Objective: Our objective was to determine the efficacy of an increased intake of red meat, or the consumption of iron-fortified milk, in improvement of iron status in toddlers at a population level.
Design: In this 20-wk randomized placebo-controlled trial, 225 healthy nonanemic 12–20-mo-old children were assigned to 1 of 3 groups: red meat (toddlers encouraged to consume 2.6 mg iron from red meat dishes daily), fortified milk [toddlers' regular milk replaced with iron-fortified (1.5 mg iron/100 g prepared milk) cow milk], or control [toddlers' regular milk replaced with nonfortified (0.01 mg iron/100 g prepared milk) cow milk]. Blood samples were collected at baseline and at 20 wk for hemoglobin, serum ferritin, serum transferrin receptor, and C-reactive protein. The prevalence of suboptimal iron status (ie, depleted iron stores, iron-deficient erythropoiesis, and iron deficiency anemia) was determined, and body iron was calculated.
Results: No intervention effects were shown on the prevalence of suboptimal iron status. Serum ferritin increased by 44% (95% CI: 14%, 82%; P = 0.002) in the fortified milk group, did not change (+10%) in the red meat group (95% CI: –7%, 30%; P = 0.241), and tended to decrease (–14%) in the control group (95% CI: –27%, 1%; P = 0.063). By 20 wk, in comparison with the control group, serum ferritin and body iron were significantly higher in the fortified milk group (both P < 0.001), and serum ferritin was significantly higher in the red meat group (P = 0.033).
Conclusions: Consumption of iron-fortified milk can increase iron stores in healthy nonanemic toddlers, whereas increased intakes of red meat can prevent their decline. This trial was registered at actr.org.au as ACTRN12605000487617.
]]>Objective: The aim was to determine the most current distribution of serum vitamin C concentrations in the United States and the prevalence of deficiency in selected subgroups.
Design: Serum concentrations of total vitamin C were measured in 7277 noninstitutionalized civilians aged ≥6 y during the cross-sectional, nationally representative NHANES 2003–2004. The prevalence of deficiency was compared with results from NHANES III.
Results: The overall age-adjusted mean from the square-root transformed (SM) concentration was 51.4 µmol/L (95% CI: 48.4, 54.6). The highest concentrations were found in children and older persons. Within each race-ethnic group, women had higher concentrations than did men (P < 0.05). Mean concentrations of adult smokers were one-third lower than those of nonsmokers (SM: 35.2 compared with 50.7 µmol/L and 38.6 compared with 58.0 µmol/L in men and women, respectively). The overall prevalence (±SE) of age-adjusted vitamin C deficiency was 7.1 ± 0.9%. Mean vitamin C concentrations increased (P < 0.05) and the prevalence of vitamin C deficiency decreased (P < 0.01) with increasing socioeconomic status. Recent vitamin C supplement use or adequate dietary intake decreased the risk of vitamin C deficiency (P < 0.05).
Conclusions: In NHANES 2003–2004, vitamin C status improved, and the prevalence of vitamin C deficiency was significantly lower than that during NHANES III, but smokers and low-income persons were among those at increased risk of deficiency.
]]>Objective: The objective was to determine whether supplementing mildly iodine-deficient children with iodine improves cognition.
Design: A randomized, placebo-controlled, double-blind trial was conducted in 184 children aged 10–13 y in Dunedin, New Zealand. Children were randomly assigned to receive a daily tablet containing either 150 µg I or placebo for 28 wk. Biochemical, anthropometric, and dietary data were collected from each child at baseline and after 28 wk. Cognitive performance was assessed through 4 subtests from the Wechsler Intelligence Scale for Children.
Results: At baseline, children were mildly iodine deficient [median urinary iodine concentration (UIC): 63 µg/L; thyroglobulin concentration: 16.4 µg/L]. After 28 wk, iodine status improved in the supplemented group (UIC: 145 µg/L; thyroglobulin: 8.5 µg/L), whereas the placebo group remained iodine deficient (UIC: 81 µg/L; thyroglobulin: 11.6 µg/L). Iodine supplementation significantly improved scores for 2 of the 4 cognitive subtests [picture concepts (P = 0.023) and matrix reasoning (P = 0.040)] but not for letter-number sequencing (P = 0.480) or symbol search (P = 0.608). The overall cognitive score of the iodine-supplemented group was 0.19 SDs higher than that of the placebo group (P = 0.011).
