Freeze-dried Strawberry Powder Research Articles

Randomized Double-Blind Controlled Trial of Freeze-Dried Strawberry Powder Supplementation in Adults with Overweight or Obesity and Elevated Cholesterol

Objective Recommended dietary patterns improve cardiovascular disease (CVD) risk factors such as blood pressure and LDL-C, as well as emerging markers that confer residual risk. Strawberry consumption has been shown to improve CVD risk factors, but further research is needed to better understand these effects using a dose-response model that evaluates a standard serving and a higher (but still achievable) dose. Methods A randomized, placebo-controlled, double-blinded crossover trial was conducted in middle-aged adults with overweight or obesity (n = 40; mean BMI = 29.4 ± 0.2 kg/m2; mean age = 50 ± 1.0 years) and moderately elevated LDL-C (mean LDL-C: 140 ± 3 mg/dL) to investigate the effect of two doses of strawberry supplementation on LDL-C and other CVD risk factors. Study interventions were: 0 g/d (control), 13 g/d (low-dose), and 40 g/d (high-dose) of freeze-dried strawberry powder (4-week supplementation periods separated by a 2-week compliance break). Results There was a significant main effect of treatment for the primary outcome of LDL-C, with a 4.9% reduction following the low-dose strawberry supplement compared to the high-dose (P = 0.01), but not compared to the control. There was also a significant effect on total cholesterol (TC), with a 2.8% and 2.4% reduction following the low-dose compared to the control and high-dose, respectively (P ≤ 0.05 in post-hoc analyses). There was a near significant effect for direct LDL-C (P = 0.07). There were no significant treatment effects for other atherogenic lipoprotein characteristics, indices of vascular function, measures of inflammation, or HDL efflux. Conclusion Low-dose supplementation with freeze-dried strawberry powder, equivalent to ∼1 serving/day of fresh strawberries, improved cholesterol in adults with overweight or obesity, compared to both the high-dose (∼3 servings/day of fresh strawberries) and control, but did not alter other markers of CVD. Supplemental data for this article is available online at

A Crossover Study of Freeze-Dried Strawberry Powder on Microvascular Function, Gut Microbiota, and Metabolic Phenotype in Overweight or Obese Postmenopausal Women

Abstract Objectives To assess the short-term intake of 39 g freeze-dried strawberry powder (FDSP), compared to an isocaloric control powder, on microvascular function and to determine the relationship with gut microbial composition and select microbial-derived metabolites from feces, serum, and urine. Methods Data were collected from overweight/obese postmenopausal women (n = 21) participating in a 2 × 2 double-blind, placebo-controlled crossover study. Participants consumed FDSP or control, mixed with water, daily for 4 weeks (separated by a 4-week washout). Microvascular function was evaluated as the Framingham reactive hyperemia index (fRHI). Serum, urine, and fecal metabolomics were performed by proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, microbiome analysis was performed by targeting the v4 region of the 16S rRNA gene. Additional measures included anthropometrics, fasting plasma lipids, glucose, and blood pressure, and the urolithin metabotype of study participants was determined by LC-MS. Results Overall, 19 women completed the protocol; with two additional women completing at least one arm of the study. Linear mixed effects modelling revealed no significant intervention effects on the primary endpoint or on other vascular measures. However, significant period effects were observed for fRHI. FDSP significantly increased serum and urine ascorbate concentrations (P < 0.05) and altered the concentration of several other metabolites, including serum acetate, alanine, dimethyl sulfone, and proline, and urine citrate, formate, glycine, alanine, and 3-hydroxybutyrate. Finally, FDSP intake shifted bacterial genera in the gut microbiome, primarily by increasing populations of Faecalibacterium, Dialister, Ruminococcus, and Lachnospira. Conclusions This study demonstrates that although short-term daily intake of FDSP does not appear to influence microvascular function in postmenopausal women with elevated CVD risk, there are measurable shifts in metabolism and the microbiome. Funding Sources This work was funded by a grant awarded by the California Strawberry Commission, and USDA-NIFA Hatch grants awarded to CLK (CA-D-NTR-5908-H) and CMS (project 1,021,411).

