Rye Intake Research Articles

Comment on “Plasma alkylresorcinol metabolite, a biomarker of whole-grain wheat and rye intake, and risk of ischemic stroke: a case–control study”

Comment on “Plasma alkylresorcinol metabolite, a biomarker of whole-grain wheat and rye intake, and risk of ischemic stroke: a case–control study”

Decreased plasma serotonin and other metabolite changes in healthy adults after consumption of wholegrain rye: an untargeted metabolomics study

Wholegrain consumption has been associated with beneficial health effects including reduction of diabetes and cancer risk; however, the underlying mechanisms are not fully understood. The aim of this study was to characterize the effects of wholegrain rye intake on circulating metabolites in a human intervention study using untargeted metabolomics. The intervention consisted of 2 successive 4-wk periods in a randomized crossover design, where 15 adults consumed wholegrain rye bread (WGR) or white wheat bread enriched with fermented rye bran (WW+RB), following a 4-wk rye-free period with white wheat bread (WW). Fasting plasma samples were collected at the end of each period and analyzed using liquid chromatography-mass spectrometry. Metabolic profiles were compared to identify compounds discriminating WGR from the WW+RB and WW periods. Because peripheral serotonin is produced mainly in the gut, a hypothesis of its altered biosynthesis as a response to increased cereal fiber intake was tested by measuring intestinal serotonin of mice fed for 9 wk on a high-fat diet supplemented with different sources of fiber (rye bran flour, ground wheat aleurone, or powdered cellulose). Five endogenous metabolites and 15 rye phytochemicals associated with WGR intake were identified. Plasma concentrations of serotonin, taurine, and glycerophosphocholine were significantly lower after the WGR than WW period (Q<0.05). Concentrations of 2 phosphatidylethanolamine plasmalogens, PE(18:2/P-18:0) and PE(18:2/P-16:0), were lower after the WGR period than the WW+RB period (Q<0.05). The concentration of serotonin was significantly lower in the colonic tissue of mice that consumed rye bran or wheat aleurone compared with cellulose (P<0.001). Wholegrain rye intake decreases plasma serotonin in healthy adults when compared with refined wheat. Intake of rye bran and wheat aleurone decreases colonic serotonin in mice. These results suggest that peripheral serotonin could be a potential link between wholegrain consumption and its associated health effects.Data used in the study were derived from a trial registered at www.clinicaltrials.gov as NCT03550365.

Long-Term Whole Grain Wheat and Rye Intake Reflected by Adipose Tissue Alkylresorcinols and Breast Cancer: A Case-Cohort Study.

Whole grain rye (WGR) and whole grain wheat (WGW) have been suggested to protect against the development of breast cancer. In this study, we estimated long-term intake of WGR and WGW, using both a food frequency questionnaire (FFQ) and alkylresorcinol concentrations in adipose tissue biopsies, in relation to the risk of developing invasive breast cancer in a case-cohort study (n = 414 in the case group, n = 933 in the subcohort group) on the Danish “Diet, Cancer and Health” cohort. The median follow-up time of the subcohort was 5.3 years. Total WGR and WGW intake estimated with FFQ or reflected by total alkylresorcinol concentration in adipose tissue was not significantly associated with risk of breast cancer. However, after adjustment for total WGR and WGW intake, women in the highest quartile of relative WGR intake, reflected by the alkylresorcinol C17:0/C21:0 ratio, had a higher risk of overall breast cancer and estrogen-receptor-positive (ER+) breast cancer than women in the lowest quartile of relative WGR intake, while the risk of estrogen-receptor-negative (ER-) breast cancer incidence was unaffected. Similar results were obtained with the FFQ data. Based on these data, further investigation of the role of specific grain types in reducing or increasing breast cancer risk, and their overall impact on health, is warranted.

