Unique trans-kingdom microbiome structural and functional signatures predict cognitive decline in older adults.

The prevalence of age-related cognitive disorders/dementia is increasing, and effective prevention and treatment interventions are lacking due to an incomplete understanding of aging neuropathophysiology. Emerging evidence suggests that abnormalities in gut microbiome are linked with age-related cognitive decline and getting acceptance as one of the pillars of the Geroscience hypothesis. However, the potential clinical importance of gut microbiome abnormalities in predicting the risk of cognitive decline in older adults is unclear. Till now the majority of clinical studies were done using 16S rRNA sequencing which only accounts for analyzing bacterial abundance, while lacking an understanding of other crucial microbial kingdoms, such as viruses, fungi, archaea, and the functional profiling of the microbiome community. Utilizing data and samples of older adults with mild cognitive impairment (MCI; n = 23) and cognitively healthy controls (n = 25). Our whole-genome metagenomic sequencing revealed that the gut of older adults with MCI harbors a less diverse microbiome with a specific increase in total viruses and a decrease in bacterial abundance compared with controls. The virome, bacteriome, and microbial metabolic signatures were significantly distinct in subjects with MCI versus controls. Selected bacteriome signatures show high predictive potential of cognitive dysfunction than virome signatures while combining virome and metabolic signatures with bacteriome boosts the prediction power. Altogether, the results from our pilot study indicate that trans-kingdom microbiome signatures are significantly distinct in MCI gut compared with controls and may have utility for predicting the risk of developing cognitive decline and dementia- debilitating public health problems in older adults.

The relationship between diet, exercise, and inflammation in college students: A cross-sectional study.

Background: Important changes in lifestyle habits, especially diet, typically occur during the transitional period between high school and college and some of these changes may increase the risk of inflammation. Aim: The purpose of this study was to investigate the relationship between lifestyle factors and inflammation in college students. Methods: Students enrolled in a southeastern university participated in this cross-sectional study. Participants completed online questionnaires for assessment of demographics, supplement and dietary intake, sleep quality, and perceived stress. Body composition was measured during a clinic visit via air displacement plethysmography and blood and urine were collected for measurement of C-reactive protein (CRP) and cortisol, respectively. Analysis of variance was used to examine associations between tertiles of CRP levels and lifestyle variables and a linear regression model was fit to investigate whether there were any significant predictors of CRP levels. Results: Analysis included data for 83 participants for whom serum CRP levels and diet intake were available. Approximately 68% of the participants were female; mean age and body mass index (BMI) were 24 years and 23.4 kg/m2, respectively. Alcohol intake was significantly associated with increasing CRP levels (P = 0.017). No other dietary variables or lifestyle characteristics such as sleep quality, perceived stress, or BMI were associated with tertiles of CRP. The best model to predict CRP levels included urinary cortisol, aerobic exercise duration, alcohol, and vitamin E intake (adjusted R2=0.27). Conclusion: Alcohol and vitamin E intake were found to be associated with increased CRP levels.

Dietary Supplement Intake is Associated with Healthier Lifestyle Behaviors in College Students Attending a Regional University in the Southeast: A Cross-Sectional Study.

The relationship between intake of dietary supplements and biomarkers such as insulin and insulin-like growth factor has not been well explored. The primary aim of this cross-sectional study was to investigate the associations between supplement intake and biological and lifestyle factors. We hypothesized that dietary supplement intake was associated with healthier lifestyle behaviors. College students attending a Southeast university were recruited between January 2018 and April 2019. Blood samples were collected to measure insulin, insulin-like growth factor 1 (IGF-1) and alanine aminotransferase (ALT). Statistical tests employed were linear regression and analysis of variance. Ninety-eight participants completed the study and 91% reported taking at least one supplement, while 5.1% reported taking 9+ supplements once per week. There were no differences in levels of insulin, IGF-1 and ALT by levels of dietary supplement intake. Although there were no differences in HEI-2015 score among the groups, those who consumed five or more supplements met a higher percentage of the recommended intake for fruits, performed aerobic exercise for longer duration, and had lower body fat percentage compared to participants who consumed two or less supplements at least once per week. These findings are consistent with previous studies and suggest that dietary supplement intake is highly prevalent in college students, and it may be related to healthy lifestyle behaviors. Future studies should employ mixed methodology to examine reasons by which college students consume dietary supplements and to assess perceived and direct health benefits associated with consumption.

