Nutrition Research

Antidiabetic effects of fermented soybean products on type 2 diabetes

Dae Young Kwon, James W. Daily, Hyun Jin Kim, Sunmin Park — 2010-01-01

Abstract: Historically, the incidence of type 2 diabetes has been lower in Asian populations compared with those in Western countries. One possible reason for the lower incidence among Asians is that they consume fermented soybean products, which are unique to the traditional Asian diet. Some have hypothesized that dietary phytoestrogens and soy peptides in fermented soybean foods consumed in traditional Asian diets may help prevent and slow the progression of type 2 diabetes. This review evaluates the existing evidence from animal studies and clinical and epidemiologic investigations on fermented soybeans in the prevention and treatment of type 2 diabetes. Nutritional studies performed in animals and intervention studies with humans suggest that the ingestion of soy protein with isoflavones improves glucose control and reduces insulin resistance. Korean fermented soybean products such as doenjang, kochujang, and chungkookjang contain alterations in the structures and content of isoflavonoids and small bioactive peptides, which are produced during fermentation. Several studies revealed improvements in insulin resistance and insulin secretion with the consumption of these fermented products. Therefore, fermented soybean products may help prevent or attenuate the progression of type 2 diabetes. Although the lack of human intervention trials does not permit definitive conclusions, the evidence does suggest that fermented soy products may be better for preventing or delaying the progression of type 2 diabetes compared with nonfermented soybeans.

Addition of whole, semiskimmed, and skimmed bovine milk reduces the total antioxidant capacity of black tea

Lisa Ryan, Sébastien Petit — 2010-01-01

Abstract: Epidemiological studies have shown that populations consuming fruits, vegetables, tea, cocoa, and red wine have lower incidences of cardiovascular disease, certain cancers, and eye disease. These health effects have largely been attributed to the polyphenol content of the foods and drinks studied. Black tea is rich in a range of polyphenolic compounds that could potentially have health-promoting properties. The scale of consumption of tea in the United Kingdom means that it could be an appropriate vehicle for increasing the antioxidant activity and polyphenol content of human plasma. However, it is common practice in the United Kingdom to add milk to tea, and some studies have suggested that this may decrease the overall antioxidant capacity. The objective of the present study was to analyze and compare the antioxidant capacity of 5 brands of tea and to test the hypothesis that the addition of different volumes of whole milk, semiskimmed, and skimmed milk may affect the antioxidant capacity. Each of the teas analyzed was a significant source of antioxidants. The addition of 10, 15, and 20 mL of whole, semiskimmed, and skimmed bovine milk to a 200-mL tea infusion decreased the total antioxidant capacity of all the brands of tea. Skimmed milk decreased the total antioxidant capacity of the tea infusion significantly (P < .05) more than either whole milk or semiskimmed milk. We conclude that black tea is a valuable source of antioxidants and that the effect of milk on the total antioxidant capacity may be related to the fat content of the milk.

Optimal cutoff value of high-density lipoprotein cholesterol for predicting coronary artery disease in Taiwanese population

2010-01-01

Abstract: The aim of this study was to determine if an optimal cutoff value for high-density lipoprotein cholesterol (HDL-C) can be obtained for predicting the risk of coronary artery disease (CAD) in Taiwanese population. We conducted a hospital-based case-control study. Patients identified by cardiac catheterization as having at least 70% stenosis of one major coronary artery and without diabetes were assigned to the case group (n = 184). The control group (n = 516) was composed of healthy individuals with normal blood biochemical values. The multiple logistic regression analysis was used to evaluate linear association between low-density lipoprotein cholesterol (LDL-C), HDL-C, or LDL-C/HDL-C ratio and CAD while adjusting for confounders. Furthermore, receiver operating characteristic curve analyses were constructed. Individuals with an HDL-C value less than or equal to 60 mg/dL had the significantly highest odds ratio (7.72; 95% confidence interval, 2.70-22.07) after adjusting for LDL-C, LDL-C/HDL-C ratio, and other potential confounders. The areas under the curves were 0.85 and 0.61 for HDL-C and LDL-C, respectively. The optimal cutoff value of HDL-C for predicting the presence of CAD was 46 mg/dL. Sensitivity and specificity using this cutoff value were 71.74% and 81.40%, respectively. Our findings suggest that subjects with lower levels of HDL-C have a much higher risk of CAD than those with higher levels of LDL-C. The optimal cutoff value for HDL-C in predicting the risk of CAD is considered as 46 mg/dL in the Taiwanese population.