Conclusions: Iodine supplementation improved perceptual reasoning in mildly iodine-deficient children and suggests that mild iodine deficiency could prevent children from attaining their full intellectual potential. The trial was registered with the Australia New Zealand Clinical Trials Register as ACTRN12608000222347.
]]>Objective: The present study evaluated serum lutein, zeaxanthin, and macular pigment optical density (MPOD) responses at 0.25°, 0.5°, and 1° retinal eccentricities to the consumption of 2 and 4 egg yolks/d by older adults taking cholesterol-lowering medications.
Design: Subjects consumed foods containing 2 followed by 4 egg yolks/d for 5 wk each with a 4-wk egg-free period at baseline and between the 2 interventions.
Results: Changes in MPOD (n = 37) with egg yolk consumption were inversely associated (P < 0.05) with baseline MPOD. Subjects with low-baseline MPOD (defined as MPOD ≤0.5 at 0.25°, ≤0.4 at 0.5°, and ≤0.35 at 1°) showed increases of ≤50% (P < 0.05) with 4 egg yolks at the 3 retinal eccentricities. MPOD increased by 31% (P = 0.059) at 0.5° with 2 egg yolks. Serum lutein increased by only 16% and 24% (P < 0.05) compared with increases of 36% and 82% (P < 0.001) in serum zeaxanthin (n = 52) after consumption of 2 and 4 egg yolks, respectively. Serum HDL cholesterol increased by 5% (P < 0.05) after consumption of 2 and 4 egg yolks. Serum LDL cholesterol did not change with either egg yolk treatment.
Conclusions: Consumption of 4 egg yolks/d, and possibly of 2 egg yolks/d, for 5 wk benefited macular health in older adults with low MPOD. Serum HDL cholesterol increased without an increase in LDL cholesterol in this study population, most of whom were taking cholesterol-lowering statins.
]]>Objectives: With the use of iron stable isotopes, we aimed to determine whether circulating hepcidin predicts dietary iron bioavailability, to quantify the amount of absorbed iron after oral iron loading, and to measure the plasma hepcidin response.
Design: In the first study, young women (n = 98) with an iron status varying from iron deficiency anemia to iron sufficiency (women with serum ferritin concentrations 25–40 µg/L were not included) were given stable isotope–labeled test meals (n = 196) containing ferrous sulfate, ferrous fumarate, or ferric pyrophosphate, after which plasma hepcidin and iron bioavailability were measured. In the second study, iron-sufficient men (n = 4) were given 3.8- and 60-mg oral doses of labeled ferrous sulfate. The stable isotope appearance curve was determined, and the plasma hepcidin response was measured over 6 h.
Results: In study 1, plasma hepcidin and plasma ferritin were strongly correlated (r = 0.79, P < 0.001). Plasma hepcidin significantly, but modestly, predicted iron bioavailability from ferrous sulfate and ferrous fumarate (r = –0.51 and –0.46, respectively; P < 0.0001) but not from ferric pyrophosphate (r = –0.30, P = 0.056, respectively). In study 2, the 3.8-mg dose increased mean circulating absorbed iron to a peak of 0.42 µmol/L at 60 min but did not increase plasma hepcidin, The 60-mg dose increased mean circulating absorbed iron to a peak of 5.9 µmol/L at 120 min and produced an 30% increase in mean plasma hepcidin at 6 h (P < 0.01).
Conclusions: Plasma hepcidin is only a modest predictor of dietary iron bioavailability in humans. Oral iron loading, measured by stable-isotope appearance curves, increases circulating hepcidin.
]]>Objective: Dietary intake modeling was undertaken to determine an amount of iron supplementation that would confer acceptably low prevalence of apparently inadequate and apparently excessive intakes.