Determinant factors associated with the use of evidence-based dietetics practice among registered dietitian nutritionists.

AIMS: There is a lack of research assessing perceived and actual evidence-based dietetics practice knowledge among registered dietitian nutritionists. This cross-sectional research examined the association between determinant factors (i.e., education attainment) and objective knowledge (i.e., quiz items) of evidence-based dietetics practices. Other determinant factors associated with perceived knowledge and skill, attitudes, behaviours and outcomes related to evidence-based dietetics practice were also assessed. Perceived knowledge items were compared to objective knowledge items to evaluate the accuracy of self-assessed evidence-based dietetics practice knowledge among dietitians in the United States. METHODS: A modified and adapted evidence-based practice survey was emailed to registered dietitian nutritionists in the United States via the Commission on Dietetic Registration database between November and December 2020. Analysis of variance assessed the relationship between highest degree held and actual knowledge of evidence-based dietetics practices. Multiple linear regression and ordinal logistic regression determined participant-level characteristics associated with survey subscales and survey items, respectively. Pearson's correlation coefficient evaluated the relationship between subjective and objective items. RESULTS: Four hundred and eighty-two dietitians completed the survey. Each increase in degree type was associated with an increase in objective knowledge score (all comparisons p < 0.001). Other determinants included recency of degree completion and peer-reviewed publications. Moderate positive associations (r = 0.35, p < 0.001) were found between subjective and objective measures. CONCLUSION: Graduate-level education, recency of degree completion and peer-reviewed publications were supportive of evidence-based dietetics practice-related outcomes. Future research should evaluate the efficacy of training, particularly among those further from their highest completed degree.

Validity and reliability of a questionnaire measuring EBDPs among registered dietitian nutritionist.

BACKGROUND: There is a lack of a valid and reliable instrument that measures objective and subjective knowledge of evidence-based dietetic practices (EBDP) among registered dietitian nutritionists (RDNs). The present study aimed to develop and assess the validity and reliability of an EBDP Questionnaire (EBDPQ) with objective knowledge items (i.e., quiz items) among RDNs in the USA. METHODS: Subscales from four existing evidence-based practice (EBP) instruments were combined and modified for dietetics. Content and face validity and internal consistency were used to assess the full survey. Survey responsiveness and test-retest reliability were evaluated within the objective knowledge subscale. Content experts (n = 11) and nutrition professionals (n = 16) completed validation reviews. Doctoral students enrolled in a research course (n = 12) were used to analyse survey responsiveness. Internal and test-retest relability analyses utilised RDN participants (time point 1, n = 482; time point 2, n = 335). RESULTS: Content validation resulted in a 38-item questionnaire. Average percent agreement among face validity reviewers was 95.1%. Only the pre-validation version of the objective knowledge subscale resulted in significantly higher post-course scores (Mdn = 11.50) compared to the pre-course (Mdn = 9.75, p = 0.05). The validated instrument had excellent internal consistency (Cronbach's α = 0.91); however, the objective knowledge subscale was low (Cronbach's α = 0.41). A good degree of reliability was found between the two time points (intraclass correlation coefficient = 0.71). CONCLUSIONS: The EBDPQ demonstrated adequate validity and reliability among RDNs. Future research should assess construct validity, with the responsiveness and objective knowledge subscale requiring additional evaluation through an EBDP course.

The effects of fermented vegetable consumption on the composition of the intestinal microbiota and levels of inflammatory markers in women: A pilot and feasibility study.

