Association of serum selenium with thyroxin in severely iodine-deficient young children from the Amhara region of Ethiopia.

BACKGROUND/OBJECTIVES: Selenium (Se) as part of glutathione peroxidase and iodothyronine deiodinase enzymes influences thyroid metabolism. This study investigated the association of serum Se levels with thyroid metabolism of severely iodine-deficient young children from the Amhara region of Ethiopia. SUBJECTS/METHODS: In a cross-sectional study, Se, thyroid-stimulating hormone, total thyroxin, total triiodothyronine and thyroglobulin in serum of children (N=628) 54-60 months of age from the Amhara region, Ethiopia, were analyzed. In addition, iodine in urine and household salt was analyzed, and the presence of goiter was assessed. RESULTS: The median serum Se concentration was 61.4 µg/l (10.7-290.9 µg/l). Selenium deficiency (serum Se <70 µg/l) was detected in 57.8% (N=349) of the children. The median urinary iodine concentration (UIC) was 9.8 µg/l. The majority (86.6%, N=449) of children had UIC below the recommended value (100 µg/l). In addition, 59.8% (N=310) of children were severely iodine deficient (UIC<20 µg/l). Only 12.7% of salt samples had iodine. Goiter was present in 44.6% (N=280) of the children. Selenium-deficient children had higher serum thyroxin (T4) than children with normal serum Se concentration (P<0.001). CONCLUSIONS: Serum Se was negatively associated with T4 level in young children from the Amhara region of Ethiopia and may endanger the effectiveness of the salt iodization program.

Green tea polyphenols attenuate deterioration of bone microarchitecture in female rats with systemic chronic inflammation.

UNLABELLED: Green tea polyphenols (GTP) are promising agents for preventing bone loss. GTP supplementation sustained microarchitecture and improved bone quality via a decrease in inflammation. Findings suggest a significant role for GTP in skeletal health of patients with chronic inflammation. INTRODUCTION: This study evaluated whether GTP can restore bone microstructure along with a molecular mechanism in rats with chronic inflammation. A 2 [placebo vs. lipopolysaccharide (LPS)]× 2 [no GTP vs. 0.5% GTP (w/v) in drinking water] factorial design was employed. METHODS: Female rats were assigned to four groups: placebo, LPS, placebo + GTP, and LPS + GTP for 12 weeks. Efficacy was evaluated by examining changes in bone microarchitecture using histomorphometric and microcomputed tomographic analyses and by bone strength using the three-point bending test. A possible mechanism was studied by assessing the difference in tumor necrosis factor-α (TNF-α) expression in tibia using immunohistochemistry. RESULTS: LPS lowered trabecular volume fraction, thickness, and bone formation in proximal tibia while increasing osteoclast number and surface perimeter in proximal tibia and eroded surface in endocortical tibial shafts. GTP increased trabecular volume fraction and number in both femur and tibia and periosteal bone formation rate in tibial shafts while decreasing trabecular separation in proximal tibia and eroded surface in endocortical tibial shafts. There was an interaction between LPS and GTP in trabecular number, separation, bone formation, and osteoclast number in proximal tibia, and trabecular thickness and number in femur. GTP improved the strength of femur, while suppressing TNF-α expression in tibia. CONCLUSION: In conclusion, GTP supplementation mitigated deterioration of bone microarchitecture and improved bone integrity in rats with chronic inflammation by suppressing bone erosion and modulating cancellous and endocortical bone compartments, resulting in a larger net bone volume. Such a protective role of GTP may be due to a suppression of TNF-α.

Assessment of serum 25(OH)D concentration in women of childbearing age and their preschool children in Northern Jordan during summer.