Plasma alkylresorcinol metabolite, a biomarker of whole-grain wheat and rye intake, and risk of ischemic stroke: a case-control study

Epidemiologic studies on whole grains and risk of stroke have reported inconsistent results, with some suggesting a protective effect but others showing a null association. The aim of this study was to examine whether plasma 3-(3,5-dihydroxyphenyl)-1-propanoic acid (DHPPA), a biomarker of whole-grain wheat and rye intake, is associated with risk of ischemic stroke. A hospital-based case-control study was conducted between March 2011 and May 2016. Cases (n=990) with first ischemic stroke were matched to controls (n=990) by sex and age. Concentrations of plasma DHPPA were determined by high-performance liquid chromatography-tandem mass spectrometry. We calculated ORs for the association of plasma DHPPA concentrations with ischemic stroke risk through the use of logistic regression. Plasma DHPPA was inversely associated with ischemic stroke risk. After adjustment for potential confounding factors, the ORs for ischemic stroke across increasing quartiles of plasma DHPPA concentrations were 1 (referent), 0.76 (95% CI: 0.58, 0.99), 0.71 (95% CI: 0.54, 0.92), and 0.59 (95% CI: 0.45, 0.77), respectively (P-trend=0.001). The inverse association was also observed in all subgroups of participants according to sex, age, body mass index, smoking status, alcohol consumption, history of hypertension, and history of diabetes. Our study showed that higher plasma DHPPA concentrations were associated with lower risk of ischemic stroke. This finding provides further evidence to support the health benefits of whole-grain consumption.

Increased Plasma Brain-Derived Neurotrophic Factor 10.5 h after Intake of Whole Grain Rye-Based Products in Healthy Subjects.

It has previously been shown in short-term interventions that kernel-based whole grain (WG) rye products have beneficial effects on test markers related to obesity and type 2 diabetes (T2D). T2D increases the risk of several severe health issues, including declined cognitive functions. The protein brain-derived neurotrophic factor (BDNF) is suggested to be a potential biomarker for neuronal integrity. The aim of this study was to investigate the effect on plasma BDNF concentrations, 10.5 h after the intake of WG rye. Healthy young adults were provided late evening meals consisting of WG rye kernel-based bread (RKB) or a white wheat flour-based bread (reference product (WWB)), in a randomized cross-over design. The BDNF concentrations were investigated at fasting in the morning 10.5 h after single evening meals with RKB and WWB, and also after three consecutive evening meals with RKB and WWB, respectively. No difference was observed in the BDNF concentrations depending on the priming setting (p > 0.05). The RKB evening meals increased the BDNF concentrations by 27% at fasting (p = 0.001), compared to WWB. The increase of BDNF after the RKB indicate that, in addition to anti-diabetic properties, the dietary fiber in WG rye may support neuronal integrity.

CELIAC DISEASE

Background: Celiac disease (CD) is an immune-mediated enteropathy stimulatedby intake of gluten, rye and barley in genetically prone persons. In children, gastrointestinalsymptoms are usual if disease is diagnosed in first two years of life but as the age at onset of theillness advances to late years, extra-intestinal manifestations have been increasingly recognizedaffecting almost all organ systems. Objectives: To determine the prevalence of varied clinicalmanifestations of CD in children. To assess classical and non-classical features in patients withCD. Study Design: Cross sectional study. Setting: Nishtar Hospital Multan. Period: July 2016to July 2017. Material &amp; Methods: Ninety-six patients with celiac disease were analyzed. Thediagnosis was confirmed by serological antibodies and positive biopsy wherever needed. Allthe cases were evaluated for different intestinal or extra-intestinal features. Also the cases werecategorized based on their primary clinical features into two groups. The classical group hadCD patients with usual symptoms. The non-classical group had atypical symptoms. Results:The mean age of CD patients at the time of diagnosis was 5.98 ± 3.19 years. Median valuefor duration of clinical symptoms was 24 months. The common typical clinical presentationsincluded failure to thrive 86 (89.6%), short stature 86 (89.6%), diarrhea 78 (81.3%), unexplainedanemia 78 (81.3%) and clubbing 41 (42.7%). The atypical features noted in our study wereconstipation 21 (21.9%), hypertransaminasemia 38 (39.6 %) and neurological symptoms likeirritability/ behavioral changes 41 (42.7%). Family history of gluten allergy or other autoimmunediseases was present in 29 (30.2%) of patients. Children presented with non-classical symptomswere older than 2 years of age and they showed high prevalence of associated immune andnon immune diseases compared to those in classical group. Conclusion: The knowledge ofvaried behavior of CD may prevent delay in diagnosis. CD must be particularly screened inpatients with unexpected anemia, rickets, clubbing, short stature and in cases with positivehistory in family.

