Takao Katagiri

Coffee and Caffeine Ameliorate Hyperglycemia, Fatty Liver, and Inflammatory Adipocytokine Expression in Spontaneously Diabetic KK-Ay Mice

Epidemiological surveys have demonstrated that habitual coffee consumption reduces the risk of type 2 diabetes. The aim of this work was to study the antidiabetic effect of coffee and caffeine in spontaneously diabetic KK-A(y) mice. KK-A(y) mice were given regular drinking water (controls) or 2-fold diluted coffee for 5 weeks. Coffee ingestion ameliorated the development of hyperglycemia and improved insulin sensitivity. White adipose tissue mRNA levels of inflammatory cytokines (MCP-1, IL-6, and TNFalpha), adipose tissue MCP-1 concentration, and serum IL-6 concentration in the coffee group were lower than the control group. Moreover, coffee ingestion improved the fatty liver. Caffeine ingestion as drinking water also caused an amelioration of hyperglycemia and an improvement of fatty liver. These results suggest that coffee exerts a suppressive effect on hyperglycemia by improving insulin sensitivity, partly due to reducing inflammatory cytokine expression and improving fatty liver. Moreover, caffeine may be one of the effective antidiabetic compounds in coffee.

Eriocitrin ameliorates diet-induced hepatic steatosis with activation of mitochondrial biogenesis

Lemon (Citrus limon) contains various bioactive flavonoids, and prevents obesity and obesity-associated metabolic diseases. We focused on eriocitrin (eriodictyol 7-rutinoside), a powerful antioxidative flavonoid in lemon with lipid-lowering effects in a rat model of high-fat diet. To investigate the mechanism of action of eriocitrin, we conducted feeding experiments on zebrafish with diet-induced obesity. Oral administration of eriocitrin (32 mg/kg/day for 28 days) improved dyslipidaemia and decreased lipid droplets in the liver. DNA microarray analysis revealed that eriocitrin increased mRNA of mitochondrial biogenesis genes, such as mitochondria transcription factor, nuclear respiratory factor 1, cytochrome c oxidase subunit 4, and ATP synthase. In HepG2 cells, eriocitrin also induced the corresponding orthologues, and reduced lipid accumulation under conditions of lipid loading. Eriocitrin increased mitochondrial size and mtDNA content, which resulted in ATP production in HepG2 cells and zebrafish. In summary, dietary eriocitrin ameliorates diet-induced hepatic steatosis with activation of mitochondrial biogenesis.

Coffee and caffeine improve insulin sensitivity and glucose tolerance in C57BL/6J mice fed a high-fat diet.

We have previously demonstrated that coffee and caffeine ameliorated hyperglycemia in spontaneously diabetic KK-Ay mice. This present study evaluates the antidiabetic effects of coffee and caffeine on high-fat-diet-induced impaired glucose tolerance in C57BL/6J mice. C57BL/6J mice fed a high-fat diet were given regular drinking water (control group), or a 2.5-fold-diluted coffee or caffeine solution (200 mg/L) for 17 weeks. The ingestion of coffee or caffeine improved glucose tolerance, insulin sensitivity, and hyperinsulinemia when compared with mice in the control group. The adipose tissue mRNA levels of inflammatory adipocytokines (MCP-1 and IL-6) and the liver mRNA levels of genes related to fatty acid synthesis were lower in the coffee and caffeine groups than those in the control group. These results suggest that coffee and caffeine exerted an ameliorative effect on high-fat-diet-induced impaired glucose tolerance by improving insulin sensitivity. This effect might be attributable in part to the reduction of inflammatory adipocytokine expression.

Effect on Blood Pressure of Daily Lemon Ingestion and Walking

Background. Recent studies suggest that the daily intake of lemon (Citrus limon) has a good effect on health, but this has not been confirmed in humans. In our previous studies, it was observed that people who are conscious of their health performed more lemon intake and exercise. An analysis that took this into account was required. Methodology. For 101 middle-aged women in an island area in Hiroshima, Japan, a record of lemon ingestion efforts and the number of steps walked was carried out for five months. The change rates (Δ%) of the physical measurements, blood test, blood pressure, and pulse wave measured value during the observation period were calculated, and correlations with lemon intake and the number of steps walked were considered. As a result, it was suggested that daily lemon intake and walking are effective for high blood pressure because both showed significant negative correlation to systolic blood pressure Δ%. Conclusions. As a result of multiple linear regression analysis, it was possible that lemon ingestion is involved more greatly with the blood citric acid concentration Δ% and the number of steps with blood pressure Δ%, and it was surmised that the number of steps and lemon ingestion are related to blood pressure improvement by different action mechanisms.

Blood Citric Acid Density Relationships with Steps and Lifestyle-related Disease Indices

[Purpose] This study examined factors affecting blood citric acid density in relation to lifestyle-related disease prevention. [Subjects] The subjects were 99 elderly and middle-aged women. Those receiving medication were excluded ?. [Method] We compared factors affecting life-style related diseases in two groups by quantity of blood citric acid density change. [Result] Significant differences between the groups were found in weight, BMI, degree of obesity, maximum blood pressure level, pulse pressure, RBC, Hb, Ht%, and LDL cholesterol. [Conclusion] The citric acid density results suggest that just a modest amount of exercise is effective at burning off fat.