OBJECTIVE: To assess vitamin D status in women and their children aged 4-5 years in Northern Jordan during summer. DESIGN: A cross-sectional study in which 93 mother-child dyads volunteered through local community centers between June and July 2007. Anthropometric measurements were performed and information on socioeconomic status, health issues, lifestyle factors and nutritional intake were obtained from mothers through a questionnaire. MAIN MEASURES: Serum 25(OH)D and serum parathyroid hormone (PTH) levels were measured. RESULTS: Mean age (s.d.) was 34.0 (6.0) years for mothers and 60.7 (5.4) months for children. Maternal body mass index (BMI) was 29.6 (5.6) kg/m(2) with 77% of women having a BMI >or=25 kg/m(2). Mean concentration of serum 25(OH)D was 25.6 (9.6) nmol/l in mothers; only two women (2.2%) had 25(OH)D concentrations <12.5 nmol/l, but 48.9% of women had <25.0 nmol/l, and 97.8% of women had <50 nmol/l. No woman had values above 75 nmol/l. Children had higher (P<0.0001) serum 25(OH)D concentrations than did their mothers with a mean of 55.8 nmol/l. The children also had lower (P<0.0001) mean serum PTH concentrations than did their mothers (1.47 vs 3.12 pmol/l, respectively). Only three children had serum 25(OH)D concentration <25 nmol/l, but 39% (n=34) had 25(OH)D <50.0 nmol/l. Older women and those with five or more pregnancies had significantly reduced mean serum 25(OH)D concentrations. Children living in families with lower income had significantly higher mean serum 25(OH)D concentration as did children consuming fortified milk compared with those consuming non-fortified milk. CONCLUSION: Despite the abundant sunlight during summer, vitamin D status is a concern for mothers and children in Jordan.

Zinc status and cognitive function of pregnant women in Southern Ethiopia.

The relation between zinc status and cognitive function was examined in a cross-sectional study in the Sidama area of Southern Ethiopia. Pregnant women >24 weeks of gestation from three adjacent rural villages volunteered to participate. Mean (s.d.) plasma zinc of 99 women was 6.97 (1.07) mumol/l (below the cutoff of 7.6 mumol/l indicative of zinc deficiency at this stage of gestation). The Raven's Coloured Progressive Matrices (CPM) test was administered individually. Scores for the Raven's scale A, which is the simplest scale, ranged from 4 to 10 of a possible 12. Women with plasma zinc <7.6 mumol/l had significantly lower Raven's CPM scale A scores than women with plasma zinc concentrations >7.6 mumol/l. Plasma zinc and maternal age and education predicted 17% of the variation in Raven's CPM scale A scores. We conclude that zinc deficiency is a major factor affecting cognition in these pregnant women.

Cranberry juice improved antioxidant status without affecting bone quality in orchidectomized male rats.

BACKGROUND: We reported that drinking citrus juice improves bone quality in orchidectomized senescent male rats. Because cranberry juice, like citrus, is rich in nutrients and phenolic compounds, beneficial effects of citrus juice might also be seen with cranberry juice. An experiment evaluated effect of drinking cranberry juice on bone quality in orchidectomized rats. METHODS: Thirty-two 1-year-old male rats were randomized to two groups: a sham-control group (n=8) and an orchidectomized group (n=24). The treatments for the 4 months duration of the study were SHAM, orchidectomy (ORX), ORX+drinking either 27% or 45% cranberry juice concentrate added to drinking water. At the termination of the study, the rats were euthanized, blood was collected for plasma antioxidant status and IGF-I. The femur, tibia and the 4th lumbar were evaluated for bone quality. Total calcium and magnesium concentration in the femurs were also evaluated. RESULTS: ORX did not affect red blood cell (RBC)-induced hemolysis despite lowering (p<0.05) plasma antioxidant capacity; reduced (p<0.05) plasma IGF-I, femoral density, femoral strength, time-induced femoral fracture, bone mineral content, bone mineral area; numerically (p=0.07) lowered 4th lumbar density; decreased (p<0.05) trabecular connectivity, trabecular number, femoral ash; increased (p<0.05) trabecular separation in comparison to the SHAM group. Drinking cranberry juice increased (p<0.05) plasma antioxidant status, protected RBC against hemolysis, but had no positive effect on bone quality or bone mineral status. CONCLUSIONS: Cranberry juice increases plasma antioxidant status without affecting bone quality.

Vitamin E provides protection for bone in mature hindlimb unloaded male rats.

