Caffeinated coffee, decaffeinated coffee, and caffeine in relation to plasma C-peptide levels, a marker of insulin secretion, in U.S. women

OBJECTIVE: Coffee consumption is associated with reduced risk of type 2 diabetes, but the mechanism is not clearly understood. Elevated C-peptide, as a marker of insulin secretion, has been linked to insulin-resistant type 2 diabetes. In this study, we examined consumption of caffeinated and decaffeinated coffee and total caffeine in relation to concentrations of plasma C-peptide. RESEARCH DESIGN AND METHODS: Plasma C-peptide concentrations were measured in a cross-sectional setting among 2,112 healthy women from the Nurses' Health Study I who provided blood samples in 1989-1990. Consumption of caffeinated and decaffeinated coffee and total caffeine was assessed using a semiquantitative food-frequency questionnaire in 1990. RESULTS: Intakes of caffeinated and decaffeinated coffee and caffeine in 1990 were each inversely associated with C-peptide concentration in age-adjusted, BMI-adjusted, and multivariable-adjusted analyses. In multivariable analysis, concentrations of C-peptide were 16% less in women who drank >4 cups/day of caffeinated or decaffeinated coffee compared with nondrinkers (P < 0.005 for each). Women in the highest quintile compared with the lowest quintile of caffeine intake had 10% lower C-peptide levels (P = 0.02). We did not find any association between tea and C-peptide. The inverse association between caffeinated coffee and C-peptide was considerably stronger in obese (27% reduction) and overweight women (20% reduction) than in normal weight women (11% reduction) (P = 0.005). CONCLUSIONS: Our findings suggest a potential reduction of insulin secretion by coffee in women. This reduction may be related to other components in coffee rather than caffeine.     

Homocysteine and oxidative stress in Egyptian children with Down syndrome

ObjectiveTo assess homocysteine, folic acid and vitamin B₁₂, trace element levels and oxidant/antioxidant status in Down syndrome (DS) mothers and children.Design and methods42 mothers with previous history of bearing DS baby with karyotypically confirmed full trisomy 21 were included. 48 healthy mothers with their healthy children were considered as control. Serum B₁₂, folic acid, total homocysteine (tHcy), vitamins E and C, TBARS and trace elements were estimated.ResultsDS mothers showed higher levels of tHCy, lower levels of folic acid and vitamin B₁₂ than controls. tHCy and folic acid concentrations were significantly decreased, while vitamin B₁₂ exhibited a slight decrease in DS children versus control. Vitamins E and C, zinc and copper levels were markedly reduced in DS mothers. By contrast, TBARS showed significant elevation in them. Furthermore, DS children had severe reduction of vitamin C and zinc levels relative to healthy children. However, vitamin E showed slight reduction and TBARS displayed a slight rise in DS children.ConclusionAbnormal folic acid-homocysteine metabolism is a potent marker to identify women at risk for having DS child and it also exposes them to oxidant/antioxidant imbalance.     

Reduced urinary excretion of homocysteine could be the reason of elevated plasma homocysteine in patients with psychiatric illnesses

ObjectivesAlthough increased plasma total homocysteine (tHcy) concentrations were reported in psychiatric diseases, currently the reasons of elevated tHcy levels were not clearly understood. In this study we aimed to investigate the contribution of renal clearance of homocysteine on plasma tHcy load in patients with depression and first episode psychosis.Design and methodsThirty depression, 14 first episode psychosis patients and 34 healthy individuals (control group) were involved in the study. In patients and control groups, plasma and urine tHcy levels, urine methylmalonic acid (uMMA), serum vitamin B12 and folate concentrations were measured.ResultsAlthough there was not any difference between depression, psychosis and control groups with respect to mean (SD) values of vitamin B12 (289(131), 230 (72) and 249(79) pg/mL, respectively) and folate (6.4(4.0), 5.3(2.3) and 5.7(2.3) ng/mL, respectively), plasma tHcy levels of depression and psychosis group were higher than the control values (16.3(6.2), 15.5(4.3) and 9.9(2.1) μmol/L, respectively). Urine tHcy values of patient groups were significantly lower than those in the control group (14.5(7.6), 15.8(6.8) and 29.6(16.9) μmol/g creatinine, respectively). There were elevated uMMA levels in depression and psychosis groups compared with control group (4.9(2.4), 6.6(3.2) and 2.8(1.2) mmol/mol creatinine, respectively). There were a significant and negative correlation between urinary tHcy and plasma tHcy levels (r = ? 0.258 and p = 0.011).ConclusionIn conclusion, reduced urinary tHcy levels in psychiatric patients could be one of the reasons of plasma tHcy elevations with normal folate and vitamin B12 levels. Altered renal handling mechanisms of homocysteine may lead to elevated plasma tHcy levels by reduced clearance of homocysteine via glomerular filtration.     