Design: The distribution of usual dietary iron intakes was estimated with the use of 24-h recalls from pregnant women aged 19–50 y in the Canadian Community Health Survey, Cycle 2.2. The prevalence of usual intakes below the Estimated Average Requirement for pregnancy (22 mg/d) or above the Tolerable Upper Intake Level (45 mg/d) was estimated. Iterative modeling with incremental iron supplement was performed to determine a suitable supplement amount. Because the sample of pregnant women was small (148 day 1 recalls), estimates of the tails of the distributions had large SDs, and supporting analyses based on intake data from nonpregnant women (4540 day 1 recalls) were made.
Results: Daily supplementation shifted the intake distribution curve without changing its shape. Supplementation with 16 mg iron/d was consistent with low (<3%) prevalence of apparently inadequate intakes. This amount of supplementation should not be associated with an increase in apparently excessive intakes by pregnant women in this population.
Conclusions: On the basis of Dietary Reference Intakes, an iron supplement of 16 mg/d throughout pregnancy is justified as both efficacious and safe for healthy women living in Canadian households. This does not preclude the need for therapeutic iron doses for some individuals on the basis of iron status. The method can be applied to other populations if suitable baseline iron intake data are available.
]]>Objective: The objective was to compare the pharmacokinetics of S-(–)equol and R-(+)equol by using [13C] stable-isotope-labeled tracers to facilitate the optimization of clinical studies aimed at evaluating the potential of these diastereoisomers in the prevention and treatment of estrogen- and androgen-dependent conditions.
Design: A randomized, crossover, open-label study in 12 healthy adults (6 men and 6 women) compared the plasma and urinary pharmacokinetics of orally administered enantiomeric pure forms of S-(–)[2-13C]equol, R-(+)[2-13C]equol, and the racemic mixture. Plasma and urinary [13C]R-equol and [13C]S-equol concentrations were measured by tandem mass spectrometry.
Results: Plasma [13C]equol concentration appearance and disappearance curves showed that both enantiomers were rapidly absorbed, attained high circulating concentrations, and had a similar terminal elimination half-life of 7–8 h. The systemic bioavailability and fractional absorption of R-(+)[2-13C]equol were higher than those of S-(–)[2-13C]equol or the racemate. The pharmacokinetics of racemic (±)[2-13C]equol were different from those of the individual enantiomers: slower absorption, lower peak plasma concentrations, and lower systemic bioavailability.
Conclusions: The high bioavailability of both diastereoisomers contrasts with previous findings for the soy isoflavones daidzein and genistein, both of which have relatively poor bioavailability, and suggests that low doses of equol taken twice daily may be sufficient to achieve biological effects.
]]>Objective: The aim of the study was to determine whether low selenium and iodine status compromises thyroid function in an older New Zealand population.
Design: We investigated the effects of selenium and iodine supplementation in a double-blind, randomized, placebo-controlled trial in 100 Dunedin volunteers aged 60–80 y. Participants received 100 µg Se/d as
Results: Plasma selenium (P < 0.0001) and whole-blood GPx activity (P<0.0001) increased from baseline to week 12 in the selenium and selenium plus iodine groups in comparison with the placebo group. Median UIC at baseline was 48 µg/L (interquartile range: 31–79 µg/L), which is indicative of moderate iodine deficiency. UIC increased in the iodine and selenium plus iodine groups and was significant only for the iodine group (P = 0.0014). Thyroglobulin concentration decreased by 24% and 13% of baseline in the iodine and selenium plus iodine groups in comparison with the placebo group (P = 0.009 and P = 0.108, respectively). No significant treatment effects were found for TSH, free T3, free T4, or ratio of T3 to T4.
Conclusions: Additional selenium improved GPx activity but not the thyroid hormone status of older New Zealanders. Iodine supplementation alleviated the moderate iodine deficiency and reduced elevated thyroglobulin concentrations. No synergistic action of selenium and iodine was observed. The trial was registered at
Objective: The objective was to evaluate the effects of Roux-en-Y gastric bypass (RYGBP) on iron status and iron absorption at different stages after surgery. We hypothesized that iron absorption would be markedly impaired immediately after surgery and would not improve after such a procedure.