Four-Week Strawberry Consumption on Selected (Poly)phenolic Metabolites: A Randomized Controlled Trial in Older Adults With Moderate Hypercholesterolemia

Abstract Objectives Strawberries are a rich source of bioactive (poly)phenols, such as anthocyanins, ellagitannins and proanthocyanidins, which are absorbed and metabolized to various (poly)phenolic metabolites in the human body. Phenolic acids metabolites have been characterized and reported previously. This study aimed to investigate the presence of anthocyanin, urolithin and phenyl-γ-valerolactone metabolites present in circulation after 4-week strawberry consumption in older adults with moderate hypercholesterolemia. Methods This research was performed using blood samples from a randomized, controlled, double-blinded, 2-arm, 2-period (4-week/period) crossover trial. Adults (n = 33, male: female 16:17, age 53 ± 1 years, body mass index 31 ± 1 kg/m2, mean ± SEM) were randomized to 1 of 2 study sequences. Subjects drank study beverages twice-daily containing freeze-dried strawberry powder (2 × 25 g) or energy-, volume-matched control powder for 4 weeks separated by a 4-week washout. Fasting plasma samples after each intervention were quantified for (poly)phenolic metabolites using an ultra-high performance liquid chromatography coupled with triple quadrupole (UHPLC-QQQ). Statistical analysis was performed using PC-SAS. Results Four-week strawberry beverage vs. control beverage intake significantly increased fasting plasma concentrations of pelargonidin 3-O-glucoside (0.2 ± 0.03 nmol/L vs. 0 ± 0 nmol/L, P < 0.0001), pelargonidin glucuronide (3.8 ± 0.9 nmol/L vs. 0 ± 0 nmol/L, P < 0.0001), 8-hydroxy-urolithin-glucuronide (urolithin A-3-glucuronide, 70.1 ± 18.1 nmol/L vs. 0.3 ± 0.3 nmol/L, P = 0.0001), phenyl-γ-valerolactone-glucuronide (4.4 ± 1.1 nmol/L vs. 0 ± 0 nmol/L, P = 0.0001), and hydroxyphenyl-γ-valerolactone-glucuronide (3.5 ± 0.9 nmol/L vs. 1.1 ± 0.4 nmol/L, P = 0.009). Conclusions Strawberry (poly)phenols are absorbed and metabolized and can persist in the circulation with daily intake. The persistent concentration of selected (poly)phenolic metabolites in older adults with moderate hypercholesterolemia warrant further research to determine their potential health benefits. Funding Sources This project was funded by the California Strawberry Commission and various donor funds to the Center for Nutrition Research, Illinois Institute of Technology.

Strawberry Consumption, Cardiometabolic Risk Factors, and Vascular Function: A Randomized Controlled Trial in Adults with Moderate Hypercholesterolemia.

Certain fruits, such as strawberries, may impart cardiometabolic benefits due to their phytochemical content. Study aims were to assess the effects of strawberry intake on cardiometabolic risk factors and vascular endothelial function in adults with moderate hypercholesterolemia. This study was a randomized, controlled, double-blinded, 2-arm, 2-period (4-wk/period) crossover trial. Adults (n=34; male/female 1:1; mean±SEM age, 53±1y; BMI, 31±1kg/m2; LDL cholesterol, 133±3mg/dL)were randomly allocated to 1 of 2 study sequences in a 1:1 ratio. Participants drank study beverages twice daily containing freeze-dried strawberry powder (2× 25 g)orenergy-, volume-matched control powder for 4 wk separated by a 4-wk washout. The primary outcome variable was the difference in fasting LDL cholesterol after 4-wk interventions. Secondary outcomes were metabolic markers, inflammation, quantitative (poly)phenolic metabolomics, flow-mediated dilation (FMD), and blood pressure (BP), with the latter (FMD, BP) also assessed acutely at 1h and 2h after a 50-gbolus strawberry or control beverage. Mixed-model analysis of repeated measures via PROC MIXED, PC-SAS was performed on primary and secondary outcome variables. LDL cholesterol did not differ after the 4-wk interventions (P>0.05), nor did fasting total cholesterol, triglycerides, glucose, insulin, high-sensitivity C-reactive protein, FMD, or BP (all P >0.05). Significant intervention-by-hour interaction for FMD (P=0.03) and BP (P=0.05) revealed increased FMD at 1h after strawberry compared with control by 1.5±0.38%(P=0.0008) and attenuated systolic BP at 2h by 3.1±0.99mmHg(P=0.02). Select phenolic metabolites increased significantly (P<0.05) in blood following strawberry consumption while others decreased, including 3-(4-methoxyphenyl)propanoic acid-3-O-glucuronide, which was significantly correlated with increased FMD (P<0.05). Strawberries may improve vascular health, independent of other metabolic changes. The effect may be related to changes in microbial-derived phenolic metabolites after strawberry consumption influencing endothelial function. Data support inclusion of strawberries in a heart-healthy diet in adults with moderate hypercholesterolemia.This trial was registered at clinicaltrials.gov as NCT02612090.

Effects of strawberries on bone biomarkers in pre- and stage 1-hypertensive postmenopausal women: a secondary analysis.

