A multicenter analytical performance evaluation of a multiplexed immunoarray for the simultaneous measurement of biomarkers of micronutrient deficiency, inflammation and malarial antigenemia.

A lack of comparative data across laboratories is often a barrier to the uptake and adoption of new technologies. Furthermore, data generated by different immunoassay methods may be incomparable due to a lack of harmonization. In this multicenter study, we describe validation experiments conducted in a single lab and cross-lab comparisons of assay results to assess the performance characteristics of the Q-plex™ 7-plex Human Micronutrient Array (7-plex), an immunoassay that simultaneously quantifies seven biomarkers associated with micronutrient (MN) deficiencies, inflammation and malarial antigenemia using plasma or serum; alpha-1-acid glycoprotein, C-reactive protein, ferritin, histidine-rich protein 2, retinol binding protein 4, soluble transferrin receptor, and thyroglobulin. Validations included repeated testing (n = 20 separately prepared experiments on 10 assay plates) in a single lab to assess precision and linearity. Seven independent laboratories tested 76 identical heparin plasma samples collected from a cohort of pregnant women in Niger using the same 7-plex assay to assess differences in results across laboratories. In the analytical validation experiments, intra- and inter-assay coefficients of variation were acceptable at <6% and <15% respectively and assay linearity was 96% to 99% with the exception of ferritin, which had marginal performance in some tests. Cross-laboratory comparisons showed generally good agreement between laboratories in all analyte results for the panel of 76 plasma specimens, with Lin's concordance correlation coefficient values averaging ≥0.8 for all analytes. Excluding plates that would fail routine quality control (QC) standards, the inter-assay variation was acceptable for all analytes except sTfR, which had an average inter-assay coefficient of variation of ≥20%. This initial cross-laboratory study demonstrates that the 7-plex test protocol can be implemented by users with some experience in immunoassay methods, but familiarity with the multiplexed protocol was not essential.

Whole egg consumption increases plasma choline and betaine without affecting TMAO levels or gut microbiome in overweight postmenopausal women.

As a crucial part of the symbiotic system, the gut microbiome is metabolically connected to many diseases and conditions, including cardiovascular diseases (CVD). Trimethylamine (TMA) is produced by gut bacteria from dietary choline, betaine, or L-carnitine, and is then converted in the liver to Trimethylamine N-oxide (TMAO), which in turn affects hepatic and intestinal lipid metabolism. Circulating TMAO is positively associated with CVD risk. Because eggs are rich in choline, it has been speculated that their consumption may increase plasma TMAO. In this study, we hypothesized that 2 eggs per day increases plasma TMAO level by altering gut microbiome composition in mildly hypercholesterolemic postmenopausal women. In this randomized, cross-over study, 20 overweight, postmenopausal women were given 2 whole eggs and the equivalent amount of yolk-free substitute as breakfast for 4 weeks, in randomized order, with a 4-week washout in between. Fasting blood draws and stool were collected at the beginning and end of each treatment period. Plasma TMAO, choline, betaine and other metabolites were analyzed using LC/MS, while gut microbiome composition was analyzed using 16S amplicon sequencing. Plasma choline and betaine were significantly increased after whole egg but not yolk-free substitute, however TMAO level was not significantly affected by treatments. Gut microbiome composition showed large inter-individual variability at baseline and in response to the treatments. The consumption of 2 eggs per day in overweight, postmenopausal mildly hypercholesterolemic women significantly increased plasma choline and betaine, but did not increase plasma TMAO or alter gut microbiome composition.

Whole egg consumption compared with yolk-free egg increases the cholesterol efflux capacity of high-density lipoproteins in overweight, postmenopausal women.

BACKGROUND: Postmenopausal women are at higher risk for cardiovascular disease (CVD) than their younger counterparts. HDL cholesterol is a biomarker for CVD risk, but the function of HDL may be more important than HDL cholesterol in deciphering disease risk. Although diet continues to be a cornerstone of treatment and prevention of CVD, little is known about how diet affects the functionality of HDL. OBJECTIVES: The aim of this study was to characterize the effects of whole eggs compared with yolk-free eggs on HDL function and composition in overweight, postmenopausal women and determine how changes in HDL composition are related to HDL functional parameters. METHODS: The study was a 14-wk, single-blind, randomized crossover dietary trial with two 4-wk intervention periods in 20 overweight, postmenopausal women. The crossover treatments were frozen breakfast meals containing 100 g of liquid (∼2) whole eggs compared with 100 g of (∼2) yolk-free eggs per day, separated by a 4-wk washout. Fasting blood samples were taken at the beginning and end of each treatment period to determine the effects on HDL composition and function. RESULTS: Cholesterol efflux capacity increased in the whole-egg treatment (mean ± SD percentage change: +5.69% ± 9.9%) compared with the yolk-free egg treatment (-3.69% ± 5.3%) (P < 0.01), but there were no other significant changes in HDL functions or antioxidant or inflammatory markers. ApoA-I, total cholesterol (TC), LDL cholesterol, and HDL cholesterol also did not change in response to the egg treatment. CONCLUSIONS: The consumption of 2 whole eggs/d by overweight, postmenopausal women showed a significant increase in cholesterol efflux capacity. This increase in cholesterol efflux capacity was seen without significant changes in apoA-I, TC, LDL cholesterol, or HDL cholesterol, supporting the idea that HDL function rather than HDL cholesterol should be addressed in this population. This trial was registered at clinicaltrials.gov as NCT02445638.

