Diabetes mellitus remains an incurable disorder in spite of intense research. As result of limitations and unmet goals associated with the use of anti-diabetic drugs, an increased number of diabetic populations globally now resort to complementary and alternative medicine (CAM) such as herbs and other natural products. There has been a renewed interest in the use of honey in the treatment of diabetes mellitus, partly due to an increase in the availability of evidence-based data demonstrating its benefits in diabetic rodents and patients. This commentary aims to underscore some of the research implications, issues and questions raised from these studies which show the beneficial effects of honey in the treatment of diabetes mellitus. Some of the issues highlighted in this article include: considering honey is sweet and rich in sugars, how could it be beneficial in the management of diabetes mellitus? Are the observed effects of honey or combined with anti-diabetic drugs exclusive to certain honey such as tualang honey? Could these beneficial effects be reproduced with other honey samples? Anti-diabetic drugs in combination with honey improve glycemic control, enhance antioxidant defenses and reduce oxidative damage. These effects are believed to be mediated partly via antioxidant mechanism of honey. This raises another question. Could similar data be obtained if anti-diabetic drugs are co-administered with other potent antioxidants such as vitamin C or E? As the evidence has revealed, the prospect of managing diabetes mellitus with honey or antioxidants (such as vitamin C or E) as an adjunct to conventional diabetes therapy is vast. However, more well-designed, rigorously conducted randomized controlled studies are necessary to further validate these findings.
The primary aim of the current management of diabetes mellitus is to achieve and/or maintain a glycated hemoglobin level of ≤6.5%. However, recent evidence indicates that intensive treatment of hyperglycemia is characterized by increased weight gain, severe hypoglycemia and higher mortality. Besides, evidence suggests that it is difficult to achieve and/or maintain optimal glycemic control in many diabetic patients; and that the benefits of intensively-treated hyperglycemia are restricted to microvascular complications only. In view of these adverse effects and limitations of intensive treatment of hyperglycemia in preventing diabetic complications, which is linked to oxidative stress, this commentary proposes a hypothesis that "simultaneous targeting of hyperglycemia and oxidative stress" could be more effective than "intensive treatment of hyperglycemia" in the management of diabetes mellitus.
Honey is a natural product known for its varied biological or pharmacological activities-ranging from anti-inflammatory, antioxidant, antibacterial, antihypertensive to hypoglycemic effects. This review article focuses on the role of honey in modulating the development and progression of tumors or cancers. It reviews available evidence (some of which is very recent) with regards to the antimetastatic, antiproliferative and anticancer effects of honey in various forms of cancer. These effects of honey have been thoroughly investigated in certain cancers such as breast, liver and colorectal cancer cell lines. In contrast, limited but promising data are available for other forms of cancers including prostate, bladder, endometrial, kidney, skin, cervical, oral and bone cancer cells. The article also underscores the various possible mechanisms by which honey may inhibit growth and proliferation of tumors or cancers. These include regulation of cell cycle, activation of mitochondrial pathway, induction of mitochondrial outer membrane permeabilization, induction of apoptosis, modulation of oxidative stress, amelioration of inflammation, modulation of insulin signaling and inhibition of angiogenesis. Honey is highly cytotoxic against tumor or cancer cells while it is non-cytotoxic to normal cells. The data indicate that honey can inhibit carcinogenesis by modulating the molecular processes of initiation, promotion, and progression stages. Thus, it may serve as a potential and promising anticancer agent which warrants further experimental and clinical studies.
Cancer cells generate reactive oxygen species (ROS) resulting from mitochondrial dysfunction, stimulation of oncogenes, abnormal metabolism, and aggravated inflammatory activities. Available evidence also suggests that cancer cells depend on intrinsic ROS level for proliferation and survival. Both physiological and pathophysiological roles have been ascribed to ROS which cause lipid peroxidation. In spite of their injurious effects, the ROS and the resulting lipid peroxidation products could be beneficial in cancer treatment. This review presents research findings suggesting that ROS and the resulting lipid peroxidation products could be utilized to inhibit cancer growth or induce cancer cell death. It also underscores the potential of lipid peroxidation products to potentiate the antitumor effect of other anticancer agents. The review also highlights evidence demonstrating other potential applications of lipid peroxidation products in cancer treatment. These include the prospect of lipid peroxidation products as a diagnostic tool to predict the chances of cancer recurrence, to monitor treatment progress or how well cancer patients respond to therapy. Further and detailed research is required on how best to successfully, effectively, and selectively target cancer cells in humans using lipid peroxidation products. This may prove to be an important strategy to complement current treatment regimens for cancer patients.
