Search PubMed⌕ Search

Biomedical subjects

S Samman

Publications and source records attributed to S Samman.

At least 37 records · Page 2Linked to original sources
PubMed1996

Ascorbic acid induces a favorable lipoprotein profile in women.

OBJECTIVES: The aim of this study was to determine the effect of ascorbic acid (AA) supplements on plasma lipids and lipoproteins in healthy, young women. METHODS: Ten women were recruited to participate in a randomized double-blind cross-over trial and supplemented with 1000 mg AA daily for 4 weeks, followed by placebo, and vice versa. RESULTS: Plasma AA concentrations were significantly higher at 2 weeks (p < 0.0001) and at 4 weeks (p < 0.001), compared with baseline. Plasma AA levels appeared to peak after 2 weeks of supplementation. Plasma concentrations of LDL-C were found to be 16% lower at 4 weeks compared with baseline (p < 0.05) and although HDL-C levels did not change significantly with AA supplementation, the change in HDL-C was positively associated with the change in plasma AA (p < 0.05). Significant decreases were observed in the total cholesterol (TC) to HDL-C at 2 weeks and LDL-C to HDL-C ratios at 2 and 4 weeks supplementation (p < 0.05). CONCLUSIONS: Our findings agree with those from epidemiological studies and suggest that increases in AA intake may favorably alter the lipoprotein profile in young women.

Adult↗
PubMed1996

The boron content of selected foods and the estimation of its daily intake among free-living subjects.

BACKGROUND: Boron is an essential micronutrient for higher plants. The results of studies in animals and humans have suggested a potential role for boron as a modulator of the steroid hormone pathway. METHODS: As part of a study to obtain baseline information on boron in humans, the boron content of selected foods (66 items) consumed in Australia was determined. Mean values are presented for the element per 100 g or 100 ml of food and per serving. RESULTS: Major sources of the element were nuts, dried fruits, legumes, fresh vegetables and fruits. The boron content of these foods correlated positively and strongly with values provided by the comprehensive Finnish Tables of mineral composition of foods and with the US Food and Drug Administration Total Diet Study. Because of the similarity in methods employed by this study and that used for the comprehensive Finnish Tables, the latter was used to analyze the boron content in 7-day weighed food records of 32 subjects. CONCLUSION: Using data obtained from the food records and assigning the corresponding values from the Finnish Tables for the boron content of foods, the average daily consumption of boron for a selected group of Australians was found to be 2.23 +/- 1.23 mg/day.

Adult↗
PubMed1996

The Australian health care system.

Medicare is Australia's universal system of health insurance, which is based on the principles of equity. It provides free accommodation and treatment in public hospitals and entitlement to medical services. Laboratories receive reimbursement from Medicare if they are accredited. Hospital funding may be directly funded, whereas in some States the funding is through structures such as Health Areas. There are increasing moves to determine the hospital share of funding based on the number and types of hospital cases. To lower the cost of Medicare, the Federal Government is considering reforms including those which will allow private health insurers to negotiate with doctors and hospitals. Some of the major issues facing the health care system are: (1) how best to deliver care to Aboriginal Australians, (2) overspending, particularly in high-technology medicine, and (3) provision of health care for the small but significant number of Australians who do not live in major metropolitan centers.

Australia↗
PubMed1995

The effect of zinc supplementation on plasma lipids and low-density lipoprotein oxidation in males.

