Dietary plant sterols supplementation does not alter lipoprotein kinetics in men with the metabolic syndrome

Dietary plant sterols supplementation has been demonstrated in some studies to lower plasma total and LDL cholesterol in hypercholesterolemic subjects. The cholesterol lowering action of plant sterols remains to be investigated in subjects with the metabolic syndrome. In a randomized, crossover study of 2 x 4 week therapeutic periods with oral supplementation of plant sterols (2 g/day) or placebo, and two weeks placebo wash-out between therapeutic periods, we investigated the effects of dietary plant sterols on lipoprotein metabolism in nine men with the metabolic syndrome. Lipoprotein kinetics were measured using [D3]-leucine, gas chromatography-mass spectrometry and compartmental modeling. In men with the metabolic syndrome, dietary plant sterols did not have a significant effect on plasma concentrations of total cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, apolipoprotein (apo) B, apoA-I or apoA-II. There were no significant changes to VLDL-, IDL-, LDL-apoB or apoA-I fractional catabolic rates and production rates between therapeutic phases. Relative to placebo, plasma campesterol, a marker of cholesterol absorption was significantly increased (2.53 +/- 0.35 vs. 4.64 +/- 0.59 mug/ml, p < 0.05), but there was no change in plasma lathosterol, a marker of endogenous cholesterol synthesis. In conclusion, supplementation with plant sterols did not appreciably influence plasma lipid or lipoprotein metabolism in men with the metabolic syndrome. Future studies with larger sample size, stratification to low and high cholesterol absorbers and cholesterol balance studies are warranted.     

Dietary vitamin E supplementation does not inhibit Candida albicans intestinal translocation in rats.

Candida albicans translocation was determined in rats receiving a normal or vitamin E-supplemented and deficient diet submitted to mesenteric ischemia and reperfusion (MIR). The antioxidant effect of vitamin E on lipid peroxidation was also assessed. The animals were divided into six groups submitted to different diets for 30 d. Groups N, NI, NC and NIC were submitted to a normal diet and used as controls, and groups VITE and DEFE received a vitamin E-supplemented and vitamin E-deficient diet, respectively. Groups NIC, VITE and DEFE were submitted to MIR, inoculated with Candida albicans and sacrificed 24 h after the surgical procedure. The antioxidant effect of vitamin E was determined in the liver and gut mucosa using the TBARS method. Candida albicans translocation was assessed in lymph node, liver and kidney specimens. The results showed that lipid peroxidation was lower (p < 0.05) in the vitamin E-supplemented group. However, vitamin E supplementation did not protect the rats against Candida albicans translocation (the translocation in the Group VITE was 100% for lymph nodes).     

Low dose supplementation with two different marine oils does not reduce pro-inflammatory eicosanoids and cytokines in vivo

In view of the reported potential anti-inflammatory activity of the New Zealand green lipped mussel (NZGLM), we aimed to compare the effect of low dose marine oil supplementation, from mussels and fish, in reducing blood markers of inflammation. Thirty apparently healthy males and females were recruited from the general public in Melbourne, Australia to participate in a double blind, randomised, parallel intervention study. Subjects were consuming approximately 73 mg of omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) daily in their background diet prior to the commencement of the intervention. Subjects were randomly assigned to consume either 2 mL/day of the NZGLM oil preparation (mixed with olive oil and dl-alpha-tocopherol) or fish oil preparation (also mixed with olive oil and dl-alpha-tocopherol) for six weeks. Two mL of the oils contained 241 mg and 181 mg of n-3 LCPUFA, respectively. Neutrophil phospholipid fatty acids, serum thromboxane B2 (TXB2), stimulated monocyte production of prostaglandin E2 (PGE2), interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNFalpha) were measured. During the intervention, the total intakes of n-3 LCPUFA from the background diet and the supplements were 199 mg/d and 173 mg/day for the NZGLM and FO groups, respectively. Following six weeks of supplementation, both groups showed a small, but significant increase in neutrophil phospholipid proportion of eicosapentaenoic acid. The NZGLM group also showed a significant increase in docosahexaenoic acid levels. There were no significant changes with time or treatment for TXB2, PGE2, IL-1 beta or TNFalpha. This study showed that low dose supplementation with n-3 LCPUFA from two different marine oil preparations showed no difference in inflammatory markers in this group of healthy individuals. Further studies are warranted including dose response trials and studies in populations with inflammatory conditions.     

