Efficacy of black rice extract on obesity in obese postmenopausal women: a 12-week randomized, double-blind, placebo-controlled preliminary clinical trial

Effect of Pigmented Rice Consumption on Cardiometabolic Risk Factors: A Systematic Review of Randomized Controlled Trials

PURPOSE OF REVIEW

Dietary patterns that include polyphenols may help manage cardiometabolic risk factors. Pigmented rice contains phenolic acids and flavonoids that contribute to its antioxidant properties. This review examined the effect of polyphenol-containing pigmented rice on antioxidant status, lipid profile, glucose/insulin, blood pressure, and weight among adults. Four electronic databases including PubMed, ProQuest, EBSCOhost, and Google Scholar were systematically searched for relevant articles published in English since 2000, using PRISMA guidelines (PROSPERO registration: CRD42022358132). Two-staged screening resulted in the inclusion of seventeen (seven acute, ten chronic) randomized controlled trials. A random effects model was conducted on cardiometabolic outcomes reported in at least three studies.

RECENT FINDINGS

Acute intake increased plasma antioxidant activity and lowered postprandial glucose and insulin levels. Chronic consumption was associated with reductions in fasting glucose (WMD: -1.60 mg/dL; 95% CI:-3.05,-0.14, p = 0.03, k = 5, n = 349), weight (WMD: -0.23 kg, 95% CI: -0.44, -0.02, p = 0.03, k = 3, n = 182), and diastolic blood pressure (WMD: -1.39 mmHg, 95% CI: -2.21, -0.56, p = 0.001, k = 3, n = 185). No effect on total cholesterol, low-density lipoprotein, high-density lipoprotein, triglycerides, body mass index, and systolic blood pressure was found. The consumption of pigmented rice may improve cardiometabolic risk factors. However, the small number of studies and differences in study design, including participants' health status, form of rice utilized, and duration of intervention, support the need for more high-quality trials to further investigate these findings.

Anthocyanins' effects on diabetes mellitus and islet transplantation

The incidence of diabetes mellitus is dramatically increasing every year, causing a huge global burden. Moreover, existing anti-diabetic drugs inevitably bring adverse reactions, and the application of islet transplantation is often limited by the damage caused by oxidative stress after transplantation. Thus, new approaches are needed to combat the growing burden of diabetes mellitus. Anthocyanins are of great nutritional interest and have been documented that have beneficial effects on chronic diseases, including diabetes mellitus. Here, we describe the health effects of anthocyanins on diabetes mellitus and islet transplantation. Epidemiological studies demonstrated that moderate intake of anthocyanins leading to a reduction in risk of diabetes mellitus. Numerous experiments both animal and clinical studies also showed positive effects of anthocyanins on prevention and treatment of diabetes and diabetic complications. These effects of anthocyanins may be related to mechanisms of improving glucose and lipid metabolism and insulin resistance, antioxidant, and anti-inflammatory activities. In addition, damage and function of pancreatic islets after transplantation are also improved by anthocyanins. These findings suggest that daily intake of anthocyanins may not only improve nutritional metabolism in healthy individuals to prevent from diabetes, but also as a supplementary treatment of diabetes mellitus and islet transplantation. Thus, more evidence is needed to better understand the potential health benefits of anthocyanins.

Effects of anthocyanin supplementation on blood lipid levels: a systematic review and meta-analysis

Introduction

Dyslipidemia is a major cardiovascular disease risk factor associated with increased mortality. The intake of plant food-derived bioactive compounds is associated with beneficial cardiovascular effects, including decreased blood lipid levels and cardiovascular risk. We aimed to evaluate the effects of anthocyanin intake on blood lipid levels by analyzing relevant randomized controlled trials.

Methods

We searched the PubMed and Embase databases using the "Patient/Population, Intervention, Comparison, and Outcomes" format to determine whether anthocyanin supplementation intervention affected blood lipid levels compared with placebo supplementation in human participants.

Results

A total of 41 studies with 2,788 participants were included in the meta-analysis. Anthocyanin supplementation significantly reduced triglyceride [standardized mean difference (SMD) = -0.10; 95% confidence interval [CI], -0.18, -0.01) and low-density lipoprotein-cholesterol (SMD = -0.16; 95% CI -0.26, -0.07) levels and increased high-density lipoprotein-cholesterol levels (SMD = 0.42; 95% CI 0.20, 0.65).

Discussion

Anthocyanin supplementation significantly improved blood lipid component levels in the included studies. Larger, well-designed clinical trials are needed to further investigate the effects of anthocyanin intake on blood lipid levels and the safety of anthocyanin supplementation for treating dyslipidemia.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021257087, identifier: CRD42021257087.

