Fecal Metagenomics to Identify Biomarkers of Food Intake in Healthy Adults: Findings from Randomized, Controlled, Nutrition Trials.

BACKGROUND: Undigested components of the human diet affect the composition and function of the microorganisms present in the gastrointestinal tract. Techniques like metagenomic analyses allow researchers to study functional capacity, thus revealing the potential of using metagenomic data for developing objective biomarkers of food intake. OBJECTIVES: As a continuation of our previous work using 16S and metabolomic datasets, we aimed to utilize a computationally intensive, multivariate, machine-learning approach to identify fecal KEGG (Kyoto encyclopedia of genes and genomes) Orthology (KO) categories as biomarkers that accurately classify food intake. METHODS: Data were aggregated from 5 controlled feeding studies that studied the individual impact of almonds, avocados, broccoli, walnuts, barley, and oats on the adult gastrointestinal microbiota. Deoxyribonucleic acid from preintervention and postintervention fecal samples underwent shotgun genomic sequencing. After preprocessing, sequences were aligned and functionally annotated with Double Index AlignMent Of Next-generation sequencing Data v2.0.11.149 and MEtaGenome ANalyzer v6.12.2, respectively. After the count normalization, the log of the fold change ratio for resulting KOs between pre- and postintervention of the treatment group against its corresponding control was utilized to conduct differential abundance analysis. Differentially abundant KOs were used to train machine-learning models examining potential biomarkers in both single-food and multi-food models. RESULTS: We identified differentially abundant KOs in the almond (n = 54), broccoli (n = 2474), and walnut (n = 732) groups (q < 0.20), which demonstrated classification accuracies of 80%, 87%, and 86% for the almond, broccoli, and walnut groups using a random forest model to classify food intake into each food group's respective treatment and control arms, respectively. The mixed-food random forest achieved 81% accuracy. CONCLUSIONS: Our findings reveal promise in utilizing fecal metagenomics to objectively complement self-reported measures of food intake. Future research on various foods and dietary patterns will expand these exploratory analyses for eventual use in feeding study compliance and clinical settings.

Separation of Lipoproteins for Quantitative Analysis of 14C-Labeled Lipid-Soluble Compounds by Accelerator Mass Spectrometry.

To date, 14C tracer studies using accelerator mass spectrometry (AMS) have not yet resolved lipid-soluble analytes into individual lipoprotein density subclasses. The objective of this work was to develop a reliable method for lipoprotein separation and quantitative recovery for biokinetic modeling purposes. The novel method developed provides the means for use of small volumes (10-200 µL) of frozen plasma as a starting material for continuous isopycnic lipoprotein separation within a carbon- and pH-stable analyte matrix, which, following post-separation fraction clean up, created samples suitable for highly accurate 14C/12C isotope ratio determinations by AMS. Manual aspiration achieved 99.2 ± 0.41% recovery of [5-14CH3]-(2R, 4'R, 8'R)-α-tocopherol contained within 25 µL plasma recovered in triacylglycerol rich lipoproteins (TRL = Chylomicrons + VLDL), LDL, HDL, and infranatant (INF) from each of 10 different sampling times for one male and one female subject, n = 20 total samples. Small sample volumes of previously frozen plasma and high analyte recoveries make this an attractive method for AMS studies using newer, smaller footprint AMS equipment to develop genuine tracer analyses of lipophilic nutrients or compounds in all human age ranges.

Fecal Metabolites as Biomarkers for Predicting Food Intake by Healthy Adults.

