Higher Intake Levels Research Articles

The impact of coffee consumption on osteoarthritis: insights from NHANES and Mendelian randomization analysis

BackgroundOsteoarthritis (OA) is a prevalent degenerative joint condition, and emerging evidence suggests that dietary factors, such as coffee consumption, may influence its risk. However, the relationship between coffee consumption and the risk of developing OA remains ambiguous. This study aims to explore the association between coffee intake and OA complemented by Mendelian randomization (MR) to infer causality.Materials and methodsWe analyzed data from 32,439 participants across 10 NHANES cycles (1999–2018), including 3,676 individuals diagnosed with OA. Osteoarthritis was diagnosed through a structured questionnaire, while coffee consumption was assessed via 24-h dietary recalls. Participants were categorized based on reported coffee intake: 0 cups, <2 cups, 2–4 cups, and >4 cups per day. We employed weighted multivariable logistic regression to examine associations between coffee consumption and OA by using data from the NHANES 1999–2018, adjusting for various covariates. Subsequently, a MR analysis was conducted using genetic variants as instrumental variables to infer causal relationships, with multiple methods including inverse-variance weighted (IVW) analysis, MR-Egger regression, and weighted median techniques to assess the robustness, heterogeneity, and potential pleiotropy of our findings.ResultsOur regression models indicated an increased risk of OA with rising coffee consumption, with significant associations noted particularly for those consuming more than 4 cups daily (OR = 1.19, 95% CI: 1.00–1.41, p = 0.049). In MR analysis, coffee intake was causally linked to OA types, demonstrating increased risk for knee OA (KOA: OR = 1.60, 95% CI: 1.08–2.35, p = 0.018), hip OA (HOA: OR = 1.85, 95% CI: 1.06–3.25, p = 0.031), and combined KOA and HOA (KHOA: OR = 1.66, 95% CI: 1.18–2.33, p = 0.003). Sensitivity analyses confirmed the stability of results across multiple evaluation methods.ConclusionOur findings highlight a significant association between coffee consumption and an increased risk of OA, suggesting that higher intake levels may contribute to OA morbidity. These results warrant further exploration into the underlying biological mechanisms and implications for dietary guidelines in populations at risk for OA.

Association between dietary carotenoids intake and fecal incontinence in American adults: evidence from NAHNES 2005-2010.

Carotenoids represent a class of bioactive compounds with potential implications for gut health. However, the relationship between dietary carotenoid intake (DCI) and fecal incontinence (FI) remains unclear. This study aims to elucidate the association between DCI and the risk of FI. Participants aged 20 and above from the National Health and Nutrition Examination Survey (NHANES, 2005-2010) were included in the study. Data on FI were derived from the bowel health questionnaire, while DCI information was obtained from dietary interviews. Survey-weighted logistic regression analysis and restricted cubic splines (RCS) were employed to evaluate the relationship between DCI, its subtypes, and FI. Weighted quantile sum (WQS) regression was utilized to assess the overall effect of DCI and its predominant subtypes. Finally, subgroup analyses were conducted. The study included a total of 11,915 participants, of whom 1,023 (7.0%) experienced FI. Logistic regression analysis revealed that, after adjusting for all covariates, there was a significant inverse association between DCI and the risk of FI (Model 2: Q4 vs. Q1, OR = 0.67, 95% CI: 0.52-0.86, p = 0.003). However, among the DCI subtypes, only β-carotene was found to have a significant inverse relationship with FI (Model 2: Q4 vs. Q1, OR = 0.68, 95% CI: 0.52-0.88, p = 0.005). The RCS curves indicated no non-linear relationship between DCI, its subtypes, and FI (all p-non-linear >0.05). WQS analysis identified β-carotene (weight 38.2%) and lutein/zeaxanthin (weight 27.8%) as the primary contributors. High levels of carotenoid intake, particularly β-carotene and lutein/zeaxanthin, are associated with a reduced risk of fecal incontinence. This discovery provides dietary recommendations for patients suffering from FI.