Correlates of total homocysteine plasma concentration in type 2 diabetes

BACKGROUND: Although well-defined in the general population, correlates of total homocysteine (tHcy) plasma concentration have not been sufficiently evaluated in diabetes. We investigated factors potentially associated with tHcy concentration in a cohort of type 2 diabetic subjects. MATERIALS AND METHODS: The common methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism, fasting tHcy, vitamin B12 and folate plasma levels were assessed in 312 diabetic subjects, whose clinical, metabolic and lifestyle information was also available. RESULTS: The MTHFR genotype distribution was comparable to the Hardy-Weinberg equilibrium, with an overall TT homozygous frequency of 22%. Fasting tHcy concentration was significantly higher in men than in women (P < 0.001). Multivariate-adjusted tHcy concentration was significantly different across the quartiles of age (P < 0.001), folate (P = 0.01), vitamin B12 (P = 0.03), creatinine concentrations (P = 0.001) and smoking (P = 0.02). Overall, significant trends were noted for creatinine clearance (P for trend = 0.02) and systolic blood pressure (BP) (unadjusted P for trend = 0.01), whereas no differences were noted according to BMI, diastolic BP, presence of hypertension, and diabetes-related variables, such as diabetes duration, fasting glucose and glycated haemoglobin concentrations, current treatment and diabetes long-term complications. Total homocysteine levels significantly correlated with age, systolic BP, vitamin B12, creatinine and creatinine clearance, but only age, creatinine, folate and vitamin B12 levels were independently associated with tHcy concentration in stepwise regression analysis. CONCLUSIONS: Age, creatinine, folate, vitamin B12, and to a minor extent, sex, smoking, TT genotype and systolic BP were significantly associated with Hcy plasma concentration in type 2 diabetes, whereas no significant associations were noted with diabetes-related variables.     

Association between elevated plasma total homocysteine and increased common carotid artery wall thickness

Homocysteine is increasingly recognized as a risk factor for atherothrombotic arterial diseases. We investigated the relation between plasma concentrations of total homocysteine (tHcy) and common carotid artery intima-media wall thickeness, measured by B-mode ultrasonography, in 513 asymptomatic men and women from eastern Finland aged 45–69 years. The subjects were examined in 1994–95 at the baseline of the Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) study, a randomized double-blind placebo-controlled two by two factorial trial on the effect of vitamin E and C supplementation in the prevention of atherosclerotic progression. The subjects were assigned into two categories according to the plasma tHcy concentration; concentration over 11.5 umol/L (highest quartile) or concentration below 11.5 umol/L. In this study population the mean plasma tHcy concentration was 10.0 μmol/L, and the prevalence of plasma tHcy concentration exceeding 11.5 μmol/L was 33% in men and 18% in women. The adjusted mean intima-media thickness of the right and left common carotid arteries was 1.12 mm in men with elevated plasma tHcy concentration and 1.02 mm in men with a plasma tHcy concentration below 11.5 μmol/L (P = 0.029). In women there was no significant difference. We conclude that elevated plasma tHcy concentrations are associated with early atherosclerosis, as manifested by increased common carotid artery intima-media wall thickeness, in middle-aged eastern Finnish men.     