BACKGROUND: The fecal metabolome is affected by diet and includes metabolites generated by human and microbial metabolism. Advances in -omics technologies and analytic approaches have allowed researchers to identify metabolites and better utilize large data sets to generate usable information. One promising aspect of these advancements is the ability to determine objective biomarkers of food intake. OBJECTIVES: We aimed to utilize a multivariate, machine learning approach to identify metabolite biomarkers that accurately predict food intake. METHODS: Data were aggregated from 5 controlled feeding studies in adults that tested the impact of specific foods (almonds, avocados, broccoli, walnuts, barley, and oats) on the gastrointestinal microbiota. Fecal samples underwent GC-MS metabolomic analysis; 344 metabolites were detected in preintervention samples, whereas 307 metabolites were detected postintervention. After removing metabolites that were only detected in either pre- or postintervention and those undetectable in ≥80% of samples in all study groups, changes in 96 metabolites relative concentrations (treatment postintervention minus preintervention) were utilized in random forest models to 1) examine the relation between food consumption and fecal metabolome changes and 2) rank the fecal metabolites by their predictive power (i.e., feature importance score). RESULTS: Using the change in relative concentration of 96 fecal metabolites, 6 single-food random forest models for almond, avocado, broccoli, walnuts, whole-grain barley, and whole-grain oats revealed prediction accuracies between 47% and 89%. When comparing foods with one another, almond intake was differentiated from walnut intake with 91% classification accuracy. CONCLUSIONS: Our findings reveal promise in utilizing fecal metabolites as objective complements to certain self-reported food intake estimates. Future research on other foods at different doses and dietary patterns is needed to identify biomarkers that can be applied in feeding study compliance and clinical settings.

Fecal Bacteria as Biomarkers for Predicting Food Intake in Healthy Adults.

BACKGROUND: Diet affects the human gastrointestinal microbiota. Blood and urine samples have been used to determine nutritional biomarkers. However, there is a dearth of knowledge on the utility of fecal biomarkers, including microbes, as biomarkers of food intake. OBJECTIVES: This study aimed to identify a compact set of fecal microbial biomarkers of food intake with high predictive accuracy. METHODS: Data were aggregated from 5 controlled feeding studies in metabolically healthy adults (n = 285; 21-75 y; BMI 19-59 kg/m2; 340 data observations) that studied the impact of specific foods (almonds, avocados, broccoli, walnuts, and whole-grain barley and whole-grain oats) on the human gastrointestinal microbiota. Fecal DNA was sequenced using 16S ribosomal RNA gene sequencing. Marginal screening was performed on all species-level taxa to examine the differences between the 6 foods and their respective controls. The top 20 species were selected and pooled together to predict study food consumption using a random forest model and out-of-bag estimation. The number of taxa was further decreased based on variable importance scores to determine the most compact, yet accurate feature set. RESULTS: Using the change in relative abundance of the 22 taxa remaining after feature selection, the overall model classification accuracy of all 6 foods was 70%. Collapsing barley and oats into 1 grains category increased the model accuracy to 77% with 23 unique taxa. Overall model accuracy was 85% using 15 unique taxa when classifying almonds (76% accurate), avocados (88% accurate), walnuts (72% accurate), and whole grains (96% accurate). Additional statistical validation was conducted to confirm that the model was predictive of specific food intake and not the studies themselves. CONCLUSIONS: Food consumption by healthy adults can be predicted using fecal bacteria as biomarkers. The fecal microbiota may provide useful fidelity measures to ascertain nutrition study compliance.

Walnut Consumption Alters the Gastrointestinal Microbiota, Microbially Derived Secondary Bile Acids, and Health Markers in Healthy Adults: A Randomized Controlled Trial.

Background: Epidemiologic data suggest that diets rich in nuts have beneficial health effects, including reducing total and cause-specific mortality from cancer and heart disease. Although there is accumulating preclinical evidence that walnuts beneficially affect the gastrointestinal microbiota and gut and metabolic health, these relations have not been investigated in humans. Objective: We aimed to assess the impact of walnut consumption on the human gastrointestinal microbiota and metabolic markers of health. Methods: A controlled-feeding, randomized crossover study was undertaken in healthy men and women [n = 18; mean age = 53.1 y; body mass index (kg/m2): 28.8]. Study participants received isocaloric diets containing 0 or 42 g walnuts/d for two 3-wk periods, with a 1-wk washout between diet periods. Fecal and blood samples were collected at baseline and at the end of each period to assess secondary outcomes of the study, including effects of walnut consumption on fecal microbiota and bile acids and metabolic markers of health. Results: Compared with after the control period, walnut consumption resulted in a 49-160% higher relative abundance of Faecalibacterium, Clostridium, Dialister, and Roseburia and 16-38% lower relative abundances of Ruminococcus, Dorea, Oscillospira, and Bifidobacterium (P < 0.05). Fecal secondary bile acids, deoxycholic acid and lithocholic acid, were 25% and 45% lower, respectively, after the walnut treatment compared with the control treatment (P < 0.05). Serum LDL cholesterol and the noncholesterol sterol campesterol concentrations were 7% and 6% lower, respectively, after walnut consumption compared with after the control treatment (P < 0.01). Conclusion: Walnut consumption affected the composition and function of the human gastrointestinal microbiota, increasing the relative abundances of Firmicutes species in butyrate-producing Clostridium clusters XIVa and IV, including Faecalibacterium and Roseburia, and reducing microbially derived, proinflammatory secondary bile acids and LDL cholesterol. These results suggest that the gastrointestinal microbiota may contribute to the underlying mechanisms of the beneficial health effects of walnut consumption. This trial was registered at www.clinicaltrials.gov as NCT01832909.