Role of Gpcpd1 in intestinal alpha-glycerophosphocholine metabolism and trimethylamine N-oxide production

Glycerophosphocholine (GPC) is an intracellular metabolite in phosphatidylcholine metabolism and has been studied for endogenous choline supply in cells. GPC, as a water-soluble supplement, has been expected to play a role in preventing brain disorders; however, recent studies have shown that intake of high levels of choline-containing compounds is related to trimethylamine N-oxide (TMAO) production in the liver, which is reportedly associated with the progression of atherosclerosis. In this study, we aimed to explore the mechanisms underlying the intestinal absorption and metabolism of GPC. Caco-2 cell monolayer experiments showed that exogenously added GPC was hydrolyzed to choline in the apical medium, and the resulting choline was transported into the Caco-2 cells and further to the basolateral medium. Subsequently, we focused on glycerophosphodiesterase 1 (Gpcpd1/GDE5), which hydrolyzes GPC to choline in vitro and is widely expressed in the gastrointestinal epithelium. Our results revealed that the Gpcpd1 protein was located not only in cells but also in the medium in which Caco-2 cells were cultured. Gpcpd1 siRNA decreased the GPC-hydrolyzing activity both inside Caco-2 cells and in conditioned medium, suggesting the involvement of Gpcpd1 in luminal GPC metabolism. Finally, we generated intestinal epithelial–specific Gpcpd1-deficient mice and found that Gpcpd1 deletion in intestinal epithelial cells affected GPC metabolism in intestinal tissues and partially abolished the increase in blood TMAO levels induced by GPC administration. These observations demonstrate that Gpcpd1 triggers choline production from GPC in the intestinal lumen and is a key endogenous enzyme that regulates TMAO levels following GPC supplementation.

The Relationships among the Urinary Iodine Concentration, Selenium Intake, and Thyroid Antibodies in Adults, Including the Interaction between Iodine and Selenium: National Health and Nutrition Examination Survey 2007-2012.

The objective of this study was to examine the urinary iodine concentration (UIC)-thyroid autoimmunity (TAI) association and UIC-selenium intake interaction in U.S. adults. We analyzed 2007-2012 National Health and Nutrition Examination Survey (NHANES) data on ≥20-year-old adults (n = 6612). Their food and supplemental selenium intake was measured. The associations of the UIC and selenium intake with thyroid peroxidase antibody (TPOAb) positivity, thyroglobulin antibody (TgAb) positivity, and TAI were assessed via weighted multivariable logistic regression. Interaction and subgroup analyses were conducted. Nonlinear relationships were explored and visualized via restricted cubic splines (RCSs). Compared with a UIC 100~200 μg/L, a UIC 500~800 μg/L was associated with a 57% increased TPOAb positivity risk (OR = 1.57 [CI = 1.07-2.30]; p = 0.022), a one-fold greater TgAb positivity risk (OR = 2.00 [CI = 1.10-3.65]; p = 0.025), and a 62% increased TAI risk (OR = 1.62 [CI = 1.07-2.45]; p = 0.024). Nonlinear relationships between the UIC and thyroid antibody positivity were observed. According to the univariate models, each 1 μg increase in selenium intake was associated with a 0.049 IU/mL decrease in the TPOAb levels (β [95% CI] = -0.049 [-0.092--0.005]; p = 0.028). In the low-selenium group, a UIC of 200~300 μg/L was a risk factor for TPOAb positivity (p = 0.046). At a moderate level of selenium intake, a UIC of 300~800 μg/L significantly increased the TPOAb positivity risk (all p < 0.05). At a high level of selenium intake, the UIC and TPOAb positivity risks were not significantly associated (all p > 0.05). A UIC of 500~800 μg/L is an independent TAI risk factor. The selenium intake modifies the UIC-thyroid antibody positivity relationship, with the association disappearing at high selenium levels.

L-shaped association of thiamine intake and risk for peripheral artery disease in US adults: a cross-sectional study.