Evidence shows that honey improves glycemic control in diabetes mellitus. Besides its hypoglycemic effect, studies indicate that honey ameliorates lipid abnormalities in rats and humans with diabetes. The majority of these studies do not examine the mechanisms by which honey ameliorates glycemic and/or lipid derangements. The gut microbiota is now recognized for its ability to increase energy harvest from the diet and alter lipid metabolism of the host. Recently available data implicate a causal role of these gut microbes in the pathophysiology of obesity, insulin resistance, and diabetes mellitus. In this review, we present some of the latest findings linking gut microbiota to pathogenesis of obesity, insulin resistance, and diabetes mellitus. The review also underlines data that demonstrate the beneficial effects of oligosaccharides on various abnormalities commonly associated with these disorders. Based on the similarities of some of these findings with those of honey, together with the evidence that honey contains oligosaccharides, we hypothesize that oligosaccharides present in honey might contribute to the antidiabetic and other health-related beneficial effects of honey. We anticipate that the possibility of oligosaccharides in honey contributing to the antidiabetic and other health-related effects of honey will stimulate a renewed research interest in this field.
The global prevalence of chronic diseases such as diabetes mellitus, hypertension, atherosclerosis, cancer and Alzheimer's disease is on the rise. These diseases, which constitute the major causes of death globally, are associated with oxidative stress. Oxidative stress is defined as an "imbalance between oxidants and antioxidants in favor of the oxidants, potentially leading to damage". Individuals with chronic diseases are more susceptible to oxidative stress and damage because they have elevated levels of oxidants and/or reduced antioxidants. This, therefore, necessitates supplementation with antioxidants so as to delay, prevent or remove oxidative damage. Honey is a natural substance with many medicinal effects such as antibacterial, hepatoprotective, hypoglycemic, reproductive, antihypertensive and antioxidant effects. This review presents findings that indicate honey may ameliorate oxidative stress in the gastrointestinal tract (GIT), liver, pancreas, kidney, reproductive organs and plasma/serum. Besides, the review highlights data that demonstrate the synergistic antioxidant effect of honey and antidiabetic drugs in the pancreas, kidney and serum of diabetic rats. These data suggest that honey, administered alone or in combination with conventional therapy, might be a novel antioxidant in the management of chronic diseases commonly associated with oxidative stress. In view of the fact that the majority of these data emanate from animal studies, there is an urgent need to investigate this antioxidant effect of honey in human subjects with chronic or degenerative diseases.
Honey is a natural substance with many medicinal properties, including antibacterial, hepatoprotective, hypoglycemic, antioxidant and antihypertensive effects. It reduces hyperglycemia in diabetic rats and humans. However, the mechanism(s) of its hypoglycemic effect remain(s) unknown. Honey comprises many constituents, making it difficult to ascertain which component(s) contribute(s) to its hypoglycemic effect. Nevertheless, available evidence indicates that honey consists of predominantly fructose and glucose. The objective of this review is to summarize findings which indicate that fructose exerts a hypoglycemic effect. The data show that glucose and fructose exert a synergistic effect in the gastrointestinal tract and pancreas. This synergistic effect might enhance intestinal fructose absorption and/or stimulate insulin secretion. The results indicate that fructose enhances hepatic glucose uptake and glycogen synthesis and storage via activation of hepatic glucokinase and glycogen synthase, respectively. The data also demonstrate the beneficial effects of fructose on glycemic control, glucose- and appetite-regulating hormones, body weight, food intake, oxidation of carbohydrate and energy expenditure. In view of the similarities of these effects of fructose with those of honey, the evidence may support the role of fructose in honey in mediating the hypoglycemic effect of honey.