Recent studies in animals and in vitro support the hypothesis that zinc, an essential micronutrient, possesses antioxidant properties. The aims of this study were to determine whether zinc provides antioxidant protection in humans by decreasing low-density lipoprotein (LDL) oxidizability and to determine the effect of zinc supplementation on plasma lipid and its distribution among lipoproteins. Ten healthy male volunteers were recruited to participate in a randomized crossover trial. Subjects were asked to consume 50 mg zinc as 220 mg zinc sulphate (equivalent to 4 x recommended dietary intake, or RDI) daily for 4 weeks, followed by placebo, and vice versa. Venous blood samples were collected at 2-week intervals for the determination of plasma lipids and the in vitro oxidizability of LDL in the presence of copper ions. No changes in the oxidizability of LDL or the plasma concentrations of total cholesterol, high-density lipoprotein (HDL) cholesterol and its subfractions, LDL cholesterol, or triacylglycerol were observed following zinc supplementation compared to placebo. Plasma zinc concentrations were increased significantly, indicating that the lack of effect was not due to poor compliance. The antioxidant effect of zinc in relation to LDL was not demonstrated in humans at this dose, and higher doses are unlikely to be effective given the adverse interaction with copper metabolism and the potential decrease in the activity of superoxide dismutase, a free radical quenching enzyme. The findings of this study suggest that zinc provides little, if any, antioxidant protection against LDL oxidation in humans.

Adult↗
PubMed1995

Nutrition.

Explore the source record for details and available documents.

Coronary Disease↗
PubMed1994

The effect of calcium carbonate and calcium citrate on the absorption of zinc in healthy female subjects.

OBJECTIVES: The aim of this study was to determine the effect of calcium carbonate and calcium citrate on zinc absorption. DESIGN: The zinc tolerance test (ZTT), which is the plasma zinc response to an oral zinc challenge, was used to quantitate zinc absorption. A physiological test dose of zinc (4.5 mg elemental zinc as 20 mg zinc sulphate) was used. Subjects underwent ZTTs on three separate occasions, each time consuming in random order, either 4.5 mg elemental zinc, zinc with 600 mg elemental calcium as calcium carbonate or zinc with 600 mg elemental calcium as calcium citrate. SETTING: Metabolic ward conditions. SUBJECTS: Nine, free-living, healthy female subjects recruited from the University population. INTERVENTIONS: Blood samples were obtained at 30 min intervals for 4 h postdose. RESULTS: The area under the plasma zinc curve (AUC) (mean +/- SEM) following the coingestion of zinc with calcium carbonate (438.4 +/- 129.0 mumol Zn.min/100 g albumin) and calcium citrate (308.0 +/- 110.5) was significantly lower (P < 0.017) than when zinc was ingested alone (1561.7 +/- 240). Urinary excretion of calcium was significantly higher (P < 0.017) at 4 h after supplementation with calcium citrate (0.83 +/- 0.12 mumol Ca/mumol creatinine) compared with calcium carbonate (0.40 +/- 0.11). CONCLUSIONS: The decrease in zinc absorption following the ingestion of zinc with different forms of calcium suggests that an antagonistic competition occurred between the minerals and that elemental calcium is the inhibiting factor.

Administration, Oral↗
PubMed1994

Urinary zinc as a marker of zinc intake: results of a supplementation trial in free-living men.

Twenty-four adult male volunteers were asked to ingest 50 or 100 mg elemental zinc (as zinc sulphate) for 7 days. The design was a randomized cross-over trial with a 3 week wash-out period. A significant increase in 24 h urinary zinc excretion occurred after supplementation with 100 mg with a change from 48.0 +/- 4.6 (mg Zn/mmol creatinine, mean +/- SE) at day 0 to 82.6 +/- 15.9 at day 7 (P < 0.05). No significant change was observed following supplementation with 50 mg zinc. Taken together with published data, this suggests urinary zinc excretion is sensitive only to extreme changes in dietary zinc intake.

Administration, Oral↗
PubMed1993

The effect of increasing dietary zinc on the activity of superoxide dismutase and zinc concentration in erythrocytes of healthy female subjects.