Postmenopausal women experience an increase in bone remodeling with the rate of bone resorption superseding the rate of bone formation. This results in a net bone loss with a subsequent increased risk for osteoporosis and fractures. High blood pressure (BP) has been associated with loss of bone mineral density and increased propensity to fractures. Strawberries are rich in polyphenols, which have been shown to have anti-hypertensive and bone-protective properties. Thus, we examined whether daily intake of strawberries would positively affect biomarkers of bone metabolism in postmenopausal women with pre- and stage 1-hypertension. Participants (age: 59 ± 6 years; body mass index: 31.5 ± 4.1 kg m-2; systolic BP: 140 ± 13 mmHg) were randomly assigned to consume (1) 50 g of freeze-dried strawberry powder (FDSP), (2) 25 g FDSP + 25 g of placebo powder, or (3) 50 g placebo powder for eight weeks. Results indicate a significant time-by-treatment interaction (P = 0.04) for serum insulin-like growth factor (IGF)-1, a hormone that plays a major role in bone formation. Serum concentrations of bone-specific alkaline phosphatase, a marker of bone formation, and tartrate-resistant acid phosphatase-5b, a specific marker of bone resorption, were not affected by FDSP compared to placebo. Although not statistically significant, after eight weeks, osteocalcin increased in the 50 g FDSP group with a large effect size (d = 0.6) when compared to the placebo-control group. Adiponectin increased by 5% and 6% in the 25 g and 50 g FDSP groups, respectively, while it declined in the placebo-control group by 25% (P = 0.03 for time-by-treatment interaction). Our findings suggest that consumption of 25 g FDSP increases IGF-1 in postmenopausal women with pre- and stage 1-hypertension. However, further studies are needed to assert the effectiveness of a strawberry intervention for bone health.

A Crossover Study of Freeze-Dried Strawberry Powder on Microvascular Function, Gut Microbiota, and Metabolic Phenotype in Overweight or Obese Postmenopausal Women

Abstract Objectives This study assessed the influence of short-term freeze-dried strawberry powder (FDSP) intake on gut microbial composition and select microbial-derived metabolites from feces, serum, and urine, and determine their relationship to microvascular function. Methods In this double-blind, controlled crossover study, postmenopausal overweight or obese women not taking any medications were randomly assigned to consume 39 g FDSP (equivalent to 3 servings fresh strawberries) or an isocaloric control powder mixed in water, daily for 4 weeks, separated by a 4-week washout period. Serum, urine, and fecal metabolomics were performed by proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, microbiome analysis was performed by targeting the v4 region of the 16S rRNA gene. Microvascular function was evaluated as the Framingham reactive hyperemia index (fRHI). Additional measures included anthropometrics, fasting plasma lipids, glucose, and blood pressure. Results Overall, 19 women completed the protocol; with two additional women completing at least one arm of the study. After 4 weeks of FDSP intake, there was a trend toward improved fRHI compared to control (P = 0.069), and a decrease in fasting blood glucose when individuals were stratified according to cardiovascular disease risk (P = 0.049). Further, FDSP intake was associated with a significant increase in propane-1,2-diol, which was negatively correlated with fRHI, as well as the urinary metabolites 1-methylnicotinamide and hypoxanthine. Potential FDSP induced shifts in gut microbial composition will be presented. Conclusions This study confirms previous reports concerning the positive effects of FDSP intake on microvascular function and provides evidence that these changes may be driven in part by changes in metabolism. Funding Sources This work was funded by a grant awarded by the California Strawberry Commission and USDA-NIFA Hatch projects.

Dose-Response Effects of Strawberries on Atherogenic Lipoproteins: A Randomized Controlled Crossover Trial

Abstract Objectives Previous research indicates that consumption of strawberries may provide benefits for reduction of atherogenic lipoproteins but has not identified an optimal dose. Our objective was to evaluate effects of 2 doses of strawberry powder, approximately equivalent to 1 and 3 servings of strawberries per day, on serum lipoprotein concentrations. Methods Middle-aged adults (n = 40, age 49 ± 1 year) with elevated LDL-C (140 ± 4 mg/dL) and elevated BMI (29.4 ± 0.4 kg/m2) consumed 0 g/d (control), 13 g/d (low-dose), and 40 g/d (high-dose) of freeze-dried strawberry powder in a randomized crossover design (4-week supplementation periods separated by a 2 week compliance break). Fasting blood samples were obtained on two separate days (and averaged) at study-entry baseline and following each supplementation period. Results There were significant main effects of treatment (P ≤ 0.05) for calculated LDL-C, nonHDL-C, and total cholesterol (TC). In post hoc tests, the low-dose resulted in 5% lower LDL-C vs. the high-dose (P = 0.01), 4% lower nonHDL-C vs. control (P = 0.04), and 3% lower TC for the low-dose vs. control and high-dose (P ≤ 0.04). Compared to baseline, low-dose strawberry supplementation also significantly reduced direct LDL-C (−6.8 mg/dL, P = 0.02), but there was not a main effect of treatment. Conclusions Our results suggest that low-dose supplementation with freeze dried strawberry powder, roughly equivalent to one serving of strawberries per day, was superior to high-dose supplementation for improving atherogenic lipoproteins in overweight adults. Funding Sources California Strawberry Commission.

