David W. Giraud

Identification and assessment of markers of biotin status in healthy adults

Human biotin requirements are unknown and the identification of reliable markers of biotin status is necessary to fill this knowledge gap. Here, we used an outpatient feeding protocol to create states of biotin deficiency, sufficiency and supplementation in sixteen healthy men and women. A total of twenty possible markers of biotin status were assessed, including the abundance of biotinylated carboxylases in lymphocytes, the expression of genes from biotin metabolism and the urinary excretion of biotin and organic acids. Only the abundance of biotinylated 3-methylcrotonyl-CoA carboxylase (holo-MCC) and propionyl-CoA carboxylase (holo-PCC) allowed for distinguishing biotin-deficient and biotin-sufficient individuals. The urinary excretion of biotin reliably identified biotin-supplemented subjects, but did not distinguish between biotin-depleted and biotin-sufficient individuals. The urinary excretion of 3-hydroxyisovaleric acid detected some biotin-deficient subjects, but produced a meaningful number of false-negative results and did not distinguish between biotin-sufficient and biotin-supplemented individuals. None of the other organic acids that were tested were useful markers of biotin status. Likewise, the abundance of mRNA coding for biotin transporters, holocarboxylase synthetase and biotin-dependent carboxylases in lymphocytes were not different among the treatment groups. Generally, datasets were characterised by variations that exceeded those seen in studies in cell cultures. We conclude that holo-MCC and holo-PCC are the most reliable, single markers of biotin status tested in the present study.

Effects of β-carotene and α-tocopherol on the levels of tissue cholesterol and triglyceride in hypercholesterolemic rabbits

Male New Zealand white rabbits were made hypercholesterolemic by feeding an atherogenic diet (0.5% cholesterol, 3% peanut oil, and 3% coconut oil) with and without β-carotene (25 mg/kg body weight given intravenously twice weekly) and/or α-tocopherol (0.5% of diet) for 8 weeks. Rabbits treated with combined β-carotene and α-tocopherol had significantly lower cholesterol contents in liver, heart, and plasma than control animals; heart and plasma cholesterol contents were also significantly lower in animals treated with β-carotene than in controls. Treatment with both antioxidants significantly increased triglyceride contents of liver and triceps, but not heart and plasma. Rabbits given both β-carotene and α-tocopherol had significantly lower values for tissue α-tocopherol than animals treated with α-tocopherol only, and significantly higher values for tissue β-carotene than animals treated with β-carotene only. Atherosclerotic lesion areas in the aortic arch, thoracic aorta, and abdominal aorta were positively correlated (r = 0.36–0.42) with plasma cholesterol concentrations and negatively correlated (r = −0.34–−0.60) with plasma, liver, triceps, and heart α-tocopherol levels. Moderate levels of α-tocopherol supplementation with or without β-carotene may have a beneficial effect on tissue cholesterol contents and on the development of aortic atherosclerotic lesions in rabbits fed an atherogenic diet.

Dietary and plasma levels of carotenoids, vitamin E, and vitamin C in a group of young and middle-aged nonsupplemented women and men

Abstract The objective of the study was to examine the relationship between dietary intake and plasma concentrations of carotenoids, tocopherols, and vitamin C in young to middle-aged nonsupplemented women and men as well as evaluate their vitamin E and vitamin C status. Subjects included young (19–24 y) and middle-aged (25–50 y) men and women. The four age x gender groups had similar dietary intakes of β-carotene, α-carotene, cryptoxanthin, lycopene, lutein, vitamin E, and vitamin C. These four groups also had similar plasma β-carotene, cryptoxanthin, lycopene, α-tocopherol, and vitamin C concentrations. The percentage of each group having low (

RNase H2-Dependent Polymerase Chain Reaction and Elimination of Confounders in Sample Collection, Storage, and Analysis Strengthen Evidence That microRNAs in Bovine Milk Are Bioavailable in Humans

Background Evidence suggests that dietary microRNAs (miRs) are bioavailable and regulate gene expression across species boundaries. Concerns were raised that the detection of dietary miRs in plasma might have been due to sample contamination or lack of assay specificity. Objectives: The objectives of this study were to assess potential confounders of plasma miR analysis and to detect miRs from bovine milk in human plasma. Methods Potential confounders of plasma miR analysis (circadian rhythm, sample collection and storage, calibration, and erythrocyte hemolysis) were assessed by quantitative reverse transcriptase polymerase chain reaction (PCR) by using blood from healthy adults (7 men, 6 women; aged 23-57 y). Bovine miRs were analyzed by RNase H2-dependent PCR (rhPCR) in plasma collected from a subcohort of 11 participants before and 6 h after consumption of 1.0 L of 1%-fat bovine milk. Results The use of heparin tubes for blood collection resulted in a complete loss of miRs. Circadian variations did not affect the concentrations of 8 select miRs. Erythrocyte hemolysis caused artifacts for some miRs if plasma absorbance at 414 nm was >0.300. The stability of plasma miRs depended greatly on the matrix in which the miRs were stored and whether the plasma was frozen before analysis. Purified miR-16, miR-200c, and cel-miR-39 were stable for ≤24 h at room temperature, whereas losses equaled ≤80% if plasma was frozen, thawed, and stored at room temperature for as little as 4 h. rhPCR distinguished between bovine and human miRs with small variations in the nucleotide sequence; plasma concentrations of Bos taurus (bta)-miR-21-5p and bta-miR-30a-5p were >100% higher 6 h after milk consumption than before milk consumption. Conclusions Confounders in plasma miR analysis include the use of heparin tubes, erythrocyte hemolysis, and storage of thawed plasma at room temperature. rhPCR is a useful tool to detect dietary miRs.