The primary objective of this pilot study was to investigate the feasibility of regular consumption of fermented vegetables for six weeks on markers of inflammation and the composition of the gut microflora in women (clinical trials ID: NTC03407794). Thirty-one women were randomized into one of three groups: 100 g/day of fermented vegetables (group A), 100 g/day pickled vegetables (group B), or no vegetables (group C) for six weeks. Dietary intake was assessed by a food frequency questionnaire and blood and stool samples were provided before and after the intervention for measurement of C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), and lipopolysaccharide binding protein (LBP). Next-generation sequencing of the V4 region of the 16S rRNA gene was performed on the Illumina MiSeq platform. Participants' ages ranged between 18 and 69 years. Both groups A and B had a mean daily consumption of 91g of vegetables for 32 and 36 days, respectively. Serum CRP ranged between 0.9 and 265 ng/mL (SD = 92.4) at baseline, while TNF-α and LBP concentrations ranged between 0 and 9 pg/mL (SD = 2.3), and 7 and 29 µg/mL (SD = 4.4), respectively. There were no significant changes in levels of inflammatory markers among groups. At timepoint 2, group A showed an increase in Faecalibacterium prausnitzii (P = 0.022), a decrease in Ruminococcus torques (P<0.05), and a trend towards greater alpha diversity measured by the Shannon index (P = 0.074). The findings indicate that consumption of ~100 g/day of fermented vegetables for six weeks is feasible and may result in beneficial changes in the composition of the gut microbiota. Future trials should determine whether consumption of fermented vegetables is an effective strategy against gut dysbiosis.

Association of Inflammatory Diets with Inflammatory Biomarkers in Women at High Genetic Risk for Breast Cancer.

Chronically elevated levels of inflammatory biomarkers may contribute to the development of cancer and diet may be an important factor in the interplay between inflammation and cancer. We examined associations between glycemic load (GL), glycemic index (GI), and adapted dietary inflammatory index (ADII) and markers of inflammation and adipokines in 135 premenopausal women at high genetic risk for breast cancer (NCT00892515). We assessed body mass index (BMI), 3-day food records, and blood biomarkers TNF-α, IL-12, CCL2, IL-10, leptin, and adiponectin. Regression models assessed associations between dietary variables and biomarkers, adjusted for caloric intake and BMI. Participants were on average 34.2 years old with mean BMI of 26.8 kg/m2. Significantly higher levels of IL-10 and leptin were observed in participants with higher GI. Leptin and adiponectin were significantly associated with ADII. Leptin remained associated with ADII after adjustment for caloric intake and BMI. There were no associations between inflammatory biomarkers of interest and GL, GI, and ADII, after adjusting for caloric intake and BMI. Elevated leptin levels were observed with higher ADII independent of caloric intake and BMI. The relationship between carbohydrate quality and inflammatory potential of the diet and markers of inflammation may be modulated by leptin.

Associations between Polymorphisms in Phase II Enzymes and Circulating Sex-Steroid Hormones in White Postmenopausal Women.

OBJECTIVES: The purpose of this cross-sectional study was to examine whether single nucleotide polymorphisms (SNPs) in enzymes that metabolize sex steroid hormones were associated with the blood levels of these hormones in postmenopausal women and if the use of menopausal hormone therapy (MHT) could modify this association. METHODS: Baseline data were collected from 932 postmenopausal women enrolled in the Minnesota Green Tea Trial. Participants filled out a questionnaire about their demographics, lifestyle factors, and medical and reproductive history. Free, bioavailable, and total serum levels of reproductive hormones were measured through liquid chromatography/tandem mass spectrometry. For genotyping of UGT1A1 (rs10928303), UGT1A4 (rs10929301, rs11673726), UGT1A6 (rs1105879, rs2070959, rs6759892), UGT1A8 (rs10167119), UGT2B7 (rs7439366), and SULT1A1 (rs9282861, rs1968752), mass spectrometry based on multiplex methods and TaqMan assays were performed. Adjusted linear models were fit to assess the associations between SNPs and blood hormones using age, body mass index (BMI), and MHT as covariates. RESULTS: The mean age was 59.8 years, and the mean BMI was 25.1 kg/m². Past or recent use of MHT was reported by 41.2% of the participants. SNPs in SULT1A1 (rs1968752 and rs9282861) and UGT1A4 (rs11673726) genes were significantly associated with estrone levels, whereas SNPs in UGT1A6 (rs6759892) and UGT1A8 (rs10167119) genes were significantly associated with bioavailable estradiol levels. CONCLUSIONS: There was no evidence that MHT use modified the association between SNPs and sex-steroid hormone levels; however, further studies are needed to establish the potential clinical significance of UGT1A4 (rs11673726), UGT1A6 (rs6759892), and UGT1A8 (rs10167119) SNPs and the modulation of hormone levels in postmenopausal women.