Evaluation of alkylresorcinols in adipose tissue biopsies as a long-term biomarker of whole-grain wheat and rye intake in free-living Swedish men and women.

Wheat and rye, the most consumed whole grains (WG) in the Nordic countries, contain alkylresorcinols (AR) in their bran. AR concentrations in human adipose tissue might reflect long-term WG rye and wheat intake. We aimed to evaluate AR concentrations in adipose tissue biopsies as a long-term biomarker of WG wheat and rye intake in free-living Swedish men and women. Cross-sectional study. AR concentrations in adipose tissue biopsies were analysed and compared with long-term WG intake assessed by three FFQ (repeated over a period of 14 years in men, 17 years in women) and with plasma AR concentrations. The Cohort of Swedish Men between 1997 and 2010 and the Swedish Mammography Cohort between 1987 and 2003, Sweden. Men (n 149) and women (n 109). Long-term WG rye intake estimated with repeated FFQ correlated (r=0·31-0·41, P<0·01) with adipose-tissue AR concentrations, while WG wheat intake correlated only weakly (r=0·17-0·33, P<0·05). Total AR concentration in adipose tissue was 61 % lower in women than in men at similar energy-adjusted WG wheat and rye intakes, but plasma concentrations were similar. AR concentrations in adipose tissue correlated well with plasma concentrations (r=0·49-0·81, P<0·001). AR in adipose tissue reflected long-term WG rye but not WG wheat intake, probably due to poor precision in estimating WG wheat intake by FFQ. AR in adipose tissue appears promising as a biomarker of long-term WG rye intake but should be adjusted for sex.

Plasma Alkylresorcinol Metabolite, a Biomarker of Whole-Grain Wheat and Rye Intake, and Risk of Type 2 Diabetes and Impaired Glucose Regulation in a Chinese Population.

To examine the association of plasma alkylresorcinol metabolite 3-(3,5-dihydroxyphenyl)-1-propanoic acid (DHPPA), a biomarker of whole-grain wheat and rye intake, with type 2 diabetes (T2D) and impaired glucose regulation (IGR) in a Chinese population. A total of 1,060 newly diagnosed T2D patients, 736 newly diagnosed IGR patients, and 1,443 control subjects with normal glucose tolerance were recruited in the case-control study. Plasma DHPPA concentrations were determined by high-performance liquid chromatography-tandem mass spectroscopy. Multivariate logistic regression analysis was used to evaluate the independent association of plasma DHPPA concentrations with the likelihood of T2D and IGR. After adjustment for age, sex, BMI, and family history of diabetes, the odds ratios (95% CI) of T2D and IGR were 0.57 (0.45, 0.73) and 0.66 (0.50, 0.85), respectively, comparing the lowest with the highest quartile of plasma DHPPA concentrations. Further adjustment for current smoking status, current alcohol consumption, physical activity, history of hypertension, and educational level did not change the observed association materially. Similar results were also obtained in T2D and IGR groups combined. The inverse association of plasma DHPPA with T2D persisted in stratified analyses according to age, sex, BMI, current smoking status, current alcohol consumption, physical activity, family history of diabetes, and history of hypertension. These findings suggested that higher plasma DHPPA concentrations were associated with lower odds of T2D and IGR. Further studies are warranted to confirm these findings in prospective cohorts.

Novel urinary alkylresorcinol metabolites as biomarkers of whole grain intake in free-living Swedish adults.

Most studies on the role of whole grain for health rely on self-reported intake data, which are prone to measurement errors. There is a need for dietary biomarkers that can provide an objective measure of intake. Alkylresorcinols (AR) and their main metabolites 3,5-dihydroxybenzoic acid (DHBA) and 3-(3,5-dihydroxyphenyl)-propanoic acid (DHPPA) have been proposed as biomarkers for whole grain (WG) wheat and rye intake. The medium-term reproducibility and relative validity of four putative urinary AR metabolites (3,5-dihydroxycinnamic acid (DHCA), 5-(3,5-dihydroxyphenyl) pentanoic acid (DHPPTA), 2-(3,5-dihydroxybenzamido)acetic acid (DHBA-glycine) and 3,5-dihydroxycinnamic acid amide (DHCA-amide)) as biomarkers for WG intake were investigated. Three-day weighed food records and 24-h urine samples from two occasions 2-3 months apart were obtained from 69 Swedish adults. WG intake was calculated and urinary AR metabolites were analyzed. The medium-term reproducibility determined for DHCA, DHPPTA, and DHBA-glycine varied from moderate-to-excellent (intra-class correlation coefficient = 0.63-0.85). Moreover, DHCA and DHPPTA excretion correlated well with self-reported total WG intake (r=0.55, p<0.001 and r=0.42, p<0.001, respectively). DHCA or DHPPTA excretion in 24-h urine might be a suitable medium- to long-term biomarker of WG wheat and rye intake. These findings need to be confirmed in populations with low and infrequent WG intake.

