Pharmacological therapies, lifestyle choices and nitric oxide deficiency: A perfect storm

Evaluation of Knowledge and Awareness of Dietary Nitrate Among Clinical Dietitians in Jeddah, Saudi Arabia: A Cross-Sectional Study

Background and objectives Dietary nitrate (NO3) plays an important role in human physiological processes. In the past, inorganic NO3 was viewed negatively due to its link with carcinogenic effects, notably nitrosamine formation in the stomach; yet, current perspectives acknowledge NO3 as a potentially beneficial dietary element. Nutrition professionals (NPs) are crucial in promoting NO3 awareness in health and academic settings. The study aimed to evaluate the knowledge of NPs in Jeddah, Saudi Arabia, regarding the biological roles of dietary NO3, taking into consideration their qualifications and years of experience. Methods A cross-sectional study was conducted among NPs who had graduated from clinical nutrition programs or were employed in clinical or academic settings. A validated 12-item online questionnaire was used to assess dietary NO3 knowledge across five areas: health effects, dietary sources, recommendations, biomarkers of intake, and metabolism. The nitrate knowledge index (NKI) score was used to evaluate responses. Results Eighty-nine female NPs out of 144 completed the questionnaire. Most were ≤30 years old (75.4%) and had an undergraduate degree in clinical nutrition (70.8%), but 37 of them had ≤3 years of experience (62.7%). Overall, poor knowledge scores were observed among NPs, with a median (25th and 75th percentile) score of 10 (6, 13) out of 23. The majority (64%) perceived NO3 to be beneficial. However, most of the participants did not know its benefits in lowering blood pressure (BP) (68.5%) and were unsure about the effects of nitrate on cognitive function (60.7%) or kidney function (57.3%). Almost half of the NPs were unaware of NO3 sources and unsure about the mechanisms of the conversion of NO3 into nitrogen dioxide (NO2) in the mouth (48.3%). Overall, knowledge of factors that affect NO3 content in food was good. No significant differences were observed in the median NKI scores among the participants based on their level of education or years of experience. Conclusion This study suggests NPs lack knowledge about dietary NO3. To address this, educational programs should be developed and implemented in clinical and academic settings.

Circulating markers of nitric oxide homeostasis and cardiometabolic diseases: insights from population-based studies

Emerging data suggest that impaired nitric oxide (NO) homeostasis has a key role in development of cardiometabolic disorders. The association between circulating levels of NO metabolites, i.e. nitrate and nitrite (NOx), and risk of chronic diseases has not yet been fully clarified. This work aims to address epidemiologic aspects of NO metabolism and discusses different physiologic and pathophysiologic conditions influencing circulating NOx. Further, cross-sectional associations of serum NOx with metabolic disorders are described and along the way, potential short-term and long-term power of serum NOx for predicting cardiometabolic outcomes are reviewed. Results from population-based studies show that circulating NOx is affected by aging, smoking habits, pregnancy, menopause status, thyroid hormones, and various pathologic conditions including type 2 diabetes, insulin resistance, hypertension, and renal dysfunction. Lifestyle factors, especially dietary habits, but also smoking habits and the degree of physical activity influence NO homeostasis and the circulating levels of NOx. Elevated serum NOx, due to increased iNOS activity, is associated with increased incidence of metabolic syndrome, different obesity phenotypes, and cardiovascular events.

Toxicological evaluation of therapeutic and supra-therapeutic doses of Cellgevity® on reproductive function and biochemical indices in Wistar rats

BACKGROUND

The misconception about dietary supplements being safe has led many into the in-patient wards. Cellgevity® (CGV) is a Max International premiere antioxidant supplement formula used by a large population. This study evaluated the effects of therapeutic and supra-therapeutic doses of CGV on reproductive function and biochemical indices in Wistar rats.

METHODS

Seventy-two Wistar rats weighing 130 ± 15.8 g were grouped into two categories (male or female) of six rats per group. Control group received distilled water (10 ml/kg). Others received therapeutic (14.3 mg/kg or 28.6 mg/kg) and supra-therapeutic CGV doses (1000, 2000 or 3000 mg/kg) body weight per oral respectively.