A group of Midwestern university students needs to improve their oral hygiene and sugar/pop consumption habits

Tami E. Luebke, Judy A. Driskell — 2010-01-01

Abstract: Poor oral hygiene and sugar/pop consumption practices are detrimental to one's overall health. College women were hypothesized to have better oral hygiene habits and to consume less sugar/pop than men and that the students' habits would be different from those the students had before college. These habits of students at a Midwestern university were evaluated by sex. The volunteers included 105 men and 91 women. Three quarters of the students reported brushing their teeth at least the recommended twice daily, with women brushing their teeth more often. About a third of the students flossed at least the recommended once daily. Not quite a third of the students reported brushing and flossing their teeth more often than they did before college. More than a third reported using mouth rinses 4 or more times weekly, with 13% reporting using a fluoride-containing mouth rinse. More than 60% reported using fluoride-containing toothpaste. Slightly more than a third reported drinking fluoridated water in their younger years. A larger percentage of women than men reported that diet pop was their pop of choice. More than two thirds of the students that drank pop indicated that regular pop was their favorite. Most of the students reported consuming sugary foods more than once daily, but they indicated that most of these sugars were not sticky. Few differences were observed in oral hygiene and sugar/pop consumption habits of these college students by sex. Nutritionists and other health professionals should work cooperatively in helping individuals improve their oral hygiene and sugar/pop consumption habits.

Dietary green tea extract increases phase 2 enzyme activities in protecting against myocardial ischemia-reperfusion

Masoumeh Akhlaghi, Brian Bandy — 2010-01-01

Abstract: Green tea catechins are dietary antioxidant compounds that have been shown to protect against myocardial ischemia-reperfusion (IR) injury. Considering reports that catechins can induce phase 2 enzymes in cultured cells and some organs, we hypothesized that part of the protection to heart against IR injury may involve elevation of phase 2 enzyme activities. Rats were fed for 10 days with either control diet (sham and control groups) or the diet mixed with 0.25% green tea extract. At the end of 10 days, hearts were excised and subjected to global ischemia for 20 min followed by reperfusion for 2 hours. The hearts were compared for indices of cell death, oxidative stress, and phase 2 enzyme activities. Hearts from the green tea group had a 65% to 85% decrease in markers of apoptosis, a tendency to higher total glutathione, and higher activities of the phase 2 enzymes glutamate cysteine ligase and quinone reductase. The results support a possible involvement of phase 2 enzymes in the protection by green tea catechins against myocardial IR injury.

Dietary (1→3), (1→4)-β-d-glucans from oat activate nuclear factor-κB in intestinal leukocytes and enterocytes from mice