Whole-Grain Intake, Reflected by Dietary Records and Biomarkers, Is Inversely Associated with Circulating Insulin and Other Cardiometabolic Markers in 8- to 11-Year-Old Children

Background: Whole-grain consumption seems to be cardioprotective in adults, but evidence in children is limited.Objective: We investigated whether intakes of total whole grain and dietary fiber as well as specific whole grains were associated with fat mass and cardiometabolic risk profile in children.Methods: We collected cross-sectional data on parental education, puberty, diet by 7-d records, and physical activity by accelerometry and measured anthropometry, fat mass index by dual-energy X-ray absorptiometry, and blood pressure in 713 Danish children aged 8-11 y. Fasting blood samples were obtained and analyzed for alkylresorcinols, biomarkers of whole-grain wheat and rye intake, HDL and LDL cholesterol, triacylglycerols, insulin, and glucose. Linear mixed models included puberty, parental education, physical activity, and intakes of energy, fruit and vegetables, saturated fat, and n-3 (ω-3) polyunsaturated fatty acids.Results: Median (IQR) whole-grain and dietary fiber intakes were 52 g/d (35-72 g/d) and 17 g/d (14-22 g/d), respectively. Fourteen percent of children were overweight or obese and most had low-risk cardiometabolic profiles. Dietary whole-grain and fiber intakes were not associated with fat mass index but were inversely associated with serum insulin [both P < 0.01; e.g., with 0.68 pmol/L (95% CI: 0.26, 1.10 pmol/L) lower insulin · g whole grain-1 · MJ-1]. Whole-grain oat intake was inversely associated with fat mass index, systolic blood pressure, and LDL cholesterol (all P < 0.05) as well as insulin (P = 0.003), which also tended to be inversely associated with whole-grain rye intake (P = 0.11). Adjustment for fat mass index did not change the associations. The C17-to-C21 alkylresorcinol ratio, reflecting whole-grain rye to wheat intake, was inversely associated with insulin (P < 0.001).Conclusions: Higher whole-grain intake was associated with lower serum insulin independently of fat mass in 8- to 11-y-old Danish children. Whole-grain oat intake was linked to an overall protective cardiometabolic profile, and whole-grain rye intake was marginally associated with lower serum insulin. This supports whole grains as healthy dietary components in childhood. This trial was registered at clinicaltrials.gov as NCT01577277.

A lifestyle intervention among elderly men on active surveillance for non-aggressive prostate cancer: a randomised feasibility study with whole-grain rye and exercise

BackgroundThe prognosis for men with non-aggressive prostate cancer is good, and several studies have investigated the impact of lifestyle changes including physical activity and diet on the prognosis. Despite positive results in animal studies and a few human interventions with whole-grain rye on markers of prostate cancer progression, the feasibility of trials investigating such dietary changes in combination with physical activity remains largely unstudied. The primary aim was to investigate the feasibility of an intervention with high whole-grain rye intake and vigorous physical activity for 6 months in men diagnosed with prostate cancer.MethodsIn total, 26 men (53–72 years) recently diagnosed with non-aggressive prostate cancer and on active surveillance, were enrolled in 2011–2012 and randomly assigned to an intervention or a control group. The intervention included 170 g/day of whole-grain rye and 3 × 45 minutes/week of vigorous physical activity. The duration of the intervention was 6 months and end of follow-up 12 months after baseline. Clinic visits were scheduled at baseline and 3, 6 and 12 months after baseline. Compliance with the intervention was evaluated by diaries, food frequency questionnaires, biomarkers, and heart rate monitor data. The effect of the intervention was evaluated by linear multiple regression analysis.ResultsIn the intervention group, the mean daily intake of whole-grain rye measured from diaries was 146 g (SD: 19) for the first 3 months and 125 g (SD: 40) for the last 3 months of the intervention. The median level (5th and 95th percentiles) of vigorous physical activity was 91 (17, 193) min/week for the first 3 months and 66 (13, 259) min/week for the last 3 months. No recordings of physical activity were done for the control group. Aerobic fitness (VO2 peak) increased in the intervention group compared to the control group after the intervention. No effects were found on other cardio-metabolic outcomes or prostate cancer progression.ConclusionsThe lifestyle intervention appeared feasible for 6 months among Danish men and the results are encouraging for conducting full-scale studies, where the impact of whole-grain rye and vigorous physical activity on prostate cancer progression and metabolic parameters can be evaluated.Trial registrationClinicalTrials.gov, NCT01300104. Registered on 18 February 2011.