Hyperhomocysteinemia and elevated ox-LDL in Tunisian type 2 diabetic patients: role of genetic and dietary factors

INTRODUCTION: Total plasma homocysteine (tHcy) is an emerging risk factor for the development of atherosclerosis. However, its relationship with diabetes is still unclear. OBJECTIVES: We evaluated the association between tHcy levels and methylenetetrahydrofolate reductase (MTHFR) 677C-->T genotype in a type 2 diabetes mellitus (DM) population and their relationship with oxidized LDL (ox-LDL) according to dietary habits and vascular complications. DESIGN AND METHODS: Eighty-six DM patients were compared to 120 healthy volunteers. RESULTS: Associated higher tHcy levels and significantly higher ox-LDL levels (p<0.001) were found in DM patients compared to healthy subjects. Homozygosity for the T allele of MTHFR was more frequent in diabetics than in healthy subjects (12.8% vs. 7.2%) and it was associated with higher tHcy levels. Moreover, this elevated level was associated with significantly higher ox-LDL levels in DM patients with hypertension (p<0.05). Improving folate and vitamin C intakes could have beneficial effects on lowering the tHcy and ox-LDL levels. CONCLUSIONS: The interplay of genetic and dietary factors modulates the effect of homocysteine on cardiovascular risk factors.     

Folate and cobalamin levels as determinants of plasma homocysteine in different age groups of healthy controls and psychogeriatric patients

Homocysteine (Hcy) is the demethylated derivate of methionine and can be metabolized by two pathways. It is either catabolized by the transulfuration pathway to cysteine or remethylated to methionine mainly by the folate- and cobalamin-dependent enzyme methionine synthase. Previous findings suggest that folate is the most important vitamin determinant of plasma total homocysteine (tHcy) concentration but also that the relation between plasma tHcy levels and levels of cobalamin and folate in the circulation might differ in different populations. In the present study, we have analyzed these parameters in different age groups of healthy subjects and psychogeriatric patients, who are known to have increased plasma tHcy. The present study shows that serum cobalamin concentration is a more important determinant of plasma tHcy concentration than blood folate concentration in the age groups <65 years in both psychogeriatric patients and control subjects, whereas with increasing age blood folate concentration becomes the most important vitamin determinant. The findings of increased plasma tHcy with folate being the main vitamin determinant in the oldest age groups of patients and controls, suggest that tissue levels of folate in elderly subjects are too low and that vitamin supplementation should be given.     

Coffee consumption is inversely associated with depressive status in Japanese patients with type 2 diabetes

Depression has been reported to be more prevalent among diabetic patients than non-diabetic individuals. Although depression and diabetes are causally and bi-directionally related, the influence of food intake frequency on depressive symptoms in diabetic patients has not been fully evaluated. This cross-sectional study analyzed data obtained from 89 patients with type 2 diabetes who completed self-administered questionnaires regarding food intake frequency, diabetic variables, physical activity and depressive states. The prevalence of a “definite” depressive state was 16.9%. The duration of diabetes, hemoglobin A1c levels, diabetic microvascular complications and physical activity levels were similar between depressed and non-depressed patients. Daily intakes of total lipids, n-6 polyunsaturated fatty acids and lipid energy ratios were significantly lower, and the carbohydrate energy ratio was significantly higher in depressed than in non-depressed patients. Coffee consumption was inversely associated with depressive symptoms, but no significant association was found between tea or green tea consumption and depressive symptoms. The logistic regression analysis showed that coffee consumption was an independent predictor of non-depressed status in diabetic patients. This might be due to biologically active compounds containing in coffee other than caffeine.     

Plasma homocysteine and markers for oxidative stress and inflammation in patients with coronary artery disease--a prospective randomized study of vitamin supplementation.

BACKGROUND: Elevated plasma levels of total homocysteine (tHcy) are associated with an increased risk of developing occlusive vascular diseases. To better illustrate the relationship between plasma tHcy concentration, oxidative stress, and inflammation in patients with coronary artery disease (CAD), we measured plasma 8-isoprostane-prostaglandin F 2 (Iso-P), plasma malondialdehyde (MDA), and several markers of inflammation. We also aimed to demonstrate the effects of vitamin supplementation on these markers. METHODS: A total of 93 patients with ischemic heart disease were investigated. Of these, 34 had plasma tHcy < or =8 micromol/L, while 59 had plasma tHcy > or = 15.0 micromol/L. The 59 patients were randomized to open therapy with folic acid, 5 mg, pyridoxine, 40 mg, and cyancobalamin, 1 mg once daily for 3 months (n = 29) or to no vitamin treatment (n = 30). