Journal of Nutrition Genomics, Proteomics, and Metabolomics

Apolipoprotein A5 Polymorphisms Interact with Total Dietary Fat Intake in Association with Markers of Metabolic Syndrome in Puerto Rican Older Adults [Genomics, Proteomics, and Metabolomics]

Mattei, J., Demissie, S., Tucker, K. L., Ordovas, J. M. — Fri, 20 Nov 2009 10:01:59 PST

APOA5 -1131T > C and S19W single nucleotide polymorphisms (SNP) have been consistently associated with plasma lipid concentration and metabolic syndrome (MetS), alone and in modulation by dietary factors. Puerto Ricans have a high prevalence of metabolic conditions and high minor allele frequency for these SNP, suggesting a possible role in disease for this population. We aimed to determine the association of APOA5 -1131T > C and S19W with plasma lipids and markers of MetS, alone and in interaction with total fat intake, as a percent of total energy intake, in Puerto Ricans. Anthropometric and demographic data, FFQ, and blood samples were collected at baseline from participants in the Boston Puerto Rican Health Study (n = 802, 45–75 y). APOA5 S19W was associated with plasma HDL cholesterol (HDL-C) (P = 0.044); minor allele carriers had lower HDL-C [1.12 ± 0.03 (mean ± SE)] than those with the common variant (1.18 ± 0.01 mmol/L), even after adjustment for plasma triglycerides (TG) (P = 0.012). Neither polymorphism was associated with TG or other lipids. Interaction of the -1131T > C SNP with total fat energy intake was observed for plasma TG (P = 0.032) and total cholesterol (P = 0.034). APOA5 S19W interacted with total fat intake in association with systolic (P = 0.002) and diastolic (P = 0.007) blood pressure. Neither SNP was associated with MetS in the overall analysis or after stratifying by total energy intake as fat. In conclusion, Puerto Ricans present a distinctive lipid profile in association with APOA5 polymorphisms. Dietary fat intake seems to modulate these associations. The results contribute to the understanding of health disparities in this population.

A Metabolite Profiling Approach to Identify Biomarkers of Flavonoid Intake in Humans [Genomics, Proteomics, and Metabolomics]

Fri, 20 Nov 2009 10:01:59 PST

Flavonoids are phytochemicals that are widespread in the human diet. Despite limitations in their bioavailability, experimental and epidemiological data suggest health benefits of flavonoid consumption. Valid biomarkers of flavonoid intake may be useful for estimating exposure in a range of settings. However, to date, few useful flavonoid biomarkers have been identified. In this study, we used a metabolite profiling approach to examine the aromatic and phenolic profile of plasma and urine of healthy men after oral consumption of 200 mg of the pure flavonoids, quercetin, (-)-epicatechin, and epigallocatechin gallate, which represent major flavonoid constituents in the diet. Following enzymatic hydrolysis, 71 aromatic compounds were quantified in plasma and urine at 2 and 5 h, respectively, after flavonoid ingestion. Plasma concentrations of different aromatic compounds ranged widely, from 0.01 to 10 µmol/L, with variation among volunteers. None of the aromatic compounds was significantly elevated in plasma 2 h after consumption of either flavonoid compared with water placebo. This indicates that flavonoid-derived aromatic compounds are not responsible for the acute physiological effects reported within 2 h in previous human intervention studies involving flavonoids or flavonoid-rich food consumption. These effects are more likely due to absorption of the intact flavonoid. Our urine analysis suggested that urinary 4-ethylphenol, benzoic acid, and 4-ethylbenzoic acid may be potential biomarkers of quercetin intake and 1,3,5-trimethoxybenzene, 4-O-methylgallic acid, 3-O-methylgallic acid, and gallic acid may be potential markers of epigallocatechin gallate intake. Potential biomarkers of (-)-epicatechin were not identified. These urinary biomarkers may provide an accurate indication of flavonoid exposure.

Diets Enriched in Oat Bran or Wheat Bran Temporally and Differentially Alter the Composition of the Fecal Community of Rats [Genomics, Proteomics, and Metabolomics]

Tue, 20 Oct 2009 10:01:50 PDT

A clear understanding of how diet alters gastrointestinal communities is important given the suggested link between gut community composition and a wide variety of disease pathologies. To characterize this link for commonly consumed dietary fiber sources, we investigated the change in the fecal community of rats fed diets containing 5% nonnutritive fiber (control), 3% (wt:wt) oat bran plus 2% nonnutritive fiber (OB), or 5% (w/w) wheat bran (WB) over a 28-d feeding trial using both molecular- and cultivation-based methodologies. Pooled fecal samples from 8 rats fed the same diet were analyzed at 4 time points. On d 28, bran-fed rats had approximately twice the total cultivable bacteria than rats fed the control diet. Over the course of feeding, the cultivable community was initially dominated by bacteroides, then by bifidobacteria, lactobacilli, enterococci, and various enterics. In contrast, molecular analysis revealed the appearance of new operational taxonomic units (phylotypes) that were both temporally and inequitably distributed throughout the fecal community. The majority of change occurred in 2 major lineages within the Firmicutes: the Clostridium coccoides group and the Clostridium leptum subgroup. The time course of change depended on the source of bran, with the majority of new phylotypes appearing by d 14 (OB) or d 28 (WB), although adaptation of the fecal community was slow and continued over the entire feeding trial. Bacterial community richness was higher in bran-fed rats than in those fed the control diet. Change within the C. coccoides and C. leptum lineages likely reflect their high abundance within the gut bacterial community and the role of clostridia in fiber digestion. The results illustrate the limitations of relying solely on cultivation to assess bacterial changes and illustrate that community changes are complex in an ecosystem containing high numbers of interdependent and competing species of bacteria.