Effects of Daily Strawberry Intake (4 weeks) on Plasma Bile Acid Composition in Humans: A Randomized, Placebo-Controlled, Crossover Trial

Abstract Objectives Bile acids (BA) are liver derived compounds that undergo host and microbial metabolism. BA metabolites have multiple physiological roles including maintaining intestinal immune homeostasis. Dietary components influence BA metabolism/excretion through several mechanisms. This study aimed to evaluate the effects of daily strawberry intake (4 weeks) on bile acid metabolism in humans. Methods Thirty overweight/obese adults (age: 53 ± 7 years, BMI: 31 ± 4 kg/m,2) were recruited for this randomized, double-blind, placebo-controlled, crossover trial. Participants were randomized to 1 of 2 study sequences in a 1:1 ratio with 4 weeks washout period between two treatments. Participants consumed a strawberry beverage containing 25 g freeze-dried strawberry powder (∼1.75 servings of fresh strawberries) or energy-matched control beverage in random order twice a day for 4 weeks. Fasting blood samples were collected at weeks 0, 4, 8, and 12. Plasma samples (500 μL) were extracted using solid-phase C18 cartridges. An ultra-high performance liquid chromatography tandem mass spectrometry method was developed to quantitate bile acids and their metabolites (sulfates, glucuronides) in plasma. The method was validated in terms of linearity, sensitivity, recovery, and matrix effect. The data were analyzed using a paired student t-test with statistical significance set at P &amp;lt; 0.05. Results Twenty-nine glucuronidated and sulfated BAs were identified in plasma samples. Concentrations of primary BAs were not affected between the study treatments, whereas a significant decrease (P &amp;lt; 0.05) was observed in total secondary BAs (52 compounds) after 4 weeks of strawberry intake (11.2 ± 1.1 µmol/L) compared to placebo (18.3 ± 3.2 µmol/L). Individual secondary BAs including lithocholic acid (LCA), sulfo-glycolithocholic acid, and C24 oxidized LCA were significantly decreased after 4-week strawberry intake compared to placebo (P &amp;lt; 0.05). Conclusions Our results indicate that regular strawberry intake could lower pro-inflammatory LCA and other secondary BAs, suggesting a potential role of strawberry in ameliorating colonic inflammation and promoting gut health. Funding Sources This work was funded by the California Strawberry Commission and various donor funds to the Center for Nutrition Research, IIT.

Effects of Acute Dietary Polyphenols and Post-Meal Physical Activity on Postprandial Metabolism in Adults with Features of the Metabolic Syndrome.

Approximately 22% of U.S. adults and 25% of adults globally have metabolic syndrome (MetS). Key features, such as dysglycemia and dyslipidemia, predict type 2 diabetes, cardiovascular disease, premature disability, and death. Acute supplementation of dietary polyphenols and post-meal physical activity hold promise in improving postprandial dysmetabolism. To our knowledge, no published review has described the effects of either intervention on postprandial glucose, insulin, lipids, and markers of oxidative damage and inflammation in adults with features of MetS. Thus, we conducted this review of controlled clinical trials that provided dietary polyphenols from oils, fruits, teas, and legumes during a dietary challenge, or implemented walking, cycling, and stair climbing and descending after a dietary challenge. Clinical trials were identified using ClinicalTrials.gov, PubMed, and Google Scholar and were published between 2000 and 2019. Dietary polyphenols from extra virgin olive oil, grapes, blackcurrants, strawberries, black tea, and black beans improved postprandial glucose, insulin, and markers of oxidative damage and inflammation, but results were not consistent among clinical trials. Freeze-dried strawberry powder distinctly improved postprandial insulin and markers of oxidative damage and inflammation. Post-meal physical activity attenuated postprandial glucose, but effects on postprandial lipids and markers of oxidative damage and inflammation were inconclusive. Consuming dietary polyphenols with a meal and completing physical activity after a meal may mitigate postprandial dysmetabolism in adults with features of MetS.