Pharmacological studies of the genus rice (Oryza L.): a literature review

Rice (Oryza L.) is an essential food for more than 50 percent of the world's population and is the world's second-largest grain crop. Pigmented rice comes in various colors, such as black, red, brown, and green. Anthocyanins, like cyanidin-3-O-glucoside and peonidin-3-O-glucoside, are the primary color pigments in colored rice, whereas proanthocyanidins and flavan-3-ol oligosaccharides, with catechins as the central synthesis unit, are found in brown rice. This review article's aim is to give information and a summary of rice activities, research methods, also mechanisms of action (Oryza L.). Intake of pigmented rice was already associated with a number of health benefits, including antioxidant activity, anticancer, antitumor, antidiabetic activity, and a reduced risk of cardiovascular disease. Rice contains several bioactive compounds, such as γ-oryzanol, phenolic acid, anthocyanins, proanthocyanidins, flavonoids, carotenoids, and phytosterols, which have been widely studied and shown to have several pharmacological activities. The use of current herbal compounds is rapidly increasing, including the practice of pharmacological disease prevention and treatment. Herbal remedies have entered the international market as a result of research into plant biopharmaceuticals and nutraceuticals. Through a variety of pharmacological activities, it is clear that Oryza L. is a popular herb. As a result, additional research on Oryza L. can be conducted to investigate more recent and comprehensive pharmacological effectiveness, to provide information and an overview of Rice (Oryza L.) activities, research methods, and mechanisms of action. Several natural substances are characterized by low water solubility, low stability, and sensitivity to light and oxygen, and the potential for poor absorption of the active substances requires modification of the formulation. To improve the effectiveness of pharmacologically active substances originating from natural ingredients, drug delivery systems that use lipid-based formulations can be considered innovations.

Resistant starch from black rice, Oryza sativa L. var. ameliorates renal inflammation, fibrosis and injury in insulin resistant rats

It has recently been reported that black rice (BR) extract has anti-obesity, anti-diabetic, and anti-osteoporosis effects. It has been shown to reduce obese-related kidney dysfunction in animal models. This study aimed to investigate the effect of resistant starch from BR (RS) on renal inflammation, oxidative stress, and apoptosis in obese insulin resistant rats. Male Wistar rats were divided into six groups: normal diet (ND), ND treated with 150 mg of RS (NDRS150), high-fat (HF) diet, HF treated with 100 and 150 mg of RS (HFRS100), (HFRS150), and HF treated with metformin as a positive control. Insulin resistance was shown in the HF rats by glucose intolerance, increased insulin, total area under the curve of glucose and homeostasis model assessment of insulin resistance and dyslipidemia. The resulting metabolic disturbance in the HF rats caused renal inflammation, fibrosis and apoptosis progressing to kidney injury and dysfunction. Prebiotic RS including anthocyanin from BR at doses of 100 and 150 mg ameliorated insulin resistance, dyslipidemia and liver injury. Treatment with RS reduced TGF-β fibrotic and apoptotic pathways by inhibition of NF-κB and inflammatory cytokines which potentially restore kidney damage and dysfunction. In conclusion, prebiotic RS from BR ameliorated obesity induced renal injury and dysfunction by attenuating inflammatory, fibrotic, and apoptotic pathways in insulin resistant rats induced by HF.

Anthocyanins in Chronic Diseases: The Power of Purple

Anthocyanins are mainly purple-coloured phenolic compounds of plant origin that as secondary metabolites are important in plant survival. Understanding their health benefits in humans requires sourcing these unstable compounds in sufficient quantities at a reasonable cost, which has led to improved methods of extraction. Dark-coloured fruits, cereals and vegetables are current sources of these compounds. The range of potential sustainable sources is much larger and includes non-commercialised native plants from around the world and agri-waste containing anthocyanins. In the last 5 years, there have been significant advances in developing the therapeutic potential of anthocyanins in chronic human diseases. Anthocyanins exert their beneficial effects through improvements in gut microbiota, oxidative stress and inflammation, and modulation of neuropeptides such as insulin-like growth factor-1. Their health benefits in humans include reduced cognitive decline; protection of organs such as the liver, as well as the cardiovascular system, gastrointestinal tract and kidneys; improvements in bone health and obesity; and regulation of glucose and lipid metabolism. This review summarises some of the sources of anthocyanins and their mechanisms and benefits in the treatment of chronic human diseases.