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Effect of oat supplementation interventions on cardiovascular disease risk markers: a systematic review and meta-analysis of randomized controlled trials.
Llanaj, E, Dejanovic, GM, Valido, E, Bano, A, Gamba, M, Kastrati, L, Minder, B, Stojic, S, Voortman, T, Marques-Vidal, P, et al
European journal of nutrition. 2022;61(4):1749-1778
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Cardiovascular disease (CVD) is one of the leading causes of mortality among adults. Changes in diet can have a beneficial effect on the prevention and management of CVD. Studies have shown that increasing intake of wholegrains, particularly those containing oat components, reduces CVD risk markers including blood cholesterol, blood glucose and body mass index (BMI). The purpose of this systematic review was to look at the effects of oat supplementation interventions (OSI) on CVD risk markers among adults, accounting for different dietary backgrounds or control arms. 74 RCTs were included (4937 subjects). Supplementing the diet with oat cereals improves CVD risk markers in healthy adults and those with mild metabolic disturbances. In particular serum total and LDL cholesterol, BMI and waist circumference. The beneficial effects on total cholesterol and LDL-Cholesterol were independent of the dietary background. The role of OSIs on blood pressure, glucose homeostasis or other markers, could not be established.
Abstract
PURPOSE Oat supplementation interventions (OSIs) may have a beneficial effect on cardiovascular disease (CVD) risk. However, dietary background can modulate such effect. This systematic review assesses the effects of OSIs on CVD risk markers among adults, accounting for different dietary backgrounds or control arms. METHODS We included randomized clinical trials (RCTs) that assessed the effect of oat, oat beta-glucan-rich extracts or avenanthramides on CVD risk markers. RESULTS Seventy-four RCTs, including 4937 predominantly hypercholesterolemic, obese subjects, with mild metabolic disturbances, were included in the systematic review. Of these, 59 RCTs contributed to the meta-analyses. Subjects receiving an OSI, compared to control arms without oats, had improved levels of total cholesterol (TC) [weighted mean difference and (95% CI) - 0.42 mmol/L, (- 0.61; - 0.22)], LDL cholesterol [- 0.29 mmol/L, (- 0.37; - 0.20)], glucose [- 0.25 nmol/L, (- 0.36; - 0.14)], body mass index [- 0.13 kg/m2, (- 0.26; - 0.01)], weight [- 0.94 kg, (- 1.84: - 0.05)], and waist circumference [- 1.06 cm, (- 1.85; - 0.27)]. RCTs on inflammation and/or oxidative stress markers were scarce and with inconsistent findings. RCTs comparing an OSI to heterogeneous interventions (e.g., wheat, eggs, rice, etc.), showed lowered levels of glycated haemoglobin, diastolic blood pressure, HDL cholesterol and apolipoprotein B. The majority of included RCTs (81.1%) had some concerns for risk of bias. CONCLUSION Dietary OSIs resulted in lowered levels of blood lipids and improvements in anthropometric parameters among participants with predominantly mild metabolic disturbances, regardless of dietary background or control. Further high-quality trials are warranted to establish the role of OSIs on blood pressure, glucose homeostasis and inflammation markers.
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The effects of saffron supplementation on cardiovascular risk factors in adults: A systematic review and dose-response meta-analysis.