Functionality of strawberry powder on frozen dairy desserts.

This study investigated the potential use of freeze-dried strawberry powder as a stabilizer in frozen dairy desserts. Five different dessert mixes were developed that contained 0%, 2.5%, 3%, 3.5%, and 4% strawberry powder. An additional dessert using strawberry extract was prepared to differentiate the effects of dietary fiber from the effect of polyphenols on sample properties. The rheological and physical characteristics of dessert mixes, fresh dessert, and stored dessert were studied. The addition of strawberry powder to dairy desserts caused an increase in the mix viscosity and a decrease in hardness and meltdown values. Complete avoidance of meltdown was achieved with the addition of 3% or greater amount of strawberry powder. The viscosity of mixes was enhanced due to the increase of total solids in the serum phase and the formation of hydrated and gel-like networks in the presence of cellulosic material, pectin, and calcium. The increase in viscosity and unfrozen water with the addition of strawberry powder also caused a reduction in ice crystallization, which resulted in softer and more stable desserts over time.

Effect of Strawberry Intake for 4 Weeks on Vascular Endothelial Function and Blood Pressure in Adults with Moderate Hypercholesterolemia (P06-128-19)

ObjectivesThe aim of this study is to investigate the effect of chronic strawberry intake on cardiovascular risk factors including fasting lipids concentrations, vascular endothelial function and blood pressure in middle-age overweight or obese individuals with moderate hypercholesterolemia. We hypothesized that 4-week strawberry intake would improve the lipids profile and concomitantly improve measures of vascular function. MethodsIn this randomized, double-blinded, controlled, crossover trial, thirty-four subjects (age 53 ± 1 years, BMI 31 ± 1 kg m-2, mean ± SD) consumed a strawberry beverage containing 25 gram freeze-dried strawberry powder or energy-matched control beverage in random order twice a day for 4 weeks. Treatment periods were separated by 4-week washout period. Fasting lipids, glucose, insulin, high sensitive c-reactive protein (hs-CRP), and postprandial flow-mediated dilation (FMD) and blood pressure, were measured at weeks 0, 4, 8 and 12. ResultsFasting lipids, glucose, insulin, and hs-CRP did not differ between strawberry and control beverage interventions. In contrast, vascular function as measured by change in %FMD was significantly increased after strawberry compared to control after 4 weeks supplementation (4.3 ± 0.3% versus 3.6 ± 0.3%, respectively, p = 0.0096). In addition, %FMD was acutely increased from 0 to 1 hour after consuming strawberry beverage (p < 0.0001), which was consistent with reduced meal-induced increases in systolic blood pressure (SBP) postmeal (mean 2 hour changes in SBP after strawberry compared to control beverage, 2.3 ± 0.4 versus 3.4 ± 0.4 mmHg, p = 0.048). ConclusionsDaily intake of strawberries may improve endothelial function and acute changes in blood pressure, independent of other metabolic changes, and may be considered a specific food/fruit to include in a heart-healthy diet in overweight or obese subjects with moderate hypercholesterolemia. Funding SourcesCalifornia Strawberry Commission, Watsonville, CA, USA. Supporting Tables, Images and/or Graphs▪

Incorporating freeze-dried strawberry powder into a high-fat meal does not alter postprandial vascular function or blood markers of cardiovascular disease risk: a randomized controlled trial1–3

Postprandial dysmetabolism-an exaggerated spike in triglycerides, glucose, and insulin-increases cardiovascular disease risk by inducing oxidative stress, inflammation, and endothelial dysfunction. Polyphenol-rich foods may blunt these effects when they are incorporated into a high-fat, calorie-dense meal. Strawberries are a rich source of polyphenols, but there is little research on their postprandial effects. This study was designed to investigate the effect of adding 40 g freeze-dried strawberry powder (∼1 lb. or 0.45 kg fresh strawberries) to a high-fat (50 g total fat) meal on postprandial vascular function, as well as triglyceride, glucose, and insulin responses. Healthy, overweight or obese [mean ± SEM body mass index (in kg/m2): 31 ± 0.5] adults (mean ± SEM age: 28 ± 2 y; 17 men and 13 women) consumed a control meal and a strawberry meal in a randomized crossover design. Testing sessions were separated by ≥1 wk for men and ∼1 mo for women to control for hormonal variations. Blood samples were obtained before the meal and 0.5, 1, 2, and 4 h after the meal. Central blood pressure and arterial stiffness indexes were measured at baseline and 2 and 4 h postmeal with the use of pulse waveform analysis. There were no significant differences between the strawberry and control meals for any outcomes. Consumption of either meal significantly decreased the augmentation index at 2 and 4 h (P < 0.002) and significantly increased triglycerides, insulin, and glucose at all time points (P < 0.001) relative to baseline. The strawberry intervention did not alter vascular function or attenuate postprandial metabolic derangements in triglycerides, glucose, or insulin relative to the control meal. Additional research is needed to clarify whether strawberries or other polyphenol-rich interventions improve postprandial responses, and future studies should take into account the acute meal-induced improvements in measures of vascular function. This trial was registered at clinicaltrials.gov as NCT01989637.

