Effect of supplementation with B vitamins and antioxidants on levels of asymmetric dimethylarginine (ADMA) and C-reactive protein (CRP): a double-blind, randomised, factorial design, placebo-controlled trial

Combination of Chemically Characterized Pomegranate Extract and Hydrophilic Vitamins against Prolonged Fatigue: A Monocentric, Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Prolonged fatigue is associated with non-pathological causes and lacks an established therapeutic approach. The current study is aimed at assessing the efficacy of a new food supplement (Improve™) based on a chemically characterized pomegranate extract and hydro-soluble vitamins (B complex and C). UHPLC-HRMS analysis of pomegranate extract showed the presence of 59 compounds, with gallotannins and ellagitannins being the most abundant phytochemicals. For the clinical study, 58 subjects were randomized into two groups, 1 and 2 (n = 29, each), which received either the food supplement or placebo. The effects of the food supplement against fatigue were assessed via validated questionnaires, recorded at time intervals t0 (at baseline), t1 (after 28 days), t2 (56 days), and t3 (after follow-up) in combination with the analysis of biochemical markers at t0 and t2. Fatigue severity scale (FSS) questionnaire scores were significantly decreased at the t2 and t3 time intervals in subjects treated with the food supplements, while the effect of the food supplement on a 12-Item Short Form Survey (SF-12) was not considerable. Moreover, the food supplement did not significantly affect biochemical parameters associated with fatigue and stress conditions. This study shows that the food supplement tested reduces prolonged fatigue following two months of supplementation in healthy subjects with mild prolonged fatigue.

The effect of l-arginine supplementation on body composition and performance in male athletes: a double-blinded randomized clinical trial

BACKGROUND/OBJECTIVE

Athletes used a lot of dietary supplements to achieve the more muscle mass and improve their athletic performance. The objective of this study was to investigate the effect of l-arginine supplementation on sport performance and body composition in male soccer players.

SUBJECTS/METHODS

This double-blinded, randomized and placebo-controlled trial was conducted on 56 male soccer players, with age range of 16-35, who referred to sport clubs in Isfahan, Iran. Subjects were randomly assigned to either l-arginine or placebo groups. Athletes received daily either 2 g per day l-arginine supplement or the same amount of placebo (maltodextrin) for 45 days. Sport performance and also body mass index (BMI), body fat mass (BFM) and lean body mass (LBM) were measured at the beginning and end of the study. Also, 3-day dietary records were collected at three different time points (before, in the middle of, and at the end of the study).

RESULTS

The mean age of subjects was 20.85±4.29 years. Sport performance (VO₂ max) significantly increased in l-arginine supplementation group (4.12±6.07) compared with placebo group (1.23±3.36) (P=0.03). This increase remained significant even after adjustment of baseline values, physical activity and usual dietary intake of subjects throughout the study. No significant effect of l-arginine supplementation was found on weight, BMI, BFM and LBM.

CONCLUSIONS

l-arginine supplementation (2 g per day) could increase the sport performance in male athletes, but had no effect on anthropometric measurements, including BMI, BFM and LBM. So, further studies are needed to shed light our findings.

L-Arginine and vitamin C attenuate pro-atherogenic effects of high-fat diet on biomarkers of endothelial dysfunction in rats

High-fat diet (HFD) is known to cause endothelial dysfunction and contribute to atherosclerosis progression. The objective of this study was to evaluate the efficacy of L-arginine (L-Arg) and vitamin C supplementation as a potentially useful strategy for modulation of serum homocysteine (Hcy) levels, tumor necrosis factor alpha (TNF-α), oxidative stress, and insulin resistance induced by HFD in rats. Six weeks-old female and male Wistar rats were divided into five groups of twelve rats each and treated for six weeks with: group 1, standard diet; group 2, HFD; group 3, HFD supplemented with L-Arg (20g/kg diet); group 4, HFD supplemented with L-Arg (20g/kg diet) plus vitamin C (100mg/kg diet); group 5, HFD supplemented with vitamin C (100mg/kg diet). HFD significantly elevated TNF-α, reduced total antioxidant status (TAS), and increased insulin resistance (HOMA-IR). Significant increases of total cholesterol (TCH), LDL cholesterol (LDL), triglyceride (TG) and a decrease of HDL cholesterol (HDL) were observed in HFD rats. Supplementation with l-Arg prevented the decrease of TAS and the increases in HOMA-IR, LDL, and TG levels. Moreover, Hcy and TNF-α levels were reduced in L-Arg supplemented group. Supplementation with vitamin C significantly atenuated TAS decrease and lowered LDL levels. L-Arg plus vitamin C enhanced L-Arg effect on TAS and protected against TNF-α increase. Western blot analysis showed that l-Arg supplementation of HFD rats reduced the level of protein carbonyls. Taken together, these findings indicate that supplemental l-arginine and/or vitamin C, by their abilities to modulate biomarkers of HFD-induced endothelial dysfunction, are anti-atherogenic.

