Nutrition Research

Isoflavone supplementation reduces DNA oxidative damage and increases O-β-N-acetyl-d-glucosaminidase activity in healthy women

2012-04-25

Abstract: Phenolic compounds are believed to boost the human antioxidant defense system and health; therefore, the aim of this research was to investigate the hypothesis that soy isoflavones (IFs) provide antioxidant protection in healthy women by evaluating DNA resistance to oxidative damage and O-β-N-acetyl-d-glucosaminidase (OGA) activity. An IF supplement (80 mg/d) was given to 9 postmenopausal women and 13 young women for 6 months and then stopped up to the 14th month. The women were allowed to consume their normal diet. Blood samples were collected at the beginning of the study after 2, 4, and 6 months and then at the 8th and 14th months. Plasma concentrations of genistein and daidzein, total antioxidant capacity, plasma vitamin status, markers of oxidative stress (red blood cell membrane fluidity, activity of the red blood cell cytosolic enzyme OGA and lymphocyte DNA susceptibility to oxidative stress), and serum lipid profile were analyzed. Analysis of variance for repeated measures was used for statistical analysis. Plasma concentrations of IFs rose significantly during the supplementation period, and plasma total antioxidant capacity increased in young women; membrane fluidity and OGA activity increased, and DNA oxidative damage decreased (P < .05) at 4 months, then returned to the basal level. There was a significant inverse correlation between DNA damage and plasma IF concentrations (P < .01). The results indicated a positive effect of IF supplementation on oxidative stress in women, thus suggesting that the healthful action ascribed to soy consumption may be partially related to the antioxidant potential of IFs.

Omega-3 fatty acids administered in phosphatidylserine improved certain aspects of high chronic stress in men

2012-05-01

Abstract: Nutrients such as omega-3 oils and phosphatidylserine have been considered to exert stress-buffering effects. In this randomized, double-blind, placebo-controlled trial, we investigated effects of omega-3 phosphatidylserine (PS) on perceived chronic stress, assessed by the Trier Inventory for Chronic Stress (Schulz P, Schlotz W, Becker P. TICS: Trierer Inventar zum chronischen Stress. Göttingen, Germany: Hogrefe, 2004.), and on psychobiological stress responses to an acute laboratory stress protocol, the Trier Social Stress Test (Neuropsychobiology.1993;28:76-81), at baseline and after the treatment period. We hypothesized that omega-3 PS supplementation lowers chronic and acute stress. Sixty healthy nonsmoking men aged 30 to 60 years either received omega-3 PS or a matching placebo for 12 weeks. Results revealed no significant main effect of omega-3 PS supplementation on stress measures. However, by accounting for chronic stress level of study participants, stress-reducing effects of omega-3 PS were found exclusively for high chronically stressed subjects. As expected, these individuals also showed a blunted cortisol response to the Trier Social Stress Test. Treatment with omega-3 PS seemed to restore the cortisol response in this particular subgroup of low responders. These results are in line with previous findings. We conclude that subgroups characterized by high chronic stress and/or a dysfunctional response of the hypothalamus-pituitary-adrenal axis may profit from omega-3 PS supplementation.

Candidate measures of whole plant food intake are related to biomarkers of nutrition and health in the US population (National Health and Nutrition Examination Survey 1999-2002)

Leah M. Lipsky, Kyeongmi Cheon, Tonja R. Nansel, Paul S. Albert — 2012-04-23

Abstract: Indices of overall dietary patterns are used in epidemiologic research to examine the relationship between nutrition and health. The objective of this study was to develop and validate an interpretable summary measure of dietary intake of whole plant foods (WPF; whole grains, vegetables, whole fruit, legumes, nuts, seeds) because of their similar nutritional characteristics and health effects. Six candidate WPF measures were calculated using data from subjects (age ≥6 years) participating in the 1999-2000 and 2001-2002 National Health and Nutrition Examination Survey. Measures differed by the inclusion or exclusion of potatoes and whether they were expressed as total intake or as a proportion of energy (4180 kJ) or mass (kg) consumed. Both standard and nontruncated (allowed to vary proportionally with intake) Healthy Eating Index-2005 (HEI-2005) scores were calculated. Regression analysis examined the associations between WPF and HEI-2005 measures, and between all diet measures and serum carotenoid concentration, serum lipids, fasting glucose, insulin, C-peptide, and C-reactive protein. Mean total WPF intake was 3.6 cup/oz equivalents, or 1.7 cup/oz equivalents per 4180 kJ and per kg. The largest R2 between WPF and HEI-2005 measures was found for energy-adjusted WPF including potatoes and nontruncated HEI-2005 (R2 = 0.50). All diet measures were positively related to serum carotenoids (P <.001) and were similarly related to health indicators (R2 range from 0.003 to 0.16, P <.045 for regressions, indicating significant associations between WPF measures and health indicators). Whole plant food measures are interpretable indicators of dietary intake that are significantly related to nutrition and health biomarkers and may be of public health use.