The gut microbiota plays a number of important roles including digestion, metabolism, extraction of nutrients, synthesis of vitamins, prevention against pathogen colonization, and modulation of the immune system. Alterations or changes in composition and biodiversity of the gut microbiota have been associated with many gastrointestinal tract (GIT) disorders such as inflammatory bowel disease and colon cancer. Recent evidence suggests that altered composition and diversity of gut microbiota may play a role in the increased prevalence of metabolic diseases. This review article has two main objectives. First, it underscores approaches (such as probiotics, prebiotics, antimicrobial agents, bariatric surgery, and weight loss strategies) and their prospects in modulating the gut microbiota in the management of metabolic diseases. Second, it highlights some of the current challenges and discusses areas of future research as it relates to the gut microbiota and metabolic diseases. The prospect of modulating the gut microbiota seems promising. However, considering that research investigating the role of gut microbiota in metabolic diseases is still in its infancy, more rigorous and well-designed in vitro, animal and clinical studies are needed.
Diabetes mellitus remains a burden worldwide in spite of the availability of numerous antidiabetic drugs. Honey is a natural substance produced by bees from nectar. Several evidence-based health benefits have been ascribed to honey in the recent years. In this review article, we highlight findings which demonstrate the beneficial or potential effects of honey in the gastrointestinal tract (GIT), on the gut microbiota, in the liver, in the pancreas and how these effects could improve glycemic control and metabolic derangements. In healthy subjects or patients with impaired glucose tolerance or diabetes mellitus, various studies revealed that honey reduced blood glucose or was more tolerable than most common sugars or sweeteners. Pre-clinical studies provided more convincing evidence in support of honey as a potential antidiabetic agent than clinical studies did. The not-too-impressive clinical data could mainly be attributed to poor study designs or due to the fact that the clinical studies were preliminary. Based on the key constituents of honey, the possible mechanisms of action of antidiabetic effect of honey are proposed. The paper also highlights the potential impacts and future perspectives on the use of honey as an antidiabetic agent. It makes recommendations for further clinical studies on the potential antidiabetic effect of honey. This review provides insight on the potential use of honey, especially as a complementary agent, in the management of diabetes mellitus. Hence, it is very important to have well-designed, randomized controlled clinical trials that investigate the reproducibility (or otherwise) of these experimental data in diabetic human subjects.
Oxidative stress is implicated in the pathogenesis and/or maintenance of elevated blood pressure in hypertension. This study investigated the effect of honey on elevated systolic blood pressure (SBP) in spontaneously hypertensive rats (SHR). It also evaluated the effect of honey on the amelioration of oxidative stress in the kidney of SHR as a possible mechanism of its antihypertensive effect. SHR and Wistar Kyoto (WKY) rats were randomly divided into 2 groups and administered distilled water or honey by oral gavage once daily for 12 weeks. The control SHR had significantly higher SBP and renal malondialdehyde (MDA) levels than did control WKY. The mRNA expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and glutathione S-transferase (GST) were significantly downregulated while total antioxidant status (TAS) and activities of GST and catalase (CAT) were higher in the kidney of control SHR. Honey supplementation significantly reduced SBP and MDA levels in SHR. Honey significantly reduced the activities of GST and CAT while it moderately but insignificantly upregulated the Nrf2 mRNA expression level in the kidney of SHR. These results indicate that Nrf2 expression is impaired in the kidney of SHR. Honey supplementation considerably reduces elevated SBP via amelioration of oxidative stress in the kidney of SHR.