Vitamin E supplementation is associated with lower levels of C-reactive protein only in higher dosages and combined with other antioxidants: The Cooperative Health Research in the Region of Augsburg (KORA) F4 study

The aim of the present study was to examine the association between intake of five common antioxidative nutrients from supplements and medications (vitamin E, vitamin C, carotenoids, Se, and Zn) and levels of high-sensitivity C-reactive protein (hs-CRP) in the general population. For this purpose, a total of 2924 participants of the population-based Cooperative Health Research in the Region of Augsburg (KORA) F4 study (2006-8) were investigated cross-sectionally. Intake of dietary supplements and medication during the last 7 d was recorded in a personal interview, when participants were asked to show product packages of ingested preparations. Linear regression models were calculated; first, the exposure to regular nutrient intake was treated with a binary response (yes/no); then regularly ingested amounts were divided into quartiles to examine dose-response relationships. Effect of single v. combined supplementation of antioxidants was assessed through the inclusion of interaction terms into the models. Regular intake of any of the five investigated antioxidants per se was not associated with hs-CRP levels. However, dose-response analyses revealed that participants who regularly ingested more than 78 mg vitamin E/d, which corresponds to the upper quartile, had 22% lower hs-CRP levels (95% CI 0·63, 0·97) compared to those of persons who were not exposed to any vitamin E supplementation. Stratified analyses showed that this association was found only in persons who took vitamin E in combination with other antioxidants. The combined supplementation of vitamin E with other antioxidants could thus be a promising strategy for the prevention of inflammation-related diseases in the general population, if further studies could confirm that the proposed association is causal.

Effect of Vitamin C Supplementation on C-reactive Protein Levels in Patients Undergoing Hemodialysis: A Randomized, Double Blind, Placebo-Controlled Study

Background:

Chronic inflammation is the most important cause of cardiovascular disease in patients undergoing hemodialysis, and vitamin C as a major antioxidant which could be effective to suppress inflammation.

Objectives:

This study was performed to evaluate the effect of vitamin C supplementation on C-reactive protein levels in patients undergoing hemodialysis.

Patients and Methods:

This randomized, placebo-controlled and double-blind trial was conducted on 151 patients on hemodialysis who were divided randomly by lottery method to three identical groups. In the intervention group, 250 mg of vitamin C was injected intravenously immediately at the end of each hemodialysis session three times a week for 8 weeks in a row. In the control group 1, same term of placebo saline was injected, and in the control group 2, no intervention was performed.

Results:

A total of 86 (61%) male and 55 female patients with mean hemodialysis duration of 39.74 ± 45.5 months, and a mean age of 61.36 ± 11.46 years-old, participated in this study. Hypertension and diabetes were the most common underlying diseases (79.4%). Median baseline CRP in the intervention, control 1 and control 2 groups were 16.8, 17.8, and 19.4 mg/L respectively. After 2 months, median CRP reduced significantly in the vitamin C group to 10.7 (P = 0.04) vs. 22.6, and 30.6 mg/L in control groups.

Conclusions:

Our findings demonstrated that vitamin C supplementation modifies the levels of CRP in patients on hemodialysis.

High tea and vegetable consumption is associated with low ADMA generation in older healthy subjects

Asymmetric dimethylarginine (ADMA) has been recognized as a marker of cardiovascular risk. We sought to investigate whether consumption of tea, coffee, fruit or vegetables is associated with ADMA. In 148 consecutive apparently healthy subjects (104 men and 44 women aged 40 to 70), daily tea, coffee, fruit and vegetable consumption was ascertained by questionnaire. Plasma ADMA, symmetric dimethylarginine (SDMA), and l-arginine levels were measured by high-performance liquid chromatography. Median tea and coffee consumption was 2 cups/d, while vegetable and fruit intake was 152 (120-179)g/d and 120 (108-134)g/d, respectively. Median plasma ADMA, SDMA and arginine were 0.47 (0.43-0.53)μmol/L, 0.59 (0.54-0.66)μmol/L and 86 (68-101)μmol/L, respectively. ADMA correlated inversely with tea (r = -0.70, P < .0001) and vegetable consumption (r = -0.50, P < .0001) even after adjustment for age, sex, body mass index, smoking status, and potential dietary and biochemical parameters. No association between ADMA and fruit consumption was found. ADMA correlated positively with coffee intake (r = 0.37, P < .0001), although these associations were less potent after adjustment for dietary factors. Higher tea and vegetable intake is associated with lower plasma ADMA levels in healthy middle-aged subjects.

Association of plasma B-6 vitamers with systemic markers of inflammation before and after pyridoxine treatment in patients with stable angina pectoris

BACKGROUND

A negative association between systemic markers of inflammation and plasma vitamin B-6 has been observed in population-based and patient cohorts; however, vitamin B-6 (pyridoxine) treatment has mostly failed to improve inflammatory indexes.

OBJECTIVE

We aimed to assess the effect of pyridoxine treatment on B-6 vitamer and inflammatory marker relations.