Absorption and metabolism of isothiocyanates formed from broccoli glucosinolates: effects of BMI and daily consumption in a randomised clinical trial.

Sulphoraphane originates from glucoraphanin in broccoli and is associated with anti-cancer effects. A preclinical study suggested that daily consumption of broccoli may increase the production of sulphoraphane and sulphoraphane metabolites available for absorption. The objective of this study was to determine whether daily broccoli consumption alters the absorption and metabolism of isothiocyanates derived from broccoli glucosinolates. We conducted a randomised cross-over human study (n 18) balanced for BMI and glutathione S-transferase µ 1 (GSTM1) genotype in which subjects consumed a control diet with no broccoli (NB) for 16 d or the same diet with 200 g of cooked broccoli and 20 g of raw daikon radish daily for 15 d (daily broccoli, DB) and 100 g of broccoli and 10 g of daikon radish on day 16. On day 17, all subjects consumed a meal of 200 g of broccoli and 20 g of daikon radish. Plasma and urine were collected for 24 h and analysed for sulphoraphane and metabolites of sulphoraphane and erucin by triple quadrupole tandem MS. For subjects with BMI >26 kg/m2 (median), plasma AUC and urinary excretion rates of total metabolites were higher on the NB diet than on the DB diet, whereas for subjects with BMI <26 kg/m2, plasma AUC and urinary excretion rates were higher on the DB diet than on the NB diet. Daily consumption of broccoli interacted with BMI but not GSTM1 genotype to affect plasma concentrations and urinary excretion of glucosinolate-derived compounds believed to confer protection against cancer. This trial was registered as NCT02346812.

Walnuts Consumed by Healthy Adults Provide Less Available Energy than Predicted by the Atwater Factors.

BACKGROUND: Previous studies have shown that the metabolizable energy (ME) content (energy available to the body) of certain nuts is less than predicted by the Atwater factors. However, very few nuts have been investigated to date, and no information is available regarding the ME of walnuts. OBJECTIVE: A study was conducted to determine the ME of walnuts when consumed as part of a typical American diet. METHODS: Healthy adults (n = 18; mean age = 53.1 y; body mass index = 28.8 kg/m(2)) participated in a randomized crossover study with 2 treatment periods (3 wk each). The study was a fully controlled dietary feeding intervention in which the same base diet was consumed during each treatment period; the base diet was unsupplemented during one feeding period and supplemented with 42 g walnuts/d during the other feeding period. Base diet foods were reduced in equal proportions during the walnut period to achieve isocaloric food intake during the 2 periods. After a 9 d diet acclimation period, subjects collected all urine and feces for ∼1 wk (as marked by a Brilliant Blue fecal collection marker) for analysis of energy content. Administered diets, walnuts, and fecal and urine samples were subjected to bomb calorimetry, and the resulting data were used to calculate the ME of the walnuts. RESULTS: One 28-g serving of walnuts contained 146 kcal (5.22 kcal/g), 39 kcal/serving less than the calculated value of 185 kcal/serving (6.61 kcal/g). The ME of the walnuts was 21% less than that predicted by the Atwater factors (P < 0.0001). CONCLUSION: Consistent with other tree nuts, Atwater factors overestimate the metabolizable energy value of walnuts. These results could help explain the observations that consumers of nuts do not gain excessive weight and could improve the accuracy of food labeling. This trial was registered at clinicaltrials.gov as NCT01832909.

