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.

Serum phenytoin levels of patients on gastrostomy tube feeding.

Serum phenytoin levels of two groups of brain-injured patients on gastrostomy tube (GT) feeding were retrospectively examined. In the first group (group C = clamped, n = 13), GT was clamped for one hour after the phenytoin dose (2-3 doses per day), and in the second group (group NC = not clamped, n = 9) GT feedings were continued without interruption. Mean +/- SD of the serum phenytoin levels was 14.4 +/- 4.7 micrograms/ml for group C, and 9.2 +/- 6.8 micrograms/ml for group NC. When serum phenytoin levels were adjusted for decreased serum albumin levels, the results were 19.8 +/- 6.4 micrograms/ml for group C and 11.7 +/- 7.9 micrograms/ml for group NC. Statistical analysis showed a significant difference between the means in both the phenytoin and adjusted phenytoin levels between the two groups (p < 0.05). No significant difference was found in phenytoin dosage per kg of body weight, protein intakes, calcium, magnesium and sodium per 24 hours between the means for the two groups. Results of this study suggest that clamping the GT for one hour after the phenytoin dose results in higher serum levels of the drug.

Daily selenium intake estimates for residents of arsenic-endemic areas.

The selenium in the diet of persons in arsenic-endemic areas, high levels of arsenic in the drinking water, was evaluated. The methodology used was that of 24-hr dietary recall. Daily selenium intakes of two rural towns in northern Mexico were found to be similar, approximating 72.9 and 60.6 micrograms. These values were similar to those of a previously arsenic-exposed area from California, Edison community. The Edison participants had a daily selenium intake of 61.8 micrograms. The possible negative effect of selenium to produce differences in reported geographical variation in disease could not be substantiated in this study. Other nutrient intakes, protein and energy were also found similar for communities. Differences were noted in vitamin A intake where one-third the daily requirement was experienced by Mexican participants compared to two-thirds the requirement being satisfied by those participants from Edison.

Human glutathione peroxidase activity in cases of high selenium exposures.

Four communities with water supplies having selenium concentrations of less than 3.1, 1.7, 189, and 496 micrograms/liter were selected for study. Samples of blood, urine, and tap water were obtained from participants in each community and analyzed for selenium content. Blood samples were also analyzed for glutathione peroxidase activity. Results showed an increase in selenium concentration in the urine as the water selenium increased. Selenium concentrations in blood did not reflect the increased selenium exposure. Glutathione peroxidase activity in whole blood decreased in highly exposed participants compared to those with low exposure. We conclude that glutathione peroxidase activity in cases of possible environmental toxic exposures will not show the increased activity seen in supplementation of selenium to deficient subjects.

Zinc, vitamin B-6, and other nutrients in pregnant women attending prenatal clinics in Mexico.

Biochemical measurements and 24-h dietary recalls were conducted early (18.9 +/- 5.9 wk) and late (35.1 +/- 2.0 wk) in pregnancy in women attending clinics in Montemorelos, Mexico. Mean weight gain per week (0.4 +/- 0.2 kg) and birth weight (3381 +/- 456 g) were normal. Intakes tended to decline during pregnancy and declined significantly for zinc (p less than 0.05) and vitamin B-6 (p less than 0.03). Mean Zn intake late in pregnancy was low (7.8 +/- 3.3 mg/d). Various supplements were taken but none contained Zn. During pregnancy mean plasma Zn levels fell (p less than 0.001) and late in pregnancy 57% of the women had values suggestive of poor Zn status (less than or equal to 8.1 mumol/L). These data indicate that Zn intakes of approximately 8 mg/d will not maintain plasma Zn levels in late pregnancy. Erythrocyte glutamic-pyruvic transaminase (EGPT) index and the index of diamine oxidase (DAO), a vitamin B-6-requiring enzyme of placental origin, were correlated suggesting that DAO index may be useful in evaluating vitamin B-6 status in pregnancy.

PIP: Biochemical measurements and 24 hour dietary recalls were conducted early (18.9 +0- 5.9 weeks) and late (35.1 +or- 2.0 weeks) in pregnancy in women attending clinics in Montemorelos, Mexico. Mean weight gain per week (0.4 +or- 0.2 kg) and birth weight (3381 +or- 456 grams) were normal. Intakes tended to decline during pregnancy and declined significantly for zinc (p 0.05) and vitamin B-6 (p 0.03). Mean zinc intake late in pregnancy was low (7.8 +or- 3.3 mg/d). Various supplements were taken but none contained zinc. During pregnancy mean plasma zinc levels fell (p 0.001) and late in pregnancy 57% of the women had values suggestive of poor zinc status (or= 8.1 micromoles/liter). These data indicate that zinc intakes of approximately 8 mg/d will not maintain plasma zinc levels in late pregnancy. Erythrocyte glutamic-pyruvic transaminase (EGPT) index and the index of diamine oxidase (DAO), a vitamin B-6-requiring enzyme of placental origin, were correlated suggesting that DAO index may be useful in evaluating vitamin B-6 status in pregnancy.