Effects of a dietary strawberry powder on parameters of vascular health in adolescent males.

Previous studies have shown that the intake of freeze-dried strawberry powder (FDSP) improves select markers of cardiovascular health in adults with cardiovascular risk factors; however, whether these improvements can be observed in at-risk adolescents is unknown. A randomised, double-blind, cross-over study enrolled twenty-five overweight or obese males, aged 14-18 years, to consume 50 g of a FDSP or a control powder, daily for 1 week. Before and after each test period, measures of microvascular function, plasma nitrate/nitrite, platelet reactivity and blood lipids were collected at baseline and acutely 1 h after FDSP intake. Acute plasma nitrate/nitrite levels increased 1 h after consuming the FDSP during Study Visit 1 before daily FDSP intake (P<0·001) and during Study Visit 2 after 1 week of FDSP intake (P<0·001) compared with control powder intake. As a group, fasting nitrate/nitrite levels did not significantly change after 1 week of control or FDSP intake. However, for those individuals where fasting nitrate levels increased after short-term FDSP intake compared with controls, an increase in reactive hyperaemia index (RHI) was observed (P=0·014), whereas RHI was unchanged in those individuals who did not have a significant increase in nitrate (P=0·396). Taken together, these data support the concept that strawberries can provide vascular health benefits to heavier adolescent males.

Effects of a Dietary Strawberry Powder on Parameters of Vascular Health in Adolescent Males

Previous studies have shown that the intake of freeze‐dried strawberry powder (FDSP) improves select markers of cardiovascular health in at risk individuals; whether these improvements can be observed in adolescents is unknown. A randomized, double‐blind, crossover study enrolled 25 overweight or obese males, ages 14–18 years, to consume 50g of FDSP or an isocaloric control powder, daily for 1 week. Before and after each test period, measures of microvascular function, plasma nitrate/nitrite, and platelet reactivity were collected at baseline and 1 hour after FDSP intake. After 1 week of FDSP intake, an acute increase in the Framingham reactive hyperemia index (fRHI) was observed (p &lt; 0.03). Plasma nitrate/nitrite levels significantly increased 1 hour after consuming the FDSP on the first study day prior to daily FDSP intake (p &lt; 0.001) and during the second visit after one week of FDSP intake (p &lt; 0.001). This increase in plasma nitrate levels was not observed with control powder intake. Taken together, the data from the present study supports the concept that strawberries can provide vascular health benefits to overweight and obese adolescent males.Support or Funding InformationResearch funding was provided in part by the California Strawberry Commission; USDA NIFA National Needs Graduate Fellowship (Djurica); and Agriculture and Food Research Initiative Competitive Grant (Holt).

Effects of Strawberry Consumption on Vascular Parameters in Pre‐ and Stage 1‐Hypertensive Postmenopausal Women: A Randomized, Double‐Blind, Placebo‐Controlled Trial

Though previous clinical, epidemiological, and preclinical research findings indicate that strawberries are cardioprotective, few clinical studies have reported the effects of strawberry consumption on blood pressure (BP) and vascular function. Since hypertension is a major modifiable risk factor for cardiovascular diseases and approximately 75% of postmenopausal women in the United States are hypertensive, we conducted an 8‐week randomized, double‐blind, placebo‐controlled clinical study to investigate the effects of daily consumption of 25 g of freeze‐dried strawberry powder (FDSP) on blood pressure and vascular function in pre‐ and stage 1‐hypertensive postmenopausal women. Forty‐seven postmenopausal women (age: 59 ± 6 years; body mass index: 31.5 ± 4.1 kg/m2, systolic BP: 140 ± 13 mmHg, diastolic BP: 80 ± 7 mmHg) were randomly assigned into one of two groups (final n = 20/group): 1) placebo‐control, 2) 25g of freeze‐dried strawberry powder (FDSP; equivalent to 1½ cups). After eight weeks, systolic BP (135 ± 14 mmHg), mean arterial pressure (103 ± 9 mmHg), pulse pressure (56 ± 10 mmHg), and baPWV and faPWV (1,480 cm/s and 1,039 cm/s, respectively) were significantly (P &lt; 0.05) lower than baseline levels in the strawberry group while only pulse pressure was significantly lower (P &lt; 0.05) in the placebo group (54 ± 7 mmHg). These findings suggest that daily consumption of strawberries may improve vascular function; however, further research is warranted.Support or Funding InformationThis study was funded by the California Strawberry Commission.