Garlic Influences Gene Expression In Vivo and In Vitro.

There is a large body of preclinical research aimed at understanding the roles of garlic and garlic-derived preparations in the promotion of human health. Most of this research has targeted the possible functions of garlic in maintaining cardiovascular health and in preventing and treating cancer. A wide range of outcome variables has been used to investigate the bioactivity of garlic, ranging from direct measures of health status such as cholesterol concentrations, blood pressure, and changes in tumor size and number, to molecular and biochemical measures such as mRNA gene expression, protein concentration, enzyme activity, and histone acetylation status. Determination of how garlic influences mRNA gene expression has proven to be a valuable approach to elucidating the mechanisms of garlic bioactivity. Preclinical studies investigating the health benefits of garlic far outnumber human studies and have made frequent use of mRNA gene expression measurement. There is an immediate need to understand mRNA gene expression in humans as well. Although safety and ethical constraints limit the types of available human tissue, peripheral whole blood is readily accessible, and measuring mRNA gene expression in whole blood may provide a unique window to understanding how garlic intake affects human health.

Absorption and Distribution Kinetics of the 13C-Labeled Tomato Carotenoid Phytoene in Healthy Adults.

BACKGROUND: Phytoene is a tomato carotenoid that may contribute to the apparent health benefits of tomato consumption. Although phytoene is a less prominent tomato carotenoid than lycopene, it is a major carotenoid in various human tissues. Phytoene distribution to plasma lipoproteins and tissues differs from lycopene, suggesting the kinetics of phytoene and lycopene differ. OBJECTIVE: The objective of this study was to characterize the kinetic parameters of phytoene absorption, distribution, and excretion in adults, to better understand why biodistribution of phytoene differs from lycopene. METHODS: Four adults (2 males, 2 females) maintained a controlled phytoene diet (1-5 mg/d) for 42 d. On day 14, each consumed 3.2 mg (13)C-phytoene, produced using tomato cell suspension culture technology. Blood samples were collected at 0, 1-15, 17, 21, and 24 h and 2, 3, 4, 7, 10, 14, 17, 21, and 28 d after (13)C-phytoene consumption. Plasma-unlabeled and plasma-labeled phytoene concentrations were determined using ultra-HPLC-quadrupole time-of-flight-mass spectrometry, and data were fit to a 7-compartment carotenoid kinetic model using WinSAAM 3.0.7 software. RESULTS: Subjects were compliant with a controlled phytoene diet, consuming a mean ± SE of 2.5 ± 0.6 mg/d, resulting in a plasma unlabeled phytoene concentration of 71 ± 14 nmol/L. A maximal plasma (13)C-phytoene concentration of 55.6 ± 5.9 nM was achieved 19.8 ± 9.2 h after consumption, and the plasma half-life was 2.3 ± 0.2 d. Compared with previous results for lycopene, phytoene bioavailability was nearly double at 58% ± 19%, the clearance rate from chylomicrons was slower, and the rates of deposition into and utilization by the slow turnover tissue compartment were nearly 3 times greater. CONCLUSIONS: Although only differing from lycopene by 4 double bonds, phytoene exhibits markedly different kinetic characteristics in human plasma, providing insight into metabolic processes contributing to phytoene enrichment in plasma and tissues compared with lycopene. This trial was registered at clinicaltrials.gov as NCT01692340.

Cranberry juice consumption lowers markers of cardiometabolic risk, including blood pressure and circulating C-reactive protein, triglyceride, and glucose concentrations in adults.

