This systematic review and meta-analysis study aimed to evaluate the effectiveness of flaxseed supplementation on blood pressure (BP) in patients with hypertension based on the data from randomized clinical trials (RCTs). Three databases (PubMed [MEDLINE], Scopus, and ISI Web of Science) were searched from inception up to August 10, 2024. Relevant studies meeting our eligibility criteria were obtained. A random-effects model was used to estimate pooled weighted mean differences (WMDs) with 95% confidence intervals (CIs). The methodological quality of individual studies was assessed using the Cochrane Collaboration risk of bias tool. A total of 5 studies were included and analyzed using STATA software version 12. The results show that there is a significant decrease in systolic BP (WMD, −8.64 mmHg; 95% CI, −15.41 to −1.87; p ≤ 0.001) and diastolic BP (WMD, −4.87 mmHg; 95% CI, −8.37 to −1.37; p = 0.006) of patients with hypertension as compared to control groups. This study supported that flaxseed supplementation had favorable effects on BP control in hypertensive patients. It may be a promising adjuvant therapy for patients with hypertension.
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Differential bitterness perception associated with genetic polymorphism in the bitter taste receptor gene taste 2 receptor member 38 (
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A systematic review and meta-analysis were designed to summarize studies conducted on the effects of raspberry and blackcurrant consumption on blood pressure (BP). Eligible studies were detected by searching numerous five online databases including PubMed, Scopus, Web of Science, Cochrane Library, and Google Scholar, until December 17, 2022. We pooled the mean difference and its 95% confidence interval (CI) by applying a random-effects model. Overall, the impact of raspberry and blackcurrant on BP was reported in ten randomized controlled trials (RCTs) (420 subjects). Pooled analysis of six clinical trials revealed that raspberry consumption has no significant reduction in systolic blood pressure (SBP) (weighted mean differences [WMDs], −1.42; 95% CI, −3.27 to 0.87; p = 0.224) and diastolic blood pressure (DBP) (WMD, −0.53; 95% CI, −1.77 to 0.71; p = 0.401), in comparison with placebo. Moreover, pooled analysis of four clinical trials indicated that blackcurrant consumption did not reduce SBP (WMD, −1.46; 95% CI, −6.62 to 3.7; p = 0.579), and DBP (WMD, −2.09; 95% CI, -4.38 to 0.20; p = 0.07). Raspberry and blackcurrant consumption elicited no significant reductions in BP. More accurate RCTs are required to clarify the impact of raspberry and blackcurrant intake on BP.
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Despite controversies, no earlier study has systematically summarized findings from earlier studies on the effect of artichoke supplementation on blood pressure. Therefore, current systematic review and meta-analysis was done on the effect of artichoke supplementation on systolic blood pressure (SBP) and diastolic blood pressure (DBP) in adults. Five databases were searched from inception to January 2022 using relevant keywords. All randomized clinical trials investigating the impact of oral artichoke supplementation on any of the blood pressure parameters including SBP or/and DBP were included. Out of 1,507 citations, 7 trials that enrolled 472 subjects were included. Artichoke supplementation resulted in significant reduction in SBP (weighted mean difference [WMD], −2.01 mmHg; 95% confidence interval [CI], −3.78, −0.24; p = 0.026) and DBP (WMD, −1.45 mmHg; 95% CI, −2.81, −0.08; p = 0.038). Greater effects on SBP were detected in trials using ≤ 500 mg artichoke, lasted > 8 weeks, participants aged < 50 years’ old and sample size ≤ 70. There was also a similar impact of artichoke on DBP. However, significant non-linear associations were found between artichoke supplementation dosage and study duration with both SBP (for dosage: pnon-linearity = 0.002, for duration: pnon-linearity = 0.016) and DBP (for dosage: pnon-linearity = 0.005, for duration: pnon-linearity = 0.003). We found a significant reduction in both SBP and DBP following artichoke supplementation in adults. It could be proposed as a hypotensive supplement in hypertension management.