The relationship between thiamine intake and risk for peripheral artery disease (PAD) is unknown. We aimed to clarify the role of thiamine intake on risk for PAD and the implications of this relationship. The secondary objective of this study is to explore the potential non-linear dose-response relationship between exposure to thiamine intake and outcome risk for PAD. We conducted a cross-sectional study involving 6,112 participants with US adults from the National Health and Nutrition Examination Survey (1999-2004). Logistic regression and restricted cubic spline were utilized to substantiate the research objectives. The overall prevalence of risk for PAD was 7.9, 51% in males and 49% in females. After multivariable adjustment, lower thiamine intake was significantly and nonlinearly associated with higher risks of PAD among participants. Furthermore, we discovered L-shaped associations (p = 0.082) between thiamine intake and the risk of PAD, with an inflection point at 0.66 mg/day. Accordingly, in the threshold effect analysis, there was an inverse association between dietary thiamine intake and the risk in participants with dietary thiamine intake <0.65 mg/day. Compared to participants with thiamine intake below the inflection points, those with higher levels had a 31% lower risk for PAD (OR, 0.69; 95% CI: 0.51, 0.95). Further subgroup analysis showed no significant interactions between the subgroups (all p values for interaction were > 0.05). A non-linear association was revealed, showing that low and high levels of thiamine intake were associated with an increased the risk of peripheral artery disease in American adults. The inflection point at 0.66 mg/day and lower risk of PAD at 0.65-1.13mg/day of dietary thiamine intake may represent intervention targets for lowering the risk of PAD. The findings of this study require further validation and confirmation.

Ethnic differences in knowledge, attitudes, and practices related to dietary salt intake and association with hypertension in Malaysia: a multi-centre cross-sectional study.

The association between high salt intake and elevated blood pressure levels has been well-documented. However, studies on how effectively this knowledge translates into actionable practices, particularly across different ethnic groups, remain limited. This study aimed to evaluate the knowledge, attitudes, and practices (KAP) towards dietary salt intake across ethnicities and determine its association with hypertension. 5128 Malaysian adults recruited from a national blood pressure screening study completed questionnaires on demographics, and KAP related to dietary salt intake. There were 57.4% Malay, 23.5% Chinese, 10.4% Indian, and 8.7% individuals of other ethnic groups. Overall, more than 90% of the participants knew that a high salt intake causes serious health problems, but only around one-third knew the relationship between high salt intake and strokes and heart failure. Participants of different ethnic groups displayed significant differences in the KAP domains, where Indians generally exhibited better knowledge, attitudes, and reported better practices such as reading salt labels and using spices. Those who were unaware of the difference between salt and sodium and who reported not reading salt labels had higher odds of having elevated blood pressure. These findings demonstrate that while there is a suboptimal translation of salt knowledge into practice in Malaysia, with significant differences in KAP observed between ethnic groups, the potential of improving health outcomes by improving the clarity and awareness of salt labels is substantial. Tailored education promoting salt-label reading, minimizing processed foods intake and discretionary salt use should be ethnic-specific to better curb this escalating hypertension epidemic.

Protein intake and episodic memory: the moderating role of the apolipoprotein E ε4 status

BackgroundThis study investigated the correlation between protein intake and Alzheimer’s disease (AD)-related cognitive decline, particularly in episodic memory, among older adults without dementia. Furthermore, we assessed the moderating effect of apolipoprotein ε4 (APOE4) on this association and analyzed its influence on other cognitive functions beyond memory.MethodsThe study involved 196 participants who underwent assessments for protein intake, cognitive performance, APOE4 genotyping, and nutritional biomarkers. Protein intake was categorized into low, medium, and high based on the consumption of dairy, legumes, eggs, meat, and fish.ResultsHigh protein intake was significantly associated with better episodic memory and overall cognition. Moreover, a significant interaction was found between high protein intake and APOE4, indicating that APOE4 moderates the association between high protein intake level and episodic memory. Sensitivity analysis confirmed these results among participants with stable food intake.ConclusionsOur study results demonstrated that high protein intake is associated with better episodic memory among older adults without dementia. Furthermore, the findings highlight the significant role of APOE4 status in moderating the relationship between protein consumption and episodic memory. These results suggest that dietary interventions focusing on protein intake could be beneficial for cognitive health, particularly in individuals with a genetic predisposition to AD.