Assessing beans as a source of intrinsic fiber on satiety in men and women with metabolic syndrome.

Dietary fiber is well-known for its satiety inducing properties. Adding fibers to mixed dishes is one way to increase fiber intake. However, adding fibers to foods versus including foods inherently containing fiber may reveal differing effects on satiety. The present study aimed to explore the satiety effects of adding fiber to a mixed meal versus using beans (Phaseolus vulgaris) as a source of intrinsic fiber in the meal. In this pilot study, 12 men and women with metabolic syndrome were randomly assigned to eat three standard meals in a crossover design on three different occasions that contained either no added fiber (control (NF)), extrinsic or added fiber (AF), or whole black beans as the source of intrinsic fiber (BN). Meals were matched for energy and macronutrient composition. Five hour postprandial subjective satiety was measured along with blood glucose, insulin, and the GI hormones, cholecystokinin (CCK) and peptide tyrosine tyrosine (PYY3-36). All meals induced fullness to a similar degree; however, the AF meal suppressed prospective consumption (F2,187 = 9.05, P = 0.0002) compared to the BN or NF meals. The NF meal tended to result in more satisfaction than the BN meal (F2,187 = 5.91, P = 0.003). The BN meal produced significantly higher postprandial CCK concentrations compared to the AF (F2,187 = 6.82, P = 0.001) and NF meals (F2,187 = 6.82, P = 0.002). Similar findings were observed for PYY3-36 response for BN > AF meal (F2,170 = 9.11, P < 0.0001). Postprandial insulin was significantly reduced after the BN meal, compared to the NF (F2,187 = 22.36, P < 0.0001) meal. These findings suggest that incorporating whole black beans into a meal has acute beneficial metabolic and GI hormone responses in adults with metabolic syndrome and are preferred over adding equivalent amounts of fiber from a supplement.

Black Beans, Fiber, and Antioxidant Capacity Pilot Study: Examination of Whole Foods vs. Functional Components on Postprandial Metabolic, Oxidative Stress, and Inflammation in Adults with Metabolic Syndrome.

Beans (Phaseolus vulgaris) contain bioactive components with functional properties that may modify cardiovascular risk. The aims of this pilot study were to evaluate the ability of black beans to attenuate postprandial metabolic, oxidative stress, and inflammatory responses and determine relative contribution of dietary fiber and antioxidant capacity of beans to the overall effect. In this randomized, controlled, crossover trial, 12 adults with metabolic syndrome (MetS) consumed one of three meals (black bean (BB), fiber matched (FM), and antioxidant capacity matched (AM)) on three occasions that included blood collection before (fasting) and five hours postprandially. Insulin was lower after the BB meal, compared to the FM or AM meals (p < 0.0001). A significant meal × time interaction was observed for plasma antioxidant capacity (p = 0.002) revealing differences over time: AM > BB > FM. Oxidized LDL (oxLDL) was not different by meal, although a trend for declining oxLDL was observed after the BB and AM meals at five hours compared to the FM meal. Triglycerides and interleukin-6 (IL-6) increased in response to meals (p < 0.0001). Inclusion of black beans with a typical Western-style meal attenuates postprandial insulin and moderately enhances postprandial antioxidant endpoints in adults with MetS, which could only be partly explained by fiber content and properties of antioxidant capacity.

Potatoes, glycemic index, and weight loss in free-living individuals: practical implications.

BACKGROUND: The role of glycemic index (GI) and foods with negative attributes related to GI as part of a weight loss regimen has not been thoroughly assessed in free-living individuals. This study examined the effects of a dietary prescription for energy intake modification, GI, and potato consumption on weight loss, dietary prescription adherence, body composition, and glucose control in a free-living, self-selecting overweight population. METHODS: Ninety overweight (body mass index [BMI] 29.6 ± 3.9) men and women were randomly assigned to one of 3 groups for 12 weeks. Two groups were counseled to reduce their energy intake by 500 kcal/day and consume diets that were predominantly composed of either low- or high-GI foods (low glycemic index energy reduced [LGI-ER] or high glycemic index energy reduced [HGI-ER] diet, respectively). The third group received no energy restriction, GI provision, or nutritional counseling. All groups were instructed to consume 5-7 servings of potatoes per week. Changes in weight, body composition, glucose tolerance, and triglycerides were determined at baseline and 12 weeks. RESULTS: There were no significant differences in weight loss or changes in body composition between the groups; however, modest weight loss and body composition changes were seen from week 0 to week 12 for all groups (p < 0.05). Difficulty achieving the prescribed GI diets was evident in this free-living setting. There were no significant changes within or among treatments for fasting concentrations of triglycerides, glucose tolerance, insulin, or insulin sensitivity. CONCLUSIONS: The results indicate that in a free-living population of men and women, weight loss is associated with energy intake reduction. Potato intake did not cause weight gain and following either a high- or low-GI dietary prescription was difficult for free-living subjects, emphasizing the complex nature of changing dietary patterns.