Associations between Diet Quality and Anthropometric Measures in White Postmenopausal Women.

The purpose of this cross-sectional study was to examine the relationship between diet and anthropometric measures in postmenopausal women. Data collected from 937 women enrolled in the Minnesota Green Tea Trial (NTC00917735) were used for this analysis. Dietary intake and health-related data were collected via questionnaires. Body weight, height, and waist circumference (WC) were measured by the study staff. The mean age of participants was 59.8 years and mean WC was 83 cm. Approximately 30% of the participants had WC greater than 88 cm. Healthy Eating Index-2015 score was 72.6 and the Dietary Inflammatory Index score was 0. Intakes of whole grains, dairy, protein, sodium, and saturated fat did not meet the dietary guidelines. Only 12.5% consumed the recommended daily amount of calcium (mean intake = 765 mg/day). When calcium supplements were considered, only 35.2% of the participants had adequate intakes, even though 68.9% reported taking a calcium supplement. We found that age and number of medications taken were significantly associated with waist circumference (p = 0.005). Women who reported taking two or more medications had greater WC (85 cm) compared to women who reported not taking any medications (82.2 cm), p = 0.002. Our findings suggest that achieving adequate calcium and vitamin D intake may be challenging to postmenopausal women.

Etiology Intervention Link Predicts Resolution of Nutrition Diagnosis: A Nutrition Care Process Outcomes Study from a Veterans' Health Care Facility.

In this article, we evaluate relationships between Nutrition Care Process (NCP) chain links and improvement or resolution of the nutrition diagnosis. We conducted a retrospective record review for 12 months in a single Veterans Health Administration health care system using the Veterans Health Administration-specific monitoring and evaluation terms, NCP terminology, and its etiology categories to evaluate outcomes. Logistic regression analysis revealed that the strongest predictor for diagnosis improvement was the etiology-intervention link. The odds of improving the nutrition diagnosis were 51.43 times higher when the etiology-intervention link was present. The odds of improving the nutrition diagnosis were 19.74 times higher when the evidence-diagnosis link was present and 9.46 times higher when the intervention-goal link was present. For every added nutrition visit by the registered dietitian nutritionist, the odds of improving the nutrition diagnosis increased by 32.5%. For every increased point on the NCP audit score, the odds of resolving or improving the nutrition diagnosis increased by 37.7%. When applying the NCP, the presence of the etiology-intervention link significantly improves the odds of resolving the nutrition diagnosis in a Veterans Health Administration population. For the first time, we show evidence that the NCP works as designed. Also, we demonstrate that the quality of NCP documentation impacts resolution of the diagnosis, and we describe the methodology for how to evaluate NCP outcomes. Registered dietitian nutritionists are encouraged to critically evaluate links of the NCP chain, assess NCP documentation for quality, and pursue follow-up visits to improve resolution of nutrition problems.

Results of an Online Survey about Food Insecurity and Eating Disorder Behaviors Administered to a Volunteer Sample of Self-Described LGBTQ+ Young Adults Aged 18 to 35 Years.