Hyperglycemia-induced increase in oxidative stress is implicated in diabetic complications. This study investigated the effect of metformin and/or glibenclamide in combination with honey on antioxidant enzymes and oxidative stress markers in the kidneys of streptozotocin (60 mg/kg; intraperitoneal)-induced diabetic rats. Diabetic rats were randomized into eight groups of five to seven rats and received distilled water (0.5 mL); honey (1.0 g/kg); metformin (100 mg/kg); metformin (100 mg/kg) and honey (1.0 g/kg); glibenclamide (0.6 mg/kg); glibenclamide (0.6 mg/kg) and honey (1.0 g/kg); metformin (100 mg/kg) and glibenclamide (0.6 mg/kg); or metformin (100 mg/kg), glibenclamide (0.6 mg/kg) and honey (1.0 g/kg) orally once daily for four weeks. Malondialdehyde (MDA) levels, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were significantly elevated while catalase (CAT) activity, total antioxidant status (TAS), reduced glutathione (GSH), and GSH:oxidized glutathione (GSSG) ratio was significantly reduced in the diabetic kidneys. CAT, glutathione reductase (GR), TAS, and GSH remained significantly reduced in the diabetic rats treated with metformin and/or glibenclamide. In contrast, metformin or glibenclamide combined with honey significantly increased CAT, GR, TAS, and GSH. These results suggest that combination of honey with metformin or glibenclamide might offer additional antioxidant effect to these drugs. This might reduce oxidative stress-mediated damage in diabetic kidneys.
Diabetes mellitus is associated with deterioration of glycemic control and progressive metabolic derangements. This study investigated the effect of honey as an adjunct to glibenclamide or metformin on glycemic control in streptozotocin-induced diabetic rats. Diabetes was induced in rats by streptozotocin. The diabetic rats were randomized into six groups and administered distilled water, honey, glibenclamide, glibenclamide and honey, metformin or metformin and honey. The animals were treated orally once daily for four weeks. The diabetic control rats showed hypoinsulinemia (0.27 ± 0.01 ng/ml), hyperglycemia (22.4 ± 1.0 mmol/L) and increased fructosamine (360.0 ± 15.6 µmol/L). Honey significantly increased insulin (0.41 ± 0.06 ng/ml), decreased hyperglycemia (12.3 ± 3.1 mmol/L) and fructosamine (304.5 ± 10.1 µmol/L). Although glibenclamide or metformin alone significantly (p < 0.05) reduced hyperglycemia, glibenclamide or metformin combined with honey produced significantly much lower blood glucose (8.8 ± 2.9 or 9.9 ± 3.3 mmol/L, respectively) compared to glibenclamide or metformin alone (13.9 ± 3.4 or 13.2 ± 2.9 mmol/L, respectively). Similarly, glibenclamide or metformin combined with honey produced significantly (p < 0.05) lower fructosamine levels (301.3 ± 19.5 or 285.8 ± 22.6 µmol/L, respectively) whereas glibenclamide or metformin alone did not decrease fructosamine (330.0 ± 29.9 or 314.6 ± 17.9 µmol/L, respectively). Besides, these drugs or their combination with honey increased insulin levels. Glibenclamide or metformin combined with honey also significantly reduced the elevated levels of creatinine, bilirubin, triglycerides, and VLDL cholesterol. These results indicate that combination of glibenclamide or metformin with honey improves glycemic control, and provides additional metabolic benefits, not achieved with either glibenclamide or metformin alone.
Glucotoxicity contributes to beta-cell dysfunction through oxidative stress. Our previous study demonstrated that tualang honey ameliorated renal oxidative stress and produced hypoglycemic effect in streptozotocin (STZ)-induced diabetic rats. This present study investigated the hypothesis that hypoglycemic effect of tualang honey might partly be due to protection of pancreas against oxidative stress. Diabetes was induced by a single dose of STZ (60 mg/kg; ip). Diabetic rats were randomly divided into two groups and administered distilled water (0.5 ml/d) and tualang honey (1.0 g/kg/d). Similarly, two groups of non-diabetic rats received distilled water (0.5 ml/d) and tualang honey (1.0 g/kg/d). The animals were treated orally for 28 days. At the end of the treatment period, the honey-treated diabetic rats had significantly (p<0.05) reduced blood glucose levels [8.8 (5.8)mmol/L; median (interquartile range)] compared with the diabetic control rats [17.9 (2.6)mmol/L]. The pancreas of diabetic control rats showed significantly increased levels of malondialdehyde (MDA) and up-regulation of superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. Catalase (CAT) activity was significantly reduced while glutathione-S-transferase (GST) and glutathione reductase (GR) activities remained unchanged in the pancreas of diabetic rats. Tualang honey significantly (p<0.05) reduced elevated MDA levels. Honey treatment also restored SOD and CAT activities. These results suggest that hypoglycemic effect of tualang honey might be attributed to its antioxidative effect on the pancreas.