Methylated niacin derivatives in plasma and urine after an oral dose of nicotinamide given to subjects fed a low-methionine diet.

Five healthy males, age 25-32 y, were fed in sequence a diet of ordinary foods (10 d, PI), a low-methionine diet (285 mg/d, 14 d, PII), and an adequate-methionine diet (725 mg/d, 7 d, PIII). Diets contained 9 g nitrogen (N) per day with soy protein and synthetic L-amino acids as the N sources in PII and PIII. In PII, subjects were in negative N balance whereas, in PIII, four subjects were in positive N balance. On the last day of each period, fasting subjects ingested a dose of nicotinamide (NAM, 102 mumol/kg body wt). Plasma and urine samples were analyzed for methylated derivatives of NAM by high-performance liquid chromatography (HPLC) methods. Mean values of methylated metabolites in urine from the three diet periods (for four subjects in N balance during PIII) were not different (59.8, 56.7, and 59.9 mumol/(kg body wt X 24 h) for PI, PII, and PIII, respectively). Plasma values of these metabolites also were similar. Results suggest that during a 2-wk period of negative N balance due to a low-methionine intake hepatic methylation processes are not impaired. These processes appear to have a higher metabolic priority than maintenance of the net protein synthesis rate.

Methods compared for determining glutathione peroxidase activity in blood.

We compared four methods for determination of glutathione peroxidase (EC 1.11.1.9) activity, using blood samples from 52 healthy volunteers. Two methods depended on direct assay of the amount of glutathione remaining at specific time intervals; the two indirect methods involved measuring the rate of disappearance of NADPH. We assessed the precision and reproducibility of each method. One of the indirect assays proved to be far superior to the other methods. Results of each of the methods were correlated with one another. We present the normal reference intervals for glutathione peroxidase activity for all four methods.

Zinc supplementation during pregnancy in low-income teenagers of Mexican descent: effects on selected blood constituents and on progress and outcome of pregnancy.

As a follow-up of our study of pregnant women, we report effects of zinc supplementation during pregnancy in another population of 138 Hispanic teenagers in Los Angeles. Teenagers were randomized (double-blind) to a control or zinc-supplemented group and received similar daily vitamin and mineral supplements except for 20 mg zinc added to the zinc-supplemented group's capsules. Initially, mean dietary zinc intakes of both groups were about 50% of the Recommended Dietary Allowance and their mean serum zinc levels did not differ significantly (69.8 +/- 11.2 micrograms/dl in control and 69.0 +/- 11.4 micrograms/dl in zinc-supplemented group). Zinc supplementation did not maintain mean serum zinc levels during pregnancy but, as in our earlier study, it reduced (p = 0.018) the number of low serum zinc values (less than or equal to 53 micrograms/dl) in late pregnancy. Zinc supplementation did not affect outcome of pregnancy but serum zinc levels were lower (p = 0.038) in teenagers with pregnancy-induced hypertension than in normotensives.

Zinc supplementation during pregnancy: effects on selected blood constituents and on progress and outcome of pregnancy in low-income women of Mexican descent.

The effects of zinc supplementation on levels of various blood constituents and the outcome of pregnancy in 213 Hispanic women attending a prenatal clinic in Los Angeles was assessed in this double-blind study. The women were randomized into either a control (C) or a zinc-supplemented (Z) group and received similar vitamin and mineral supplements except that 20 mg zinc was added to the Z group's capsules. At the final interview, women (C + Z) with low serum Zn levels (less than or equal to 53 micrograms/dl) had higher (p less than 0.01) mean ribonuclease activity and lower (p less than 0.01) mean delta-aminolevulinic acid dehydratase activity than women with acceptable serum zinc levels. The incidence of pregnancy-induced hypertension was higher (p less than 0.003) in the C than in the Z group, but pregnancy-induced hypertension was not associated with low serum zinc levels at either the initial or final interview. The expected increase in serum copper levels was greater (less than 0.001) in women with pregnancy-induced hypertension (C + Z) than in normotensives. Except for pregnancy-induced hypertension, there was a higher incidence of abnormal outcomes of pregnancy in the noncompliers than in the compliers (C + Z).

