Cardioprotective effects of vegetables: Is nitrate the answer?

Boston University, Boston, Massachusetts, United States
Nitric Oxide (Impact Factor: 3.52). 01/2007; 15(4):359-62. DOI: 10.1016/j.niox.2006.01.013
Source: PubMed


A diet rich in fruits and vegetables is associated with a lower risk of certain forms of cancer and cardiovascular disease, but the mechanisms behind this protection are not completely understood. Recent epidemiological studies suggest a cardioprotective action afforded specifically by green leafy vegetables. We here propose that these beneficial effects are related to the high content of inorganic nitrate, which in concert with symbiotic bacteria in the oral cavity is converted into nitrite, nitric oxide, and secondary reaction products with vasodilating and tissue-protective properties.

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Available from: Martin Feelisch
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    • "Epidemiological studies have not provided any evidence that there is an increased risk of cancer related to high nitrate intake from sources other than vegetables (Gangolli et al., 1994). On the other hand, there are some suggestions that the protective effect of certain vegetables on the cardiovascular system is related to their high content of inorganic nitrate , which in concert with symbiotic bacteria in the oral cavity is converted into nitrite, nitric oxide and secondary reaction products with vasodilating and tissue-protective properties (Lundberg et al., 2006). "
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    ABSTRACT: The standard method of EN 12014-7 was used for the determination of nitrate content in vegetables in the Central Laboratory of the Agricultural Institute of Slovenia. Trueness of the method was verified by the analysis of samples in the interlaboratory proficiency testing scheme Bipea (Bureau Interprofessionnel d'Etudes Analytiques). Linearity was confirmed by multiple linear regression; the correlation coefficient (R2) was 0.9993. The limit of detection (LOD) was calculated as 0.8 mg NO3-/kg and limit of quantification (LOQ) 3.0 mg NO3-/kg. Relative standard deviation (RSD) of repeatability was 4.6% and RSD of reproducibility 8.9%. The relative uncertainty of repeatability and reproducibility were 10.5% and 20.2%, respectively. The method has been accredited by the French Accreditation Committee COFRAC in 2007 and by the national Slovene Accreditation in 2012.
    Full-text · Article · Jan 2015 · Archives of Biological Sciences
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    • "Some studies indicate that the excessive intake of nitrates results in an increased risk of gastrointestinal tumours and the development of methemoglobinemia . Other studies demonstrate beneficial effects of nitrate activity, which may turn out to be useful in the prevention and treatment of many diseases (Hord et al., 2009; Lundberg et al., 2006; Gilchrist et al., 2010). Apart from generally increased nitrate consumption, the consumption of foods rich in antioxidant compounds is increasing. "
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    ABSTRACT: Antioxidants are widely considered to be a preventive measure for many diseases and beneficial for health. However, an increasing number of reports suggest a lack of any influence by antioxidants on health or even harmful pro-oxidative effects of antioxidants. In most cases, the research was conducted with respect to a chosen antioxidant, without considering the presence of other chemical substances present in food, with which these compounds may react. The aim of this work was to determine whether and to what extent the simultaneous presence of quercetin and sodium nitrate influences oxidative-reductive homeostasis in fibroblast cultures. Superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and nitric oxide synthase (NOS) activities were measured together with nitric oxide (NO) concentration and total antioxidant status (TAS). An increase in the activity of all the enzymes measured and in the NO concentration was determined compared with the control culture. The most prominent changes were observed at the highest quercetin concentration. These results indicate that the simultaneous presence of quercetin and sodium nitrate disrupts the oxidative-reductive homeostasis in fibroblasts.
    Full-text · Article · Jul 2014 · Environmental Toxicology and Pharmacology
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    • "Moreover, the restriction in overall dietary energy [9], in addition to a specific decrease in dietary protein [10,11], has been reported to reduce ROS, suggesting that these dietary modifications may collectively attenuate oxidative stress [12]. Finally, increasing the intake of plant-based polyphenols [13] and nitrates [14] may improve endothelial function by increasing nitric oxide bioavailability (which is often verified by measuring the surrogate marker, nitrate/nitrite [NOx]). "
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    ABSTRACT: We have recently reported that short-term (21-day) dietary modification in accordance with a stringent vegan diet (i.e., a Daniel Fast) lowers blood lipids as well as biomarkers of oxidative stress. However, this work only involved measurements obtained in a fasted state. In the present study, we determined the postprandial response to a high-fat milkshake with regards to blood triglycerides (TAG), biomarkers of oxidative stress, and hemodynamic variables before and following a 21-day Daniel Fast. Twenty-two subjects (10 men and 12 women; aged 35 ± 3 years) completed a 21-day Daniel Fast. To induce oxidative stress, a milkshake (fat = 0.8 g·kg-1; carbohydrate = 1.0 g·kg-1; protein = 0.25 g·kg-1) was consumed by subjects on day one and day 22 in a rested and 12-hour fasted state. Before and at 2 and 4 h after consumption of the milkshake, heart rate (HR) and blood pressure were measured. Blood samples were also collected at these times and analyzed for TAG, malondialdehyde (MDA), hydrogen peroxide (H2O2), advanced oxidation protein products (AOPP), nitrate/nitrite (NOx), and Trolox Equivalent Antioxidant Capacity (TEAC). A time effect was noted for HR (p = 0.006), with values higher at 2 hr post intake of the milkshake as compared to pre intake (p < 0.05). Diastolic blood pressure was lower post fast as compared to pre fast (p = 0.02), and a trend for lower systolic blood pressure was noted (p = 0.07). Time effects were noted for TAG (p = 0.001), MDA (p < 0.0001), H2O2 (p < 0.0001), AOPP (p < 0.0001), and TEAC (p < 0.0001); all concentrations were higher at 2 h and 4 h post intake compared to pre intake, except for TEAC, which was lower at these times (p < 0.05). A condition effect was noted for NOx (p = 0.02), which was higher post fast as compared to pre fast. No pre/post fast × time interactions were noted (p > 0.05), with the area under the curve from pre to post fast reduced only slightly for TAG (11%), MDA (11%), H2O2 (8%), and AOPP (12%), with a 37% increase noted for NOx. Partaking in a 21-day Daniel Fast does not result in a statistically significant reduction in postprandial oxidative stress. It is possible that a longer time course of adherence to the Daniel Fast eating plan may be needed to observe significant findings.
    Full-text · Article · Mar 2012 · Nutrition Journal
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