The relationship between dietary intake of live microbes and insulin resistance among healthy adults in the US: a cross-sectional study from NHANES 2003–2020

Dietary intake of live microbes may benefit human health, but less is known about the role in insulin resistance. This study was developed with the goal of evaluating potential relationships between IR and dietary live microbes. The National Health and Nutrition Examination Survey (NHANES) dataset was leveraged to collect data from 6,333 subjects 18 + years of age. The Sanders system for the classification of dietary live microbe intake (containing Low (< 104 CFU/g), Medium (104–107 CFU/g), or High (> 107 CFU/g) levels of live microbes) was then used to separate these patients into three groups (low, medium, or high). Fasting blood glucose and insulin levels were used to approximate IR based on the homeostasis model of insulin resistance (HOMA-IR). Weighted linear regressions were used to assess the relationship between IR and live microbe intake. After fully adjusting for confounding factors, subjects in the groups exhibiting medium and high levels of live microbe intake exhibited HOMA-IR scores that were below those of subjects in the low group. The relationship between live microbe intake and HOMA-IR scores was also potentially impacted by ethnicity. In summary, a negative correlation was detected between dietary live microbe intake and HOMA-IR values.

Non-genetic factors and breast cancer: an umbrella review of meta-analyses

BackgroundPrevious research has found associations between various non-genetic factors and breast cancer (BrCa) risk. This study summarises and appraises the credibility of the available evidence on the association between non-genetic factors and BrCa risk.MethodsWe conducted an umbrella review of meta-analyses. Medline, Scopus, and the Cochrane databases were systematically searched for meta-analyses examining non-genetic factors and BrCa incidence or mortality. The strength of the evidence was graded in four categories (i.e., weak, suggestive, highly suggestive, convincing).ResultsA total of 781 meta-analyses from 280 publications were evaluated and graded. We included exposures related to anthropometric measurements, biomarkers, breast characteristics and diseases, diet and supplements, environment, exogenous hormones, lifestyle and social factors, medical history, medication, reproductive history, and pregnancy. The largest number of examined associations was found for the category of diet and supplements and for exposures such as aspirin use and active smoking. The statistically significant (P-value < 0.05) meta-analyses were 382 (49%), of which 204 (53.4%) reported factors associated with increased BrCa risk. Most of the statistically significant evidence (n = 224, 58.6%) was graded as weak. Convincing harmful associations with heightened BrCa risk were found for increased body mass index (BMI), BMI and weight gain in postmenopausal women, oral contraceptive use in premenopausal women, increased androstenedione, estradiol, estrone, and testosterone concentrations, high Breast Imaging Reporting and Data System (BIRADS) classification, and increased breast density. Convincing protective factors associated with lower BrCa risk included high fiber intake and high sex hormone binding globulin (SHBG) levels while highly suggestive protective factors included high 25 hydroxy vitamin D [25(OH)D] levels, adherence to healthy lifestyle, and moderate-vigorous physical activity.ConclusionsOur findings suggest some highly modifiable factors that protect from BrCa. Interestingly, while diet was the most studied exposure category, the related associations failed to reach higher levels of evidence, indicating the methodological limitations in the field. To improve the validity of these associations, future research should utilise more robust study designs and better exposure assessment techniques. Overall, our study provides knowledge that supports the development of evidence-based BrCa prevention recommendations and guidance, both at an individual level and for public health initiatives.Trial registrationPROSPERO CRD42022370675.

Association between dietary magnesium intake and liver fibrosis among type 2 diabetes mellitus patients: a cross-sectional study from the NHANES database.