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The association between dietary antioxidant quality score (DAQS) and cardiovascular risk factors such as low cardiovascular fitness (CRF) and elevated blood pressure (BP) has rarely been investigated. To investigate the association between DAQS, CRF, and BP. This cross-sectional study was conducted on 270 adult subjects living in Tehran, Iran. Dietary intake was evaluated using a validated food frequency questionnaire. The DAQS was calculated using antioxidant-nutrient intake. Socio-economic status, anthropometric measures, and BP were recorded by a trained interviewer, using standard methods. A significant increase was found in maximal oxygen uptake (p value = 0.01) across tertiles of DAQS. After adjusting for confounders, the association remained unchanged (p value = 0.02). Participants in the highest tertile of DAQS had higher systolic BP (SBP) (p value = 0.01) and diastolic BP (DBP) (p value = 0.03), although adjustment for confounding factors attenuated the results (p value = 0.3 for DBP and p value = 0.6 for SBP). Our results revealed that higher DAQS is associated with better CRF in Iranian adults. Further studies are needed to establish the veracity of our results.
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The receptor of vitamin D is expressed in almost all body cells, including vascular endothelial cells and cardiomyocytes. Vitamin D deficiency has been observed widespread amongst heart failure (HF) patients, which could have harmful effects on their health condition. This study aims to investigate the effect of vitamin D supplements on blood pressure (BP) and physical activity of HF patients. Thirty-nine systolic HF patients with low ejection fraction (EF) < 50% and class III of New York Heart Association functional classification were randomly divided into 2 groups including intervention and placebo to enroll in an 8 weeks double-blind clinical trial. During the trial 6-minute walk test (6MWT), 25-hydroxyvitamin D (25[OH]D) level, BP, sodium and potassium intakes were assessed. The mean 25(OH)D level increased to 28.9 ± 11.7 ng/mL (p < 0.001) in the intervention group. There was a poor but non-significant reduction in systolic BP (−0.033 ± 4.71 mmHg, p = 0.531) in the intervention group. The BP also did not change in the placebo group at the end of the trial. A negligible decrease of 6MWT was observed in the intervention group (−6.6 ± 29.2 m) compared to the placebo (−14.1 ± 40.5 m). However, differences between the 2 groups were not statistically significant (p = 0.325). The results solely showed a slight positive correlation between 25(OH)D level and 6MWT. No significant improvements in BP and 6MWT were observed after vitamin D3 supplementation.
Iranian Registry of Clinical Trials Identifier:
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Flaxseed is one of the rich sources of α-linolenic acid and lignan. Flaxseed and its components have antioxidant, hypolipidemic and hypoglycemic effects. The study aimed to investigate the effect of flaxseed enriched yogurt on glycemic control, lipid profiles and blood pressure in patients with type 2 diabetes. A randomized, open-labeled, controlled clinical trial was conducted on 57 patients with type 2 diabetes. Participants were assigned to receive 200 g 2.5% fat yogurt containing 30-g flaxseed or plain yogurt daily for 8 weeks. Anthropometrics and biochemical parameters were evaluated at the beginning and end of the study. After 8 weeks of supplementation, Hemoglobin A1c was significantly decreased in the intervention group compared to control (p = 0.007). Also, at the end of the study, significant differences were seen between the flaxseed enriched yogurt and control groups in triglycerides and total cholesterol concentrations (p = 0.04 and p = 0.01), systolic blood pressure and diastolic blood pressure (p = 0.02 and p = 0.002, respectively). However, we did not find any difference between 2 groups in low-density lipoprotein, high-density lipoprotein, body weight and waist circumference (p > 0.05). Our results showed that the addition of flaxseed to yogurt can be effective in the management of type 2 diabetes.
ClinicalTrials.gov Identifier:
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Iranian Registry of Clinical Trials Identifier:
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Pickle is consumed in high amount among Iranians. Pickle consumption may be related to body mass index (BMI) and blood pressure (BP) but limited evidence exist in this regard. The aim of current study was to determine the association between pickle consumption and risk of overweight, central obesity and BP among Isfahanian female youths. A cross-sectional study was conducted on 289 female students aged 18–27 years randomly selected from students of Isfahan University of Medical Sciences, Isfahan, Iran. Diet was assessed by a validated and reliable food-frequency questionnaire. Mean pickle consumption was 15.1 ± 2.2 g/day. Individuals in the highest tertile of pickle consumption had a significantly higher BMI, systolic and diastolic BP (p = 0.001, 0.03, and 0.03, respectively), whereas we did not observe significant association for waist circumference (p = 0.21). Total energy intake (p = 0.02) and consumption of carbohydrate (p = 0.01), protein (p = 0.03), and fat (p = 0.05) in the upper tertile was higher than lower tertiles. There was a significant association between pickle consumption and obesity and BP among Iranian female youths. Further prospective studies are needed to confirm this association.