Dietary supplementation with n-3 PUFA does not promote weight loss when combined with a very-low-energy diet

Obesity is associated with elevated levels of inflammation and metabolic abnormalities which are linked to CVD. The aim of the present study was to investigate whether long-chain n-3 PUFA (LCn-3PUFA), combined with a very-low-energy diet (VLED), facilitated weight loss and weight maintenance, and improvements in blood lipids and inflammatory mediators. This was a double-blind, randomised, controlled trial with two parallel groups. For 14 weeks, one group consumed 6?×?1?g capsules/d of monounsaturated oil (placebo group, PB), and the other group consumed 6?×?1?g capsules/d of LCn-3PUFA (fish oil group, FO), each comprising 70?mg EPA and 270?mg DHA. Both groups were on VLED for 4 weeks (n 14 PB, n 18 FO), which was then followed by 10 weeks of weight maintenance (n 12 PB, n 17 FO). Fasting blood samples, anthropometric measurements and 3?d food diaries were collected at baseline, at 4 and 14 weeks. A greater-than-2-fold increase occurred in plasma levels of EPA and DHA in the FO group (P?相似文献   

Short-term creatine supplementation does not reduce increased homocysteine concentration induced by acute exercise in humans

Purpose

The purpose of the study is to evaluate the effects of creatine supplementation on homocysteine (Hcy) plasma levels after acute exercise in humans.

Methods

Twenty-three young (under-20) soccer players were divided into 2 groups: creatine (Cr)- and placebo (Pla)-supplemented groups. The supplementation was performed in double-blind controlled manner using creatine or placebo tablets with 0.3 g/kg during 7 days. Before and after 7 days of supplementation, the athletes performed an acute high-intensity sprint exercise (two consecutive running-based anaerobic sprint test protocol consisted in 6 × 35 m sprint with 10 s between them). Blood samples were collected before and after 7 days of supplementation as well as 0 and 1 h after exercise protocol.

Results

Homocysteine concentration significant increased (P < 0.05) 1 h after acute exercise (18 %). Acute exercise also decreased red blood cell S-adenosylmethionine (SAM) 30 % with no changes in SAM/SAH ratio. Seven days of creatine supplementation were able to increase (P < 0.05) plasma creatine concentration (Pla 130.1 ± 21.7 vs Cr 1,557.2 ± 220.3 μmol/L) as well as decrease (P < 0.05) plasma guanidinoacetic acid (33 %). Controversially, creatine supplementation did not change Hcy plasma level after 7-day supplementation (Pla 6.9 ± 0.2 vs Cr 7.2 ± 0.2 μmol/L) or after acute exercise (Pla 8.2 ± 0.3 vs Cr 8.4 ± 0.3 μmol/L). No changes in plasma vitamin B12 and folate as well as cysteine and methionine were found.

Conclusions

Seven days of creatine supplementation does not avoid increased plasma Hcy induced by acute sprint exercise in humans.     

Oral iodine supplementation does not reduce neutralizing antibody responses to oral poliovirus vaccine.

Iodine deficiency is a major cause of impaired mental development, goitre, and cretinism in many parts of the world. Because existing immunization programmes can be used to deliver oral iodized oil (OIO) to infants at risk, it was important to know whether OIO could adversely affect the antibody response to vaccines, such as trivalent oral poliovirus vaccine (OPV). A randomized, double-blind, placebo-controlled clinical trial was conducted in Subang, West Java, Indonesia, in which 617 eight-week-old infants received either OIO or a placebo (poppy-seed oil) during a routine visit for their first dose of OPV as part of the Expanded Programme on Immunization (EPI). The infants received two boosters of OPV at 4-week intervals after the first dose, and were followed up when 6 months old. Neutralizing antibody titres to poliovirus serotypes 1, 2, and 3 were compared in serum samples that were taken from 478 of these infants just before the first dose of OPV and at 6 months. It was found that oral iodized oil did not reduce the antibody responses to any of the three serotypes of OPV. These results indicate that oral iodine may safely be delivered to infants at the same time as oral poliovirus vaccine according to current EPI immunization schedules.     