BACKGROUND: Cardiometabolic risk is the risk of cardiovascular disease (CVD), diabetes, or stroke, which are leading causes of mortality and morbidity worldwide. OBJECTIVE: The objective of this study was to determine the potential of low-calorie cranberry juice (LCCJ) to lower cardiometabolic risk. METHODS: A double-blind, placebo-controlled, parallel-arm study was conducted with controlled diets. Thirty women and 26 men (mean baseline characteristics: 50 y; weight, 79 kg; body mass index, 28 kg/m(2)) completed an 8-wk intervention with LCCJ or a flavor/color/energy-matched placebo beverage. Twice daily volunteers consumed 240 mL of LCCJ or the placebo beverage, containing 173 or 62 mg of phenolic compounds and 6.5 or 7.5 g of total sugar per 240-mL serving, respectively. RESULTS: Fasting serum triglycerides (TGs) were lower after consuming LCCJ and demonstrated a treatment × baseline interaction such that the participants with higher baseline TG concentrations were more likely to experience a larger treatment effect (1.15 ± 0.04 mmol/L vs. 1.25 ± 0.04 mmol/L, respectively; P = 0.027). Serum C-reactive protein (CRP) was lower for individuals consuming LCCJ than for individuals consuming the placebo beverage [ln transformed values of 0.522 ± 0.115 ln(mg/L) vs. 0.997 ± 0.120 ln(mg/L), P = 0.0054, respectively, and equivalent to 1.69 mg/L vs. 2.71 mg/L back-transformed]. LCCJ lowered diastolic blood pressure (BP) compared with the placebo beverage (69.2 ± 0.8 mm Hg for LCCJ vs. 71.6 ± 0.8 mm Hg for placebo; P = 0.048). Fasting plasma glucose was lower (P = 0.03) in the LCCJ group (5.32 ± 0.03 mmol/L) than in the placebo group (5.42 ± 0.03 mmol/L), and LCCJ had a beneficial effect on homeostasis model assessment of insulin resistance for participants with high baseline values (P = 0.035). CONCLUSION: LCCJ can improve several risk factors of CVD in adults, including circulating TGs, CRP, and glucose, insulin resistance, and diastolic BP. This trial was registered at clinicaltrials.gov as NCT01295684.

A Single Meal Containing Raw, Crushed Garlic Influences Expression of Immunity- and Cancer-Related Genes in Whole Blood of Humans.

BACKGROUND: Preclinical and epidemiologic studies suggest that garlic intake is inversely associated with the progression of cancer and cardiovascular disease. OBJECTIVE: We designed a study to probe the mechanisms of garlic action in humans. METHODS: We conducted a randomized crossover feeding trial in which 17 volunteers consumed a garlic-containing meal (100 g white bread, 15 g butter, and 5 g raw, crushed garlic) or a garlic-free control meal (100 g white bread and 15 g butter) after 10 d of consuming a controlled, garlic-free diet. Blood was collected before and 3 h after test meal consumption for gene expression analysis in whole blood. Illumina BeadArray was used to screen for genes of interest, followed by real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) on selected genes. To augment human study findings, Mono Mac 6 cells were treated with a purified garlic extract (0.5 µL/mL), and mRNA was measured by qRT-PCR at 0, 3, 6, and 24 h. RESULTS: The following 7 genes were found to be upregulated by garlic intake: aryl hydrocarbon receptor (AHR), aryl hydrocarbon receptor nuclear translocator (ARNT), hypoxia-inducible factor 1α (HIF1A), proto-oncogene c-Jun (JUN), nuclear factor of activated T cells (NFAT) activating protein with immunoreceptor tyrosine-based activation motif 1 (NFAM1), oncostatin M (OSM), and V-rel avian reticuloendotheliosis viral oncogene homolog (REL). Fold-increases in mRNA transcripts ranged from 1.6 (HIF1A) to 3.0 (NFAM1) (P < 0.05). The mRNA levels of 5 of the 7 genes that were upregulated in the human trial were also upregulated in cell culture at 3 and 6 h: AHR, HIF1A, JUN, OSM, and REL. Fold-increases in mRNA transcripts in cell culture ranged from 1.7 (HIF1A) to 12.1 (JUN) (P < 0.01). OSM protein was measured by ELISA and was significantly higher than the control at 3, 6, and 24 h (24 h: 19.5 ± 1.4 and 74.8 ± 1.4 pg/mL for control and garlic, respectively). OSM is a pleiotropic cytokine that inhibits several tumor cell lines in culture. CONCLUSION: These data indicate that the bioactivity of garlic is multifaceted and includes activation of genes related to immunity, apoptosis, and xenobiotic metabolism in humans and Mono Mac 6 cells. This trial is registered at clinicaltrials.gov as NCT01293591.