The deleterious effects of skeletal unloading on bone mass and strength may, in part, result from increased production of oxygen-derived free radicals and proinflammatory cytokines. This study was designed to evaluate the ability of vitamin E (alpha-tocopherol), a free-radical scavenger with antiinflammatory properties, to protect against bone loss caused by skeletal unloading in mature male Sprague-Dawley rats. A 2 x 3 factorial design was used with either hindlimb unloading (HU) or normal loading (ambulatory; AMB), and low-dose (LD; 15 IU/kg diet), adequate-dose (AD; 75 IU/kg diet), or high-dose (HD; 500 IU/kg diet) vitamin E (DL-alpha-tocopherol acetate). To optimize the effects of vitamin E on bone, dietary treatments were initiated 9 weeks prior to unloading and continued during the 4-week unloading period, at which time animals were euthanized and blood and tissue samples were collected. Serum vitamin E was dose-dependently increased, confirming the vitamin E status of animals. The HD treatment improved oxidation parameters, as indicated by elevated serum ferric-reducing ability and a trend toward reducing tissue lipid peroxidation. Histomorphometric analysis of the distal femur revealed significant reductions in trabecular thickness (TbTh), double-labeled surface (dLS/BS), and rate of bone formation to bone volume (BFR/BV) due by HU. AMB animals on the HD diet and HU animals on the LD diet had reduced bone surface normalized to tissue volume (BS/TV) and trabecular number (TbN); however, the HD vitamin E protected against these changes in the HU animals. Our findings suggest that vitamin E supplementation provides modest bone protective effects during skeletal unloading.

The effects of chromium and copper supplementation on mitogen-stimulated T cell proliferation in hypercholesterolaemic postmenopausal women.

The purpose of this study was to analyse effects of chromium and/or copper supplementation on immune function in hypercholesterolaemic postmenopausal women. A 2 x 2 factorial research design was used and 40 subjects were supplemented with 0.394 g lactose, 200 microg Cr, 3.0 mg Cu, or 200 microg Cr and 3.0 mg Cu/d for 12 weeks. A significant interactive effect of Cr and Cu supplementation on lymphocyte proliferation was observed with ConA 50 microg/ml stimulation. After 12 weeks of supplementation, ConA-stimulated (50 microg/ml) lymphocyte proliferation was significantly lower when Cu was added to the Cr supplementation group. Moreover, ConA-stimulated (100 microg/ml) lymphocyte proliferation was significantly lower in the Cu supplementation group compared to the Cr supplementation group after 12 weeks of supplementation. These results suggest that Cu blocks enhancement of lymphocyte proliferation by Cr supplementation and that Cu supplementation has potential suppressive effects on the immune function in these subjects.

Prune suppresses ovariectomy-induced hypercholesterolemia in rats.

Elevated cholesterol among women who have experienced natural or surgical menopause has been linked to ovarian hormone deficiency. The purpose of this study was to investigate the efficacy of prune, a good source of dietary fiber and phytochemicals, on lowering cholesterol in an ovariectomized (ovx) rat model. Forty-eight 90-day-old female Sprague-Dawley rats were randomly assigned to four groups: sham-operated (sham) + control diet, ovx + control diet, ovx + low-dose (LD; 5%) prune, and ovx + high-dose (HD; 25%) prune. After 45 days of treatment, rats were euthanized and tissues were collected for analyses. Ovariectomy elevated serum total cholesterol by 22% compared with sham, and HD prune diet prevented this increase without affecting high density lipoprotein cholesterol concentrations. Animals fed the HD prune diet had 13% lower liver total lipids compared with ovx animals. The findings of this study showed that prune exhibits hypocholesterolemic properties in ovarian hormone deficiency. Dose-response studies should be conducted to establish the effectiveness of prune in prevention of hypercholesterolemia in postmenopausal women who are not on estrogen replacement therapy and seek dietary alternatives. Mechanistic studies also are needed to establish its mode of action.

Interleukin-1alpha-induced changes in chromium-51 absorption, tissue retention, and urinary excretion in rats.

The effects of interleukin-1 alpha (IL-1alpha) on chromium-51 absorption, tissue retention, and urinary excretion were studied in adult male Sprague-Dawley rats. Ten rats were deprived of food for 12 h, injected intraperitoneally with mouse recombinant IL-1alpha (1 microg/kg of body weight in phosphate-buffered saline [PBS]) or control (0.1% bovine serum albumin [BSA] in PBS). Two hours after dosing with the IL-1alpha, rats were fed 50 microL (200 microCi, 0.36 microg Cr) of 51CrCl3 by micropipet. Blood was collected from the tail at 0.25, 0.5, 1, 2, and 4 h. Six hours after dosing with 51CrCl3, rats were exsanguinated and blood and tissues were sampled. The IL-1alpha significantly decreased chromium-51 in blood, urine, and some tissues compared to the control. The decreased absorption, retention, and urinary excretion of chromium-51 from 51CrCl3 in this study may be due to IL-1alpha-mediated increases in the production of prostaglandins and/or decreased production of gastric acid.