Hyperglycemia exerts toxic effects on the pancreatic beta-cells. This study investigated the hypothesis that the common antidiabetic drugs glibenclamide and metformin, in combination with tualang honey, offer additional protection for the pancreas of streptozotocin (STZ)-induced diabetic rats against oxidative stress and damage. Diabetes was induced in male Sprague Dawley rats by a single dose of STZ (60 mg/kg; ip). Diabetic rats had significantly elevated levels of lipid peroxidation (TBARS), up-regulated activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) while catalase (CAT) activity was significantly reduced. Glibenclamide and metformin produced no significant effects on TBARS and antioxidant enzymes except GPx in diabetic rats. In contrast, the combination of glibenclamide, metformin and honey significantly up-regulated CAT activity and down-regulated GPx activity while TBARS levels were significantly reduced. These findings suggest that tualang honey potentiates the effect of glibenclamide and metformin to protect diabetic rat pancreas against oxidative stress and damage.
Oxidative stress is implicated in the pathogenesis and/or complications of hypertension and/or diabetes mellitus. A combination of these disorders increases the risk of developing cardiovascular events. This study investigated the effects of streptozotocin (60 mg/kg; ip)-induced diabetes on blood pressure, oxidative stress and effects of honey on these parameters in the kidneys of streptozotocin-induced diabetic Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Diabetic WKY and SHR were randomized into four groups and received distilled water (0.5 mL) and honey (1.0 g/kg) orally once daily for three weeks. Control SHR had reduced malondialdehyde (MDA) and increased systolic blood pressure (SBP), catalase (CAT) activity, and total antioxidant status (TAS). SBP, activities of glutathione peroxidase (GPx) and glutathione reductase (GR) were elevated while TAS was reduced in diabetic WKY. In contrast, SBP, TAS, activities of GPx and GR were reduced in diabetic SHR. Antioxidant (honey) treatment further reduced SBP in diabetic SHR but not in diabetic WKY. It also increased TAS, GSH, reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio, activities of GPx and GR in diabetic SHR. These data suggest that differences in types, severity, and complications of diseases as well as strains may influence responses to blood pressure and oxidative stress.
Oxidative stress plays a crucial role in the development of diabetic complications. The aims of this study were to investigate whether honey could reduce hyperglycemia and ameliorate oxidative stress in kidneys of streptozotocin-induced diabetic rats.
Diabetic dyslipidemia contributes to an increased risk of cardiovascular disease. Hence, its treatment is necessary to reduce cardiovascular events. Honey reduces hyperglycemia and dyslipidemia. The reproducibility of these beneficial effects and their generalization to honey samples of other geographical parts of the world remain controversial. Currently, data are limited and findings are inconclusive especially with evidence showing honey increased glycosylated hemoglobin in diabetic patients. It was hypothesized that this deteriorating effect might be due to administered high doses. This study investigated if Nigerian honey could ameliorate hyperglycemia and hyperlipidemia. It also evaluated if high doses of honey could worsen glucose and lipid abnormalities. Honey (1.0, 2.0 or 3.0 g/kg) was administered to diabetic rats for three weeks. Honey (1.0 or 2.0 g/kg) significantly (p < 0.05) increased high density lipoprotein (HDL) cholesterol while it significantly (p < 0.05) reduced hyperglycemia, triglycerides (TGs), very low density lipoprotein (VLDL) cholesterol, non-HDL cholesterol, coronary risk index (CRI) and cardiovascular risk index (CVRI). In contrast, honey (3.0 g/kg) significantly (p < 0.05) reduced TGs and VLDL cholesterol. This study confirms the reproducibility of glucose lowering and hypolipidemic effects of honey using Nigerian honey. However, none of the doses deteriorated hyperglycemia and dyslipidemia.