Dietary intake of advanced glycation end products did not affect endothelial function and inflammation in healthy adults in a randomized controlled trial.

When food is heated to high temperatures, the characteristic "browning" generates advanced glycation end products (AGEs). AGEs are associated with an increased risk of cardiovascular disease, diabetes, and other adverse outcomes. Whether dietary AGEs are absorbed and are harmful to human health remains highly controversial. The objective of this study was to compare the effects of a diet high or low in AGEs on endothelial function, circulating AGEs, inflammatory mediators, and circulating receptors for AGEs in healthy adults. A randomized, parallel-arm, controlled dietary intervention was conducted for 6 wk with 24 healthy adults, aged 50-69 y, that compared isocaloric, food-equivalent diets that were prepared at either high or mild temperatures. Peripheral arterial tonometry, serum and urine carboxymethyl-lysine (CML), inflammatory mediators (interleukin-6, C-reactive protein, vascular adhesion molecule-1, and tumor necrosis factor-α receptors I and II), soluble receptor for AGEs, and endogenous secretory receptor for AGEs were measured at baseline and after 6 wk of dietary intervention. In the low-AGE diet group, the following changed from baseline to 6 wk (mean ± SE): serum CML from 763 ± 24 to 679 ± 29 ng/mL (P = 0.03) and urine CML from 1.37 ± 1.47 to 0.77 ± 2.01 µg/mL creatinine (P = 0.02). There were no significant changes in serum and urinary CML concentrations from baseline to follow-up in the high-AGE diet group. A high- or low-AGE diet had no significant impact on peripheral arterial tonometry or any inflammatory mediators after 6 wk of dietary intervention. In healthy middle-aged to older adults, consumption of a diet high or low in AGEs for 6 wk had no impact on endothelial function and inflammatory mediators, 2 precursors of cardiovascular disease.

Effects of almond and pistachio consumption on gut microbiota composition in a randomised cross-over human feeding study.

The modification of microbiota composition to a 'beneficial' one is a promising approach for improving intestinal as well as overall health. Natural fibres and phytochemicals that reach the proximal colon, such as those present in various nuts, provide substrates for the maintenance of healthy and diverse microbiota. The effects of increased consumption of specific nuts, which are rich in fibre as well as various phytonutrients, on human gut microbiota composition have not been investigated to date. The objective of the present study was to determine the effects of almond and pistachio consumption on human gut microbiota composition. We characterised microbiota in faecal samples collected from volunteers in two separate randomised, controlled, cross-over feeding studies (n 18 for the almond feeding study and n 16 for the pistachio feeding study) with 0, 1·5 or 3 servings/d of the respective nuts for 18 d. Gut microbiota composition was analysed using a 16S rRNA-based approach for bacteria and an internal transcribed spacer region sequencing approach for fungi. The 16S rRNA sequence analysis of 528 028 sequence reads, retained after removing low-quality and short-length reads, revealed various operational taxonomic units that appeared to be affected by nut consumption. The effect of pistachio consumption on gut microbiota composition was much stronger than that of almond consumption and included an increase in the number of potentially beneficial butyrate-producing bacteria. Although the numbers of bifidobacteria were not affected by the consumption of either nut, pistachio consumption appeared to decrease the number of lactic acid bacteria (P< 0·05). Increasing the consumption of almonds or pistachios appears to be an effective means of modifying gut microbiota composition.

Single nucleotide polymorphisms in CETP, SLC46A1, SLC19A1, CD36, BCMO1, APOA5, and ABCA1 are significant predictors of plasma HDL in healthy adults.

