of this study was to validate an improved 4-dimethylaminocinnamaldehyde (DMAC) colorimetric method using a commercially available standard (procyanidin A2), for the standard method for quantification of proanthocyanidins (PACs) in cranberry powders, in order to establish dosage guidelines for the uropathogenic bacterial anti-adhesion effect of cranberry. RESULTS: Commercially available cranberry samples were obtained (five from U.S. sources and six from European sources) for PAC quantification in five different analytical laboratories. Each laboratory extracted and analyzed the samples using the improved DMAC method. Within-laboratory variation (mean +/- SD) was 4.1 +/- 1.7% RSD (range, 2.3-6.1% RSD) and the between laboratory variability was 16.9 +/- 8.5% RSD (range, 8-32% RSD). For comparative purposes, the cranberry samples were alternatively quantified using weights of extracted PACs (gravimetric). The correlation coefficient between the two methods was 0.989. CONCLUSION: This improved DMAC method provides a simple, robust and relatively specific spectrophotometric assay for total PACs in cranberry samples using commercially available procyanidin A2 dimer as a standard. DMAC is most useful within a given type of food such as cranberries, but may not be appropriate for comparing concentrations across different food types, particularly in those cases where large differences exist among the relative amounts of each oligomer and polymer.

Dietary black raspberry anthocyanins do not alter development of obesity in mice fed an obesogenic high-fat diet.

Anthocyanins (ACNs) from various foods have been shown to minimize the development of obesity in some animal models. The objective of the current study was to compare the effects of feeding purified black raspberry (BRB) ACNs or the freeze-dried whole BRB on the development of obesity. Male C57BL/6J mice (25 days of age) were assigned at random to treatments (7/treatment; 3/cage). The treatments included (1) control low-fat diet (10% calories from fat) (LF); (2) LF plus BRB juice in place of drinking water; (3) LF diet plus purified BRB ACNs in drinking water (1.25 mg/mL); (4) control high-fat diet (60% calories from fat) (HF60); (5) HF60 diet + BRB juice in place of drinking water; (6) HF60 diet + ACNs in drinking water (1.25 mg/mL); and (7) HF60 + freeze-dried whole BRB powder (21.7 g/kg of diet). Body weight gains in mice fed HF60 diet plus purified BRB ACNs tended to be lower after 56, 63, and 70 days than in mice fed HF60 alone. Body weights were increased at time of sacrifice, but heart, liver, and kidney weights as a percentage of body weight were decreased in mice fed HF60 diet compared to LF fed mice. Weights (g or g/body weight) of epididymal and retroperitoneal fat were increased in the HF60 fed mice compared to LF fed mice. Fasting serum glucose, leptin, and insulin levels as well as homeostasis assessment of insulin resistance (HOMA-IR) were elevated in mice fed the HF60 diet relative to LF-fed controls. Serum cholesterol, triglycerides, and monocyte chemoattractant protein-1 (MCP-1) were not altered by diet. Serum levels of resistin were increased in mice fed the HF60 diet compared to mice fed the LF diet. None of the responses measured were altered by whole BRB powder included in the diet relative to the HF60 control diet. Cyanidin containing di- or triglycosides in BRB was ineffective in altering the development of obesity in contrast to cyanidin-monoglycosides, which have been shown to be effective. The sugar moiety on the anthocyanidins may be an important factor in determining the response in the development of obesity.

Purified blueberry anthocyanins and blueberry juice alter development of obesity in mice fed an obesogenic high-fat diet.

Male C57BL/6J mice (25 days of age) were fed either a low-fat diet (10% kcal from fat) (LF) or a high-fat diet (45% kcal from fat) (HF45) for a period of 72 days. Blueberry juice or purified blueberry anthocyanins (0.2 or 1.0 mg/mL) in the drinking water were included in LF or HF45 treatments. Sucrose was added to the drinking water of one treatment to test if the sugars in blueberry juice would affect development of obesity. Total body weights (g) and body fat (%) were higher and body lean tissue (%) was lower in the HF45 fed mice compared to the LF fed mice after 72 days, but in mice fed HF45 diet plus blueberry juice or blueberry anthocyanins (0.2 mg/mL), body fat (%) was not different from those mice fed the LF diet. Anthocyanins (ACNs) decreased retroperitoneal and epididymal adipose tissue weights. Fasting serum glucose concentrations were higher in mice fed the HF45 diet. However, it was reduced to LF levels in mice fed the HF45 diet plus 0.2 mg of ACNs/mL in the drinking water, but not with blueberry juice. beta cell function (HOMA-BCF) score was lowered with HF45 feeding but returned to normal levels in mice fed the HF45 diet plus purified ACNs (0.2 mg/mL). Serum leptin was elevated in mice fed HF45 diet, and feeding either blueberry juice or purified ACNs (0.2 mg/mL) decreased serum leptin levels relative to HF45 control. Sucrose in drinking water, when consumption was restricted to the volume of juice consumed, produced lower serum leptin and insulin levels, leptin/fat, and retroperitoneal and total fat (% BW). Blueberry juice was not as effective as the low dose of anthocyanins in the drinking water in preventing obesity. Additional studies are needed to determine factors responsible for the differing responses of blueberry juice and whole blueberry in preventing the development of obesity.