Carotenoids and alkylresorcinols as objective biomarkers of diet quality when assessing the validity of a web-based food record tool and a food frequency questionnaire in a middle-aged population

Recently, two web-based dietary assessment tools were developed; a 4-day food record tool (the Riksmaten method), and a food frequency questionnaire (MiniMeal-Q). The aim of this study was to use objective biomarkers to examine the ability of the two methods to capture habitual dietary intake. In total, 200 individuals from the pilot study of the Swedish CArdioPulmonary bioImage Study (SCAPIS) participated. Plasma concentration of carotenoids were determined with high-performance liquid chromatography (HPLC) and used as biomarkers of fruit and vegetable intake. A gas chromatography mass spectrometry (GC-MS) method was used to quantify alkylresorcinol homologues, which were used as biomarkers of whole grain wheat and rye intake. The correlations between energy-adjusted fruit and vegetable intakes and plasma carotenoid concentrations (except lycopene) were stronger amongst women than men (r = 0.46 and r = 0.20 for the Riksmaten method, and r = 0.50 and r = 0.31 for MiniMeal-Q, respectively). For whole grains, the correlations of energy-adjusted intakes and alkylresorcinols were higher using the Riksmaten method (r = 0.30 and r = 0.29 for women and men) than the MiniMeal-Q (r = 0.25 and r = 0.20, respectively). In regression analyses between plasma carotenoids (except lycopene) and reported intake of fruits and vegetables, the R2 were 21.6 % and 5.1 % for women and men by the Riksmaten method, and correspondingly, 18.0 % and 6.6 % by the MiniMeal-Q. In the final full models, adjusted for smoking and BMI, all regression models remained statistically significant. The regression analyses of plasma alkylresorcinols and reported intake of whole grains showed an R2 of 9.4 % and 9.7 % for women and men by the Riksmaten method, and correspondingly, 5.3 % and 8.4 % by the MiniMeal-Q. In the final full models, adjusted for smoking and age, all regression models remained statistically significant, except for women in MiniMeal-Q. Both dietary assessment methods were able to capture dietary intake based on food groups with a similar precision. Agreements with objective biomarkers ranged from low to moderate, depending on sex and diet quality indicator. While the ability to capture whole grain intake was weak for both methods and sexes, the assessment of vegetable and fruit intake performed in a satisfactory manner for women in both methods.

Plasma alkylresorcinols, biomarkers of whole-grain wheat and rye intake, and risk of type 2 diabetes in Scandinavian men and women