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Although it has been proposed that trace minerals have anti-oxidative functions and are related to the control of blood pressure, only a limited number of studies directly address the issue. Thus, the purpose of our study was to assess the intake of copper and manganese, which are trace minerals, and to clarify their relation to blood pressure. In a cross-sectional study, the blood pressure of 640 normotensive adults, from 19 to 69 year-old (320 males and 320 females), was measured, and its correlation with the intake of copper and manganese was assessed using a 24-hour dietary recall method. The average value of the blood pressure was 126.4/80.2 mmHg for the males and 117.8/75.8 mmHg for the females. The daily copper intake was 1.3 mg/day for the males and 1.2 mg/day for the females. For manganese, the daily intake was 4.2 mg/day for the males and 4.1 mg/day for the females. Although the copper intake of all subjects showed a positive correlation with the systolic and diastolic blood pressures, there was no significant correlation when the potential confounding factors were adjusted. The manganese intake of the male subjects had a significantly negative correlation with the systolic blood pressure after adjusting for gender, age, body mass index, and energy intake. In conclusion, the daily manganese intake of the normotensitve adults showed a significantly negative correlation with the systolic blood pressure indicating a possibility of a positive effect of manganese on blood pressure.
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Diets rich in fruits and vegetables reduce risk of adverse cardiovascular events. However, the constituents responsible for this effect have not been well established. Lately, the attention has been brought to vegetables with high nitrate content with evidence that this might represent a source of vasoprotective nitric oxide. We hypothesized that short-term consumption of spinach, a vegetable having high dietary nitrate content, can affect the arterial waveform indicative of arterial stiffness, as well as central and peripheral blood pressure (BP). Using a placebo-controlled, crossover design, 27 healthy participants were randomly assigned to receive either a high-nitrate (spinach; 845 mg nitrate/day) or low-nitrate soup (asparagus; 0.6 mg nitrate/day) for 7 days with a 1-week washout period. On days 1 and 7, profiles of augmentation index, central, and brachial BP were obtained over 180 min post-consumption in 4 fasted visits. A postprandial reduction in augmentation index was observed at 180 min on high-nitrate compared to low-nitrate intervention (-6.54 ± 9.7% vs. -0.82 ± 8.0%, p = 0.01) on Day 1, and from baseline on Day 7 (-6.93 ± 8.7%, p < 0.001; high vs. low: -2.28 ± 12.5%, p = 0.35), suggesting that the nitrate intervention is not associated with the development of tolerance for at least 7 days of continued supplementation. High vs. low-nitrate intervention also reduced central systolic (-3.39 ± 5.6 mmHg, p = 0.004) and diastolic BP (-2.60 ± 5.8 mmHg, p = 0.028) and brachial systolic BP (-3.48 ± 7.4 mmHg, p = 0.022) at 180 min following 7-day supplementation only. These findings suggest that dietary nitrate from spinach may contribute to beneficial hemodynamic effects of vegetable-rich diets and highlights the potential of developing a targeted dietary approach in the management of elevated BP.
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The purpose of this study was to investigate effect of nutrition education at worksite program in male workers. The subjects were 75 male workers who had received nutrition education by a clinical dietitian for 4 months. The anthropometric data, blood pressure and biochemical blood indices were measured before and after nutrition education. Dietary habits and lifestyle were investigated by self-administered questionnaires. Nutrients intake was determined by 24-hour dietary recall method. The results showed significant decreases in body mass index (p < 0.05), fasting blood sugar (p < 0.01), total cholesterol (p < 0.05), and LDL-cholesterol (p < 0.05) after nutrition education. The correlation analyses among anthropometric and clinical parameters after nutrition education indicated that there was a significantly positive correlations between blood pressure and weight, r-GTP. A significantly positive correlations was observed between fasting blood sugar and triglycerides. A significantly positive correlations was observed between triglycerides and body mass index, r-GTP, SGPT. A significantly positive correlations was observed between SGPT and weight, body mass index. A significantly negative correlations was observed between HDL-cholesterol and weight. It could be concluded that nutrition education might be effective tool to improve anthropometric measures and clinical parameters in male workers. Continuing and systematic nutritional management programs should be developed and implemented for male workers at the worksites to maintain optimal health status.
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