Maternal and fetal insulin-like growth factor system and embryonic survival during pregnancy in rats: interaction between dietary chromium and diabetes.

Chromium (Cr) depletion may exacerbate hyperglycemia and negative outcomes of pregnancy in the streptozotocin (STZ) diabetic pregnant rat model through the regulation of the insulin-like growth factor (IGF) system. To test this hypothesis, 40 female rats, all fed a low Cr diet (i.e., 70 microgram Cr/kg diet ) from 21 d of age, were randomly assigned one of four treatments, applied on Day 1 of pregnancy, in a 2 x 2 factorial design: 1) very low Cr diet (40 microgram Cr/kg diet) + citrate buffer injection, 2) very low Cr diet + STZ injection (30 mg STZ/kg body wt in citrate buffer), 3) adequate Cr diet (2 mg Cr [from added CrK(SO4)2]/kg diet) + citrate buffer injectionand 4) adequate Cr diet + STZ injection. Blood and tissues were collected on Day 20 of pregnancy. Chromium depletion increased (P < 0.05) urinary hydroxyproline excretion, 22-kDa IGF binding protein (IGFBP) concentration and litter size but decreased (P < 0. 05) placental wt, percentage of protein per fetus, and fetal IGF-I and -II concentrations. Chromium had no effect (P > 0.10) on maternal hormones, 32-kDa IGFBP, glucose, or placental and fetal hydroxyproline concentrations. Diabetes decreased (P < 0.05) maternal wt gain, embryonic survival, litter size, mean pup wt and maternal insulin concentrations, increased (P < 0.05) maternal blood glucose, IGF-I concentrations and maternal hydroxyproline excretion but did not affect fetal concentrations of hormones, IGFBP, glucose or hydroxyproline. Interaction between chromium and diabetes tended (P < 0.10) to affect maternal IGF-II concentrations, but had no effect on other maternal or fetal variables. In conclusion, maternal chromium depletion did not exacerbate hyperglycemia or pregnancy outcome in STZ-induced diabetic rats, but may negatively affect fetal protein content by decreasing fetal IGF-II concentrations. Diabetes may negatively affect fetal growth through its effect on maternal glucose, insulin and IGF-I.

L-ascorbyl-2-polyphosphate as a vitamin C source for segregated and conventionally weaned pigs.

We conducted two experiments to evaluate the efficacy of a stable source of vitamin C for improving performance and iron status in early-weaned pigs. A preparation of L-ascorbyl-2-polyphosphate (Rovimix Stay-C 25, Roche Vitamins, Ames, IA and Bramus, NJ), which supplies 25% ascorbic acid activity in a stable form, served as the vitamin C source and was incorporated at dietary vitamin C levels of 0, 75, or 150 ppm. In Exp. 1, 72 pigs (14 +/- 2 d of age and 4.98 kg BW) were blocked based on initial BW and penned in groups of three (eight pens per treatment) in an off-site nursery for 42 d. Phase 1 lasted from d 0 to 14, Phase 2 from d 14 to 28, and Phase 3 from d 28 to 42 after weaning. Daily gain and gain:feed ratio (G/F) increased during Phase 1 (quadratic, P < .1 and P < .05, respectively), Phase 3 (linear, P < .1 and P < .01, respectively), and for the overall 42-d experiment (linear, P < .05 and P < .1, respectively) in response to increasing dietary vitamin C. At 14 d after weaning, plasma vitamin C increased (linear, P < .05) with increasing dietary vitamin C, but plasma iron, hemoglobin, and hematocrit were not influenced by dietary vitamin C. In Exp. 2, 120 pigs (20 +/- 3 d of age and 7.2 kg BW) were blocked based on initial BW and penned in groups of five (eight pens per treatment) in a conventional nursery system for 31 d. Phase 1 consisted of d 0 to 7, Phase 2 from d 7 to 17, and Phase 3 from d 17 to 31 after weaning. During the period from d 0 to 17 after weaning, ADG and G/F were improved (linear, P < .1) with increasing dietary vitamin C. At d 17 after weaning, plasma vitamin C and serum iron increased (linear, P < .05), but unbound iron-binding capacity and total iron-binding capacity decreased (linear, P < .05 and P < .1, respectively) with increasing dietary vitamin C. These results suggest that dietary vitamin C is needed during the first 42 d after weaning when pigs are weaned as early as 12 d of age and reared in an off-site nursery and during the first 17 d after weaning when pigs are weaned as early as 17 d of age and reared in a conventional nursery system. L-Ascorbyl-2-polyphosphate at a supplemental level of 75 ppm was adequate to meet the dietary vitamin C requirement of early-weaned pigs. Vitamin C supplementation with a stable product will improve performance in young pigs during the high-stress postweaning period and may be particularly beneficial to pigs weaned at a very early age.