Liver fibrosis (LF) is a common complication of type 2 diabetes mellitus (T2DM). Studies have found that dietary magnesium (Mg), as an antioxidant nutrient, may be related to the occurrence and development of liver diseases. The aim of the present study was to evaluate the association between dietary Mg and the risk of LF in T2DM patients. In this cross-sectional study, data of T2DM patients, aged ≥18 years, were extracted from the National Health and Nutrition Examination Survey (NHANES 2017-2018). Dietary Mg intake information was obtained by 24-hour dietary recall review. Covariates included sociodemographic information, lifestyle, laboratory data, disease history and medication history, extracted from the database. Weighted univariable and multivariable logistic regression models were used to assess the association between dietary Mg intake and LF among T2DM patients, with odds ratio (OR) and 95% confidence interval (CI). Subgroup analyses based on patients with or without a history of hepatic steatosis were further assessed. A total of 945 participants were finally included, of whom 219 (23.17%) had LF. After adjusting for covariates, a high level of dietary Mg intake (OR=0.40, 95%CI: 0.17-0.93) was associated with lower odds of LF in T2DM patients, especially in patients with a history of hepatic steatosis (OR=0.39, 95%CI: 0.17-0.87). High dietary Mg intake has potential benefits in maintaining a healthy liver in T2DM patients. Sufficient Mg-rich foods and Mg supplementation may be beneficial for liver health management among T2DM patients. Further cohort studies are needed to confirm these findings.

Dietary salt intake and kidney function in rural Senegalese populations: a cross-sectional study

IntroductionHigh salt intake is a major risk factor for hypertension and its complications such as chronic kidney disease (CKD) and cardiovascular diseases. The present study aimed to determine level of sodium consumption and its relation with kidney function in the rural populations of Ferlo (centre of Senegal).Subjects and methodsWe performed a cross-sectional study including 400 volunteers aged > 18 years. Clinical, biological and dietary data were collected during household visits. Daily sodium intake was measured in the 24 h-urine outpout and CKD was defined as eGFR < 60 ml/min. Linear regression analysis was used to assess association between sodium intake and covariates.ResultsMean age was 46.42 ± 15.60 and sex-ratio was 1.05. Prevalence of hypertension, CKD and overweight were 21.5, 11.7 and 20.5%, respectively. The median daily salt intake was 11.7 g with interquartile range of 14.8 g. Only 11.25% of participants consumed less than 5 g/day. After multivariate analysis, high salt intake was associated with age > 60 years, overweight and CKD. However, gender and hypertension were not significantly associated with salt intake. Industrial broths (91.5%) and bread (85%) represented the main sources of dietary salt.ConclusionThis study revealed high levels of daily salt intake contrasting with low potassium intakes in the majority of participants. Participants with CKD, overweight and age > 60 years presented higher salt consumption. Stategies to reduce salt consumption are urgently needed to reduce burden of CKD in rural Senegalese populations.

Tea consumption and risk of all-cause, cardiovascular disease, and cancer mortality: a meta-analysis of thirty-eight prospective cohort data sets.

Tea consumption has been considered beneficial to human health because tea contains phytochemicals such as polyphenols and theaflavins. We conducted a systematic review and meta-analysis on the association between tea consumption and mortality from all causes, cardiovascular disease (CVD), and cancer to provide a quantitative assessment of current evidence. The PubMed, Web of Science, and Scopus databases were searched through April 2024 to identify eligible studies. Random effects models were used to combine study-specific effect estimates (ESs). A total of 38 prospective cohort data sets (from 27 papers) with 1,956,549 participants were included in this meta-analysis. The pooled ESs of the highest versus lowest categories of tea consumption were 0.90 (95% confidence interval [CI], 0.86 to 0.95) for all-cause mortality, 0.86 (95% CI, 0.79 to 0.94) for CVD mortality, and 0.90 (95% CI, 0.78 to 1.03) for cancer mortality. In the dose-response analysis, a non-linear association was observed. The greatest risk reductions were observed for the consumption of 2.0 cup/day for all-cause mortality (ES, 0.91; 95% CI, 0.88 to 0.94) and 1.5 cup/day for cancer mortality (ES, 0.92; 95% CI, 0.89 to 0.96), whereas additional consumption did not show a further reduction in the risk of death. A plateau was observed for CVD mortality at moderate consumption levels (1.5-3.0 cup/day), but a sustained reduction in mortality risk was observed at higher intake levels. Moderate tea consumption (e.g., 1.5-2.0 cup/day) was associated with lower all-cause, CVD, and cancer mortality compared to no tea consumption. Further well-designed prospective studies are needed for a definitive conclusion.

