Gail Thames

Pomegranate juice and extracts provide similar levels of plasma and urinary ellagitannin metabolites in human subjects.

Pomegranate juice (PJ), a rich source of polyphenols including ellagitannins, has attracted much attention due to its reported health benefits. This has resulted in the consumption of liquid and powder pomegranate extracts as alternatives to PJ. Therefore establishing the bioavailability of polyphenols from these extract preparations is necessary. Sixteen healthy volunteers sequentially consumed, with a 1-week washout period between treatments, PJ (8 ounces, Wonderful fruit variety), a pomegranate polyphenol liquid extract (POMxl, 8 ounces), and a pomegranate polyphenol powder extract (POMxp, 1,000 mg). The three interventions provided 857, 776, and 755 mg of polyphenols as gallic acid equivalents, respectively. Plasma bioavailability, judged based on ellagic acid levels over a 6-hour period, did not show statistical differences in area under the curve for the three interventions: 0.14 +/- 0.05, 0.11 +/- 0.03, and 0.11 +/- 0.04 micromol . hour/L for PJ, POMxl, and POMxp, respectively. The time of maximum concentration was delayed for POMxp (2.58 +/- 0.42 hours) compared to PJ (0.65 +/- 0.23 hours) and POMxl (0.94 +/- 0.06 hours). Urolithin-A glucuronide, a urinary metabolite of ellagic acid, was not significantly different with the three interventions, reaching levels of approximately 1,000 ng/mL. This study demonstrates that ellagitannin metabolites, delivered from pomegranate fruits, as PJ, POMxl, and POMxp, reach equivalent levels with a delay in time of maximum concentration of POMxp compared to PJ and POMxl.

Pistachio Nuts Reduce Triglycerides and Body Weight by Comparison to Refined Carbohydrate Snack in Obese Subjects on a 12-Week Weight Loss Program

Objective: There is a widely held view that, due to high fat content, snacking on nuts will lead to weight gain, ultimately causing unhealthy changes in lipid profiles. This study is designed to study the effects of pistachio snack consumption on body weight and lipid levels in obese participants under real-world conditions. Methods: Participants were randomly assigned to consume 1 of 2 isocaloric weight reduction diets for 12 weeks, with each providing 500 cal per day less than resting metabolic rate. Each diet included an afternoon snack of either 53 g (240 cal) of salted pistachios (n  =  31) or 56 g of salted pretzels (220 cal; n  =  28). Results: Both groups lost weight during the 12-week study (time trend, p < 0.001), but there were significant differences in the changes in body mass index between the pretzel and pistachio groups (pistachio, 30.1 ± 0.4 to 28.8 ± 0.4 vs. pretzel, 30.9 ± 0.4 to 30.3 ± 0.5). At 6 and 12 weeks, triglycerides were significantly lower in the pistachio group compared with the pretzel group (88.04 ± 9.80 mg/dL vs. 144.56 ± 18.86 mg/dL, p  =  0.01 at 6 weeks and 88.10 ± 6.78 mg/dL vs. 132.15 ± 16.76 mg/dL, p  =  0.02 at 12 weeks), and there was a time trend difference between the 2 groups over the 12 weeks (p < 0.01). There were no significant differences in total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, insulin, or glucose between the 2 groups. Conclusion: Pistachios can be consumed as a portion-controlled snack for individuals restricting calories to lose weight without concern that pistachios will cause weight gain. By comparison to refined carbohydrate snacks such as pretzels, pistachios may have beneficial effects on triglycerides as well.

A controlled trial of protein enrichment of meal replacements for weight reduction with retention of lean body mass

BackgroundWhile high protein diets have been shown to improve satiety and retention of lean body mass (LBM), this study was designed to determine effects of a protein-enriched meal replacement (MR) on weight loss and LBM retention by comparison to an isocaloric carbohydrate-enriched MR within customized diet plans utilizing MR to achieve high protein or standard protein intakes.MethodsSingle blind, placebo-controlled, randomized outpatient weight loss trial in 100 obese men and women comparing two isocaloric meal plans utilizing a standard MR to which was added supplementary protein or carbohydrate powder. MR was used twice daily (one meal, one snack). One additional meal was included in the meal plan designed to achieve individualized protein intakes of either 1) 2.2 g protein/kg of LBM per day [high protein diet (HP)] or 2) 1.1 g protein/kg LBM/day standard protein diet (SP). LBM was determined using bioelectrical impedance analysis (BIA). Body weight, body composition, and lipid profiles were measured at baseline and 12 weeks.ResultsEighty-five subjects completed the study. Both HP and SP MR were well tolerated, with no adverse effects. There were no differences in weight loss at 12 weeks (-4.19 ± 0.5 kg for HP group and -3.72 ± 0.7 kg for SP group, p > 0.1). Subjects in the HP group lost significantly more fat weight than the SP group (HP = -1.65 ± 0.63 kg; SP = -0.64 ± 0.79 kg, P = 0.05) as estimated by BIA. There were no significant differences in lipids nor fasting blood glucose between groups, but within the HP group a significant decrease in cholesterol and LDL cholesterol was noted at 12 weeks. This was not seen in the SP group.ConclusionHigher protein MR within a higher protein diet resulted in similar overall weight loss as the standard protein MR plan over 12 weeks. However, there was significantly more fat loss in the HP group but no significant difference in lean body mass. In this trial, subject compliance with both the standard and protein-enriched MR strategy for weight loss may have obscured any effect of increased protein on weight loss demonstrated in prior weight loss studies using whole food diets.