Absorption, retention and urinary excretion of chromium-51 in rats pretreated with indomethacin and dosed with dimethylprostaglandin E2, misoprostol or prostacyclin.

Drug-nutrient interactions affecting chromium were investigated in this study. Rats were injected with indomethacin to reduce endogenous prostaglandin synthesis and dosed with prostaglandin analogues or prostacyclin. Effects on absorption, tissue distribution and urinary excretion of 51Cr from 51CrCl3 were evaluated using a 2 x 4 factorial experimental design. Forty-eight adult male rats were food deprived for 12 h and then injected intraperitoneally with indomethacin (5 mg/kg body wt) or placebo. Thirty minutes later, rats were intubated and dosed with one of four treatments: a prostaglandin E1 analogue (misoprostol) at 50 microg/kg body wt; a prostaglandin E2 analogue (16,16-dimethylprostaglandin E2) at 7.5 microg/kg body wt; prostacyclin at 20 microg/kg body wt; or control (7.64 mmol/L Tween-80 suspended in 0.15 mol/L NaCl containing 0.48 mol/L ethanol). Immediately after intubation, rats were dosed with 3.7 mBq of 51CrCl3 by micropipette. Blood was collected from the tail at intervals after 51Cr dosing. Six hours after dosing, 51Cr rats were exsanguinated by cardiac puncture. Indomethacin, an inhibitor of prostaglandin synthesis, significantly increased (P < 0.05) 51Cr in blood at all time periods tested except at 15 min. In tissues, indomethacin significantly increased 51Cr retention. Urinary 51Cr excretion at 6 h was higher (P < 0.05) in indomethacin-pretreated rats than in control rats. Administration of indomethacin, which blocks prostaglandin synthesis, enhanced 51Cr absorption, whereas dosing with 16,16-dimethylprostaglandin E2 decreased 51Cr absorption.

Deliberations and evaluations of the approaches, endpoints and paradigms for boron, chromium and fluoride dietary recommendations.

The 10th edition (1989) of the Recommended Dietary Allowances provided estimated safe and adequate daily dietary intakes (ESADDI) for chromium and fluoride and summarized the substantial evidence for boron essentiality in animals. New endpoints, approaches and paradigms to use to formulate dietary guidance for these elements were reviewed by a discussion group that met as part of a national workshop. Deliberations of the group are summarized to facilitate future discussions on dietary guidance for these elements. The category, "provisional RDA" was recommended to replace the current ESADDI category because of the ambiguities associated with the ESADDI. A provisional RDA would be defined for a dietary substance that meets one of two sets of criteria: class 1, clear evidence of essentiality but uncertain or limited quantitative data or endpoints to define dietary requirements; and class 2, strong evidence of essentiality, and clear nutritional benefit based on reasonably certain quantitative data, but lack of clear information on function or endpoints to use for deficiency dietary requirements. A summary of background information and possible approaches for assigning provisional RDAs for boron, chromium and fluoride is presented.

Vitamin and trace mineral withdrawal effects on broiler breast tissue riboflavin and thiamin content.

An investigation was carried out to determine whether a Day 28 to 49 dietary vitamin, trace mineral, and vitamin plus trace mineral premix withdrawal would impact Pectoralis major thiamin or riboflavin concentration in chicks reared under thermoneutral (24 C) and heat-stressed (24 to 35 C) conditions. No significant (P > 0.1) environment by nutrient withdrawal interactions were detected. Heat stress and vitamin withdrawal reduced (P < 0.05) P major thiamin and riboflavin concentration. In contrast, trace mineral withdrawal failed (P> 0.1) to impact either vitamin. In conclusion, results from this study suggest that a 21-d vitamin withdrawal and heat stress exposure have the potential to reduce muscle riboflavin and thiamin concentration.