An error in concept and definition of recommended dietary allowance developed in 1941: Time to create new ones

The recommended dietary allowance (RDA) for vitamin C differs greatly (40–110 mg/d) across countries. In addition, vitamin D deficiency is, effectively, a pandemic, with a prevalence of approximately 25% to 80% across countries according to the findings in the recent scientific literature. However, these phenomena are attributable to a serious error in the concept and definition of RDA, which was developed in 1941. The current definition of RDA is the average daily dietary nutrient intake level that is deemed sufficient to meet the nutrient requirements of almost all (97–98%) healthy individuals. This is an extremely high intake level for a specific nutrient affecting only a few individuals (the upper 2.5%) of the generally healthy population. The RDA should be redefined by investigating at which intake level of a specific nutrient the incidence of a specific disease or mortality increases or decreases based on prospective cohort studies.

Methamphetamine and the Synthetic Cathinone 3,4-Methylenedioxypyrovalerone (MDPV) Produce Persistent Effects on Prefrontal and Striatal Microglial Morphology and Neuroimmune Signaling Following Repeated Binge-like Intake in Male and Female Rats.

Psychostimulants alter cellular morphology and activate neuroimmune signaling in a number of brain regions, yet few prior studies have investigated their persistence beyond acute abstinence or following high levels of voluntary drug intake. In this study, we examined the effects of the repeated binge-like self-administration (96 h/week for 3 weeks) of methamphetamine (METH) and 21 days of abstinence in female and male rats on changes in cell density, morphology, and cytokine levels in two addiction-related brain regions-the prefrontal cortex (PFC) and dorsal striatum (DStr). We also examined the effects of similar patterns of intake of the cocaine-like synthetic cathinone derivative 3,4-methylenedioxypyrovalerone (MDPV) or saline as a control. Robust levels of METH and MDPV intake (~500-1000 infusions per 96 h period) were observed in both sexes. We observed no changes in astrocyte or neuron density in either region, but decreases in dendritic spine densities were observed in PFC pyramidal and DStr medium spiny neurons. The microglial cell density was decreased in the PFC of METH self-administering animals, accompanied by evidence of microglial apoptosis. Changes in microglial morphology (e.g., decreased territorial volume and ramification and increased cell soma volume) were also observed, indicative of an inflammatory-like state. Multiplex analyses of PFC and DStr cytokine content revealed elevated levels of various interleukins and chemokines only in METH self-administering animals, with region- and sex-dependent effects. Our findings suggest that voluntary binge-like METH or MDPV intake induces similar cellular perturbations in the brain, but they are divergent neuroimmune responses that persist beyond the initial abstinence phase.

Highly Selective and Scalable Molecular Fluoride Sensor for Naked-Eye Detection.

Fluoride is widely present in nature, and human exposure to it is generally regarded as inevitable. High levels of fluoride intake induce acute and chronic illnesses. To reduce potential harm to the general public, it is essential to create selective fluoride detectors capable of providing a colorimetric response for naked-eye detection without the need for sophisticated equipment. Here, we report a one-pot synthesis of four different diaminomaleonitrile-derived Schiff base sensors. The terephthalaldehyde adduct provided a strong color change visible to the naked eye at a F- concentration level as low as 2 ppm. From the evaluation against other anions, such as CN-, I-, Br-, Cl-, NO3-, PO43-, OAc-, and HSO4-, the molecular sensor displayed a visible color change exclusively upon exposure to fluoride, underscoring exceptional selectivity. As a key intermediate for understanding the mechanism, HF2- was confirmed by 19F nuclear magnetic resonance. Theoretical calculations suggested a deprotonation-triggered bathochromic shift brought about by the unique electronic structure of the sensor. Furthermore, the simple synthetic protocol from economically accessible materials allowed for the preparation of the compound on a large scale, rendering it a highly practical visual fluoride sensor.

Effect of Cumulative Spirulina Intake on Broiler Meat Quality, Nutritional and Health-Related Attributes.