RESULTS

After 60 days, supra-therapeutic doses of CGV reduced sperm motility (p < 0.05) by 31.8%, 31.3% and 34.5% respectively and increased (p < 0.05) abnormality in sperms by 200%, 241% and 141.3% respectively. CGV altered male (luteinizing, follicle stimulating hormones and testosterone) and female reproductive hormones (luteinizing, follicle stimulating hormones estrogen and progesterone) respectively. Therapeutic doses of CGV elevated reduced glutathione, superoxide dismutase, catalase and glutathione S-transferase, although, this was exceeded by supra-therapeutic doses and more in females than male rats. Supra-therapeutic dose (3000 mg/kg CGV) decreased body weight in both male and female rats by 50% (F(1.5, 30) = 1.2, p = 0.041) and 62.7% (F(2.1, 30) = 0.38, p = 0.038) respectively in treated rats. Supratherapeutic (3000 mg/kg) dose of CGV increased (p < 0.05) creatinine level by 99.1% while serum total protein was reduced (p < 0.05) by 60.1% (2000 mg/kg) and 57.2% (3000 mg/kg) respectively in male animals. In Female rats, supra-therapeutic doses of CGV elevated creatinine levels by 72.2% (1000 mg/kg), 60.2% (2000 mg/kg) and 124.8% (3000 mg/kg) respectively and 3000 mg/kg produces elevated serum low density lipoprotein by 34.6% in treated rats. Serum cholesterol, triglycerides, albumin, alkaline phosphatase were unaltered by CGV dosing. Histology shows seminiferous tubules with reduced spermatogenic cells. Also, female rat kidney revealed acute tubular necrosis at highest dose used in this study.

CONCLUSION

Overall, these data suggest that pro-oxidant potential of the supra-therapeutic CGV doses is evident. Hence, it is necessary that its administration be done with caution using appropriate doses.

Dietary nitrate and blood pressure: evolution of a new nutrient?

Dietary nitrate is mainly obtained from vegetables, especially green leafy vegetables and beetroot. As a result of early research, dietary nitrate is currently viewed as a contaminant linked to increased risks of stomach cancer and methaemoglobinaemia. Consequently, nitrate levels are restricted in certain vegetables and in water supplies to ensure exposure levels remain below an acceptable daily intake of 3·7 mg/kg per d. The average nitrate intake in the UK is approximately 70 mg/d, although some population groups, such as vegetarians, may consume three times that amount. However, recent studies in the last decade suggest that dietary nitrate can significantly reduce systolic blood pressure via the nitrate-nitrite-NO pathway. A small, downward shift in systolic blood pressure across the population could significantly reduce the incidence of hypertension and mortality from CVD such as stroke. Interestingly, vegetarians tend to have lower levels of blood pressure than omnivores and epidemiological studies suggest that vegetarians have lower risks of CVD. Recent evidence is mainly focused on the acute effects of dietary nitrate supplementation and there is a lack of data looking at the chronic effects of high nitrate consumption in humans. Nevertheless, due to potential health benefits, some authors are recommending that nitrate should be considered as a nutrient necessary for health, rather than as a contaminant which needs to be restricted. This review will discuss the emerging role of dietary nitrate in the control of blood pressure and whether there is sufficient evidence to state that nitrate is a 'new' nutrient.

A select review reporting the quality of studies measuring endothelial dysfunction in randomised diet intervention trials

A quality assessment of the primary studies reported in the literature carried out using select dietary ingredients (DI) purported to affect vascular endothelial function was conducted through a systematic PubMed search from January 2000 to August 2012. A total of seventy randomised controlled trials with defined DI (folic acid (fifteen), n-3 fatty acids (twenty), cocoa (fifteen) and isoflavones (twenty)) and standardised measures of vascular endothelial function were evaluated. Jadad scores, quality scoring parameters for DI and flow-mediated dilation (FMD) methodology used were ascertained. A total of 3959 randomised subjects, mean age 51 (se 0·21) years (range 9-79 years), were represented in the dataset. The mean Jadad scores did not differ statistically among the DI studies, with the majority of the studies being of good quality. Higher DI quality scores were achieved by studies using the botanical ingredients cocoa and isoflavones than by those using the nutrient ingredients folic acid and n-3 fatty acids. The mean DI quality scores were 4·13 (se 0·34), 5·20 (se 0·47), 6·13 (se 0·41) and 6·00 (se 0·59) for the folic acid, n-3 fatty acid, cocoa and isoflavone intervention studies, respectively (and significantly different). The mean Corretti FMD scores were 7·27 (se 0·56), 7·46 (se 0·79), 6·29 (se 0·61) and 7·11 (se 0·56) for the folic acid, n-3 fatty acid, cocoa and isoflavone intervention studies, respectively (NS). FMD studies failed to adequately describe the equipment used and more than half failed to provide an adequate description of the procedures used for vascular image acquisition and measurement. DI can be utilised for dietary intervention studies; however, the methodology should be clearly reported using the guidelines for assessment for both DI and FMD.