Nitrate Content of Foods — Public Health Implications

Nitrate, nitrite and nitrosamines in the global food supply

Inorganic nitrate provided by either nitrate salts or food supplements may improve cardiometabolic health. However, current methods to assess dietary nitrate, nitrite and nitrosamine consumption are inadequate. The purpose of this study was to develop a reference database to estimate the levels of nitrate, nitrite and nitrosamines in the global food supply. A systematic literature search was undertaken; of the 5,747 articles screened, 448 met the inclusion criteria. The final database included data for 1,980 food and beverages from 65 different countries. There were 5,105 unique records for nitrate, 2,707 for nitrite, and 954 for nitrosamine. For ease of use, data were sorted into 12 categories; regarding nitrate and nitrite concentrations in food and beverages, 'vegetables and herbs' were most reported in the literature (n = 3,268 and n = 1,200, respectively). For nitrosamines, 'protein foods of animal origin' were most reported (n = 398 records). This database will allow researchers and practitioners to confidently estimate dietary intake of nitrate, nitrite and nitrosamines. When paired with health data, our database can be used to investigate associations between nitrate intake and health outcomes, and/or exercise performance and could support the development of key dietary nitrate intake guidelines.

COX-2/iNOS regulation during experimental hepatic injury and its mitigation by cloudy apple juice

A number of enzymes and transcription factors have been correlated with disease etiology. In this study, involvement of cyclooxygenase-2 and inducible-nitric oxide synthase is examined during diethylnitrosamine (DEN)-induced hepatic injury and cloudy apple juice (CAJ) supplementation. Liver injury was administered in rats by single dose of DEN (10 ml/kg bwt of 1% DEN), while 10 ml/kg bwt CAJ daily was given after 2 h of latency in DEN-treated animals for two weeks. CAJ was characterized by HPLC and subsequently examined for antioxidant power. During the course of treatment liver function, collagen (hydroxyproline), malondialdehyde, protein oxidation, antioxidant enzymes, ATPases, nitrite levels were investigated along with liver histopathology and electron microscopy. COX-2 and iNOS proteins were also localized in liver specimens. The results demonstrated rich polyphenols and antioxidant activity in CAJ. CAJ supplementation significantly restored liver biochemistry and anatomy as revealed by the refurbished investigated parameters. CAJ treatment also declined COX-2 and iNOS activities in injured animals. Electron microscopy demonstrated rejuvenated hepatocytes, Kupffer cells, RER, mitochondria and nucleus in CAJ supplemented animals. The novel outcomes of this study suggest that CAJ potentiates hepatoprotection by stimulating antioxidant power and regulating the COX-2 and iNOS proteins in the liver during experimental liver injury.