Background: Studies that use dietary biomarkers to investigate the association between whole-grain intake and the risk of developing type 2 diabetes (T2D) are lacking.Objective: We examined the association between plasma total alkylresorcinols and the alkylresorcinol C17:0-to-C21:0 ratio, biomarkers of whole-grain wheat and rye intake and relative whole-grain rye over whole-grain wheat intake, respectively, and the risk of T2D among Scandinavian men and women.Design: A nested case-control study was established within the Northern Sweden Health and Disease Study and the Danish Diet, Cancer and Health cohort. Alkylresorcinol concentrations and the ratios of C17:0 to C21:0 were determined in plasma samples from 931 case-control pairs. ORs for T2D were calculated for plasma total alkylresorcinol concentration or C17:0-to-C21:0 ratio in quartiles with the use of conditional logistic regression that was adjusted for potential confounders. Additional analyses with whole-grain wheat and rye intake estimated from food-frequency questionnaires (FFQs) as exposures were also performed.Results: The plasma total alkylresorcinol concentration was not associated with T2D risk (OR: 1.34; 95% CI: 0.95, 1.88) for the highest compared with the lowest quartiles in multivariable adjusted models. However, the C17:0-to-C21:0 ratio was associated with a lower diabetes risk (OR: 0.54; 95% CI: 0.37, 0.78). Analyses with whole-grain intake estimated from FFQs yielded similar results.Conclusions: Total whole-grain wheat and rye intake, reflected by alkylresorcinols in plasma, was not associated with a lower risk of T2D in a population with high whole-grain intake. In contrast, the proportion of whole-grain rye to whole-grain wheat intake, indicated by the plasma C17:0-to-C21:0 ratio, was inversely associated with T2D. This suggests that whole-grain intake dominated by rye may be favorable for T2D prevention.

Validation of Reported Whole-Grain Intake from a Web-Based Dietary Record against Plasma Alkylresorcinol Concentrations in 8- to 11-Year-Olds Participating in a Randomized Controlled Trial

Background: Whole-grain (WG) intake is important for human health, but accurate intake estimation is challenging. Use of a biomarker for WG intake provides a possible way to validate dietary assessment methods.Objective: Our aim was to validate WG intake from 2 diets reported by children, using plasma alkylresorcinol (AR) concentrations, and to investigate the 3-mo reproducibility of AR concentrations and reported WG intake.Methods: AR concentrations were analyzed in fasting blood plasma samples, and WG intake was estimated in a 7-d web-based diary by 750 participants aged 8–11 y in a 2 school meal × 3 mo crossover trial. Reported WG intake and plasma AR concentrations were compared when children ate their usual bread-based lunch (UBL) and when served a hot lunch meal (HLM). Correlations and cross-classification were used to rank subjects according to intake. The intraclass correlation coefficients (ICCs) between subjects’ measurements at baseline and after the UBL were used to assess reproducibility.Results: Correlations between reported WG wheat + rye intake and plasma AR were 0.40 and 0.37 (P < 0.001) for the UBL and the HLM diets, and 78% and 77% were classified in the same or adjacent quartiles for the UBL and HLM diets, respectively. The ICC over 3 mo was 0.47 (95% CI: 0.38, 0.55) for plasma total ARs and 0.64 (95% CI: 0.58, 0.70) for reported WG intake. Correlations were higher when using the AR C17:0 homolog as a biomarker, reflecting rye intake instead of plasma total ARs [UBL: r = 0.47; HLM: r = 0.43, P < 0.001; ICC = 0.51 (95% CI: 0.43, 0.59)].Conclusions: Self-reported WG wheat + rye intake among children showed moderate correlations with plasma AR concentrations. Substantial intraindividual variation was found in WG intake and plasma AR concentrations. The AR homolog C17:0 may be used as a biomarker for WG intake when the WG intake primarily comes from rye as in the present study. This trial was registered at clinicaltrials.gov as NCT01457794.

A high-throughput method for liquid chromatography–tandem mass spectrometry determination of plasma alkylresorcinols, biomarkers of whole grain wheat and rye intake

Plasma alkylresorcinols are increasingly analyzed in cohort studies to improve estimates of whole grain intake and their relationship with disease incidence. Current methods require large volumes of solvent (>10 ml/sample) and have relatively low daily sample throughput. We tested five different supported extraction methods for extracting alkylresorcinols from plasma and improved a normal-phase liquid chromatography coupled to a tandem mass spectrometer method to reduce sample analysis time. The method was validated and compared with gas chromatography–mass spectrometry analysis. Sample preparation with HybridSPE supported extraction was most effective for alkylresorcinol extraction, with recoveries of 77–82% from 100 μl of plasma. The use of 96-well plates allowed extraction of 160 samples per day. Using a 5-cm NH2 column and heptane reduced run times to 3 min. The new method had a limit of detection and limit of quantification equivalent to 1.1–1.8 nmol/L and 3.5–6.1 nmol/L plasma, respectively, for the different alkylresorcinol homologues. Accuracy was 93–105%, and intra- and inter-batch precision values were 4–18% across different plasma concentrations. This method makes it possible to quantify plasma alkylresorcinols in 100 μl of plasma at a rate of at least 160 samples per day without the need for large volumes of organic solvents.