Urinary excretion of phenolic acids in rats fed cranberry.

Dietary flavonoids can be converted into phenolic acids by colonic microflora. Phenolic acids can then be absorbed into the circulation and may contribute to the health-promoting effects of the parent compounds. Phenolic acids can be further metabolized in other tissues via methylation and conjugation with glucuronide or sulfate. The objectives of this study were to identify and quantify the urinary excretion of 19 phenolic acids and their conjugates in rats fed three levels of a concentrated cranberry powder (3.3, 6.6, and 33 mg/kg of diet). The basic diet used was AIN93G diet containing very low amounts of any polyphenolic compounds. Of the phenolic acids studied, the amounts excreted varied by 4 orders of magnitude, with hippuric acid being excreted in the highest quantities. Amounts of 4-hydroxyphenylacetic acid (4HPAA), 3-hydroxyphenylacetic acid (3HPAA), 3-hydroxyphenylpropionic acid (3HPPA), and 4-hydroxycinnamic acid (4HCA) excreted were in the range of 18-33 microg/mg creatinine in animals fed the highest level of cranberry powder, whereas phenylacetic acid (PAA), gallic acid (GA), 3,4-dihydroxyphenylacetic acid (34HPAA), 3,4-dihydroxybenzoic acid (34HBA), 3,4-dihydroxycinnamic acid (34HCA), and 4-hydroxy-3-methoxycinnamic acid (FA) were excreted in the urine in concentrations of 0.1-2 microg/mg creatinine. As the amount of cranberry in the diet was increased, the amount of 4HPAA excreted decreased but the percentage of conjugated 4HPAA excreted increased (from 57 to 91%). For other phenolic acids analyzed, the percentage excreted in the conjugated form was approximately constant across levels of cranberry in the diet and ranged from 65 to 100% for the individual phenolic acids. Studies of bioactivity and health effects need to consider more than just the compound(s) in the food, because they can be metabolized to other lower molecular weight compounds, which in turn may also be methylated or conjugated in some form that may affect the perceived health effects.

Effects of dietary consumption of cranberry powder on metabolic parameters in growing rats fed high fructose diets.

The effect of dietary consumption of a cranberry powder (CP) containing increased amounts of procyanidins and other phytochemicals on metabolic parameters associated with metabolic syndrome was investigated in growing rats fed a high fructose diet. Dietary treatments were control (starch based), high fructose (HF), and HF containing either 3.3, 6.6, or 33 g CP/kg diet. Fasting plasma glucose and triglycerides tended to be higher with HF feeding and were reduced by feeding CP. The area under curve following an oral glucose tolerance test was 35-50% higher in animals fed HF diet vs. control and was decreased to control levels by the low or medium but not high CP diet. Feeding CP tended to lower fasting plasma insulin. Homeostatic models of insulin resistance (HOMA-IR) and ß-cell function (HOMA-BCF) were lowest in animals fed low or medium CP diets (p < 0.05). Rats fed the control starch diet had slightly higher food intake, final body weight, and abdominal fat compared to animals fed other diets. Kidney weight was higher in HF group and feeding CP decreased kidney weight to normal levels. In the fed state, plasma triglyceride was increased with HF diet, whereas insulin was lower in animals fed HF diet. Overall, inclusion of CP in the diet was effective in modulating some aspects of metabolic parameters associated with metabolic syndrome and the medium level of CP in the diet produced a better response than the lower and higher CP levels.

Proximate and polyphenolic characterization of cranberry pomace.

The proximate composition and identification and quantification of polyphenolic compounds in dried cranberry pomace were determined. Proximate analysis was conducted based on AOAC methods for moisture, protein, fat, dietary fiber, and ash. Other carbohydrates were determined by the difference method. Polyphenolic compounds were identified and quantified by HPLC-ESI-MS. The composition of dried cranberry pomace was 4.5% moisture, 2.2% protein, 12.0% fat, 65.5% insoluble fiber, 5.7% soluble fiber, 8.4% other carbohydrates, 1.1% ash, and 0.6% total polyphenolics. It contained six anthocyanins (111.5 mg/100 g of DW) including derivatives of cyanidin and peonidin. Thirteen flavonols were identified (358.4 mg/100 g of DW), and the aglycones myricetin (55.6 mg/100 g of DW) and quercetin (146.2 mg/100 g of DW) were the most prominent. Procyanidins with degrees of polymerization (DP) of 1-6 were identified (167.3 mg/100 g of DW), the most abundant being an A-type of DP2 (82.6 mg/100 g of DW).