Effects of freeze-dried Fragaria x ananassa powder on alloxan-induced diabetic complications in Wistar rats

Abstract Objectives Strawberries contain antioxidant phytochemicals, which have been shown to beneficial against inflammation, cardiovascular disease, cancer, obesity, neurodegeneration, hyperglycaemia and associated diabetic complications. Freeze-dried strawberry powder (FSP) is effective in controlling metabolic syndrome and cardiovascular risk factors. The present investigation was designed to evaluate the effect of FSP on alloxan-induced diabetes in rats. Methods Diabetes was induced in male Wistar albino rats by intraperitoneal injection of alloxan monohydrate (150 mg/kg bw), and treatment with FSP (700 mg/day for 45 days) was started 48 h after alloxan injection. Blood glucose, insulin, C-peptide, haemoglobin, renal function markers (urea, uric acid and creatinine) and enzyme markers (aspartate and alanine transaminases and alkaline phosphatase) were assayed with suitable methods. Results Animals given alloxan had significant body weight loss, poor glucose tolerance and increased blood glucose with concomitant decreases in insulin, C-peptide and haemoglobin values, and significant (p Conclusions FSP can revert alloxan-induced diabetes and its complications. The antioxidant properties of the fruit probably play a major role in the observed changes.

Flavonoid-rich beverage effects on lipid profile and blood pressure in diabetic patients.

To compare freeze-dried strawberry (FDS) beverage and strawberry-flavored drink effects on lipid profile and blood pressure in type 2 diabetic (T2D) patients. In a randomized, double-blind, controlled trial, 36 subjects with T2D (23 females; mean ± SE age: 51.57 ± 10 years) were randomly divided into two groups. Participants consumed two cups of either pure FDS beverage (each cup containing 25 g freeze-dried strawberry powder equivalent to one serving of fresh strawberries; intervention group) or an iso-caloric drink with strawberry flavoring (similar to the FDS drink in fiber content and color; placebo group) daily for 6 wk. Anthropometric measurements, 3 d, 24 h dietary recall, and fasting blood samples were collected at baseline and at weeks 6 intervention. After lying down and relaxing for approximately 10 min, each participant's blood pressure was recorded in triplicate with 5 min intervals; recordings were made at baseline and the trial end-point. Each participant's lipid profile was assessed before and after intervention. Assessment at the weeks 6 intervention showed a significant reduction from baseline in total cholesterol levels and total cholesterol to high-density lipoprotein cholesterol (HDL-C) ratio in the intervention group (179.01 ± 31.86 to 165.9 ± 32.4 mg/L; P = 0.00 and 3.9 ± 0.88 to 3.6 ± 0.082 mg/L; P = 0.00 respectively), but the change was not significantly different between the two groups (P = 0.07, P = 0.29 respectively). Systolic blood pressure levels were significantly reduced from baseline in both the FDS and placebo drink groups (129.95 ± 14.9 to 114.3 ± 27.5 mmHg; P = 0.02 and 127.6 ± 15.6 to 122.9 ± 14.47 mmHg; P = 0.00 respectively), but the reduction was not significantly different between the two groups. Diastolic blood pressure was significantly reduced post-intervention in the FDS drink group compared to placebo group (78.7 ± 7.2 vs 84.4 ± 5.8; P = 0.01), the reduction was also significant within the FDS drink group (84.2 ± 8.03 to 78.7 ± 7.2; P = 0.00). Triglycerides, HDL-C concentrations and anthropometric indices showed no significant differences between or within groups. Short-term FDS supplementation improved selected cardiovascular risk factors in subjects with T2D. Long-term effects on other metabolic biomarkers need to be investigated in future trials.