Zinc supplementation during pregnancy: zinc concentration of serum and hair from low-income women of Mexican descent.

The effect of zinc supplementation on concentrations of zinc in hair and serum of 213 pregnant Hispanic women attending a clinic in Los Angeles was assessed using a random, double-blind experiment. Both the treatment (T) and control (C) groups received similar vitamin and mineral supplements except that 20 mg zinc was added to the supplements for the treatment group. Nutrient intakes were calculated from 24-h recalls. The initial mean dietary zinc intake of both groups was about 50% of the Recommended Dietary Allowance (9 +/- 5 mg). Initially there were no significant differences between the two groups in mean zinc levels in serum (66 +/- 11 micrograms/dl, C, and 65 +/- 12 micrograms/dl, T) or in hair (184 +/- 41 micrograms/g, C, and 175 +/- 38 micrograms/g, T). Zinc supplementation did not alter mean zinc levels in serum or hair but significantly (p less than 0.05) reduced the number of low serum zinc values (less than or equal to 53.3 micrograms/dl) toward the end of pregnancy. Although serum zinc levels do decline in pregnancy, our results suggest that severely depressed levels (less than or equal to 50 to 55 micrograms/dl) indicate inadequate zinc status.

Growth rate, tissue zinc levels and activities of selected enzymes in rats fed a zinc-deficient diet by gastric tube.

Male Sprague-Dawley rats (125 g) were fed by gastric tube either a zinc-deficient or a zinc-adequate diet for 32 days. In an additional study, rats were administered similar diets per os. Growth rate, zinc levels in plasma and tissues, and selected enzyme activities were measured. In tube fed rats receiving 13.5 g/day of a zinc-deficient diet, growth rates were similar to controls for 25 days but were somewhat lower by 32 days. The mean food intake of the rats fed the zinc-deficient diet per os was 7.6 +/- 2.1 g/day, and on day 25 growth rate was significantly lower than pair-fed and ad libitum-fed controls. Zinc levels of plasma and tissues and delta-aminolaevulinic acid dehydratase (ALAD) activity in erythrocytes and liver were reduced in rats fed the zinc-deficient diet in both studies. Alkaline ribonuclease activity remained unchanged. The larger nutrient intake provided by gastric tube feeding appears to delay the growth-retarding effect of zinc-deficient diets, but changes in zinc tissue levels and ALAD activity are similar in tube fed and per os fed rats.

Binding of zinc and iron to wheat bread, wheat bran, and their components.

Wholemeal wheat bread decreases the availability and intestinal absorption of divalent metals. To define this action further, binding of zinc in vitro to a wheat wholemeal bread (Tanok), dephytinized Tanok, and cellulose was determined at pH 5.0 to 7.5. Zinc binding by each was highly pH-dependent and reached a maximum at pH 6.5 to 7.5. Removal of phytate from Tanok did not reduce its binding capability. Wheat bran at pH 6.5 and 6.8 bound 72% of iron (0.5 microgram/ml of solution) and 82.5% of zinc (1.43 microgram/ml solution), respectively. Lignin and two of the hemicellulose fractions of wheat bran and high binding capabilities for zinc (85.6, 87.1, and 82.1%, respectively) whereas a third had a lower zinc-binding capability (38.7%). Binding of zinc to various celluloses and dextrans is also demonstrated. Formation of complexes of these metals with wheat fiber can explain, at least in part, the decreased availability of dietary iron and zinc in wholemeal wheat bread.

Effects of cellulose added to diets of low and high fiber content upon the metabolism of calcium, magnesium, zinc and phosphorus by man.

Addition of 10 g of cellulose dispersed in 150 g of apple compote to the daily diet with a low fiber content for a 20-day period caused the fecal excretion of calcium and zinc of three men to increase significantly. Balances of both metals became negative and their concentrations in plasma decreased. Magnesium balances became negative in two subjects while phosphorus balance changed to negative in one. In a similar experiment in which the cellulose was added to a fiber-rich diet, fecal excretions of calcium and zinc increased significantly in each of two men and excretion of magnesium in one. Previously negative balances became more negative, and calcium and zinc concentrations decreased in plasma. The dependence of fecal dry weight upon fecal fiber content measured by the acid-detergent method was confirmed. However, increments of dry matter per g of fiber were less fecal fiber concentrations were high. Fecal calcium content correlated significantly with fecal fiber in two subjects, and fecal fiber and zinc in one. No correlations were demonstrated in the subject who apparently digested fiber most effectively. Our findings indicate that high intakes of fiber can explain to a considerable extent the impaired utilization of zinc, calcium, and magnesium among villagers in rural Iran.