BACKGROUND: There are few published studies addressing food insecurity and eating disorders in lesbian, gay, bisexual, transgender, queer, or questioning (LGBTQ+) individuals. OBJECTIVE: The primary objective of this study was to describe the proportion of food insecurity and eating disorder behaviors in a volunteer sample of LGBTQ+ individuals aged 18 to 35 years. DESIGN: This study was a cross-sectional analysis of questionnaire data collected from 253 participants between March 2018 and March 2019. PARTICIPANTS AND SETTING: To be included in the study, participants had to be aged 18 to 35 years and identify as being LGBTQ+. MAIN OUTCOME MEASURES: Food security score, Eating Attitudes Test score, Eating Disorder Examination Self-Report Questionnaire score, anxiety score (Beck), and depressive symptoms score. STATISTICAL ANALYSES PERFORMED: The χ2 test was used to analyze the categorical outcomes. One-way analysis of variance was used to compare continuous variables across gender identity groups. All P values < 0.05 were taken as statistically significant. RESULTS: The proportion of participants identifying as a woman, trans male, gender nonconforming, and a man were 39%, 24%, 24%, and 13%, respectively. Food insecurity was reported by 54.4% of respondents with trans males reporting the highest proportions (64.8%). High levels of depressive symptoms were reported by 68.2% of men, 89.8% of women, 91.4% of trans males, and 95.5% of gender-nonconforming respondents (P = 0.009). High anxiety was reported by 20.5%. Eating Disorder Examination Self-Report Questionnaire scores were significantly higher (P < 0.001) compared with a community-based sample. The eating disorder behavior most frequently reported by respondents was binge eating. Only 4.3% reported having sought treatment for an eating disorder. CONCLUSIONS: Members of the LGBTQ+ community are at greater risk for food insecurity, eating disorders, and depression, particularly those who identify as trans males. These findings denote the need to focus future research efforts on effective prevention and treatment strategies that are specific to sexual and gender identity groups within the LGBTQ+ community.

Inhibitory Effects of Green Tea Polyphenols on Microbial Metabolism of Aromatic Amino Acids in Humans Revealed by Metabolomic Analysis.

The bioactivities and potential health benefits of green tea polyphenols (GTP) have been extensively investigated, but the metabolic impact of chronic GTP intake on humans is not well defined. In this study, fecal and urine samples from postmenopausal female subjects taking a GTP supplement or placebo for 12 months were compared by liquid chromatography-mass spectrometry-based metabolomic analysis. The GTP-derived and GTP-responsive metabolites were identified and characterized by structural elucidation and quantitative analysis of the metabolites contributing to the separation of control and treatment samples in the multivariate models. Major GTP and their direct sulfate and glucuronide metabolites were absent in feces and urine. In contrast, GTP-derived phenyl-γ-valerlactone and phenylvaleric acid metabolites were identified as the most abundant GTP-derived metabolites in feces and urine, suggesting extensive microbial biotransformation of GTP in humans. Interestingly, GTP decreased the levels of microbial metabolites of aromatic amino acids (AAA), including indoxyl sulfate, phenylacetylglutamine, and hippuric acid, in urine. However, it did not affect the levels of AAA, as well as other microbial metabolites, including short-chain fatty acids and secondary bile acids, in feces. 16S rRNA gene sequencing indicated that the fecal microbiome was not significantly affected by chronic consumption of GTP. Overall, microbial metabolism is responsible for the formation of GTP metabolites while GTP metabolism may inhibit the formation of AAA metabolites from microbial metabolism. Because these GTP-derived and GTP-responsive metabolites have diverse bioactivities, microbial metabolism of GTP and AAA may play important roles in the beneficial health effects of green tea consumption in humans.

Associations between food insecurity and prediabetes in a representative sample of U.S. Adults (NHANES 2005-2014).

AIMS: The primary aim of this research was to investigate the association between food insecurity and prediabetes and to identify specific subgroups for early clinical intervention. METHODS: Cross-sectional data from 25,814 participants were analyzed from the National Health and Nutrition Examination Survey for years 2005-2014. Multivariable logistic regression was used to explore the association between food security status and laboratory-confirmed prediabetes. All models were adjusted for age, sex, race, and body mass index. RESULTS: When compared to participants with full and marginal food security, participants with low/very food security were 1.35 (95% CI: 1.17-1.55) times more likely to have prediabetes. Younger individuals with low/very low food security had a greater likelihood of prediabetes, 1.50 (95% CI: 1.19-1.81), when compared with their food secure counterparts. CONCLUSIONS: Food insecurity at any level, whether low or very low, is positively associated with prediabetes in the U.S. general adult population. Food insecure young adults, particularly those aged 20-34 years, should be targeted for early clinical intervention.