Dietary diacylglycerol induces the regression of atherosclerosis in rabbits

Recent studies of the relation between serum triacylglycerol concentration and the risk for coronary artery disease suggest that inefficient clearance of postprandial triacylglycerols promotes atherogenesis. We recently demonstrated that dietary diacylglycerol (DAG), rich in the 1,3-species, suppresses the postprandial increase in serum triacylglycerol levels compared with dietary triacylglycerol (TAG). Here, we investigated the effects of dietary DAG on atherosclerosis in rabbits with cholesterol-induced atherosclerosis. New Zealand White rabbits (n = 20) were fed a diet containing 3% lard and 1.3% cholesterol for 50 d to induce atherosclerotic lesions. Thereafter, the rabbits were assigned to 2 groups and fed 90 g/d nonpurified diet and orally administered 5 g DAG or TAG for an additional 34 d. Reference rabbits (n = 5) were fed only the nonpurified diet throughout the 84-d study. The area of atherosclerotic lesions and aortic lipid concentrations were significantly lower in DAG-fed rabbits compared with TAG-fed rabbits. The VLDL receptor and macrophage antigen-1 mRNA expression levels were significantly lower in DAG-fed rabbits than in TAG-fed rabbits. In the liver of DAG-fed rabbits, the triacylglycerol concentration was lower and the carnitine palmitoyltransferase activity higher than in TAG-fed rabbits. Stimulation of hepatic lipid catabolism might be related to the reduced lipid accumulation in the liver and aorta by reducing the release of triacylglycerol into the circulation. Thus, long-term consumption of DAG, which reduces postprandial lipemia, might be useful for the regression of atherosclerosis by stimulating hepatic lipid catabolism and thereby modulating monocyte/macrophage migration and aortic lipid accumulation.     

Dietary broccoli mildly improves neuroinflammation in aged mice but does not reduce lipopolysaccharide-induced sickness behavior

Aging is associated with oxidative stress and heightened inflammatory response to infection. Dietary interventions to reduce these changes are therefore desirable. Broccoli contains glucoraphanin, which is converted to sulforaphane (SFN) by plant myrosinase during cooking preparation or digestion. Sulforaphane increases antioxidant enzymes including NAD(P)H quinone oxidoreductase and heme oxygenase I and inhibits inflammatory cytokines. We hypothesized that dietary broccoli would support an antioxidant response in brain and periphery of aged mice and inhibit lipopolysaccharide (LPS)–induced inflammation and sickness. Young adult and aged mice were fed control or 10% broccoli diet for 28 days before an intraperitoneal LPS injection. Social interactions were assessed 2, 4, 8, and 24 hours after LPS, and mRNA was quantified in liver and brain at 24 hours. Dietary broccoli did not ameliorate LPS-induced decrease in social interactions in young or aged mice. Interleukin-1β (IL-1β) expression was unaffected by broccoli consumption but was induced by LPS in brain and liver of adult and aged mice. In addition, IL-1β was elevated in brain of aged mice without LPS. Broccoli consumption decreased age-elevated cytochrome b-245 β, an oxidative stress marker, and reduced glial activation markers in aged mice. Collectively, these data suggest that 10% broccoli diet provides a modest reduction in age-related oxidative stress and glial reactivity, but is insufficient to inhibit LPS-induced inflammation. Thus, it is likely that SFN would need to be provided in supplement form to control the inflammatory response to LPS.     

Dietary supplementation with blueberry extract improves survival of transplanted dopamine neurons

The exact mechanisms contributing to poor neuronal survival in cell transplantation paradigms for Parkinson's disease (PD) are unknown. However, transplantation-induced host immune response, inflammation, and subsequent oxidative stress are likely contributors to cell death since dopamine (DA) neurons are exquisitely sensitive to oxidative damage. Multiple studies have attempted to improve cell survival by treating transplant material with antioxidant and antiinflammatory compounds, whereas far fewer studies have attempted to modify the host environment to reduce these threats. Flavonoids, phytochemicals found in fruits and vegetables, have antioxidant, antiinflammatory, and immunomodulatory properties. For example, supplementation with dietary blueberry extract (BBE) prevents oxidative stress-associated impairment of striatal motor function during aging and restores lost motor function in aged rats. We hypothesized that dietary supplementation of rodent diets with BBE would improve the survival of embryonic DA neurons transplanted into the unilaterally DA-depleted striatum. Inclusion of 2% BBE in a custom chow diet significantly increased the survival of implanted DA neurons and ameliorated rotational behavior asymmetries as compared to transplanted animals consuming a standard diet. These findings provide support for the potential of dietary phytochemicals as an easily administered and well-tolerated therapy that can be used to improve the effectiveness of DA neuron replacement.     

