Oxidized Pork Induces Disorders of Glucose Metabolism in Mice.

SCOPE: Consumption of red meat, particularly processed red meat, has been reported to be associated with type 2 diabetes risk, and oxidized proteins and amino acids may be involved in this process. This study explores the effects of pork with varying degrees of oxidative injury caused by cooking on glucose metabolism in mice. METHODS AND RESULTS: Cooked pork is freeze-dried to prepare animal feed. Mice are fed either a control diet (CON), a low- (LOP), or a high-oxidative injury pork diet (HOP) for 12 weeks. Intake of HOP causes hyperglycemia, hypoinsulinemia, and impaired glucose tolerance, indicating a glucose metabolism disorder. Accumulation of oxidation products increases oxidative stress and inflammatory response, which impairs pancreatic islet ß cells function and reduces insulin secretion. Moreover, HOP-mediated hyperglycemia can be partly attributed to elevated hepatic glucose output, as indicated by increased gluconeogenesis and glycogenolysis, and decreased glycolysis and glycogen content. Changes in these processes may be regulated by reduced insulin levels and suppression of the insulin receptor substrate-1 (IRS-1)/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway and its downstream signaling molecules. CONCLUSION: HOP intake induces disorders of glucose metabolism by impairing pancreatic insulin secretion and increasing hepatic glucose output. Protein oxidation plays a key role in abnormal glucose metabolism induced by HOP.

High intake of chicken and pork proteins aggravates high-fat-diet-induced inflammation and disorder of hippocampal glutamatergic system.

High-fat diets have been associated with neurodegenerative diseases, which are also largely related to the type and amount of dietary proteins. However, to our knowledge, it is little known how dietary proteins affect neurodegenerative changes. In this study, we investigated the effects of dietary proteins in a high-fat diet on hippocampus functions related to enteric glial cells (EGCs) in Wistar rats that were fed either 40% or 20% (calorie) casein, chicken protein or pork protein for 12 weeks (n=10 each group). Inflammatory factors, glutamatergic system, EGCs, astrocytes and nutrient transporters were measured. A high-chicken-protein diet significantly increased the levels of systemic inflammatory factors, Tau protein and amyloid precursor protein mRNA level in the rat hippocampus. The type and level of dietary proteins in high-fat diets did not affect the gene expression of glial fibrillary acidic protein and α-synuclein (P>.05), indicating a negligible effect on astrocyte activity. However, the high-protein diets up-regulated glutamate transporters compared with the low-protein diets (P<.05), while they reduced the γ-aminobutyric acid content in high-chicken and -pork-protein diets (P<.05). Thus, compared with a low-protein diet (20%), a high-chicken or -pork-protein diet (40%) under a high-fat background could alter the balance between glutamatergic system and neurotransmitter and have a stronger effect on the interactions between hippocampal glutamatergic system and EGCs.

Consumer knowledge and practices to pork safety in two Taenia solium cysticercosis endemic districts in Eastern Cape Province of South Africa.

BACKGROUND: Globally, Taenia solium can cause cysticercosis in humans (including neurocysticercosis) and in pigs through ingestion of eggs and taeniasis in humans through ingestion of raw/undercooked pork contaminated with mature cysts. It is now recognised globally as one of the most prevalent food-borne parasitic diseases. The majority of cases have been reported in developing countries where consumption of food produced under unhygienic conditions is prevalent, exacerbated by lack of food safety education. The aim of this study was to determine the knowledge and practices of consumers towards pork safety in two districts of the Eastern Cape Province of South Africa, where T. solium cysticercosis is endemic in pigs and humans. METHODS: Three-hundred-and-sixty-one (361) participants were conveniently interviewed on consumer knowledge (harmfulness of T. solium cysticercosis, ability to identify cysts, trustworthiness of registered butcheries and legal requirements) and practices (storage of pork and method(s) of cooking pork safely) through a structured questionnaire. Chi-square for association of variables was used to compare differences in the districts. RESULTS: Overall, 73.1% of the study group from both districts agreed that pork forms an important part of their diet. Consumers (54.2%: 189/349) agreed that pork infected with T. solium cysts could be harmful, and 57.3% (188/328) indicated their inability to identify T. solium cysts in pork when slaughtered at home. Although 69.5% (234/352) trusted pork bought from butcheries, only 52.2% (187/358) were aware that butcheries must present a registration certificate in order to operate. This coincides with the fact that very few (< 10%) were aware of the legal requirements in terms of disease control, slaughter and food preparation. Most consumers (88.7%: 268/302) kept pork in the fridge and only 11.3% (34/302) kept it in a freezer (p = 0.02). Although not significantly different between the districts (p = 0.15), consumers in Alfred Nzo (71.4%: 152/213) and OR Tambo (61.2%: 74/12) mostly cooked pork as a stew, followed by braai/barbeque and frying or baking. This was in line with the fact that consumers in Alfred Nzo (79%: 147/186) and OR Tambo (80.8%: 120) preferred well-cooked pork; the main reason for this was the belief that cooking kills germs (43.6%: 121/277) followed by rendering the meat tasty (26.4%: 73/277). CONCLUSIONS: Consumers surveyed in the two districts were somewhat aware that T. solium cysticercosis could be harmful, although some were not able to identify T. solium cysts in pork. They also lacked sufficient knowledge regarding butchery certification and other legal requirements related to disease control, slaughter and food preparation. Practices related to cooking have the potential to promote the transmission of human taeniasis and the fact that most respondents preferred stewed pork could be a positive sign, as the cysts are destroyed during the cooking process. Results from this study are useful for the development of a control and prevention strategy targeted towards consumers, and the creation of awareness of food safety, with special emphasis on T, solium cysticercosis.

Oxidized Pork Induces Oxidative Stress and Inflammation by Altering Gut Microbiota in Mice.

SCOPE: Reduced digestibility of foods containing oxidized proteins and the subsequent excessive accumulation of undigested components in the colon may cause changes in the intestinal flora composition. This study evaluates the characteristics of this change and the potential adverse effects on organisms. METHODS AND RESULTS: Pork is cooked using sous-vide or at high temperature and pressure (HTP), then freeze-dried, resulting in different levels of oxidized damage. Mice are fed diets containing low- (LOP), medium- (MOP), or high-oxidative damage pork (HOP) for 12 weeks. HOP intake increases mice body weight, induces inflammatory response, and causes oxidative stress, as indicated by the accumulation of oxidative products. Increased serum LPS levels and downregulation of tight junction-related genes in the mucosa suggest mucosal barrier damage. Alterations in the cecal microbiota include reduced relative abundance of the mucin-degrading bacteria Akkermansia, beneficial bacteria Lactobacillus and Bifidobacterium, and H2 S-producing bacteria Desulfovibrio and increased relative abundance of the pro-inflammatory bacteria Escherichia-Shigella and pathobiont Mucispirillum. CONCLUSION: HOP intake causes the accumulation of oxidative products, increases body weight, damages the intestinal barrier, and induces oxidative stress and inflammatory response, likely by altering gut microbiota through protein oxidation (POX).