Nutritional epidemiology in the context of nitric oxide biology: A risk-benefit evaluation for dietary nitrite and nitrate
ABSTRACT The discovery of the nitric oxide (NO) pathway in the 1980s represented a critical advance in understanding cardiovascular disease, and today a number of human diseases are characterized by NO insufficiency. In the interim, recent biomedical research has demonstrated that NO can be modulated by the diet independent of its enzymatic synthesis from l-arginine, e.g., the consumption of nitrite- and nitrate-rich foods such as fruits, leafy vegetables, and cured meats along with antioxidants. Regular intake of nitrate-containing food such as green leafy vegetables may ensure that blood and tissue levels of nitrite and NO pools are maintained at a level sufficient to compensate for any disturbances in endogenous NO synthesis. However, some in the public perceive that dietary sources of nitrite and nitrate are harmful, and some epidemiological studies reveal a weak association between foods that contain nitrite and nitrate, namely cured and processed meats, and cancer. This paradigm needs revisiting in the face of undisputed health benefits of nitrite- and nitrate-enriched diets. This review will address and interpret the epidemiological data and discuss the risk-benefit evaluation of dietary nitrite and nitrate in the context of nitric oxide biology. The weak and inconclusive data on the cancer risk of nitrite, nitrate and processed meats are far outweighed by the health benefits of restoring NO homeostasis via dietary nitrite and nitrate. This risk/benefit balance should be a strong consideration before there are any suggestions for new regulatory or public health guidelines for dietary nitrite and nitrate exposures.
Full-textDOI: · Available from: James Coughlin, Jul 25, 2014
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ABSTRACT: A national survey of the nitrate ( NO 3-) and nitrite ( NO 2-) concentrations in raw and highly consumed vegetables available at retail in the United States was conducted. A total of 194 samples of fresh broccoli, cabbage, celery, lettuce, and spinach categorized as conventional or organic by label were collected from 5 major cities in different geographic regions of the United States and analyzed to determine NO 3- and NO 2- concentrations. There were no differences in the mean NO 2- values of conventional compared with organic vegetables taken from the 5 metropolitan areas. However, significant differences in mean pairwise comparisons between some conventional and organic vegetables for NO 3- content were observed. The mean NO 2- concentration of both conventional and organic vegetables ranged between 0.1 and 1.2 mg/kg of fresh weight (FW) with the exception of conventional spinach that contained 8.0 mg/kg FW. Mean NO 3- contents of conventional broccoli, cabbage, celery, lettuce, and spinach were 394, 418, 1496, 851, and 2797 mg/kg FW, respectively, while their organic-labeled counterparts averaged 204, 552, 912, 844, and 1318 mg/kg FW. In most cases, organic vegetables were numerically lower in NO 3- content than their conventional counterparts. Based on survey results, the finding that low NO 3- levels were observed in some organic vegetables in different cities may warrant further study to determine if true differences exist, due to production practices, seasonal differences, and the magnitudes of those differences. Furthermore, the geographic differences in NO 3- content of vegetables may flaw estimates of daily NO 2- and NO 3- exposure. © 2015 Institute of Food Technologists®Journal of Food Science 04/2015; 80(5). DOI:10.1111/1750-3841.12858 · 1.79 Impact Factor
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ABSTRACT: This paper provides an overview of the current literature and scientific evidence surrounding inorganic nitrate (NO3-) supplementation and its potential for improving human health and physical performance. As indicative of the ever-expanding organic and natural food consumer market, athletes and health enthusiasts alike are constantly searching for ingredient-specific "super foods" and dietary supplements capable of eliciting health and performance benefits. Evidence suggests that NO3- is the viable active component within beetroot juice (BRJ) and other vegetables, responsible for health-promoting and ergogenic effects. Indeed, multiple studies support NO3- supplementation as an effective method to improve exercise performance. NO3- supplementation (either as BRJ or sodium nitrate [NaNO3-]) has also demonstrated modest benefits pertaining to cardiovascular health, such as reducing blood pressure (BP), enhancing blood flow, and elevating the driving pressure of O2 in the microcirculation to areas of hypoxia or exercising tissue. These findings are important to cardiovascular medicine/exercise physiology and suggest a possible role for NO3- supplementation: (1) as a low-cost prevention and treatment intervention for patients suffering from blood flow disorders; and (2) an effective, natural ergogenic aid for athletes. Benefits have been noted following a single bolus, as well as daily supplementation of NO3-. While results are promising, additional research is needed to determine the impact of NO3- supplementation on anaerobic exercise performance, to identify principle relationships between isolated nitrate and other ingredients found in nitrate-rich vegetables (e.g., vitamin C, polyphenols, fatty acids, thiocyanate), to explore the specific dose-response relationships needed to elicit health and ergogenic benefits, to prolong the supplementation period beyond a relatively short period (i.e., >15 days), to determine if more robust effects can be observed with longer-term treatment, and to fully examine the safety of chronic NO3- supplementation, as this continues to be a concern of some.Nutrients 11/2014; 6(11):5224-5264. DOI:10.3390/nu6115224 · 3.15 Impact Factor