Validity of a web-based dietary questionnaire designed especially to measure the intake of phyto-oestrogens.

A diet questionnaire (DQ) designed to assess habitual diet and phyto-oestrogen intake was developed. This study aimed to examine the validity of the DQ in men, with and without having prostate cancer. The DQ was validated against alkylresorcinol metabolites measured in urine as objective biomarkers of whole grain wheat and rye (WG) intake, and a 4-d estimated food record (FR) was used for relative comparison. Participants (n 61) completed both methods and provided spot urine samples. We found a statistically significant correlation between the DQ and FR for reported whole grain intake and isoflavonoids, as well as for intake of macronutrients, except protein. The correlation coefficient between the two methods was on average r 0·30, lowest for lignans (r -0·11) and highest for alcohol (r 0·65). Reported energy intake was lower in the DQ compared with FR (8523 v. 9249 kJ (2037 v. 2211kcal), respectively; P=0·014). Bland-Altman plots showed an acceptable agreement; most cases were within the limits (95% CI) of agreement on reported energy intake, as well as intake of macronutrients, except protein (which was underestimated in the DQ compared with the FR). The correlation of alkylresorcinol with WG intake was statistically significant in the DQ (r 0·31, P=0·015), but not in the FR (r 0·18, P=0·12) and the weighted κ was 0·29 and 0·11, respectively. In conclusion, the results showed that the DQ have a reasonable validity for measuring WG intake and most nutrients, and, after some adjustments regarding protein intake assessment have been made, the DQ will be a promising tool.

Discovery of urinary biomarkers of whole grain rye intake in free-living subjects using nontargeted LC-MS metabolite profiling.

Whole grain (WG) intake is associated with decreased risk of developing colorectal cancer, type 2 diabetes, and cardiovascular disease and its comorbidities. However, the role of specific grains is unclear. Moreover, intake of specific WG is challenging to measure accurately with traditional dietary assessment methods. Our aim was to use nontargeted metabolite profiling to discover specific urinary biomarkers for WG rye to objectively reflect intake under free-living conditions. WG rye intake was estimated by weighed food records, and 24 h urine collections were analyzed by LC-MS. Multivariate modeling was undertaken by repeated double cross-validated partial least squares regression against reported WG rye intake, which correlated well with multivariate prediction estimates (r = 0.67-0.80, p < 0.001), but not with intakes of WG wheat or oats. Hydroxyhydroxyphenyl acetamide sulfate, 3,5-dihydroxyphenylpropionic acid sulfate, caffeic acid sulfate, and hydroxyphenyl acetamide sulfate were among the 20 features that had the greatest potential as intake biomarkers of WG. In addition, three compounds exhibited MS/MS fragmentation of carnitine structures. With this nontargeted approach, we confirmed the specificity of alkylresorcinol metabolites as biomarkers for WG rye intake, but also discovered other compounds that should be evaluated as putative biomarkers in future studies.

Alkylresorcinols in adipose tissue biopsies as biomarkers of whole-grain intake: an exploratory study of responsiveness to advised intake over 12 weeks.

Alkylresorcinols (ARs) have been suggested as biomarkers of whole-grain wheat and rye intake. Plasma AR concentrations have a short half-life; hence, long-term biomarkers are needed. This study evaluated the responsiveness of ARs in adipose tissue biopsies as biomarkers after a whole-grain intake intervention. Samples and data of 27 participants from a 12-week randomized parallel-group dietary intervention were available. The participants were replacing their habitual diet with a whole-grain-enriched diet (WGDG) or a refined grain diet (RDG) during the intervention. Blood samples and adipose tissue biopsies were collected at baseline and after 12 weeks, and AR concentrations in the plasma and adipose tissues from the participants were compared against estimated whole-grain intake. AR concentrations in the adipose tissue and plasma did not change after 12 weeks in the WGDG group, as no significant increase in whole-grain intake was observed, but was significantly lower than baseline in the RDG group (P<0.05), owing to decreased whole-grain intake in this group. Plasma and adipose tissue AR concentrations were significantly higher in the WGDG group than in the RDG group (P<0.05), and were highly correlated with average whole-grain intake estimated by food records (Spearman's r=0.60-0.72 (P<0.05, n=16) for total and individual AR homolog concentrations in the plasma; r=0.60--0.84, (P<0.05, n=16) for total and individual AR homolog concentrations in the adipose tissue). In this small pilot study, AR concentrations in adipose tissue responded to reduced intake of whole grain over 12 weeks. Although not significantly different from plasma AR, adipose tissue AR concentrations were highly correlated with whole-grain intake after a 12-week intervention. These results show that adipose tissue AR concentrations have promise as biomarkers of whole-grain wheat and rye intake. Larger studies are needed to evaluate whether they are better long-term biomarkers than AR in the plasma.