Design: Anthropometric, body-composition, dietary, hematologic, and iron-absorption measures were determined in 67 severe and morbidly obese women [mean age: 36.9 ± 9.8 y; weight: 115.1 ± 15.6 kg, body mass index (BMI: in kg/m2); 45.2 ± 4.7] who underwent RYGBP. The Roux-en-Y loop length was 125–150 cm. Determinations were carried out before and 6, 12, and 18 mo after surgery. Fifty-one individuals completed all 4 evaluations.
Results: The hemoglobin concentration decreased significantly throughout the study (repeated-measures analysis of variance). The percentage of anemic subjects changed from 1.5% at the beginning of the study to 38.8% at 18 mo. The proportion of patients with low serum ferritin increased from 7.5% to 37.3%. The prevalence of iron deficiency anemia was 23.9% at the end of the experimental period. Iron absorption from both a standard diet and from a standard dose of ferrous ascorbate decreased significantly after 6 mo of RYGBP to 32.7% and 40.3% of their initial values, respectively. No further significant modifications were noted.
Conclusion: Iron absorption is markedly reduced after RYGBP with no further modifications, at least until 18 mo after surgery.
]]>Objectives: The objectives of this study were to evaluate site-specific concentrations of carotenoids in adipose tissue and to examine relations between carotenoid concentrations in the diet, serum, and adipose tissue.
Design: Healthy adults (12 women and 13 men) participated in this cross-sectional study. Dietary carotenoids over the past year were assessed with a food-frequency questionnaire. Serum and adipose tissue biopsy samples were collected from the abdomen, buttock, and inner thigh for the measurement of carotenoids by HPLC.
Results: Many adipose carotenoids were inversely related to percentage body fat, although lycopene was the only carotenoid inversely correlated with all 3 sites. Most of the carotenoids were significantly higher in the abdominal adipose tissue than in the thigh (P < 0.05). Concentrations of -carotene, β-carotene, 5-cis-lycopene, and total carotenoids were significantly higher in the buttocks than in the thigh (P < 0.05). Concentrations of -carotene, cis-lycopene, and lutein (with or without zeaxanthin) were significantly higher in the abdomen than in the buttocks (P < 0.05). Dietary intake was significantly correlated with serum concentrations of -carotene, β-carotene, β-cryptoxanthin, and total carotenoids. Carotenoid intake was significantly correlated with adipose tissue concentrations of -carotene, β-carotene, β-cryptoxanthin, cis-lycopene, and total carotenoids (P < 0.05) but varied by site. Of all the adipose tissue sites evaluated, the abdomen showed the strongest correlation with long-term dietary carotenoid intakes and with serum (indicator of short-term intake) for most carotenoids.
Conclusions: Body fat may influence the tissue distribution of carotenoids. Abdominal adipose tissue carotenoid concentrations may be a useful indicator of carotenoid status.
]]>Objective: The objective was to study the potential link between chronic vitamin C deficiency and neuronal damage in newborn guinea pigs.
Design: Thirty 6- to 7-d-old guinea pigs were randomly assigned to 2 groups to receive either a vitamin C–sufficient diet or the same diet containing a low concentration of vitamin C (but adequate to prevent scurvy) for 2 mo. Spatial memory was assessed by the Morris Water Maze, and hippocampal neuron numbers were quantified by stereologic techniques.
Results: The results showed a reduction in spatial memory (P < 0.05) and an increased time to first platform hit (P < 0.05) in deficient animals compared with controls. The deficient animals had a lower total number of neurons in hippocampal subdivisions (dentate gyrus, cornu ammonis 1, and cornu ammonis 2–3) than did the normal controls (P < 0.05).
Conclusions: Our data show that vitamin C deficiency in early postnatal life results in impaired neuronal development and a functional decrease in spatial memory in guinea pigs. We speculate that this unrecognized effect of vitamin C deficiency may have clinical implications for high-risk individuals, such as in children born from vitamin C–deficient mothers.
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