DESIGN

We measured pyridoxal 5'-phosphate (PLP), pyridoxal, 4-pyridoxic acid (PA), C-reactive protein (CRP), neopterin, and the kynurenine-to-tryptophan ratio (KTR) in plasma and the white blood cell count (WBC). A partial Spearman's correlation was used to assess associations of B-6 vitamers with inflammatory markers before and after daily treatment with 40 mg pyridoxine hydrochloride. Generalized additive models and segmented regression analysis were used for nonlinear relations.

RESULTS

A 9-60-fold increase in B-6 vitamer concentrations over baseline values was observed after 28 d of treatment with pyridoxine. PLP was negatively associated with all 4 inflammatory markers at baseline and, predominantly, with CRP and KTR at day 28. The catabolite PA was positively associated with neopterin and KTR before and after treatment. The dose-response relation between CRP and B-6 vitamers at day 28 was nonlinear, with an increased steepness of slope at CRP >7 mg/L. Finally, changes in B-6 vitamer concentrations were correlated with changes in inflammatory marker concentrations over a time span of 4 wk.

CONCLUSIONS

The associations between plasma vitamin B-6 and inflammatory markers were preserved or even increased after pyridoxine treatment. The results suggest that the acute phase and activated cellular immunity are associated with increased cellular uptake and catabolism of vitamin B-6, respectively.

Vitamin B6 and the immunity in kidney transplant recipients

OBJECTIVE

The study aimed to determine vitamin B6 status in elderly (age ≥ 60 years) and younger (age <60 years) recipients of allogeneic kidney graft and to investigate associations between vitamin B6 status and immunity markers.

DESIGN

A retrospective observational study.

SETTING

The study was conducted at the Medical University of Gdańsk, Poland.

SUBJECTS

We recruited 34 kidney allograft recipients (17 males and 17 females) and allocated them into 2 groups: patients aged ≥ 60 years (18 patients) and those aged <60 years (16 patients). Exclusion criteria included patients receiving vitamin B6 supplementation or drugs known to influence vitamin B6 metabolism.

MAIN OUTCOME MEASURE

Plasma levels of pyridoxal 5'-phosphate (PLP), pyridoxal, pyridoxine, pyridoxamine, pyridoxamine 5'-phosphate, and 4 pyridoxic acid were determined by high-performance liquid chromatography. Measured immunity markers were serum cytokines (interleukin-6, interleukin-10, and transforming growth factor-β), levels of T-lymphocyte subsets, and the proliferative ability of peripheral blood mononuclear cells.

RESULTS

Concentrations of all vitamin B6 vitamers in plasma (PLP, pyridoxal, pyridoxamine 5'-phosphate, pyridoxamine, pyridoxine, 4 pyridoxic acid) were comparable in the 2 studied groups. There were no cases of PLP deficiency in the study population, but 29% of patients had PLP concentrations more than the upper reference limit. Vitamin B6 vitamer concentrations were not influenced by gender, estimated glomerular filtration rate, and circulating phosphate concentration. There was no difference in immunity markers according to age. However, the plasma concentrations of vitamin B6 vitamers were inversely associated with levels of CD28(+) lymphocyte subsets, as well as with the proliferative response of peripheral blood mononuclear cells in both groups.

CONCLUSIONS

No cases of vitamin B6 deficiency were found among kidney allograft recipients, and we report inverse links between vitamin B6 vitamer concentrations and markers of cellular immunity, suggesting that bioactive vitamin B6 concentration in kidney allograft recipients merits further investigation.

Memory improvements in elderly women following 16 weeks treatment with a combined multivitamin, mineral and herbal supplement: A randomized controlled trial

RATIONALE

There is potential for multivitamin supplementation to improve cognition in the elderly. This randomized, double-blind, placebo-controlled trial was conducted to investigate the effects of 16 weeks multivitamin supplementation (Swisse Women's 50+ Ultivite ®) on cognition in elderly women.

METHODS

Participants in this study were 56 community dwelling, elderly women, with subjective complaints of memory loss. Cognition was assessed using a computerized battery of memory and attention tasks designed to be sensitive to age-related declines to fluid intelligence, and a measure of verbal recall. Biochemical measures of selected nutrients, homocysteine, markers of inflammation, oxidative stress, and blood safety parameters were also collected. All cognitive and haematological parameters were assessed at baseline and 16 weeks post-treatment.

RESULTS

The multivitamin improved speed of response on a measure of spatial working memory, however benefits to other cognitive processes were not observed. Multivitamin supplementation decreased levels of homocysteine and increased levels of vitamin B(6) and B(12), with a trend for vitamin E to increase. There were no hepatotoxic effects of the multivitamin formula indicating this supplement was safe for everyday usage in the elderly.

CONCLUSION

Sixteen weeks ssupplementation with a combined multivitamin, mineral and herbal formula may benefit working memory in elderly women at risk of cognitive decline.