Exploring the association between polycyclic aromatic hydrocarbons and diabetes among adults in the United States.

OBJECTIVE: To explore the association between polycyclic aromatic hydrocarbons (PAHs) and diabetes and to determine whether effects are heterogeneous when examined by body mass index (BMI). METHODS: Cross-sectional data from 8664 participants were analyzed from the National Health and Nutrition Examination Survey for years 2005-2014. Multivariable logistic regression was used to explore the association between urinary biomarkers of PAHs and diabetes. All models were adjusted for age, sex, race, poverty-income ratio, and serum cotinine. RESULTS: When compared with the lowest quintiles of exposure, the highest quintiles of exposure to 2-hydroxynaphthalene, 2-hydroxyfluorene, 9-hydroxyfluorene, 2-hydroxyphenanthrene, and a summed variable of all low molecular weight PAHs (aOR = 1.73; 95% CI: 1.17-2.55) showed a positive association with diabetes. Stratified analyses by BMI indicated that the positive association between PAHs and diabetes was found among both normal weight and obese participants. CONCLUSIONS: High levels of exposure to PAHs are positively associated with diabetes in the U.S. general population and these effects are modified by BMI. These findings suggest the importance of strong environmental regulation of PAHs to protect population health.

Dietary Fiber, C-Reactive Protein, and Leisure-Time Physical Activity Among U.S. Adults.

BACKGROUND: Some evidence suggests an inverse association between increased fiber intake and C-reactive protein (CRP). However, few studies have examined the associations among CRP, dietary fiber, and leisure-time physical activity (LTPA) in a nationally representative sample of U.S. adults. METHODS: Sample (n = 8372) included adults (≥20 years of age) who participated in the 2007-2010 National Health and Nutrition Examination Survey. Tertiles of reported fiber intake were created. The dependent variable was elevated CRP (>3-10 mg/L). Logistic regression models were stratified by LTPA participation and adjusted for age, gender, race, waist circumference (WC), and standing height. RESULTS: In adults reporting any volume of LTPA participation, increased fiber intake was significantly (P < 0.05 for the upper tertile of fiber intake) associated with lower odds of having an elevated CRP concentration when compared with the lowest tertile. Similar associations were not revealed in analyses limited to adults reporting no LTPA participation. After additional adjustment for WC and standing height, this protective association was no longer statistically significant. CONCLUSIONS: Results suggest that WC and standing height may mediate the beneficial association between increased fiber intake and lower odds of elevated CRP in adults reporting LTPA participation.

Effects of a parallel-arm randomized controlled weight loss pilot study on biological and psychosocial parameters of overweight and obese breast cancer survivors.

BACKGROUND: Weight gain often occurs after breast cancer (BC) diagnosis and obesity along with sedentary behavior are associated with increased risk of BC recurrence and mortality. The primary objective of this study was to determine whether a significant weight loss, of approximately 10%, would lead to beneficial changes in biomarkers associated with cancer and/or cancer recurrence, and quality of life (QOL) in overweight and obese BC survivors. METHODS: This parallel-arm study took place in Minneapolis, Minnesota, from January 2009 until March 2010. Participants were overweight and obese postmenopausal BC survivors who had completed treatment at least 3 months prior to enrollment and who did not smoke. Twenty-one BC survivors were randomized, via a random number generator computer software, to a 1000-calorie deficit feeding and exercise intervention (CR) or a weight management counseling intervention (WM) for 12 weeks followed by a 6-week follow-up. Body weight, biomarkers, and QOL were measured at baseline, weeks 6, 12, and 18. Body composition and fitness level were measured at only two time points. RESULTS: Twenty-one women were enrolled into the study and 20 completed all time points. Weight loss occurred with both interventions. Body weight in CR changed from 85.5 (95% confidence interval (CI) 77, 94) kg to 76.7 (95% CI 68.1, 85.2) kg, whereas in WM it changed from 98.3 (95% CI 89.8, 106.8) kg to 93.2 (95% CI 84.6, 101.7) kg. Fitness in CR changed from 4.9 (95% CI 4, 5.8) to 6.3 (95% CI 5.4, 7.2). CR led to lower plasma levels of leptin, F2-isoprostanes, and CRP. Quality of life seemed to improve with both interventions, while sleep quality decreased only in CR. CONCLUSIONS: Overweight and obese BC survivors were able to adhere to a strict diet and exercise program, which significantly decreased body weight, increased fitness level, and improved biomarkers and QOL. However, the strict dietary intervention in CR seemed to decrease participants' sleep quality and social relationships. Future larger randomized controlled trials should focus on behavioral modification and personalized nutrition counseling to help breast cancer survivors achieve a sustainable weight loss and fitness level. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02940470.