Strawberry Consumption Is Associated with Increased Antioxidant Capacity in Serum

Strawberries are known to contain antioxidants, but the significance of ingesting antioxidant-rich fruits remains to be established. In order to determine whether the consumption of strawberries impacted measures of in vivo antioxidant capacity, frozen strawberries (250 g) were administered daily for 3 weeks to 21 healthy female volunteers. Compliance was confirmed by quantitating pelargonidin-glucuronide, urolithin A-glucuronide, and 2,5-dimethyl-4-hydroxy-3-[(2)H]furanone-glucuronide in plasma and urine by liquid chromatography-mass spectrometry and antioxidant capacity in serum measured by the increase in lag phase of low-density lipoprotein after copper sulfate exposure, DNA strand breaks in lymphocytes, and activity of phase II enzymes. Among these measures lipid peroxidation lag time increased by 20% (P < .01), whereas other measures did not change significantly. The potent antioxidant defenses in humans make determination of changes due to dietary ingestion in healthy individuals difficult. In summary, daily consumption of strawberries resulted in a modest but significant increase in antioxidant capacity in a healthy population.

Antioxidant-rich spice added to hamburger meat during cooking results in reduced meat, plasma, and urine malondialdehyde concentrations

Background: Emerging science has shown the effect of oxidation products and inflammation on atherogenesis and carcinogenesis. Cooking hamburger meat can promote the formation of malondialdehyde that can be absorbed after ingestion. Objective:We studied the effect of an antioxidant spice mixture on malondialdehyde formation while cooking hamburger meat and its effects on plasma and urinary malondialdehyde concentrations. Design: Eleven healthy volunteers consumed 2 kinds of burgers in a randomized order: one burger was seasoned with a spice blend, and one burger was not seasoned with the spice blend. The production of malondialdehyde in burgers and malondialdehyde concentrations in plasma and urine after ingestion were measured by HPLC. Results:Rosmarinic acid from oregano was monitored to assess the effect of cooking on spice antioxidant content. Forty percent (19 mg) of the added rosmarinic acid remained in the spiced burger (SB) after cooking. There was a 71% reduction in the malondialdehyde concentration (mean ± SD: 0.52 ± 0.02 μmol/250 g) in the meat of the SBs compared with the malondialdehyde concentration (1.79 ± 0.17 μmol/250 g) in the meat of the control burgers (CBs). The plasma malondialdehyde concentration increased significantly in the CB group as a change from baseline (P = 0.026). There was a significant time-trend difference (P = 0.013) between the 2 groups. Urinary malondialdehyde concentrations (μmol/g creatinine) decreased by 49% (P = 0.021) in subjects consuming the SBs compared with subjects consuming the CBs. Conclusions: The overall effect of adding the spice mixture to hamburger meat before cooking was a reduction in malondialdehyde concentrations in the meat, plasma, and urine after ingestion. Therefore, cooking hamburgers with a polyphenol-rich spice mixture can significantly decrease the concentration of malondialdehyde, which suggests potential health benefits for atherogenesis and carcinogenesis. This trial was registered at clinical trials.gov as NCT01027052.

Protein-enriched meal replacements do not adversely affect liver, kidney or bone density: an outpatient randomized controlled trial