Vitamin A Inadequacy Observed in a Group of 2- to 6-Year-Old Children Living in Kwangju, Republic of Korea

Dietary intakes and plasma concentrations of retinol and carotenoids were estimated in assessing the vitamin A status of young children in Kwangju, Republic of Korea. Three consecutive 24-hour food recalls and fasting blood samples were obtained from 123 healthy children (58 boys, 65 girls), aged 2-6 years. The daily vitamin A intake (mean +/- SD) was 355.9 +/- 178.1 microg retinol equivalents or 239.0 +/- 111.2 microg retinol activity equivalents. Provitamin A carotenoid intakes were 1211.2 +/- 840.0 microg/day beta-carotene, 234.6 +/- 231.7 microg/day alpha-carotene, and 149.1 +/- 160.7 microg/day beta-cryptoxanthin. Approximately 15-26% of subjects consumed < Korean Estimated Average Requirements (EAR) for vitamin A; whereas, 57-64% consumed < EAR for vitamin A for USA/Canadians. The mean plasma retinol concentration was 1.108 +/- 0.244 micromol/L. There were no significant correlations between intakes and plasma concentrations of retinol and carotenoids. Only 2.4% of children were vitamin A-deficient based on having plasma retinol concentrations <0.70 micromol/L. Plasma retinol concentrations of 42.3% of subjects were 0.70 - <1.05 micromol/L, which is considered indicative of potentially suboptimal vitamin A status. Therefore, some children may be at risk of inadequate vitamin A status in Kwangju, Republic of Korea.

Vitamin B-6 status of tobacco smokers, chewers, and nonusers

Abstract Vitamin B-6 status measurements of young men (x¯±SD, 20.6±1.5 y) who were users and nonusers of tobacco were determined. The subjects included 9 men who had smoked for a mean of 2.4 pack-years (packs daily x years), 11 who had chewed for a mean of 3.3 chew-years (chews daily x years), and 15 nonusers of tobacco. All subjects had acceptable hemoglobin and hematocrit values. The protein and vitamin B-6 intakes and the vitamin B-6/protein ratios of the three groups of subjects as estimated by 24-h recalls and 2-d food records were similar, although the differences in vitamin B-6 intakes of the three groups approached significance (P

Effect of Cooking Method, Distiller's Grains, and Vitamin E Supplementation on the Vitamin Content of Value Cuts from Beef Steers Fed Wet Distiller's Grains and Solubles and Supplemental Vitamin E

Vitamin E, thiamin, riboflavin, niacin, vitamin B(6), and vitamin B(12) concentrations of flat iron steaks and petite tenders from steers fed finishing rations containing 0% and 40% corn wet distillers grains and solubles (WDGS) with and without supplemental vitamin E were determined. Feeding treatment groups were: 0% WDGS with basal vitamin E, 0% WDGS with supplemental vitamin E (500 IU daily), 40% WDGS with basal vitamin E, and 40% WDGS and supplemental vitamin E. Cattle can be fed 40% WDGS diets more economically than corn diets. The incorporation of 40% WDGS, with and without vitamin E, was hypothesized to have little effect on the vitamin concentrations of these value meat cuts. Flat iron steaks and petite tenders were broiled and/or grilled to 70 degrees C internal temperature. Mean cooking yields ranged from 68.7% to 78.2%. The majority of the vitamin concentrations of broiled and of grilled meat were significantly different (P < 0.05) from that of raw meat. Vitamin E concentrations of raw and cooked meat from steers that received supplemental vitamin E were significantly higher (P < 0.05) than those fed basal vitamin E. Significant differences in thiamin, riboflavin, vitamin B(6), and vitamin B(12) concentrations in raw flat iron steaks and in vitamin B(6) in raw petite tenders were observed by WDGS. Thiamin, vitamin B(6), and vitamin B(12) concentrations of broiled flat iron steaks were significantly different (P < 0.05) than grilled. A few differences in vitamin concentrations of the flat iron steaks and petite tenders were observed by WDGS, vitamin E supplementation, and cooking treatments, but most of the vitamin concentrations were statistically similar.

Legume Intake of Childbearing Aged Women in Rural Tajikistan

Legume intake among women of childbearing age living in “vilojati” (region) Khatlon of Tajikistan was investigated. Tajik women (n = 151) between 19 and 41 years old completed a survey on legumes. Anthropometric and skinfold measurements were collected with body mass index (kg/m2) of 22.6 ± 4.7, waist circumference (cm) of 74.8 ± 12.2, and sum of skinfold measurements (triceps, thigh, and suprailiac) (mm) of 60.1 ± 19.3. Overall, 19% of the participants were underweight, 20% overweight, and 9% obese. Consumption of legumes in the Tajik diet was at least two to three times per week or more (73.5%), suggesting a positive dietary approach for increasing folate and iron intake of Tajik women of childbearing age.

Beliefs and Usage of Vitamin/mineral Supplements by Graduate Students

Abstract LEARNING OUTCOME: To examine vitamin/mineral supplementation habits of graduate students by gender The vitamin/mineral supplementation habits of 88 female and 88 male graduate students, 22-45 years, nonpregnant and nonlactating, were compared. All but four rated their health as excellent or good. Thirty-two percent of the women and 17 % of the men reported taking supplements regularly, while 35 % of women and 35 % of men took them occasionally or seldom. A larger percentage of women than men (P=.09) reported taking supplements. Subjects taking supplements indicated that the reasons they did were (descending order) for present illness or to prevent future disease, inadequate diet, increase energy/makes me feel better, to improve athletic performance/build muscle, self-determined health risk, prescribed/recommended by health professional, recommended by nonhealth professional, smoker or other tobacco user, media, and other. A significantly larger (P