Uptake and retention in suckling rats of 51chromium fed with human milk or infant formulas.

Optimum concentration of Cr for infant formulas has not been established. Such components as soy protein or supplemental Fe could influence absorption and retention. Suckling rat pups were used to evaluate the influence of three commercial formulas and human milk, all of which had been incubated with 51CrCl3 for 1 h, on the uptake and retention of the added 51Cr. After fasting 3 h, the pups were intubated with a single dose of 25 microCi 51CrCl3 in either a cow's milk-based formula, an Fe-supplemented cow's milk-based formula, a soy-based formula, or human milk. Six hours later, 51Cr was counted in five organs, thymus, blood, and total urine. Absorption of 51Cr was low. At 6 h, percent 51Cr in blood was < 0.2% of the dose, and total 51Cr excretion in urine was < 1.8%. The uptake and retention of 51Cr and its concentration in any of the organs, thymus, blood, and urine were not influenced by different types of formula or by human milk.

Chromium and chronic ascorbic acid depletion effects on tissue ascorbate, manganese, and 14C retention from 14C-ascorbate in guinea pigs.

Chromium (Cr) potentiates the effects of insulin and a role for insulin in ascorbic acid transport has been reported. Therefore, the effects of Cr and ascorbate depletion on tissue ascorbic acid and 14C distribution and excretion after a 14C ascorbate dose were investigated in guinea pigs. As utilization of dietary Cr is affected by interaction with other minerals, tissue manganese (Mn), zinc (Zn), copper (Cu), and iron (Fe) were examined. For 20 wk, 40 weanling animals were fed either a Cr-deficient (< 0.06 micrograms Cr/g diet, -Cr) or a Cr-adequate (2 micrograms Cr from CrCl3/g diet, +Cr) casein-based diet and were given 1 mg ascorbate/d (-C) or 10 mg ascorbate/d (+C) for 20 wk. Animals fed the Cr-depleted diet had decreased weight at 20 wk (p < 0.01). Six hours before necropsy, animals were dosed by micropipette with 1.8 microCi of L-[carboxyl-14C] ascorbic acid and placed in metabolic cages. Ascorbate supplementation increased Fe concentrations in most analyzed tissues, hepatic 14C, tissue ascorbate and Mn concentration in the adrenal and testes, but decreased the concentrations of Cu in the kidney and Mn in the spleen. Liver Mn concentration was higher and kidney Mn concentration was lower in +Cr animals. Interactions between Cr and ascorbic acid affected Mn concentrations in bone and brain. These results indicate that ascorbate and Cr may affect Mn distribution. Chromium supplementation decreased plasma cortisol, brain 14C and the amount of 14C expired as carbon dioxide. These findings suggest that dietary Cr may affect ascorbic acid metabolism and the metabolic response to stress.

Dehydroepiandrosterone sulfate, cholesterol, hemoglobin, and anthropometric measures related to growth in male adolescents.

Sixty-four white boys between 10.6 and 14.3 years old participated in an adolescent nutrition assessment study evaluating dehydroepiandrosterone sulfate (DHEAS) as a measure of maturation. DHEAS, an adrenal androgen, is low in childhood and rises with the development of secondary sexual characteristics. Biochemical measures included plasma DHEAS assessed by radioimmunoassay, cholesterol assessed by an enzymatic method, and hemoglobin assessed by the cyanmethemoglobin method. Midarm muscle area (MAMA) was calculated from midarm circumference and triceps fatfold measurements. DHEAS was correlated significantly with height, weight, MAMA, and hemoglobin. By age, significant differences were found for height, weight, and MAMA, but not for any of the biochemical measures. For boys with DHEAS concentration less than 3 mumol/L, values for height, weight, body mass index, MAMA, and hemoglobin were significantly different from those for boys with higher DHEAS concentrations. No significant differences were found for age or nutrient intakes by DHEAS concentration groups. Mean plasma cholesterol concentrations decreased with increases in age and with maturation evidenced by higher DHEAS concentration. Cholesterol concentration was negatively correlated with height and MAMA. Mean nutrient intakes estimated by a quantitative food frequency questionnaire met or exceeded the Recommended Dietary Allowances for these age groups. DHEAS identified maturation differences in male adolescents.

Vanadium and ascorbate effects on 3-hydroxy-3-methylglutaryl coenzyme A reductase, cholesterol and tissue minerals in guinea pigs fed low-chromium diets.