Calcium supplementation for 1 y does not reduce body weight or fat mass in young girls

BACKGROUND: Accumulating evidence from observational studies indicates that a high calcium intake may reduce body weight and body fat. However, few randomized trials have been conducted. OBJECTIVE: We examined whether calcium supplementation affects body weight and body fat in young girls and whether a relation exists between habitual calcium intake and body weight and body fat. DESIGN: A randomized, double-blind, placebo-controlled intervention study was conducted in 110 young girls. The subjects were randomly assigned to receive 500 mg Ca/d as calcium carbonate or placebo for 1 y. Two groups of girls were selected according to habitual calcium intake from a large group; one group consumed 1000-1304 mg/d (40th-60th percentile; n = 60) and the other group consumed <713 mg/d (<20th percentile; n = 50). Height, body weight, body fat, and calcium intake were measured at baseline and after 1 y. RESULTS: At baseline a significant negative correlation was observed between habitual dietary calcium intake and percentage of body fat (r = -0.242, P = 0.011). However, calcium supplementation had no effect on height, body weight, or percentage body fat. CONCLUSIONS: Habitual dietary calcium intake was inversely associated with body fat, but a low-dose calcium supplement had no effect on body weight, height, or body fat over 1 y in young girls. It is possible that the effect of calcium on body weight is only exerted if it is ingested as part of a meal, or the effect may be due to other ingredients in dairy products, and calcium may simply be a marker for a high dairy intake.     

Dietary supplementation with aged garlic extract inhibits ADP-induced platelet aggregation in humans

Garlic has been widely reported to protect against cardiovascular disease by reducing serum cholesterol concentrations and blood pressure and by inhibiting platelet aggregation. However, most of these studies have been performed in hypercholesterolemic subjects or in animal models. We performed a 13-wk study in normolipidemic subjects who ingested 5 mL of aged garlic extract (AGE, Kyolic) per day. Blood was drawn from these subjects at the beginning and end of the study. Aggregation of platelet-rich plasma was induced by ADP; full lipid profiles and liver function tests were determined on serum, and plasma concentrations of eicosanoids were also measured. Dietary supplementation with AGE significantly inhibited both the total percentage and initial rate of platelet aggregation at concentrations of ADP up to 10 micromol/L. The K:(M) for ADP-induced aggregation were approximately doubled after supplementation with AGE, whereas the maximum rate of aggregation was unaffected. No significant changes in plasma thromboxane B(2) and 6-ketoprostaglandin F(1alpha) concentrations or serum lipid profiles were observed. We conclude that AGE, when taken as a dietary supplement by normolipidemic subjects, may be beneficial in protecting against cardiovascular disease as a result of inhibiting platelet aggregation.     

Dietary supplementation with bean extract improves lipid profile in overweight and obese subjects

The aim of this study was to evaluate the long-term effects of a dietary supplementation of bean extract on serum lipids, nutritional parameters, and fat excretion in feces.Sixty-two overweight and obese (body mass index > 25 kg/m(2)) volunteers were randomized to receive the dietary supplement (n = 31, supplement group) or the placebo (n = 31, placebo group). There were 41 women and 21 men, ages 22 to 66 years. Two capsules of a dietary supplement or a placebo were administered three times daily for 3 mo. The supplement group was then invited to participate in an open-label study for 9 mo. Twenty-four subjects (7 men and 17 women) were randomized to receive two or four capsules of the supplement three times daily. Lipids and nutritional blood parameters were measured at baseline, after 3 mo, and at 12 mo. Excretion of fat in feces was measured.At 3 mo, reduction in serum concentration of cholesterol was found in the supplement group but not in the placebo group. High-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triacylglycerols in serum did not change in either group. In the 9-mo open-label study, no further reduction in serum cholesterol was observed. Low-density lipoprotein and the ratio of low- to high-density lipoprotein decreased, whereas triacylglycerols remained unchanged. Serum vitamin B12 and folic acid decreased but remained within the normal range. Ferritin and albumin in serum remained unchanged. No differences were observed in serum lipids and nutritional parameters between groups. The bean extract significantly increased fat excretion in feces.In conclusion, this dietary supplementation improved lipoprotein profile and enhanced fat excretion in feces in overweight and obese subjects.     