Determination of alkylresorcinols and their metabolites in biological samples by gas chromatography-mass spectrometry.

High throughput GC-MS methods for quantification of alkylresorcinols (AR), biomarkers of whole grain wheat and rye intake, in plasma and adipose tissue and their metabolites in urine were developed and optimised. Alkylresorcinols in plasma (200μL) and adipose tissues (10-50mg) were extracted with diethyl ether, whereas main AR metabolites such as DHBA and DHPPA and newly identified metabolites in urine (50μL) were extracted with ethyl acetate after enzymatic deconjugation. All extracts were purified on OASIS-MAX solid phase extraction cartridges. Plasma and adipose tissue sample extracts were then derivatised with trifluoroacetic anhydride and reconstituted in undecane, whereas AR metabolites in urine samples were derivatised with BSTFA+TMCS (99:1, v/v, 100μL). Prepared samples were quantified by GC-MS (EI-SIM). Analysis of all compounds in the different matrices showed good selectivity, sensitivity, linearity, precision (<15% within and between batches), adequate recovery (75-108%), and short total run time (10-12min). The methods developed are applicable to large-scale sample sets such as epidemiological studies.

Simultaneous Pharmacokinetic Modeling of Alkylresorcinols and Their Main Metabolites Indicates Dual Absorption Mechanisms and Enterohepatic Elimination in Humans

Background:Alkylresorcinols have proven to be useful biomarkers of whole-grain wheat and rye intake in many nutritional studies. To improve their utility, more knowledge regarding the fate of alkylresorcinols and their metabolites after consumption is needed. Objective:The objective of this study was to develop a combined pharmacokinetic model for plasma concentrations of alkylresorcinols and their 2 major metabolites, 3,5-dihydroxybenzoic acid (DHBA) and 3-(3,5-dihydroxyphenyl)-propanoic acid (DHPPA). Methods:The model was established by using plasma samples collected from 3 women and 2 men after a single dose (120 g) of rye bran and validated against fasting plasma concentrations from 8 women and 7 men with controlled rye bran intake (23, 45, or 90 g/d). Alkylresorcinols in the lymph and plasma of a pig fed a single alkylresorcinol dose (1.3 mmol) were quantified to assess absorption. Human ileostomal effluent and pig bile after high and low alkylresorcinol doses were analyzed to evaluate biliary alkylresorcinol metabolite excretion. Results:The model contained 2 absorption compartments: 1 that transferred alkylresorcinols directly to the systematic circulation and 1 in which a proportion of absorbed alkylresorcinols was metabolized before reaching the systemic circulation. Plasma concentrations of alkylresorcinols and their metabolites depended on absorption and formation, respectively, and the mean ± SEM terminal elimination half-life of alkylresorcinols (1.9 ± 0.59 h), DHPPA (1.5 ± 0.26 h), and DHBA (1.3 ± 0.22 h) did not differ. The model accurately predicted alkylresorcinol and DHBA concentrations after repeated alkylresorcinol intake but DHPPA concentration was overpredicted, possibly because of poorly modeled enterohepatic circulation. During the 8 h following administration, <2% of the alkylresorcinol dose was recovered in the lymph. DHPPA was identified in both human ileostomal effluent and pig bile, indicating availability of DHPPA for absorption and enterohepatic circulation. Conclusion:Intact alkylresorcinols have advantages over DHBA and DHPPA as plasma biomarkers for whole-grain wheat and rye intake because of lower susceptibility to factors other than alkylresorcinol intake.