Zinc has many diverse functions and is essential for growth and development. Although a number of dietary constituents inhibit its absorption, a reliable index of zinc intake and/or bioavailability remains to be identified. The aim of this study was to test the hypothesis that recent changes in zinc intake and/or bioavailability are reflected in a subfraction of erythrocytes. Six healthy female volunteers were asked to supplement their diet with 50 mg of elemental zinc per day for 12 days. Venous blood samples were obtained before and during supplementation at 4-day intervals. A subfraction of erythrocytes was isolated from each sample and zinc concentration was measured in this subfraction, in the unfractionated erythrocytes and in the plasma. These showed no significant temporal change. Erythrocyte superoxide dismutase (E-SOD), a marker of copper status, showed a significant 20% decrease (P < 0.02) in its activity in both the subfraction and the unfractionated erythrocytes following supplementation. Hence, a detrimental effect on copper metabolism (as measured by the marker enzyme E-SOD) can be detected within 12 days of supplementation with a moderate amount of zinc.

Administration, Oral↗
PubMed1991

The effect of Max Epa on low density lipoprotein metabolism: perspectives from an animal model.

Rabbits were fed low fat cholesterol-free diets containing casein as the source of protein (27% w/w). One group of 6 animals was supplemented with fish oil (Max Epa; 0.5 ml oil/kg body weight) and compared with 6 animals which were supplemented with a mixture of corn, palm and soybean oils (1:1:1 v/v). VLDL triacylglycerol concentrations were lower in those supplemented with Max Epa. LDL cholesterol and the kinetics of LDL-apo B were unaffected. The results indicate that in endogenously hypercholesterolaemic animals with low triacyglycerol concentrations, casein and possibly other animal proteins, override any effect of this dose of fish oil on LDL metabolism.

Animals↗
PubMed1991

Nutritional considerations in the variability of plasma cholesterol measurements.

The concentration of plasma cholesterol is influenced by biological factors as well as clinical and analytical ones. Day-to-day variation can provide a misleading estimate of plasma cholesterol as it can differ by up to 12%. Seasonal variations occur with elevated concentrations in (northern hemisphere) winter relative to summer, possibly due to diet and life-style influences. Clinical and analytical factors also contribute to the variation. These include the manner with which blood is collected, the nutritional state of the subject and subsequent specimen handling. Analytical factors such as the effectiveness of the reagents and controls chosen, as well as the extent of interference by agents of metabolic or dietary origin, can introduce a bias into the analysis. More control can be exerted over the clinical and analytical factors compared with biological variation.

Blood Specimen Collection↗
PubMed1990

Influence of dietary minerals on apolipoprotein B metabolism in rabbits fed semipurified diets containing casein.

Rabbits were fed semipurified casein diets containing either 4% or 2.5% mineral mix for 8 weeks. Both groups maintained weight throughout the experimental period. The plasma total cholesterol concentration was significantly higher after 4 weeks on diet and slightly higher after 8 weeks in animals fed the lower level of minerals. Plasma IDL- and LDL-cholesterol concentrations after 4 weeks and HDL-cholesterol concentrations after 8 weeks were significantly higher in animals fed the 2.5% compared to those fed the 4% mineral mix. Kinetic experiments showed that in rabbits fed the lower level, the fractional catabolic and production rates of VLDL-apo B were lower and a greater proportion of IDL-apo B was derived from sources other than VLDL compared to the animals fed the higher level. LDL-apo B kinetics were not significantly different between the 2 groups. These data suggest that a reduction in dietary minerals enhances casein-induced hypercholesterolemia.

Animals↗
PubMed1990

Intermediate density lipoprotein-apolipoprotein B turnover in rabbits fed semipurified diets containing casein or soy protein.

The aim of this study was to investigate the underlying causes of elevated levels of intermediate density lipoprotein (IDL) in rabbits fed casein compared to soy protein in a cholesterol-free, semipurified diet. Kinetic studies were carried out in which homologous, radiolabelled IDL was injected into casein- and soy protein-fed animals after a period of 7 months on diet. Total plasma cholesterol and IDL cholesterol and protein were significantly higher in animals fed casein compared to those fed soy protein. The fractional catabolic rate of IDL-apolipoprotein B was significantly lower in casein-fed animals but the difference in mean values for the production rate did not reach statistical significance. The effect of feeding casein on IDL can be attributed to its reduced efficiency of removal from the plasma.

Animals↗