Dietary strawberries increase the proliferative response of CD3/CD28-activated CD8+ T cells and the production of TNF-α in lipopolysaccharide-stimulated monocytes from obese human subjects

Obesity increases the risk of developing bacterial and viral infections compared with normal weight. In a 7-week double-blind, randomised, cross-over trial, twenty obese volunteers (BMI between 30 and 40 kg/m²) were fed freeze-dried strawberry powder or strawberry-flavoured placebo preparations to determine the effects of dietary strawberries on immune function. Blood was collected at six time points during the study and peripheral blood mononuclear cells (PBMC) were isolated at each time point and activated with CD3 plus CD28 antibodies (T-lymphocyte activation) or lipopolysaccharide (LPS, monocyte activation). Interferon-γ, TNF-α, IL-4 and IL-10 were measured in supernatants from the activated T cells. Supernatants from the activated monocytes were analysed for the production of TNF-α, IL-1β, IL-6 and IL-8. PBMC were pre-stained with PKH (Paul Karl Horan) dye and activated with CD3 plus CD28 antibodies to determine the proliferative responses of CD4⁺ and CD8⁺ T-lymphocytes by flow cytometry. To detect global changes in gene expression, microarray analysis was performed on LPS- and vehicle-treated PBMC from two subjects before and after the strawberry intervention. No difference was observed for the production of T-cell cytokines between the intervention groups. The production of TNF-α was increased in the supernatants from LPS-activated PBMC in the group consuming strawberries compared with the placebo. A modest increase in the proliferation of the CD8⁺ T-lymphocyte population was observed at 24 h post-activation. These data suggest that dietary strawberries may increase the immunological response of T-lymphocytes and monocytes in obese people who are at greater risk for developing infections.

A pilot study to investigate bioavailability of strawberry anthocyanins and characterize postprandial plasma polyphenols absorption patterns by Q-TOF LC/MS in humans

BACKGROUND: Information on absorption and metabolism of strawberry polyphenols is limited. OBJECTIVE: The aim of this study was to characterize and quantify plasma polyphenols/anthocyanins across 4 doses of strawberry using Q-TOF LC/MS and LC-MS/MS analysis. METHOD: Plasma was collected from 5 subjects (n = 5) every 30–60 min for 6 h after consuming beverages containing 0, 10, 20 or 40 g freeze-dried strawberry powder with a meal. RESULTS: Q-TOF LC/MS and LC-MS/MS analysis of plasma revealed 33 compounds; 7 not reported previously. Pelargonidin-O-glucuronide (PG) was the most abundant metabolite. Maximum concentrations (Cmax) of PG were achieved at 148 ± 31 min and were significantly different among beverages containing 0, 10, 20, 40 g strawberry powder: 0, 93.4 ± 21.9, 166.5 ± 16.2 and 226.7 ± 36.7 nmol/L, respectively (P < 0.05). Area under the concentration curve (AUC) also increased with dose (P < 0.05); however, Cmax and AUC of PG was reduced as a percent of pelargonidin-3-O-glucoside (P3G) delivered in the strawberry beverages (P < 0.05). CONCLUSION: Use of both Q-TOF LC/MS and LC-MS/MS allowed for detection of compounds in plasma not previously reported, which may be a useful approach for characterizing postprandial plasma metabolites of lesser known plant foods. Additionally, higher concentrations of key strawberry compounds/metabolites are achieved with eating more strawberry; however, saturation of absorptive capacity of pelargonidin-based anthocyanins was suggested.

Dietary strawberry powder reduces blood glucose concentrations in obese and lean C57BL/6 mice, and selectively lowers plasma C-reactive protein in lean mice

The purpose of the present study was to test the anti-inflammatory and blood glucose (BG)-regulating capacity of strawberries in a mouse model of diet-induced obesity. A total of thirty-six male C57BL/6J mice were randomly divided into four groups (nine mice per group). Mice were fed a low-fat diet (LF, 13 % fat), the LF supplemented with 2·6 % freeze-dried strawberry powder (LFSB), a high-fat diet (HF, 44 % fat) or the HF supplemented with 2·6 % strawberry powder (HFSB). Blood samples were collected to measure BG, inflammation and systemic markers for endocrine function of pancreas and adipose tissue. Splenocytes were harvested at the end of the study and activated with either anti-cluster of differentiation (CD) 3/anti-CD28 antibodies or lipopolysaccharide to test immune responsiveness. The HF increased non-fasted BG, insulin, soluble intracellular adhesion molecule-1, E-selectin, leptin, resistin and plasminogen activator protein-1 (P < 0·05). High dietary fat decreased IL-4 production from activated splenocytes (P < 0·05). BG concentrations were lower in the mice supplemented with SB (10·64 mmol/l) compared to the non-supplemented mice (11·37 mmol/l; P = 0·0022). BG values were approximately 6·5 % lower in the supplemented mice. Additionally, SB lowered plasma C-reactive protein in the LFSB group compared to the other three groups (P < 0·05). The dietary intake of SB approximated one human serving of strawberries. These results, although modest, support a promising role for dietary strawberries in reducing the risks associated with obesity and diabetes, and regulating the levels of inflammatory markers in non-obese individuals.