Dietary arginine supplementation does not enhance lymphocyte proliferation or interleukin-2 production in young and aged rats

Recent studies indicate that supplemental arginine may enhance in vitro lymphocyte mitogenesis. To determine whether dietary arginine could reverse age-associated losses in immune functions, we fed purified amino acid diets to young (2-mo-old) and aged (24-mo-old) Fischer 344 rats. Rats receiving control (1.12% arginine) or supplemented (3% arginine) diets were pair fed to intakes of deficient (0% arginine) rats. Another group was fed the supplemented diet ad libitum. On d 15, responses of splenocytes to phytohemagglutinin (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM) were lower (P less than 0.01), but interleukin-2 (IL-2) production was higher (P less than 0.05) in aged rats than in young rats. At mitogen doses producing maximal stimulation, supplemental arginine did not enhance PHA-, Con A- or PWM-stimulated lymphocyte proliferation; PWM responses at sub-maximal doses were higher in pair-fed supplemented rats than in control or ad libitum supplemented rats (P less than 0.05). Arginine supplements did not increase thymus weights or IL-2 production above controls. In another experiment, weanling rats received control and supplemented diets in amounts equal to the intake of deficient rats for an average of 37 d. Splenocytes were cultured with mitogens at various arginine levels. No diet effect was observed. Mitogenesis was maximal when media arginine approximated normal plasma levels. Our results suggest that supplemental arginine has little effect on lymphocyte proliferation or IL-2 production in healthy young and aged rats.     

Ivermectin does not reduce the burden of itching in an onchocerciasis endemic community.

Degrees of itching were estimated before and for 6 months after a fourth dose of ivermectin or placebo was given to 97 subjects in Sierra Leone. There was no reduction in itching attributable to ivermectin at any stage, but there were non-significant increases in the prevalence, severity and localization of itching within the first 2 months after ivermectin compared to placebo. We also found that cell-mediated immune responses to Onchocerca volvulus were significantly increased 4 weeks after a single dose of ivermectin compared to before treatment. A temporary reversal of the state of immunosuppression in people with onchocerciasis may counterbalance the reduction in skin microfilarial loads following ivermectin, with no consequent reduction in itching. The lack of effect of ivermectin on itching, a major symptom of onchocerciasis, while disappointing, need not detract from the success of mass distribution programmes.     

Selenium supplementation does not alter platelet activation in subjects with normal selenium status

The effect of Se supplementation on the plasma concentrations of platelet specific proteins, beta-thromboglobulin (beta TG) and platelet factor 4 (PF4), was determined in twenty young women with normal selenium (Se) status using a double blind protocol. Selenium supplementation for 4 weeks (150 micrograms/day), did not elevate the initial mean plasma Se level 95 +/- 4 ng/ml above this level, nor did it alter the plasma beta TG/PF4. Moreover, all the other parameters of the body antioxidative status (plasma alpha-tocopherol, retinol and uric acid and whole blood glutathione) measured in this experiment stayed unaltered during the 4-week supplementation period. The results indicate no relationship between Se supplementation and platelet function in subjects with normal Se status.     

Long-term supplementation with iron does not enhance growth in malnourished Bangladeshi children.

To evaluate the effect of long-term oral iron supplementation on growth, 250 children aged 6-71 mo were studied in a randomized double-blind controlled trial. The intervention group received 125 mg of ferrous gluconate (15 mg elemental iron) plus multivitamins (vitamins A, D and C); the comparison group received only multivitamins daily for 12 mo. Weight (kg) and height (cm) were measured every month. Eighty three percent of the children continued the treatment for one year. The weight increment over the 12-mo period was 1.35 +/- 0.65 kg (mean +/- SD) in the intervention group and 1.39 +/- 0.54 kg in the comparison group. The height increments were 6.01 +/- 1.47 and 6.18 +/- 1.58 cm in the intervention and comparison groups, respectively. Mean weight and height increments did not differ; in an analysis stratified according to different age and nutritional categories, they also did not differ between the two groups, indicating that long-term iron supplementation does not increase growth in children.     

Advanced provision of emergency contraception does not reduce abortion rates

A number of small studies have demonstrated increased use of emergency contraception (EC) when women have a supply available at home. It has been suggested that widespread use of EC could reduce abortion rates. We undertook a community intervention study designed to determine whether offering advanced supplies of EC to large numbers of women influenced abortion rates. All women aged between 16 and 29 years living in Lothian, Scotland, were offered, through health services, five courses of EC without cost to keep at home. Of a population of around 85,000 women in this age group, the study showed that an estimated 17,800 women took a supply of EC home and over 4500 of them gave at least one course to a friend. It was found that nearly half (45%) of women who had a supply used at least one course during the 28 months that the study lasted. In total, an estimated 8081 courses of EC were used. EC was used within 24 h after intercourse on 75% of occasions. Abortion rates in Lothian were compared with those from three other health board areas of Scotland. No effect on abortion rates was demonstrated with advanced provision of EC. The results of this study suggest that widespread distribution of advanced supplies of EC through health services may not be an effective way to reduce the incidence of unintended pregnancy in the UK.