Plasma F2-isoprostanes Are Positively Associated with Glycemic Load, but Inversely Associated with Dietary Polyunsaturated Fatty Acids and Insoluble Fiber in Postmenopausal Women.

Background: Dietary factors, such as antioxidant nutrients, contribute significantly to the maintenance of an appropriate balance between antioxidant defense and free radical production in the body.Objective: The objective of this study was to examine the relation between oxidative stress as assessed by plasma F2-isoprostane (IsoP) concentration, glycemic load (GL), glycemic index (GI), intake of antioxidant nutrients, dietary fiber, and polyunsaturated fatty acids (PUFAs).Methods: This study was a cross-sectional secondary analysis of baseline data collected from a random sample of 269 postmenopausal women participating in the Minnesota Green Tea Trial. GL, GI, and dietary variables were calculated from the diet history questionnaire. Subjects filled out surveys about the use of anti-inflammatory drugs and physical activity. Plasma IsoP concentration was assessed by GC-mass spectrometry. IsoP concentrations were compared across quartiles of GL, GI, insoluble fiber, PUFAs, and antioxidant nutrients with the use of linear regression.Results: Antioxidant supplement intake, including zinc, copper, vitamin C and vitamin E, was reported by >60% of the participants. Mean intake of PUFAs was 12.5 g. Mean plasma IsoP concentrations increased from 34 to 36.7 pg/mL in the lowest quartiles of GL and GI, respectively, to 45.2 and 41.6 pg/mL, respectively, in the highest quartiles (P-trend = 0.0014 for GL and P-trend = 0.0379 for GI), whereas mean IsoP concentrations decreased from 41.8 pg/mL in the lowest quartile of PUFAs to 34.9 pg/mL in the highest quartile (P-trend = 0.0416). Similarly, mean IsoP concentrations decreased from 44.4 pg/mL in the lowest quartile of insoluble fiber to 36 pg/mL in the highest quartile (P-trend = 0.0243) after adjustment for potential confounders.Conclusions: We concluded that dietary PUFAs and insoluble fiber are inversely associated with oxidative stress whereas GL and GI are positively associated with oxidative stress in postmenopausal women. This trial was registered at clinicaltrials.gov as NCT00917735.

Green Tea Extract and Catechol-O-Methyltransferase Genotype Modify Fasting Serum Insulin and Plasma Adiponectin Concentrations in a Randomized Controlled Trial of Overweight and Obese Postmenopausal Women.

