The epidemic of type 2 diabetes and impaired glucose tolerance is one of the main causes of morbidity and mortality worldwide. In both disorders, tissues such as muscle, fat and liver become less responsive or resistant to insulin. This state is also linked to other common health problems, such as obesity, polycystic ovarian disease, hyperlipidaemia, hypertension and atherosclerosis. The pathophysiology of insulin resistance involves a complex network of signalling pathways, activated by the insulin receptor, which regulates intermediary metabolism and its organization in cells. But recent studies have shown that numerous other hormones and signalling events attenuate insulin action, and are important in type 2 diabetes.

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Insulin signalling and the regulation of glucose and lipid metabolism

Obesity is a principal causative factor in the development of metabolic syndrome. Here we report that increased oxidative stress in accumulated fat is an important pathogenic mechanism of obesity-associated metabolic syndrome. Fat accumulation correlated with systemic oxidative stress in humans and mice. Production of ROS increased selectively in adipose tissue of obese mice, accompanied by augmented expression of NADPH oxidase and decreased expression of antioxidative enzymes. In cultured adipocytes, elevated levels of fatty acids increased oxidative stress via NADPH oxidase activation, and oxidative stress caused dysregulated production of adipocytokines (fat-derived hormones), including adiponectin, plasminogen activator inhibitor-1, IL-6, and monocyte chemotactic protein-1. Finally, in obese mice, treatment with NADPH oxidase inhibitor reduced ROS production in adipose tissue, attenuated the dysregulation of adipocytokines, and improved diabetes, hyperlipidemia, and hepatic steatosis. Collectively, our results suggest that increased oxidative stress in accumulated fat is an early instigator of metabolic syndrome and that the redox state in adipose tissue is a potentially useful therapeutic target for obesity-associated metabolic syndrome.

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Increased oxidative stress in obesity and its impact on metabolic syndrome

Adiponectin (Ad) is a hormone secreted by adipocytes that regulates energy homeostasis and glucose and lipid metabolism. However, the signaling pathways that mediate the metabolic effects of Ad remain poorly identified. Here we show that phosphorylation and activation of the 5'-AMP-activated protein kinase (AMPK) are stimulated with globular and full-length Ad in skeletal muscle and only with full-length Ad in the liver. In parallel with its activation of AMPK, Ad stimulates phosphorylation of acetyl coenzyme A carboxylase (ACC), fatty-acid oxidation, glucose uptake and lactate production in myocytes, phosphorylation of ACC and reduction of molecules involved in gluconeogenesis in the liver, and reduction of glucose levels in vivo. Blocking AMPK activation by dominant-negative mutant inhibits each of these effects, indicating that stimulation of glucose utilization and fatty-acid oxidation by Ad occurs through activation of AMPK. Our data may provide a novel paradigm that an adipocyte-derived antidiabetic hormone, Ad, activates AMPK, thereby directly regulating glucose metabolism and insulin sensitivity in vitro and in vivo.

Adiponectin stimulates glucose utilization and fatty-acid oxidation by activating AMP-activated protein kinase

TLR4 is the receptor for LPS and plays a critical role in innate immunity. Stimulation of TLR4 activates proinflammatory pathways and induces cytokine expression in a variety of cell types. Inflammatory pathways are activated in tissues of obese animals and humans and play an important role in obesity-associated insulin resistance. Here we show that nutritional fatty acids, whose circulating levels are often increased in obesity, activate TLR4 signaling in adipocytes and macrophages and that the capacity of fatty acids to induce inflammatory signaling in adipose cells or tissue and macrophages is blunted in the absence of TLR4. Moreover, mice lacking TLR4 are substantially protected from the ability of systemic lipid infusion to (a) suppress insulin signaling in muscle and (b) reduce insulin-mediated changes in systemic glucose metabolism. Finally, female C57BL/6 mice lacking TLR4 have increased obesity but are partially protected against high fat diet-induced insulin resistance, possibly due to reduced inflammatory gene expression in liver and fat. Taken together, these data suggest that TLR4 is a molecular link among nutrition, lipids, and inflammation and that the innate immune system participates in the regulation of energy balance and insulin resistance in response to changes in the nutritional environment.

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TLR4 links innate immunity and fatty acid–induced insulin resistance

Adipose tissue as an endocrine organ.

Objective The primary goal was to evaluate the validity of food photographic estimation for nutritional assessment compared with weighed food record (WFR). Methods We evaluated the validity and reproducibility of photographic estimation of foods provided in evacuation shelters. We analyzed 35 meals served at 12 shelters in Kumamoto Prefecture in Japan, affected by a heavy rain disaster in 2020. In this context, we compared 21 senior students' portion size estimation by food photographs to WFR. In addition, we assigned five meals for each of the 21 senior students, and the same meal photograph was estimated by three students to test reproducibility. Results No statistically significant difference was detected between the two methods regarding energy, the total grams of meal, the protein, and vitamins B1, B2, and C, except for salt. In addition, the students who never self-cooked underestimated the total grams. Conclusion Food photographic estimation could simplify the nutritional assessment in evacuation shelters. However, unclear photographs and food items served by weight could weaken the estimation accuracy. According to previous studies and the applied postestimation questionnaire, photographs taken from specified angles and reference food photobooks for portion size estimation may improve accuracy.

https://doi.org/10.3934/publichealth.2023013

Validity and reproducibility of food photographic estimation for evaluating meals in evacuation shelters