Adoption of diet-related self-monitoring behaviors varies by race/ethnicity, education, and baseline binge eating score among overweight-to-obese postmenopausal women in a 12-month dietary weight loss intervention

2012-05-01

Abstract: Recent research has identified self-monitoring behaviors as important strategies for both initial weight loss and weight loss maintenance, but relatively little is known about adopters and nonadopters of these behaviors. To test our hypothesis that key characteristics distinguish adopters from nonadopters, we examined the demographic characteristics and eating behaviors (eg, restrained, uncontrolled, emotional, and binge eating) associated with more frequent compared with less frequent use of these behaviors. Baseline demographic characteristics and eating behaviors as well as 12-month self-monitoring behaviors (ie, self-weighing, food journaling, monitoring energy intake) were assessed in 123 postmenopausal women enrolled in a dietary weight loss intervention. Logistic regression models were used to test associations of self-monitoring use with demographic characteristics and eating behaviors. Nonwhites, compared with non-Hispanic whites, were less likely to monitor energy intake regularly (adjusted odds ratio [OR], 0.36; 95% confidence interval [CI], 0.13-0.97; P < .05), controlling for intervention arm and baseline body mass index. Participants with a college degree or higher education were less likely to self-weigh daily (adjusted OR, 0.30; 95% CI, 0.13-0.67; P < .01) compared with individuals who attended some college or less. Those with higher baseline binge eating scores were less likely to monitor energy intake (adjusted OR, 0.84; 95% CI, 0.73-0.97; P < .01) compared with participants with lower binge eating scores. In summary, use of diet-related self-monitoring behaviors varied by race/ethnicity, education, and binge eating score in postmenopausal women who completed a year-long dietary weight loss intervention. Improved recognition of groups less likely to self-monitor may be helpful in promoting these behaviors in future interventions.

Comparison of different assessments for evaluating malnutrition in Chinese patients with end-stage renal disease with maintenance hemodialysis

2012-04-20

Abstract: Nutritional status can be evaluated by the malnutrition-inflammation score (MIS), bioelectrical impedance analysis (BIA), and modified quantitative subjective global assessment (MQSGA). This study sought to determine the value of these methods for detecting malnutrition in patients with end-stage renal disease (ESRD) who were undergoing maintenance hemodialysis. A total of 84 patients with ESRD with maintenance hemodialysis were recruited for the evaluation of their nutritional states by MQSGA, MIS, and BIA. The potential correlation among these methods was analyzed, and there was a significant difference in the percentage of patients with malnutrition as determined by these methods. Although only 1 of 84 patients had a body fat percentage that was below normal, based on the BIA, all of the patients displayed malnutrition as analyzed by MIS, and 56 of 84 patients had malnutrition as determined by MQSGA. Importantly, the MQSGA scores were positively correlated with the MIS scores (r = 0.924, r2 = 0.855, P < .05), whereas no close association was found in results obtained by MQSGA score and BIA (r = −0.169, r2 = 0.029, P > .05) in this population. Our data indicate that MIS, not BIA, is a sensitive method for the evaluation of malnutrition in Chinese patients with ESRD with maintenance hemodialysis.

l-glutamine absorption is enhanced after ingestion of l-alanylglutamine compared with the free amino acid or wheat protein

Roger C. Harris, Jay R. Hoffman, Adrian Allsopp, Naomi B.H. Routledge — 2012-04-11