This work aimed to assess how different cumulative levels of Spirulina (Arthrospira platensis) intake influence individual broiler meat quality parameters, nutritional value and health-related traits. The data analysed showed varying cumulative Spirulina intake levels, ranging from 3.46 to 521 g/bird, with large changes in meat traits. The key findings indicate that Spirulina intake significantly enhances meat colour, primarily due to its rich carotenoid content. However, this enhancement shows a saturation effect at higher intake levels, where additional Spirulina does not further improve the colour. Regarding the meat nutritional profile, Spirulina increases beneficial n - 3 polyunsaturated fatty acids and reduces lipid oxidation. These effects on meat, however, are not linear and become more complex at higher microalga intake levels. Regarding meat sensory attributes, moderate Spirulina levels positively influence flavour and texture. Still, higher levels may lead to changes not universally preferred by meat consumers, highlighting the need for balanced Spirulina inclusion in diets. Optimal Spirulina cumulative intake levels must be identified to balance meat's nutritional benefits with consumer preferences. Additionally, ensuring Spirulina's purity and adherence to regulatory standards is essential for consumer safety and market access. These findings provide valuable insights for poultry nutritionists and the food industry, emphasising the necessity of a balanced approach to Spirulina's incorporation in poultry diets.

The association of dietary nitrates/nitrites intake and the gut microbial metabolite trimethylamine N-oxide and kynurenine in adults: a population-based study.

Dietary nitrate and nitrite may affect the gut microbiota and its metabolites, such as trimethylamine N-oxide (TMAO) and kynurenine (KYN). However, this association and the exact mechanism are still unclear. Therefore, this study aimed to assess the association between dietary consumption of nitrite and nitrate on TMAO and KYN levels in adults. This cross-sectional study was employed on a subsample baseline phase of the Tehran University of Medical Sciences (TUMS) Employee's Cohort Study (TEC). A total of 250 adults aged 18 years or older were included in the current analysis. Data on the dietary intakes were collected using a validated dish-based food frequency questionnaire (FFQ), and dietary intakes of nitrite and nitrate were estimated using the FFQ with 144 items. Serum profiles and TMAO and KYN were measured using a standard protocol. The findings of this study demonstrate a significant association between the intake of animal sources of nitrate and nitrite and the likelihood of having elevated levels of TMAO and KYN. Specifically, after adjustment, individuals with the highest intake adherence to nitrates from animal sources exhibited increased odds of having the highest level of TMAO (≥51.02 pg/ml) (OR = 1.51, 95% CI = 0.59-3.88, P = 0.03) and KYN (≥417.41 pg/ml) (OR = 1.75, 95% CI = 0.73-4.17, P = 0.02). Additionally, subjects with the highest animal intake from nitrite sources have 1.73 and 1.45 times higher odds of having the highest levels of TMAO and KYN. These results emphasize the potential implications of animal-derived nitrate and nitrite consumption on the levels of TMAO and KYN. The present evidence indicates that a high level of nitrate and nitrite intake from animal sources can increase the odds of high levels of TMAO and KYN. Further studies suggest that we should better evaluate and understand this association.

Exposure to heavy metal elements may significantly increase serum prostate-specific antigen levels with overdosed dietary zinc

BackgroundSerum prostate-specific antigen (PSA) is a primary metric for diagnosis and prognosis of prostate cancer (PCa). Exposure to heavy metals, such as lead, cadmium, mercury, and zinc can impact PSA levels in PCa patients. However, it is unclear whether this effect also occurs in men without PCa, which may lead to the overdiagnosis of PCa. MethodData on a total of 5089 American men who had never been diagnosed with PCa were obtained from the National Health and Nutrition Examination Survey performed from 2003–2010. The relationship between serum PSA levels (dependent variable) and concentrations of lead (μmol/L), cadmium (nmol/L), and mercury (μmol/L) were investigated with dietary zinc intake being used as a potential modifier or covariate in a weighted linear regression model and a generalized additive model. A series of bootstrapping analyses were performed to evaluate sensitivity and specificity using these models. ResultsRegression analyses suggested that, in general, lead, cadmium, or mercury did not show an association with PSA levels, which was consistent with the results of the bootstrapping analyses. However, in a subgroup of participants with a high level of dietary zinc intake (≥14.12 mg/day), a significant positive association between cadmium and serum PSA was identified (1.06, 95% CI, P = 0.0268, P for interaction=0.0249). ConclusionsWith high-level zinc intake, serum PSA levels may rise in PCa-free men as the exposure to cadmium increases, leading to a potential risk of an overdiagnosis of PCa and unnecessary treatment. Therefore, environmental variables should be factored in the current diagnostic model for PCa that is solely based on PSA measurements. Different criteria for PSA screening are necessary based on geographical variables. Further investigations are needed to uncover the biological and biochemical relationship between zinc, cadmium, and serum PSA levels to more precisely diagnose PCa.