Disaster and space environments are similar in that they are closed environment, with limited lifelines. Here, we examined the similarity between disaster food and space food, to explore interactive problem-solving of food support for disaster and space environments. The Japan Disaster Food Certification Standards (Japan Disaster Food Society) and the Japanese Space Food Certification Standards (Japan Aerospace Exploration Agency) requirements and certified products, which were posted on the websites as of June 16, 2021, were compared. Certified products were classified into "staple foods," "main and/or side dishes," "milk and dairy products," "fruits," "confectionery and favorite beverages," "condiments," "dietary supplements," and "sets." Certification standards involved six items for Japan Disaster Food and eight items for Japanese Space Food. Most standards were similar. Concretely, both standards demanded room temperature storage, tough packaging and hygiene management in facilities. Both emphasized habitual food and easy eating. However, the best-by date was ≥6 mo for Japan Disaster Food, but ≥1.5 y for Japanese Space Food. In addition, Japanese Space Food required noted nutritious, food hygienic, eatable in space, cookable by specific equipment, endurable pressure by launch, and domestically produced food. There were 171 and 47 products of Japan Disaster Food and Japanese Space Food, respectively. Staple foods (pregelatinized rice, etc.) and main and/or side dishes were commonest among Japan Disaster Foods and Japanese Space Foods, respectively. It is possible to utilize of Space Food as Disaster Food, but there are some issues that must be cleared before "utilization of Disaster Food as Space Food."

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Similarities between Disaster Food and Space Food.

We have suggested "Revised Nutritional Reference Values for Feeding at Evacuation Shelters" (Revised RV) as a daily nutritional recommendation for meals served at evacuation shelters where poor diets had been reported. Since there are no meal examples to satisfy the Revised RV, our objectives were, for the future meal provision, to develop nutritionally adequate meal plans using the foods served at shelters in the past and to examine if the Revised RV could be met by changing combination of foods available.In this case study using secondary data, we analyzed food weights of 86 meals served and recorded at 12 shelters after the heavy rains in July 2020. We obtained these data from Kumamoto Prefecture that was damaged and asked us dietary assessment for nutrition assistance. Foods were classified into 3 types according to the check mark in the record sheets: food aid (commercial packaged food), boxed meal, and hot meal service. We counted serving frequency of each food and analyzed nutritional differences by their combinations. Menus were devised by choosing foods that were served more frequently or were more nutritious among those served at shelters. The target values for one meal were set at 1/3 of the Revised RV for energy, protein, vitamins B1, B2, and C, and salt.None of the meals served in the shelters satisfied the target. We created 2 menus using food aid only: (#1 curry doughnut, milk with long shelf-life, and orange jelly) and (#2 salmon rice ball, ham and cheese sandwich, and vegetable juice); 1 menu by combination of boxed meal and food aid: (#3 boxed meal and vegetable juice); and 2 menus by combination of hot meal service and food aid: (#4 chicken meatball soup, packaged tofu, soy sauce, preprocessed white rice, and bottled green tea) and (#5 bamboo shoots rice, chicken and vegetable miso soup, and bottled green tea). Planned menus generally contained more energy, protein, and vitamins and less salt than the meals served. Their vitamin C contents were especially higher.Nutritionally adequate meals could be planned by changing the combination of foods available in shelters. 

https://bmcnutr.biomedcentral.com/counter/pdf/10.1186/s40795-023-00726-9

Meal plans for meeting the reference values using food items available in shelters

The Japanese Ministry of Health, Labour and Welfare compiled an Excel sheet — “Simple simulator for calculating nutritional food stocks in preparation for large-scale disasters” (Simulator). We examined the level of recognition and use of the Simulator by local governments and identified the points for its improvement. In stage 1, we surveyed local government personnel who participated in the “Workshop for nutrition assistance during large-scale disasters” held in November 2020 (n = 458; 313 responded) with an online questionnaire on the use of the Simulator and associated issues. Stage 2 involved group interviews with 15 public health dietitians who had been involved in food assistance during past natural disasters to identify points for improving the Simulator and the problems with food assistance during natural disasters. In stage 1, 233 responders (74.4%) confirmed their awareness of the existence of the Simulator. While 85 individuals (36.6%) used the Simulator, 63 individuals (74.1%) confirmed that they would use it in the future to plan and evaluate local government stocks. In stage 2, multiple comments regarding the Simulator's applicability and improvement in a realistic situation were collected. In order for the administrative staff in charge of disaster management to understand the nutritional importance of stockpiling main/side dishes, it was suggested that specific combinations of foods that meet the required amounts should be shown and that visualization using food products and the number of people covered by stockpiled foods may be easier to understand than pure nutritional values.

https://doi.org/10.3934/publichealth.2022051

Attitudes toward using “Simple simulator for calculating nutritional food stocks in preparation for large-scale disasters” among local governmental personnel and public health dietitians in Japan: An explanatory mixed methods study

Nobuyo Tsuboyama-Kasaoka

Papers

Validity and reproducibility of food photographic estimation for evaluating meals in evacuation shelters

Similarities between Disaster Food and Space Food.

Meal plans for meeting the reference values using food items available in shelters

Attitudes toward using “Simple simulator for calculating nutritional food stocks in preparation for large-scale disasters” among local governmental personnel and public health dietitians in Japan: An explanatory mixed methods study