Abstract: Differences in plasma l-glutamine (L-Gln) concentrations from ingestion of different formulations of L-Gln were examined in 8 men (26.8 ± 4.2 years old, 181.1 ± 10.9 cm, 85.8 ± 15.4 kg). Subjects reported to the laboratory on 4 separate occasions and randomly consumed 1 of 4drinks containing 60 mg/kg of L-Gln; 89 mg/kg of Sustamine (l-alanylglutamine [AlaGln]; Kyowa Hakko Europe GmbH, Düsseldorf, Germany), which contained an equivalent L-Gln dose as consumed in L-Gln); 200 mg/kg of an enzymatically hydrolyzed wheat protein (HWP) with an L-Gln content of 31 mg/kg; or a control that consisted only of water. It was hypothesized that the AlaGln trial would increase plasma glutamine concentrations greater than the other experimental trials. Ingestion of L-Gln, AlaGln, and HWP resulted in significant increases in the plasma L-Gln concentration, peaking at 0.5, 0.5, and 0.75 hours, respectively. The corresponding mean peak increases were 179 ± 61, 284 ± 84, and 134 ± 36 μmol/L, respectively. Concentrations returned to baseline in all subjects by 2 hours after L-Gln and HWP and by 4 hours after AlaGln. Mean areas under the plasma concentration curve, calculated between 0 and 4 hours, were 127 ± 61, 284 ± 154, and 151 ± 63 μmol∙h∙L−1 for L-Gln, AlaGln, and HWP, respectively. When allowance was made for the lower L-Gln dose administered as HWP, the peak plasma concentration and area under the plasma concentration curve were approximately the same as for AlaGln. The results suggest a greater transfer from the gut to plasma of L-Gln when supplied as AlaGln and possibly also as HWP compared with when the same dose was provided as the free amino acid.

Postprandial impairment of flow-mediated dilation and elevated methylglyoxal after simple but not complex carbohydrate consumption in dogs

Jennifer L. Adolphe, Murray D. Drew, Qian Huang, Tawni I. Silver, Lynn P. Weber — 2012-05-01

Abstract: Hyperglycemia produces oxidative stress, which may impair endothelial function. Methylglyoxal, a reactive intermediate metabolite of glucose, is known to cause oxidative stress and is produced when excess carbohydrate is consumed in diabetic patients, but postprandial responses in healthy patients are unknown. We hypothesize that methylglyoxal levels will cause impaired endothelial function via increased oxidative stress after consuming a high glycemic index meal in healthy animals. Normal-weight laboratory beagles (n = 6) were used in a crossover study that tested postprandial responses of 4 complex carbohydrate sources (barley, corn, peas, rice) vs a simple carbohydrate (glucose). Blood samples were taken prefeeding and at timed intervals after feeding to measure serum glucose, insulin, nitrotyrosine, and methylglyoxal. Flow-mediated dilation (FMD), cardiac function (echocardiography), and blood pressure measurements were determined before and 60 minutes after feeding. The mean (±SEM) glycemic indices of the complex carbohydrate sources were 29 ± 5 for peas, 47 ± 10 for corn, 51 ± 7 for barley, and 55 ± 6 for rice. Postprandial FMD was lowest in the glucose group and significantly different from both the corn group and the FMD value for all complex carbohydrates combined. Methylglyoxal was significantly elevated at 60 minutes postprandial after glucose compared with the other carbohydrate sources. No significant effects of carbohydrate source were observed for blood pressure, nitrotyrosine, or echocardiographic variables. The novel finding of this study was that methylglyoxal levels increased after a single feeding of simple carbohydrate and may be linked to the observed postprandial decrease in endothelial function. Thus, consuming low-glycemic-index foods may protect the cardiovascular system by reducing oxidative stress.

A lower proportion of dietary saturated/monounsaturated/polyunsaturated fatty acids reduces the expression of adiponectin in rats fed a high-fat diet

2012-04-20

Abstract: The role for the amount of different dietary fatty acids in regulating expression of adiponectin and metabolism of glucose and lipids has been implicated, but the optimal amount has not been established yet. To address this issue, we fed male Wistar rats with either chow diet or various high-fat diets (HFDs) for 12 weeks. The HFDs contained the same percentage of fat (35% energy from fat) but had different proportions of saturated/monounsaturated/polyunsaturated (S/M/P) (1:1.7:1.2, 1:1:1, 2:1.5:1, 1:2:1, or 1:1:2) fat. Glucose and lipid metabolism and adiponectin expression were subsequently examined. In comparison with chow diet, HFD with any proportion of S/M/P increased energy intake but had no obvious effect on body weight gain. The HFD with the S/M/P proportion at 1:1:1 or 1:1:2 significantly decreased the serum triglyceride level and increased the serum level of high-density lipoprotein cholesterol in comparison with the HFD with the S/M/P proportion at 1:1.7:1.2, 2:1.5:1, or 1:2:1. The HFD containing the highest level of saturated fatty acids (S/M/P proportion at 2:1.5:1) increased levels of total cholesterol, low-density lipoprotein cholesterol, and blood glucose. Levels of serum insulin and the homeostasis model assessment of insulin resistance index were significantly increased by HFD with S/M/P proportions at 1:1.7:1.2, 1:1:1, 2:1.5:1, or 1:2:1 but not by the HFD with the S/M/P proportions at 1:1:2 (containing the highest level of polyunsaturated fatty acids). Levels of adiponectin messenger RNA in subcutaneous and visceral adipose tissues were reduced by the HFD with the S/M/P proportion at 1:1.7:1.2 or 1:1:1 but increased by the HFD with the S/M/P proportion at 1:1:2. These changes in expression of adiponectin were inversely associated with those in levels of triglyceride, insulin, and homeostasis model assessment of insulin resistance. Together, the proportion of different fatty acids in diets plays an important role in expression of adiponectin and metabolism of glucose and lipids. Specifically, the proportion of S/M/P at 1:1:2 can promote expression of adiponectin, improve metabolism of glucose and lipids, and increase insulin sensitivity.

