Total antioxidant capacity of the diet modulates the association between habitual nitrate intake and cardiovascular events: A longitudinal follow-up in Tehran Lipid and Glucose Study

Consumption of water contaminated by nitrate and its deleterious effects on the human thyroid gland: a review and update

Nowadays, the nitrates have been established as carcinogenic components due to the endogenous formation of N-nitroso compounds, however, the consumption of water contaminated with nitrates has only been strongly related to the presence of methemoglobinemia in infants, as an acute effect, leaving out other side effects that demand attention. The thyroid gland takes relevance because it can be altered by many pollutants known as endocrine disruptors, which are agents capable of interfering with the synthesis of hormones, thus far, it is known that nitrates may disrupt the amount of iodine uptake causing most of the time hypothyroidism and affecting the metabolic functions of the organism in all development stages, resulting in an important health burden for the exposed population. Here, this review and update highlighted the impact of consumption of water contaminated with nitrates and effects on the thyroid gland in humans, concluding that nitrates could act as true endocrine disruptor.

Relationship between dietary macronutrient composition and non-alcoholic fatty liver disease in lean and non-lean populations: a cross-sectional study

OBJECTIVE

The current study aimed to customize dietary changes for lean patients with non-alcoholic fatty liver disease (NAFLD).

DESIGN

The current study was done with a population-based cross-sectional design. The FFQ was used to analyse dietary macronutrient intake and ultrasonography results for NAFLD diagnosis. The study subjects were divided into the lean and non-lean groups based on their BMI (< 25 and ≥ 25). Multivariable logistic regression was used to evaluate the relationship between dietary macronutrients and NAFLD. Substitution analyses were also performed.

SETTING

Amol and its suburban areas in Iran.

PARTICIPANTS

Adults in the age range of 18 to < 65 with full relevant data.

RESULTS

Among the total study subjects (2308), 46·7 % had fatty liver. The substitution of polysaccharides for animal protein and SFA in the lean group resulted in a significant NAFLD reduction, whereas the substitution of SFA for all types of macronutrients, except for n-6 and mono-disaccharides, led to a significant increase in NAFLD (P < 0·05). In non-lean participants, the substitution of MUFA for mono-disaccharides resulted in a significant reduction of NAFLD (P < 0·05). In this group, the substitution of SFA and mono-disaccharides for MUFA, and n-6 for all macronutrients, except vegetable protein and SFA, were significantly related to an increase in NAFLD (P < 0·05).

CONCLUSIONS

Lower lean NAFLD is correlated with increasing polysaccharides in exchange for SFA and animal protein intake, whereas lower non-lean NAFLD is correlated with increasing MUFA in exchange for mono-disaccharides and reducing n-6 and SFA.

Lost-in-Translation of Metabolic Effects of Inorganic Nitrate in Type 2 Diabetes: Is Ascorbic Acid the Answer?

Beneficial metabolic effects of inorganic nitrate (NO3-) and nitrite (NO2-) in type 2 diabetes mellitus (T2DM) have been documented in animal experiments; however, this is not the case for humans. Although it has remained an open question, the redox environment affecting the conversion of NO3- to NO2- and then to NO is suggested as a potential reason for this lost-in-translation. Ascorbic acid (AA) has a critical role in the gastric conversion of NO2- to NO following ingestion of NO3-. In contrast to AA-synthesizing species like rats, the lack of ability to synthesize AA and a lower AA body pool and plasma concentrations may partly explain why humans with T2DM do not benefit from NO3-/NO2- supplementation. Rats also have higher AA concentrations in their stomach tissue and gastric juice that can significantly potentiate gastric NO2--to-NO conversion. Here, we hypothesized that the lack of beneficial metabolic effects of inorganic NO3- in patients with T2DM may be at least in part attributed to species differences in AA metabolism and also abnormal metabolism of AA in patients with T2DM. If this hypothesis is proved to be correct, then patients with T2DM may need supplementation of AA to attain the beneficial metabolic effects of inorganic NO3- therapy.

The Nitrate-Nitrite-Nitric Oxide Pathway: Findings from 20 Years of the Tehran Lipid and Glucose Study

CONTEXT

We describe here the contributions of the Tehran lipid and glucose study (TLGS) to understanding different aspects of the nitrate (NO3)-nitrite (NO2)-nitric oxide (NO) pathway in health and disease.

EVIDENCE ACQUISITION

All English-language documents from the TLGS, focused on NO pathway were searched using the PubMed, Scopus, and Embase databases.

RESULTS

Reference values of serum concentrations of NO metabolites (nitrate+nitrite or NOx) were 11.5 - 76.4, 10.1 - 65.6, and 10.3 - 66.8 μmol/L in men, women, and the total population, respectively. Circulating NOx was affected by age, smoking habits, menopause status, thyroid hormones, and various pathologic conditions. Elevated serum NOx was related to increased incidence of metabolic syndrome (odds ratio (OR) = 1.75, 95% confidence interval (CI) = 1.19 - 2.59), hypertriglyceridemic-waist phenotype (OR = 1.39, 95% CI = 1.05 - 1.93), chronic kidney disease (OR = 1.86, 95% CI = 1.10 - 3.14) in women, and cardiovascular disease (hazard ratio (HR) = 1.35, 95% CI = 1.01 - 1.80] in the total population. In participants with low vitamin C intake, higher intakes of NO2 (≥ 8.77 mg/d) were accompanied with increased risk of diabetes (HR = 2.43, 95% CI = 1.45 - 4.05). A decreased risk of hypertension (OR = 0.58, 95% CI = 0.33 - 0.98) and chronic kidney disease (OR = 0.50, 95% CI = 0.24 - 0.89) was observed in response to higher intakes of NO2.

CONCLUSIONS

Circulating NOx is associated with and could predict the risk of metabolic disorders in a general population. Moreover, dietary NO3/NO2 exposure from usual diets seems to contribute to development of noncommunicable diseases.