BACKGROUND: In a marker-trait association study we estimated the statistical significance of 65 single nucleotide polymorphisms (SNP) in 23 candidate genes on HDL levels of two independent Caucasian populations. Each population consisted of men and women and their HDL levels were adjusted for gender and body weight. We used a linear regression model. Selected genes corresponded to folate metabolism, vitamins B-12, A, and E, and cholesterol pathways or lipid metabolism. METHODS: Extracted DNA from both the Sacramento and Beltsville populations was analyzed using an allele discrimination assay with a MALDI-TOF mass spectrometry platform. The adjusted phenotype, y, was HDL levels adjusted for gender and body weight only statistical analyses were performed using the genotype association and regression modules from the SNP Variation Suite v7. RESULTS: Statistically significant SNP (where P values were adjusted for false discovery rate) included: CETP (rs7499892 and rs5882); SLC46A1 (rs37514694; rs739439); SLC19A1 (rs3788199); CD36 (rs3211956); BCMO1 (rs6564851), APOA5 (rs662799), and ABCA1 (rs4149267). Many prior association trends of the SNP with HDL were replicated in our cross-validation study. Significantly, the association of SNP in folate transporters (SLC46A1 rs37514694 and rs739439; SLC19A1 rs3788199) with HDL was identified in our study. CONCLUSIONS: Given recent literature on the role of niacin in the biogenesis of HDL, focus on status and metabolism of B-vitamins and metabolites of eccentric cleavage of ß-carotene with lipid metabolism is exciting for future study.

Impact of roasting on javamide-I/-II in Arabica and Robusta coffee beans.

Javamide-I/-II are anti-inflammatory compounds found in coffee beans. However, potential effects of roasting on javamide-I/-II in coffee beans are currently unknown. Therefore, in this paper, the effects of roasting on javamide-I/-II were investigated in Arabica and Robusta beans. Coffee beans were roasted light, medium and dark, and the amounts of javamide-I/-II in the beans were quantified by a HPLC method. The data showed the different amounts of javamide-I/-II in the beans; not detected and ≤ 3.1 mg in Arabica beans, and 0.5-3.7 mg and 1.0-13.8 mg in Robusta beans, respectively. Furthermore, the data showed that roasting process significantly reduced the amounts of javamide-I/-II in both Arabica and Robusta beans (p < 0.05). These data were also confirmed by multivariate analyses. Additionally, these differences were validated in light, medium and dark roast coffee products in the market. Altogether, roasting can have a significant impact on javamide-I/-II amounts in coffee beans.

Mixed Berry Juice and Cellulose Fiber Have Differential Effects on Peripheral Blood Mononuclear Cell Respiration in Overweight Adults.

Berries and other anthocyanin-rich foods have demonstrated anti-obesity effects in rodents and humans. However, the bioactive components of these foods and their mechanisms of action are unclear. We conducted an intervention study with overweight and obese adults to isolate the effects of different berry components on bioenergetics. Subjects consumed whole mixed berries (high anthocyanin, high fiber), pressed berry juice (high anthocyanin, low fiber), berry-flavored gelatin (low anthocyanin, low fiber), or fiber-enriched gelatin (low anthocyanin, high fiber) for one week prior to a meal challenge with the same treatment food as the pre-feed period. Peripheral blood mononuclear cells were collected 2 h after the meal challenge, and cellular respiration was assessed via high-resolution respirometry. The high-anthocyanin, low-fiber treatment (berry juice) and the low-anthocyanin, high-fiber treatment (fiber-enriched gelatin) had opposite effects on cellular respiration. In the fasted state, berry juice resulted in the highest oxygen-consumption rate (OCR), while fiber-enriched gelatin resulted in the highest OCR in the fed state. Differences were observed in multiple respiration states (basal, state 3, state 4, uncoupled), with the greatest differences being between the pressed berry juice and the fiber-enriched gelatin. Different components of berries, specifically anthocyanins/flavonoids and fiber, appear to have differential effects on cellular respiration.

An LC/MS method for d8-ß-carotene and d4-retinyl esters: ß-carotene absorption and its conversion to vitamin A in humans.