Vanadium has been reported to affect numerous physiological processes; however, a demonstration that vanadium deficiency consistently impairs biological function is lacking. The purpose of this study was to determine if the activity of hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, the rate-limiting enzyme in cholesterol synthesis, is affected by dietary supplementation of vanadate and/or chronic ascorbic acid deficiency. To determine if vanadium and/or ascorbic acid affected mineral metabolism, tissue minerals also were analyzed. Weanling male guinea pigs were assigned randomly to groups of 10 in a 2 x 2 factorial design. The dietary variables were ascorbate, 0.5 or 10 mg/day, and vanadium < 0.01 microgram or 0.5 microgram/g diet as NH4VO3 in a low Cr diet containing < 0.07 microgram Cr/g diet. After 21 weeks on this diet, guinea pigs receiving more ascorbate had lower liver weight/body weight ratios and increased bone copper. Testes weight/body weight ratios, hepatic glycogen and bone copper decreased while hepatic lipids, fecal bile acids, plasma cortisol and bone calcium and magnesium were increased by vanadium supplementation. An interaction between vanadium and ascorbate affected cholesterol excretion in feces, hepatic iron, plasma cholesterol concentration and the activity of HMG CoA reductase. This study provides evidence of increased bone mineral concentrations with vanadium supplementation and of an interaction between vanadium and ascorbate which affected cholesterol metabolism.

Effects of starch, sucrose, fructose and glucose on chromium absorption and tissue concentrations in obese and lean mice.

Forty-eight male genetically obese (OB) mice (C57BL/6J-OB) and 48 lean male littermates were randomly assigned within main plots (OB or lean) to one of eight diets. Diets were low chromium or supplemented with 1 mg chromium as CrCl3 per kg. Starch, sucrose, fructose or glucose comprised 50% of the diet, which met AIN recommendations except for chromium. Experimental diets and deionized water were available ad libitum for 26 d. Mice were fasted 10 h and were intubated 2 h before killing with 15 microCi of 51CrCl3 in a 25% carbohydrate solution (2 mg carbohydrate/g body wt) of either starch, sucrose, glucose or fructose corresponding to the diet previously fed. 51Cr concentrations were significantly higher in the blood, liver, spleen, epididymal fat pad, testes and femur of animals given their carbohydrate load as starch than in animals fed sucrose, fructose or glucose. Carbohydrate had a significant effect on chromium concentrations of testes, spleen, kidney and liver with values generally being higher with the starch diet. Chromium supplementation increased bone and kidney chromium concentrations and heart and muscle glycogen. These data indicate that the source of carbohydrate can alter chromium absorption and retention.

Cholesterol concentration of longissimus muscle, subcutaneous fat and serum of two beef cattle breed types.

The cholesterol concentration of uncooked and cooked longissimus muscle, uncooked subcutaneous fat and serum, as affected by days on feed, breed type and sex class in a factorial arrangement, and the relationship between serum cholesterol and tissue cholesterol were studied. Days on feed, breed type and sex class had no effect (P greater than .05) on tissue cholesterol concentrations. Overall least-squares means for uncooked and cooked longissimus muscle and subcutaneous fat were 63.32, 80.27 and 98.90 mg of cholesterol/100 g of tissue, respectively. Cholesterol concentration was 26.8% higher in cooked vs uncooked muscle and 56.2% higher in uncooked subcutaneous fat compared with uncooked muscle. Serum cholesterol concentration was lower (P less than .05) for fullblood Chianinas and steers (122.6 and 133.9 mg/dl) compared with crossbreds and heifers (162.3 and 151.0 mg/dl), respectively. Serum cholesterol concentration showed a cubic response (P less than .05) over days on feed; it was lowest at 0 d (79.6 mg/dl), increased up to 77 d (156.3 mg/dl), leveled off (154.7 mg/dl), then increased again (179.3 mg/dl). Serum cholesterol had low and insignificant correlation coefficients with all tissue cholesterol concentrations (r = .08 to .22; P greater than .05). Results indicate that muscle and fat tissue cholesterol concentrations do not vary in response to the differences in breed type, sex class or time on feed represented in the present study and thus may be an inherent characteristic dependent upon quantitative needs for cellular membrane functions. However, serum cholesterol concentration was affected by treatments evaluated in this study and may be related to factors affecting lipid metabolism.