2010-01-01

Abstract: Dietary components, like β-glucans, can modulate the intestinal immune response. We previously showed that fecal water enriched with oat β-glucan stimulated the cytokine-induced immune response of enterocytes. It is, however, unclear whether β-glucans activate nuclear factor-κB (NF-κB) pathways in the intestine in vivo and if so, whether enterocytes, intestinal leukocytes, or both respond to β-glucans. We evaluated the effects of an oral gavage of 3 mg dietary oat (1→3), (1→4)-β-d-glucans that was administered twice daily during 3.5 days on intestinal NF-κB transactivation and subsequent cytokine production of intestinal leukocytes and enterocytes in 16 NF-κB reporter mice. We hypothesized that oat β-glucan activates the central immune transcription factor NF-κB and increased cytokine secretion, as we previously reported immune stimulating effects by oat β-glucan. We found that mice that were administered oat β-glucans (n = 8) showed an increased intestinal NF-κB transactivation in leukocytes (P = .021) and enterocytes (P = .012), particularly in the proximal part of the small intestine (ileum), as compared to placebo mice (n = 8). Surprisingly, NF-κB was not activated in the colon. Furthermore, the level of interleukin 12 was increased in intestinal lysates from all compartments, whereas the concentration of interferon γ was decreased in the proximal small intestine (P = .046). Finally, tumor necrosis factor α showed a trend toward a reduced production in the colon (P = .057). Because we have earlier shown that human enterocyte cell lines do not express the β-glucan receptor dectin-1 in vitro, we now conclude that after consumption, dietary oat β-glucans most likely firstly activate the intestinal leukocytes, which in turn increases cellular activation of enterocytes.

White button mushroom (Agaricus bisporus) lowers blood glucose and cholesterol levels in diabetic and hypercholesterolemic rats

2010-01-01

Abstract: Agaricus bisporus (white button mushroom; WBM) contains high levels of dietary fibers and antioxidants including vitamin C, D, and B12; folates; and polyphenols that may provide beneficial effects on cardiovascular and diabetic diseases. The objective of this study was to examine the hypothesis that intake of the fruiting bodies of WBM regulates anticholesterolemic and antiglycemic responses in rats fed a hypercholesterolemic diet (0.5% cholesterol; 14% fat) and rats with type 2 diabetes induced by injection of streptozotocin (STZ) (50 mg/kg body weight), respectively. The STZ-induced diabetic male Sprague-Dawley rats fed the Agaricus bisporus powder (ABP; 200 mg/kg of body weight) for 3 weeks had significantly reduced plasma glucose and triglyceride (TG) concentrations (24.7% and 39.1%, respectively), liver enzyme activities, alanine aminotransferase and aspartate aminotransferase (11.7% and 15.7%, respectively), and liver weight gain (P < .05). In hypercholesterolemic rats, oral feeding of ABP for 4 weeks resulted in a significant decrease in plasma total cholesterol (TC) and low-density lipoprotein (LDL) (22.8% and 33.1%, respectively) (P < .05). A similar significant decrease in hepatic cholesterol and TG concentrations was observed (36.2% and 20.8%, respectively) (P < .05). Decrease in TC, LDL, and TG concentrations was accompanied by a significant increase in plasma high-density lipoprotein concentrations. It was concluded that A bisporus mushroom had both hypoglycemic and hypolipidemic activity in rats.

Icariin protects murine chondrocytes from lipopolysaccharide-induced inflammatory responses and extracellular matrix degradation

Man-Hai Liu, Jui-Sheng Sun, Shaio-Wen Tsai, Shiow-Yunn Sheu, Ming-Hong Chen — 2010-01-01

Abstract: Septic arthritis is an inflammatory arthropathy characterized by degeneration of articular cartilage. Icariin, the main active flavonoid glucoside isolated from Epimedium pubescens, is used as antirheumatics (or antiinflammatory), tonics, and aphrodisiacs in traditional Chinese medicine. In this study, we used lipopolysaccharide (LPS) to simulate the in vitro inflammatory response of chondrocytes during septic arthritis. Our hypothesis is that the icariin can protect chondrocytes from LPS-induced inflammation and extracellular matrix degradation. The inflammation of neonatal mice chondrocytes was induced by LPS and the antiinflammatory effects were examined. The synthesis of nitric oxide was analyzed, whereas the titer of glycosaminoglycan and total collagen were measured and the gene expressions (including inducible nitric oxide synthase [iNOS], matrix metalloproteinase [MMP]–1, MMP-3, and MMP-13) were evaluated. The results showed that the viability of chondrocytes, extracellular matrix synthesis, was significantly decreased, whereas nitric oxide synthesis was significantly increased in the presence of 10−5 g/mL LPS. Icariin pretreatment can partially reverse these effects. The up-regulated expressions of MMP-1, 3, 13, cyclooxygenase-2 (COX-2), and iNOS genes by LPS treatment were also significantly down-regulated by the pretreatment of icariin to 1.8%, 0.056%, 7.7%, 3.1%, and 5.3% of the LPS-positive control sample, respectively. Our results demonstrate that icariin is a safe anabolic agent of chondrocytes. Icariin may exert its protective effects through inhibition of nitric oxide and MMP synthesis, and may then reduce the extracellular matrix destruction.