The intestinal absorption and metabolism of ß-carotene is of vital importance in humans, especially in populations that obtain the majority of their vitamin A from provitamin A carotenoids. MS has provided a better understanding of the absorption of ß-carotene, the most potent provitamin A carotenoid, through the use of stable isotopes of ß-carotene. We report here an HPLC-MS method that eliminates the need for complicated sample preparation and allows us to detect and quantify newly absorbed d8-ß-carotene as well as its d4-retinyl ester metabolites in human plasma and chylomicron fractions. Both retinoids and ß-carotene were recovered in a single simple extraction that did not involve saponification, thus allowing subsequent quantitation of individual fatty acyl esters of retinol. Separation of d8-ß-carotene and its d4-retinyl ester metabolites was achieved using the same C30 reversed-phase liquid chromatography followed by mass spectrometry in selected ion monitoring and negative atmospheric pressure chemical ionization modes, respectively. Total time for the two successive runs was 30 min. This HPLC-MS method allowed us to quantify the absorption of intact d8-ß-carotene as well as its extent of conversion to d4-retinyl esters in humans after consumption of a single 5 mg dose of d8-ß-carotene.

This kinetic, bioavailability, and metabolism study of RRR-α-tocopherol in healthy adults suggests lower intake requirements than previous estimates.

Kinetic models enable nutrient needs and kinetic behaviors to be quantified and provide mechanistic insights into metabolism. Therefore, we modeled and quantified the kinetics, bioavailability, and metabolism of RRR-α-tocopherol in 12 healthy adults. Six men and 6 women, aged 27 ± 6 y, each ingested 1.81 nmol of [5(-14)CH(3)]-(2R, 4'R, 8'R)-α-tocopherol; each dose had 3.70 kBq of (14)C. Complete collections of urine and feces were made over the first 21 d from dosing. Serial blood samples were drawn over the first 70 d from dosing. All specimens were analyzed for RRR-α-tocopherol. Specimens were also analyzed for (14)C using accelerator MS. From these data, we modeled and quantified the kinetics of RRR-α-tocopherol in vivo in humans. The model had 11 compartments, 3 delay compartments, and reservoirs for urine and feces. Bioavailability of RRR-α-tocopherol was 81 ± 1%. The model estimated residence time and half-life of the slowest turning-over compartment of α-tocopherol (adipose tissue) at 499 ± 702 d and 184 ± 48 d, respectively. The total body store of RRR-α-tocopherol was 25,900 ± 6=220 µmol (11 ± 3 g) and we calculated the adipose tissue level to be 1.53 µmol/g (657 µg/g). We found that a daily intake of 9.2 µmol (4 mg) of RRR-α-tocopherol maintained plasma RRR-α-tocopherol concentrations at 23 µmol/L. These findings suggest that the dietary requirement for vitamin E may be less than that currently recommended and these results will be important for future updates of intake recommendations.

Gender and single nucleotide polymorphisms in MTHFR, BHMT, SPTLC1, CRBP2, CETP, and SCARB1 are significant predictors of plasma homocysteine normalized by RBC folate in healthy adults.

Using linear regression models, we studied the main and 2-way interaction effects of the predictor variables gender, age, BMI, and 64 folate/vitamin B-12/homocysteine (Hcy)/lipid/cholesterol-related single nucleotide polymorphisms (SNP) on log-transformed plasma Hcy normalized by RBC folate measurements (nHcy) in 373 healthy Caucasian adults (50% women). Variable selection was conducted by stepwise Akaike information criterion or least angle regression and both methods led to the same final model. Significant predictors (where P values were adjusted for false discovery rate) included type of blood sample [whole blood (WB) vs. plasma-depleted WB; P < 0.001] used for folate analysis, gender (P < 0.001), and SNP in genes SPTLC1 (rs11790991; P = 0.040), CRBP2 (rs2118981; P < 0.001), BHMT (rs3733890; P = 0.019), and CETP (rs5882; P = 0.017). Significant 2-way interaction effects included gender × MTHFR (rs1801131; P = 0.012), gender × CRBP2 (rs2118981; P = 0.011), and gender × SCARB1 (rs83882; P = 0.003). The relation of nHcy concentrations with the significant SNP (SPTLC1, BHMT, CETP, CRBP2, MTHFR, and SCARB1) is of interest, especially because we surveyed the main and interaction effects in healthy adults, but it is an important area for future study. As discussed, understanding Hcy and genetic regulation is important, because Hcy may be related to inflammation, obesity, cardiovascular disease, and diabetes mellitus. We conclude that gender and SNP significantly affect nHcy.