BACKGROUND: Green tea consumption has been associated with favorable changes in body weight and obesity-related hormones, although it is not known whether these changes result from green tea polyphenols or caffeine. OBJECTIVE: We examined the impact of decaffeinated green tea extract (GTE) containing 843 mg of (-)-epigallocatechin-3-gallate on anthropometric variables, obesity-associated hormones, and glucose homeostasis. METHODS: The Minnesota Green Tea Trial was a 12-mo randomized, double-blind, placebo-controlled clinical trial of 937 healthy postmenopausal women assigned to either decaffeinated GTE (1315 mg total catechins/d) or a placebo, stratified by catechol-O-methyltransferase (COMT) genotype. This study was conducted in a subset of 237 overweight and obese participants [body mass index (BMI) ≥25 kg/m(2)]. RESULTS: No changes in energy intake, body weight, BMI, or waist circumference (WC) were observed over 12 mo in women taking GTE (n = 117) or placebo (n = 120). No differences were seen in circulating leptin, ghrelin, adiponectin, or glucose concentrations at month 12. Participants randomly assigned to GTE with baseline insulin ≥10 µIU/mL (n = 23) had a decrease in fasting serum insulin from baseline to month 12 (-1.43 ± 0.59 µIU/mL), whereas those randomly assigned to placebo with baseline insulin ≥10 µIU/mL (n = 19) had an increase in insulin over 12 mo (0.55 ± 0.64 µIU/mL, P < 0.01). Participants with the homozygous high-activity (G/G) form of COMT had significantly lower adiponectin (5.97 ± 0.50 compared with 7.58 ± 0.53 µg/mL, P = 0.03) and greater insulin concentrations (7.63 ± 0.53 compared with 6.18 ± 0.36 µIU/mL, P = 0.02) at month 12 compared with those with the low-activity (A/A) genotype, regardless of treatment group. CONCLUSIONS: Decaffeinated GTE was not associated with reductions in body weight, BMI, or WC and did not alter energy intake or mean hormone concentrations in healthy postmenopausal women over 12 mo. GTE decreased fasting insulin concentrations in those with elevated baseline fasting concentrations. The high-activity form of the COMT enzyme may be associated with elevations in insulin and a reduction in adiponectin concentrations over time. This trial was registered at http://www.clinicaltrials.gov as NCT00917735.

Cross-sectional study of factors influencing sex hormone-binding globulin concentrations in normally cycling premenopausal women.

OBJECTIVE: To assess the relationship between SHBG and 18 other hormonal and metabolic parameters in well characterized, normally cycling premenopausal women. DESIGN: Cross-sectional study. SETTING: University general clinical research center. SUBJECT(S): A total of 319 young healthy women with ovulatory menstrual cycles. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Midfollicular serum SHBG concentrations. RESULT(S): In our final linear regression model, SHBG was negatively associated with bioavailable T and positively associated with adiponectin, associations that were independent from other parameters. SHBG was also positively associated with estrone sulfate, but only when taking into account confounding variables. Unexpectedly, there was no straightforward relationship between SHBG and insulin resistance according to homeostasis-model assessment. CONCLUSION(S): Our results highlight the link between androgen action, as reflected by bioavailable T, and circulating SHBG concentrations in all premenopausal women and speak to the importance of the relationship between SHBG and adiponectin, which is at least in part independent from androgen action. CLINICAL TRIAL REGISTRATION NUMBER: NCT00393172.

Consumption of a high glycemic load but not a high glycemic index diet is marginally associated with oxidative stress in young women.

Research studies have suggested that chronic consumption of high glycemic index foods may lead to chronically high oxidative stress. This is important because oxidative stress is suspected to be an early event in the etiology of many disease processes. We hypothesized that dietary glycemic index and glycemic load were positively associated with oxidative stress assessed by plasma F2-isoprostanes in healthy, premenopausal women (body mass index [BMI] = 24.7 ± 4.8 kg/m(2) and age 25.3 ± 3.5 years, mean ± SD). We measured plasma F2-isoprostanes in 306 healthy premenopausal women at the baseline visit for the Women In Steady Exercise Research study, using gas chromatography-mass spectrometry. Dietary glycemic index and load were calculated from the National Cancer Institute Diet History Questionnaire, and participants were divided into quartiles of dietary glycemic index and of glycemic load. Plasma F2-isoprostanes were compared across quartile groups of dietary glycemic index and glycemic load using linear regression models. Plasma F2-isoprostanes (pg/mL) increased with quartile of glycemic load (test for linear trend, P = .033), and also increased with quartile of glycemic index in participants with BMI ≥ 25 (P = .035) but not in those with BMI <25 (P = .924). After adjustment for BMI, alcohol consumption and total energy intake, both these positive trends remained marginally significant (P = .123 for quartiles of glycemic index and P = .065 for quartiles of glycemic load).