Zamani, M, Zarei, M, Nikbaf-Shandiz, M, Gholami, F, Hosseini, AM, Nadery, M, Shiraseb, F, Asbaghi, O
Frontiers in nutrition. 2022;9:1055517
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Cardiovascular disease (CVD) is a leading cause of death and disability around the world and presents a significant burden for healthcare systems. CVD has many risk factors, including diet and lifestyle habits. Hence, favourable interventions in those areas can help prevent and manage CVD. This systematic review examined the effects of saffron crocus on cardiovascular risk factors. Saffron is derived from the flowering plant Saffron Crocus (Crocus sativus). It contains many active compounds such as crocetin, crocin, picrocrocin, and safrana, which in various studies demonstrated positive effects on blood glucose levels, insulin resistance and sensitivity and blood fats, besides also having antioxidant and anti-inflammatory qualities. Yet, results were not always consistent, and hence this meta-analysis gathered evidence from 32 randomised controlled trials (RCTs) which included a total of 1674 subjects and investigated the effect of saffron supplements on cardiovascular risk factors such as blood fats, blood glucose control, blood pressure, anthropometric measures, and inflammatory markers. In conclusion, the analysis showed that saffron supplementation aided the reduction of some inflammatory markers (CRP, TNF-α), had favourable effects on antioxidant capacity, reduced blood fats except high-density lipoprotein (HDL), enhanced blood control and insulin sensitivity, reduced blood pressure and was linked to a reduction in waist circumference but with no significant effect on weight itself, BMI or fat mass. The authors discussed how their results relate to previous research and what underlying mechanisms can explain the effects or discrepancies. Given the positive results, saffron presents itself as a promising supplement and adjunct therapy for managing CVD and its risk factors.
Abstract
INTRODUCTION Cardiovascular disease (CVD) is one of the leading causes of death and disability in the world and is estimated to involve more people in the next years. It is said that alternative remedies such as herbs can be used to manage the complications of this disease. For this reason, we aimed to conduct this meta-analysis to systematically assess and summarize the effects of saffron supplementation as an important herb on cardiovascular risk factors in adults. METHODS A systematic search was done in PubMed, Scopus, and Web of Science to find eligible articles up to September 2022. Randomized controlled trials (RCTs) that evaluated the effects of saffron on lipid profiles, glycemic control, blood pressure, anthropometric measures, and inflammatory markers were included. In the meta-analysis, 32 studies were taken into account (n = 1674). RESULTS Consumption of saffron significantly decreased triglyceride (TG) (WMD = -8.81 mg/dl, 95%CI: -14.33, -3.28; P = 0.002), total cholesterol (TC) (WMD = -6.87 mg/dl, 95%CI: -11.19, -2.56; P = 0.002), low density lipoprotein (LDL) (WMD = -6.71 mg/dl, 95%CI: -10.51, -2.91; P = 0.001), (P = 0.660), fasting blood glucose (FBG) level (WMD = -7.59 mg/dl, 95%CI: -11.88, -3.30; P = 0.001), HbA1c (WMD = -0.18%, 95%CI: -0.21, -0.07; P < 0.001), homeostasis model assessment-insulin resistance (HOMA-IR) (WMD = -0.49, 95%CI: -0.89, -0.09; P = 0.016), systolic blood pressure (SBP) (WMD = -3.42 mmHg, 95%CI: -5.80, -1.04; P = 0.005), tumor necrosis factor α (TNF-α) (WMD = -2.54 pg/ml, 95%CI: -4.43, -0.65; P = 0.008), waist circumference (WC) (WMD = -1.50 cm; 95%CI: -2.83, -0.18; P = 0.026), malondialdehyde (MDA) (WMD = -1.50 uM/L, 95%CI: -2.42, -0.57; P = 0.001), and alanine transferase (ALT) (WMD = -2.16 U/L, 95%CI: -4.10, -0.23; P = 0.028). Also, we observed that saffron had an increasing effect on total antioxidant capacity (TAC) (WMD = 0.07 mM/L, 95%CI: 0.01, 0.13; P = 0.032). There was linear regression between FBG and the duration of saffron intake. Additionally, the non-linear dose-response analysis has shown a significant association of saffron intervention with HDL (P = 0.049), HOMA-IR (P = 0.002), weight (P = 0.036), ALP (P = 0.016), FBG (P = 0.011), HbA1c (P = 0.002), and TNF-α (P = 0.042). A non-linear association between the length of the intervention and the level of HDL and DBP was also found. DISCUSSION That seems saffron could effectively improve TG, TC, LDL, FBG, HbA1c, HOMA-IR, SBP, CRP, TNF-α, WC, MDA, TAC, and ALT.