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.

ApoE isoform does not influence skeletal muscle regeneration in adult mice.

Introduction: Apolipoprotein E (ApoE) has been shown to be necessary for proper skeletal muscle regeneration. Consistent with this finding, single-cell RNA-sequencing analyses of skeletal muscle stem cells (MuSCs) revealed that Apoe is a top marker of quiescent MuSCs that is downregulated upon activation. The purpose of this study was to determine if muscle regeneration is altered in mice which harbor one of the three common human ApoE isoforms, referred to as ApoE2, E3 and E4. Methods: Histomorphometric analyses were employed to assess muscle regeneration in ApoE2, E3, and E4 mice after 14 days of recovery from barium chloride-induced muscle damage in vivo, and primary MuSCs were isolated to assess proliferation and differentiation of ApoE2, E3, and E4 MuSCs in vitro. Results: There was no difference in the basal skeletal muscle phenotype of ApoE isoforms as evaluated by section area, myofiber cross-sectional area (CSA), and myonuclear and MuSC abundance per fiber. Although there were no differences in fiber-type frequency in the soleus, Type IIa relative frequency was significantly lower in plantaris muscles of ApoE4 mice compared to ApoE3. Moreover, ApoE isoform did not influence muscle regeneration as assessed by fiber frequency, fiber CSA, and myonuclear and MuSC abundance. Finally, there were no differences in the proliferative capacity or myogenic differentiation potential of MuSCs between any ApoE isoform. Discussion: Collectively, these data indicate nominal effects of ApoE isoform on the ability of skeletal muscle to regenerate following injury or the in vitro MuSC phenotype.

Acetate and succinate benefit host muscle energetics as exercise-associated post-biotics.

Recently, the gut microbiome has emerged as a potent modulator of exercise-induced systemic adaptation and appears to be crucial for mediating some of the benefits of exercise. This study builds upon previous evidence establishing a gut microbiome-skeletal muscle axis, identifying exercise-induced changes in microbiome composition. Metagenomics sequencing of fecal samples from non-exercise-trained controls or exercise-trained mice was conducted. Biodiversity indices indicated exercise training did not change alpha diversity. However, there were notable differences in beta-diversity between trained and untrained microbiomes. Exercise significantly increased the level of the bacterial species Muribaculaceae bacterium DSM 103720. Computation simulation of bacterial growth was used to predict metabolites that accumulate under in silico culture of exercise-responsive bacteria. We identified acetate and succinate as potential gut microbial metabolites that are produced by Muribaculaceae bacterium, which were then administered to mice during a period of mechanical overload-induced muscle hypertrophy. Although no differences were observed for the overall muscle growth response to succinate or acetate administration during the first 5 days of mechanical overload-induced hypertrophy, acetate and succinate increased skeletal muscle mitochondrial respiration. When given as post-biotics, succinate or acetate treatment may improve oxidative metabolism during muscle hypertrophy.

The Effect of Downhill Running on Quadriceps Muscle in Growth-Restricted Mice.

INTRODUCTION: Growth restriction (GR) reduces ribosome abundance and skeletal muscle mass in mice. A reduction in skeletal muscle mass increases the risk of frailty and is associated with high morbidity and mortality rates. As eccentric type exercise increases muscle mass, this investigation aimed to determine if eccentric loading of skeletal muscle via downhill running (DHR) increased muscle mass in GR mice. METHODS: Mice were growth-restricted either gestational undernutrition (GUN, n = 8 litters), postnatal undernutrition (PUN, n = 8 litters), or were not restricted (CON, n = 8 litters) via a validated cross-fostering nutritive model. On postnatal day (PN) 21, all mice were weaned to a healthy diet, isolating the period of GR to early life as seen in humans. At PN45, mice were assigned to either a DHR (CON, n = 4 litters; GUN, n = 4 litters; PUN, n = 4 litters) or sedentary (SED: CON, n = 4 litters; GUN, n = 4 litters; PUN, n = 4 litters) group. Downhill running (16% decline: 18 m·min -1 ) was performed in 30-min bouts, three times per week, for 12 wk on a rodent treadmill. At PN129, the quadriceps femoris was dissected and evaluated for mass, myofiber size and type, and molecular markers of growth. RESULTS: Following training, CON-DHR mice having larger cells than CON-SED, GUN-SED, PUN-SED, and PUN-DHR mice ( P < 0.05). The PUN group (as compared with CON) had reduced body mass ( P < 0.001), upstream binding factor abundance ( P = 0.012), phosphor-mTOR ( P < 0.001), and quadriceps mass ( P = 0.02). The GUN and PUN groups had increased MuRF1 abundance ( P < 0.001) compared with CON ( P < 0.001). CONCLUSIONS: The blunted response to training suggests GR mice may have anabolic resistance when exposed to eccentric type exercise.

Urolithiasis: Prevalence, risk factors, and public awareness regarding dietary and lifestyle habits in Jeddah, Saudi Arabia in 2017.

INTRODUCTION: Urolithiasis is a public health concern, yet there are limited studies in our community. This study aimed to provide a current estimate of the prevalence of urolithiasis and to evaluate the public's awareness about dietary and lifestyle habits that impact on urolithiasis among the Jeddah population in 2017. METHODS: This is an observational cross-sectional study design where a self-administered questionnaire was distributed in two major malls in Jeddah. The total number of participants was 2173, who were Saudis and non-Saudis aged 18 years and above. The questionnaire includes five sections: demographics, general information related to urolithiasis, dietary information related to urolithiasis, lifestyle habits, and medical conditions. RESULTS: The overall prevalence of urolithiasis was 11.2%, 48.8% of which had a family history with a first-degree relative. The odds of urolithiasis among males was 1.8 times higher than in females (odds ratio [OR] =1.8, 95% confidence interval [CI], 1.4-2.4). The median age of stone disease was 33 years (25%-75%: 26-42 years). Diabetic individuals were 3.2 times more likely to have urolithiasis when compared to nondiabetic individuals (OR = 3.2, 95% CI, 2.1-4.9). Low level of awareness was observed in this cohort group with a mean score of 37.7%; 64.1% of the population were in the low awareness level, 35.3% were in the medium level, and only 0.6% participants were in the high level of awareness. CONCLUSION: This study highlights the lack of public awareness about urolithiasis and knowledge about its causation despite the high prevalence. There is a clear need to inform and educate the public on matters relating to the known risk factors associated with urolithiasis.