Tomato powder is more protective than lycopene supplement against lipid peroxidation in rats

2010-01-01

Abstract: The hypothesis that tomato powder (TP) is more protective than lycopene-beadlet (LB) treatment in rats fed with or without H2O2 was tested by comparing their beneficial effects on serum and hepatic lipids, peroxidation product (malondialdehyde [MDA]), and serum lipoproteins. In groups receiving no H2O2, TP and LB similarly lowered MDA, a major lipid peroxidation product, moderately in the serum but markedly in the liver, more than their respective controls. Hydrogen peroxide consumption elevated liver and serum MDA levels similarly among all treatments, but induced no increase in serum MDA for the TP group, which indicated a stronger protection against lipid peroxidation by TP than by LB treatment. Although the TP and LB diets provided equal amounts of lycopene, serum, and liver lycopene levels for treatments with or without H2O2, they were markedly elevated in TP but still higher in LB group than controls. This indicated a greater lycopene bioavailability in LB than TP. Importantly, TP and LB treatments with or without H2O2 consumption lowered serum total cholesterol and triglycerides by one fifth, as well as decreased serum low-density lipoprotein cholesterol by more than one third of their respective levels in controls. Similarly, liver total cholesterol was markedly lowered (>1/3) by TP or LB treatment, but liver triglycerides were lowered to one fourth by only TP treatment, of the levels in their respective controls. Thus, TP appeared to be more protective because of its additional ability to prevent the H2O2-induced rise in serum MDA and seemed to lower liver triglycerides more than LB treatment.

Inhibition by licorice flavonoid oil of glutathione S-transferase–positive foci in the medium-term rat hepatocarcinogenesis bioassay

2010-01-01

Abstract: Licorice flavonoid oil (LFO) is a new functional food ingredient consisting of hydrophobic licorice polyphenols in medium-chain triglycerides. Recently, it was reported that licorice and its derivatives have anticarcinogenic activity in some types of tumors. However, the anticarcinogenic activity has not been identified in the liver, which is a major target organ for carcinogenesis in human. Therefore, we hypothesized that LFO has antihepatocarcinogenic activity, and we tested this hypothesis using the rat medium-term liver bioassay for carcinogens. Six-week-old male F344 rats (15 animals/group) received N-diethylnitrosamine (200 mg/kg by intraperitoneal injection) to initiate carcinogenesis. From the second week after initiation, animals received a 6-week regimen of either LFO concentrate solution (0, 150, 300, or 600 mg/kg) intragastrically or phenobarbital sodium salt in the diet (500 ppm) as a positive control. During the third week after initiation, animals were subjected to a two-thirds partial hepatectomy. During the eighth week of the treatment period, liver samples were taken from animals and examined immunohistochemically for expression of glutathione S-transferase placental form. No increase in the number of glutathione S-transferase placental form–positive liver foci was observed in all LFO groups compared with the negative control (solvent) group, and the number of foci in the 600 mg/kg LFO group was significantly lower than that in the negative control group. These results indicate that LFO concentrate solution has a significant inhibitory effect on liver carcinogenesis at 600 mg/kg.