BackgroundThere is concern that recommending protein-enriched meal replacements as part of a weight management program could lead to changes in biomarkers of liver or renal function and reductions in bone density. This study was designed as a placebo-controlled clinical trial utilizing two isocaloric meal plans utilizing either a high protein-enriched (HP) or a standard protein (SP) meal replacement in an outpatient weight loss program.Subjects/methods100 obese men and women over 30 years of age with a body mass index (BMI) between 27 to 40 kg/m2 were randomized to one of two isocaloric weight loss meal plans 1). HP group: providing 2.2 g protein/kg of lean body mass (LBM)/day or 2). SP group: providing 1.1 g protein/kg LBM/day. Meal replacement (MR) was used twice daily (one meal, one snack) for 3 months and then once a day for 9 months. Body weight, lipid profiles, liver function, renal function and bone density were measured at baseline and 12 months.ResultsSeventy subjects completed the study. Both groups lost weight (HP -4.29 ± 5.90 kg vs. SP -4.66 ± 6.91 kg, p < 0.01) and there was no difference in weight loss observed between the groups at one year. There was no significant change noted in liver function [AST (HP -2.07 ± 10.32 U/L, p = 0.28; SP 0.27 ± 6.67 U/L, p = 0.820), ALT (HP -1.03 ± 10.08 U/L, p = 0.34; SP -2.6 ± 12.51 U/L, p = 0.24), bilirubin (HP 0.007 ± 0.33, U/L, p = 0.91; SP 0.07 ± 0.24 U/L, p = 0.120), alkaline phosphatase (HP 2.00 ± 9.07 U/L, p = 0.240; SP -2.12 ± 11.01 U/L, p = 0.280)], renal function [serum creatinine (HP 0.31 ± 1.89 mg/dL, p = 0.380; SP -0.05 ± 0.15 mg/dL, p = 0.060), urea nitrogen (HP 1.33 ± 4.68 mg/dL, p = 0.130; SP -0.24 ± 3.03 mg/dL, p = 0.650), 24 hour urine creatinine clearance (HP -0.02 ± 0.16 mL/min, p = 0.480; SP 1.18 ± 7.53 mL/min, p = 0.400), and calcium excretion (HP -0.41 ± 9.48 mg/24 hours, p = 0.830; SP -0.007 ± 6.76 mg/24 hours, p = 0.990)] or in bone mineral density by DEXA (HP 0.04 ± 0.19 g/cm2, p = 0.210; SP -0.03 ± 0.17 g/cm2, p = 0.320) in either group over one year.ConclusionsThese studies demonstrate that protein-enriched meals replacements as compared to standard meal replacements recommended for weight management do not have adverse effects on routine measures of liver function, renal function or bone density at one year. Clinicaltrial.gov: NCT01030354.

Health benefit of vegetable/fruit juice-based diet: Role of microbiome

The gut microbiota is an important contributor to human health. Vegetable/fruit juices provide polyphenols, oligosaccharides, fiber and nitrate (beet juice), which may induce a prebiotic-like effect. Juice-based diets are becoming popular. However, there is a lack of scientific evidence of their health benefits. It was our hypothesis that changes in the intestinal microbiota induced by a juice-based diet play an important role in their health benefits. Twenty healthy adults consumed only vegetable/fruit juices for 3 days followed by 14 days of customary diet. On day 4 we observed a significant decrease in weight and body mass index (p = 2.0E−05), which was maintained until day 17 (p = 3.0E−04). On day 4 the proportion of the phylum Firmicutes and Proteobacteria in stool was significantly decreased and Bacteroidetes and Cyanobacteria was increased compared to baseline and was partially reversed on day 17. On day 4 plasma and urine nitric oxide was increased by 244 ± 89% and 450 ± 360%, respectively, and urinary lipid peroxidation marker malondialdehyde was decreased by 32 ± 21% compared to baseline. General well-being score was increased at the end of the study. In summary a 3-day juice-based diet altered the intestinal microbiota associated with weight loss, increase in the vasodilator NO, and decrease in lipid oxidation.

Decrease of postprandial endothelial dysfunction by spice mix added to high-fat hamburger meat in men with Type 2 diabetes mellitus

Consumption of a high‐fat diet has been demonstrated to promote endothelial dysfunction, possibly through an increase in lipid peroxidation and decrease in serum nitric oxide. The present study was designed to investigate whether consumption of a hamburger cooked with a polyphenol‐rich spice mixture will reduce postprandial lipid oxidation and endothelial dysfunction in men with Type 2 diabetes.

Soy protein isolate does not affect ellagitannin bioavailability and urolithin formation when mixed with pomegranate juice in humans.

We investigated the effect of mixing soy protein isolate and pomegranate juice (PJ) on the bioavailability and metabolism of ellagitannins (ETs) in healthy volunteers. Eighteen healthy volunteers consumed PJ alone or PJ premixed with soy protein isolate (PJSP). The concentration of plasma ellagic acid (EA) and urine urolithins was measured. There was no significant difference in plasma EA over a 6-h period between the two interventions. While the maximum concentration of plasma EA after PJSP consumption was slightly but significantly lower than after PJ consumption, EA remained in the plasma longer with an elimination half-life t1/2E at 1.36±0.59 versus 1.06±0.47h for PJSP and PJ consumption, respectively. Urinary urolithin A, B and C was not significantly different between the two interventions. In conclusion, premixing soy protein isolate and PJ did not affect the bioavailability or the metabolism of pomegranate ETs in healthy volunteers.