The American journal of clinical nutrition
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Randomized Controlled Trial Clinical Trial
No effect of supplementation with vitamin E, ascorbic acid, or coenzyme Q10 on oxidative DNA damage estimated by 8-oxo-7,8-dihydro-2'-deoxyguanosine excretion in smokers.
The protective effect of fruit and vegetables against cancer has been related to their high antioxidant content. However, results from intervention trials have not been conclusive on the protective effect of antioxidant supplementation. In a randomized placebo-controlled trial we investigated the effect of dietary supplementation with antioxidants on a biomarker of oxidative DNA damage with mechanistic relation to carcinogenesis. ⋯ Two months of supplementation did not result in significant changes in the urinary excretion rate of 8-oxodG in any group. The lack of effect of antioxidant supplementation on the excretion rate of 8-oxodG, despite substantial increases in plasma antioxidant concentrations, agrees with the results from recent large intervention studies with cancer as an endpoint. The cancer-protective effect of fruit and vegetables seems to rely not on the effect of single antioxidants but rather on other anticarcinogenic compounds or on a concerted action of several micronutrients present in these foods.
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Randomized Controlled Trial Comparative Study Clinical Trial
A double-blind, prospective, randomized study of glutamine-enriched compared with standard peptide-based feeding in critically ill patients.
Arterial and venous plasma amino acids were determined in 28 intensive care patients randomly assigned to receive 10 d of isoenergetic, isonitrogenous feedings that differed sixfold in glutamine content. Subjects were generally well-matched for age, injury severity, and disease diagnoses. Nasojejunal feedings were started within 48 h of admission. ⋯ There were, however, significant (P < 0.05) increases in arterial or venous plasma total, indispensable, and branched-chain amino acids of 125-144% by day 5 only in patients fed the standard control diet. The phenylalanine-tyrosine ratio was elevated on day 1 in both groups (1.3-1.4) but decreased significantly only in the glutamine-supplemented group (1.1 compared with 1.4) by day 5. Glutamine supplementation blunted the hyperaminoacidemia and elevated aromatic amino acid response to injury.
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Randomized Controlled Trial Clinical Trial
Adherence to iron supplementation during pregnancy in Tanzania: determinants and hematologic consequences.
Limited adherence to iron supplementation is thought to be a major reason for the low effectiveness of anemia-prevention programs. In rural Tanzania, women at 21-26 wk of gestation were randomly given either 120 mg of a conventional (Con) iron supplement or 50 mg of a gastric-delivery-system (GDS) iron supplement for 12 wk. Adherence was assessed by using a pill bottle equipped with an electronic counting device. ⋯ Fewer side effects were observed in the GDS group. In a subgroup of women with a low initial hemoglobin concentration (< or = 120 g/L), the response to the iron supplements suggested that both of the applied doses were unnecessarily high for adequate hematologic response in a population with a marginal hemoglobin concentration. The GDS group appeared to require a dose one-fourth as high as that of the Con group for an equal effect on improving hemoglobin to normal concentrations.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Effects of weekly iron supplementation on pregnant Indonesian women are similar to those of daily supplementation.
The effect of daily rather than weekly iron supplementation was compared in women who were 8-24 wk pregnant. One group (n = 68) received 60 mg Fe/d, the second group (n = 71) received 120 mg Fe/wk, given at once. Supplementation lasted 11.3 wk on average, depending on gestational date at entry, and was not supervised. ⋯ In a subgroup of women with a hemoglobin concentration < 110 g/L at baseline (n = 45 daily; n = 54 weekly) no significant within-group changes occurred in serum ferritin, but the change in the daily group was 4.1 micrograms/L higher than in the weekly group (P = 0.049). Compliance, as indicated by two positive stool tests, was approximately equal to 54.3% in the daily group and 62.2% in the weekly group. We conclude that for the complete sample of subjects, the treatment effect of daily compared with weekly supplementation was similar under conditions resembling a normal antenatal care program.
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Randomized Controlled Trial Comparative Study Clinical Trial
Intestinal calcium absorption of women during lactation and after weaning.
We investigated whether intestinal calcium absorption and serum 1,25-dihydroxycholecalciferol (calcitriol) concentrations are higher in women during lactation and after weaning to compensate for calcium lost in breast milk. Measurements were obtained at 4.6 mo postpartum in 24 lactating women and 24 nonlactating women, at 9.6 mo postpartum in 24 lactating women (2.6 mo after complete weaning) and 24 nonlactating women. One-half of the women in each group were randomly assigned to receive 1 g supplemental Ca/d as calcium carbonate. ⋯ Lactating women who had resumed menses had higher fractional absorption and serum calcitriol than did lactating women who had not. Serum calcium and phosphorus concentrations were greater in lactating compared with nonlactating women; there were no differences between groups after weaning. We conclude that lactation stimulates increases in fractional calcium absorption and serum calcitriol, but the responses are only apparent after weaning or the resumption of menses.