The role of caffeine in headache disorders.

Caffeine is known to have both beneficial and adverse effects in individuals with headache disorders. This review describes recent findings regarding caffeine that are relevant to headache disorders and puts these findings into the context of clinical management. Preclinical studies show that caffeine has complex effects on sleep, brain blood flow, and intracranial pressure that may depend on the timing of caffeine intake relative to the sleep-wake cycle. Caffeine metabolism may have significant inter-individual variation that influences its therapeutic and/or adverse effects. Caffeine has acute therapeutic benefit for some primary headache disorders. For migraine, this benefit is predominantly in milder headache without cutaneous allodynia. High levels of caffeine intake may contribute to progression of headache disorders. Caffeine-containing combination analgesics commonly cause medication overuse headache. Abrupt reduction in caffeine consumption is a trigger for migraine that may be important in situations including the hospital setting, religious and cultural fasting, and pregnancy. There is not sufficient evidence to support universal guidelines for the use of dietary and medicinal caffeine in headache disorders. A sensible approach based upon available evidence is to limit dietary caffeine intake to moderate amounts with consistent timing before noon, and to use caffeine-containing combination analgesics infrequently for milder headache.

The interaction between dietary nitrates/nitrites intake and gut microbial metabolites on metabolic syndrome: a cross-sectional study.

Metabolic syndrome (MetS) prevalence has increased globally.The evidence shows thatdiet and gut microbial metabolites includingtrimethylamine N-oxide (TMAO) and kynurenine (KYN) play an important role in developing MetS. However, there is a lack of evidence on associations between between diet and these metabolites. This study aimed to investigate the interaction between dietary nitrate/nitrite and gut microbial metabolites (TMAO, KYN) on MetS and its components. This cross-sectional study included 250 adults aged 20-50 years. Dietary intake was assessed using food frequency questionnaires (FFQ), and serum TMAO and KYN levels were measured. MetS was defined usingthe National Cholesterol Education Program Adult Treatment Panel (NCEP ATP III) criteria. The ATPIII index revealed an 11% prevalence of metabolic syndrome among the study participants. After adjusting for confounders, significant positive interactions were found: High animal-source nitrate intake and high TMAO levels with elevated triglycerides (TG) (p interaction = 0.07) and abdominal obesity (p interaction = 0.08). High animal-source nitrate intake and high KYN levels with increased TG (p interaction = 0.01) and decreased high-density lipoprotein cholesterol (HDL) (p interaction = 0.01).Individuals with high animal-source nitrite intake and high TMAO levels showed increased risk of hypertriglyceridemia (OR: 1.57, 95%CI: 0.35-2.87, p = 0.05), hypertension (OR: 1.53, 95%CI: 0.33-2.58, p = 0.06), and lower HDL (OR: 1.96, 95%CI: 0.42-2.03, p = 0.04). Similarly, high animal-source nitrite intake with high KYN levels showed lower HDL (OR: 2.44, 95%CI: 1.92-3.89, p = 0.07) and increased risk of hypertension (OR: 2.17,95%CI: 1.69-3.40, p = 0.05). Conversely, Negative interactions were found between high plant-source nitrate/nitrite intake with high KYN and TMAO levels on MetS and some components. There is an interaction between dietary nitrate/nitrite source (animal vs. plant) and gut microbial metabolites (TMAO and KYN) on the risk of of MetS and its components. These findings highlight the importance of considering diet, gut microbiome metabolites, and their interactions in MetS risk assessment.