Polyphenolic composition and antioxidant capacity of extruded cranberry pomace.

Cranberry pomace was mixed with corn starch in various ratios (30:70, 40:60, 50:50 pomace/corn starch DW) and extruded using a twin-screw extruder at three temperatures (150, 170, 190 degrees C) and two screw speeds (150, 200 rpm). Changes in the anthocyanin, flavonol, and procyanidin contents due to extrusion were determined by HPLC. Antioxidant capacity of the extrudates was determined using oxygen radical absorbance capacity (ORAC). Anthocyanin retention was dependent upon barrel temperature and percent pomace. The highest retention was observed at 150 degrees C and 30% pomace. Flavonols increased by 30-34% upon extrusion compared to an unextruded control. ORAC values increased upon extrusion at 170 and 190 degrees C. An increase in DP1 and DP2 procyanidins was also observed; however, a decrease was observed in DP4-DP9 oligomers. These data suggest that extrusion alters the polyphenolic distribution of cranberry pomace and has application in the nutraceutical industry as a means of improving the functionality of this coproduct.

In utero and lactational exposure to blueberry via maternal diet promotes mammary epithelial differentiation in prepubescent female rats.

Early developmental events influence the fine tuning of later susceptibility to adult diseases. Diet is a determinant of breast cancer risk, and our previous studies showed that diet-mediated changes in transcriptional programs promote early mammary gland differentiation. Although consumption of fruits is considered to elicit multiple health benefits, little is known on whether associated bioactive components modify the early differentiation program in developing mammary glands. Here, we evaluated the hypothesis that early exposure (in utero and lactational) to blueberry through maternal diet enhances mammary epithelial differentiation in female offspring. Pregnant Sprague-Dawley rats beginning at gestation day 4 were fed American Institute of Nutrition-based diets containing casein and whole blueberry powders added to casein at 2.5%, 5.0%, and 10% weight/weight. Female pups at weaning were evaluated for growth and mammary tissue parameters. Blueberry at 5% dose increased body and adipose fat weights, relative to the other diets. Mammary branch density and terminal end bud size were highest for the 5% blueberry group, whereas terminal end bud numbers were not affected by all diets. Mammary ductal epithelial cells of the 5% blueberry group had lower nuclear phosphorylated histone 3 and higher nuclear tumor suppressor phosphatase and tensin homolog deleted in chromosome 10 (PTEN) levels than the casein group. Although sera of both diet groups had similar antioxidant capacity, 5% blueberry sera elicited higher nuclear PTEN accumulation in human MCF-10A mammary epithelial cells. Our studies identify developing mammary glands as early targets of blueberry-associated bioactive components, possibly through systemic effects on epithelial PTEN signaling.

Lack of efficacy of blueberry in nutritional prevention of azoxymethane-initiated cancers of rat small intestine and colon.

BACKGROUND: Blueberries may lower relative risk for cancers of the gastrointestinal tract. Previous work indicated an inhibitory effect of consumed blueberry (BB) on formation of aberrant crypt foci (ACF) in colons of male Fisher F344 rats (inbred strain). However, effects of BB on colon tumors and in both genders are unknown. METHODS: We examined efficacy of BB in inhibition of azoxymethane (AOM)-induced colon ACF and intestine tumors in male and female Sprague-Dawley rats (outbred strain). Pregnant rats were fed a diet with or without 10% BB powder; progeny were weaned to the same diet as their dam and received AOM as young adults. RESULTS: Male and female rats on control diet had similar numbers of ACF at 6 weeks after AOM administration. BB increased (P < 0.05) ACF numbers within the distal colon of female but not male rats. There was a significant (P < 0.05) diet by gender interaction with respect to total colon ACF number. Colon and duodenum tumor incidences were less in females than males at 17 weeks after AOM. BB tended (0.1 > P > 0.05) to reduce overall gastrointestinal tract tumor incidence in males, however, tumor incidence in females was unaffected (P > 0.1) by BB. There was a tendency (0.1 > P > 0.05) for fewer adenocarcinomas (relative to total of adenomatous polyps plus adenocarcinomas) in colons of female than male tumor-bearing rats; in small intestine, this gender difference was significant (P < 0.05). BB favored (P < 0.05) fewer adenocarcinomas and more adenomatous polyps (as a proportion of total tumor number) in female rat small intestine. CONCLUSION: Results did not indicate robust cancer-preventive effects of BB. Blueberry influenced ACF occurrence in distal colon and tumor progression in duodenum, in gender-specific fashion. Data indicate the potential for slowing tumor progression (adenomatous polyp to adenocarcinoma) by BB.