Effect of oat supplementation interventions on cardiovascular disease risk markers: a systematic review and meta-analysis of randomized controlled trials.

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.

A systematic review of phytochemicals in oat and buckwheat.

Consumption of oat and buckwheat have been associated with various health benefits that may be attributed to their nutritional composition. We performed a systematic review to evaluate the profile and quantity of bioactive compounds present in oat and buckwheat. Among 154 studies included in final analysis, 113 and 178 bioactive compounds were reported in oat and buckwheat, respectively. Total phytosterols, tocols, flavonoids and rutin content were generally higher in buckwheat, ß-glucans were significantly higher in oat, while avenanthramides and saponins were characteristically present in oat. The majority of studies included in current review were published before 2010s. The heterogeneous methodological procedures used across the studies precluded our possibility to meta-analyse the evidence and raises the need for harmonization of separation and extraction methods in future studies. Our findings should further stimulate the exploration of metabolites related to identified phytochemicals and their roles in human health.

Phytochemical characterization of turnip greens (Brassica rapa ssp. rapa): A systematic review.

OBJECTIVE: The Turnip (Brassica rapa L. ssp. rapa) is a leaf and root vegetable grown and consumed worldwide. The consumption of Turnip has been associated with beneficial effects on human health due to their phytochemicals that may control a variety of physiological functions, including antioxidant activity, enzyme regulation, and apoptotic control and the cell cycle. The current systematic review of the literature aims to evaluate both the profile and quantity of phytochemicals commonly found in Turnip greens and to provide perspectives for further investigation. METHODS: This review was conducted following the PRISMA guidelines. Four bibliographic databases (PubMed, Embase, Web-of-Science and Cochrane Central Register of Controlled Trials) were searched to identify published studies until April 8th, 2020 (date last searched) without data and language restriction. Studies were included if they used samples of Turnip greens (the leaves), and evaluated its phytochemical content. Two reviewers independently evaluated the titles and abstracts according to the selection criteria. For each potentially eligible study, two reviewers assessed the full-texts and independently extracted the data using a predesigned data extraction form. RESULTS: Based on the search strategy 5,077 potentially relevant citations were identified and full texts of 37 studies were evaluated, among which 18 studies were eligible to be included in the current review. The majority of included studies were focused on identification of glucosinolates and isothiocyanates (n = 14, 82%), four studies focused on organic acids, and five studies reported phenolic component profile in Turnip greens. Among included studies nine studies (50%) provided information on phytochemical's content. We found 129 phytochemicals (19 glucosinolates, 33 glucosinolate-breakdown products, 10 organic acids and 59 polyphenolic compounds) reported in Turnip greens. Flavonoids were mainly present as quercetin, kaempferol and isorhamnetin derivatives; while aliphatic forms were the predominant glucosinolate (gluconapin was the most common across five studies, followed by glucobrassicanapin). In general, the phytochemical content varied among the leaves, tops and Turnip roots. CONCLUSIONS: Emerging evidence suggests the Turnip as a substantial source of diverse bioactive compounds. However, detailed investigation on the pure compounds derived from Turnip green, their bioavailability, transport and metabolism after consumption is further needed. Additional studies on their biological activity are crucial to develop dietary recommendations on the effective dosage and dietary recommendation of Turnip greens for nutrition and health.

Effects of phytoestrogen supplementation on intermediate cardiovascular disease risk factors among postmenopausal women: a meta-analysis of randomized controlled trials.

IMPORTANCE: Phytoestrogens are becoming popular constituents of human diets and are increasingly used by postmenopausal women. OBJECTIVE: Our study aims to determine the effects of phytoestrogen supplementation on intermediate cardiovascular disease (CVD) risk factors in postmenopausal women. EVIDENCE REVIEW: Five electronic databases (Medline, EMBASE, Web of Science, Cochrane CENTRAL, Google Scholar) were systematically searched to identify eligible studies, that is, randomized controlled trials (RCTs) that assessed the association of phytoestrogen supplementation with CVD risk factors (serum lipids, homocysteine, fibrinogen, markers of inflammation, oxidative stress and endothelial function, carotid intima-media thickness [CIMT]) in postmenopausal women. Data were extracted by two independent reviewers using a predefined data collection form. FINDINGS: In total, 56 RCTs were identified, including 4,039 individual postmenopausal women. There was substantial heterogeneity in quality across studies. Twenty-six (46%) RCTs showed poor quality and there was an indication of publication bias presence for some of the biomarkers. Results are reported in pooled mean difference (95% CI) of changes. Use of phytoestrogens was associated with a decrease in serum total cholesterol (-0.27 mmol/L [-0.41 to -0.13]), low-density lipoprotein (-0.25 mmol/L [-0.37 to -0.13]), triglycerides (-0.20 mmol/L [-0.28 to -0.11]), and apolipoprotein B (-0.13 g/L [-0.23 to -0.03]) and with an increase in serum apolipoprotein A-1 (0.04 g/L [0.02-0.07]. Also, phytoestrogen supplementation was associated with a decrease in serum intercellular adhesion molecule 1 (-18.86 ng/mL [-30.06 to -7.65]) and E-selectin (-2.32 ng/mL [-4.05 to -0.59]). There was no association observed between phytoestrogen supplementation and inflammatory markers, fibrinogen, homocysteine, or other endothelial function markers. In contrast, use of phytoestrogens was associated with an increase in CIMT (9.34 µm [95% CI, 0.39-18.29]). Effect estimates of phytoestrogen supplementation on oxidative stress could not be pooled. CONCLUSIONS AND RELEVANCE: Phytoestrogen supplementation seems to modestly improve the CVD risk profile of postmenopausal women by influencing blood lipids and parameters of endothelial function. In women with an increased risk of atherosclerosis, although modest, a harmful effect on CIMT progression may be present. Because of limited quality and the heterogeneous nature of the current evidence, additional rigorous studies are needed to explore the role of phytoestrogens in menopausal cardiovascular health. : Video Summary: http://links.lww.com/MENO/A593.

Video Summary: http://links.lww.com/MENO/A593.