Plant sterols and casein-derived tripeptides attenuate blood pressure increase in spontaneously hypertensive rats

2012-05-04

Abstract: In this study, we investigated the synergistic effects of plant sterols (PS) and casein-derived tripeptides on arterial tone and blood pressure in experimental hypertension. We hypothesized that PS and tripeptides could have positive, synergistic effects on the development of hypertension and endothelial dysfunction in young spontaneously hypertensive rats (SHR). Six-week-old male SHR were divided into 3 groups to receive milk products containing PS, or PS with tripeptides, or a control containing no active components for 8 weeks. Systolic blood pressure (SBP) was measured weekly, and vascular reactivity measurements with isolated mesenteric arteries were performed at the end of the study. Biochemical measurements for several parameters were performed by enzyme-linked immunosorbent assay using plasma samples. Levels of angiotensin-converting enzyme 1, cyclooxygenase-2, endothelial nitric oxide synthase, and P-selectin messenger RNA expressions were determined from aortic tissue by real-time polymerase chain reaction. The study showed that long-term treatment with PS + tripeptides attenuated the development of hypertension in SHR (SBP, 187 ± 5 mm Hg vs 169 ± 4 mm Hg in control group; P < .01). Plant sterols alone did not affect SBP significantly. Endothelial dysfunction was observed in all SHR; however, treatment with PS resulted in poorer endothelium-dependent and nitric oxide–mediated relaxation compared with other groups. Aortic cyclooxygenase-2 and P-selectin were significantly down-regulated in PS and PS + tripeptides groups when compared with the control group. The expression of endothelial nitric oxide synthase was significantly lower in PS than in PS + tripeptides group. In conclusion, long-term treatment with PS has a slight but not significant antihypertensive effect. Plant sterols do not provide any beneficial effects on endothelial function in hypertensive rats; however, treatment with both PS and tripeptides showed mild anti-inflammatory effects.

Supplementation of broccoli or Bifidobacterium longum–fermented broccoli suppresses serum lipid peroxidation and osteoclast differentiation on alveolar bone surface in rats fed a high-cholesterol diet

2012-04-30

Abstract: High-cholesterol diet enhances osteoclastic activity on alveolar bone by increasing serum lipid peroxidation. We hypothesized that supplementation with dietary antioxidants, such as found in broccoli and its fermented products, might suppress increases in serum lipid peroxidation, contributing to the inhibition of osteoclastic activity after high-cholesterol diet intake. The purpose of the present study was to investigate the effects of broccoli and fermented broccoli consumption on serum lipid peroxidation and osteoclast differentiation in alveolar bone of rats fed a high-cholesterol diet. In this 12-week study, rats were divided into 4 groups (n = 6/group): a control group (fed regular diet) and 3 experimental groups (fed a high-cholesterol [1% wt/wt] diet, or a high-cholesterol diet supplemented with either broccoli powder [5% wt/wt] or Bifidobacterium longum–fermented broccoli powder [5% wt/wt]). Serum hexanoyl-lysine (HEL) levels were measured as a parameter of lipid peroxidation. The number of tartrate-resistant acid phosphatase (TRAP)–positive osteoclasts in alveolar bone was enumerated to evaluate osteoclast differentiation. When compared with regular diet, the high-cholesterol diet increased serum HEL levels and resulted in a higher number of TRAP-positive osteoclasts at 12 weeks. The high-cholesterol diet supplemented with broccoli or B. longum–fermented broccoli showed lower levels of serum HEL and fewer TRAP-positive osteoclasts than the high-cholesterol diet at 12 weeks. In conclusion, consumption of broccoli, or its fermented product, inhibited the effects of a high-cholesterol diet on osteoclast differentiation in rat alveolar bone by suppressing serum lipid peroxidation.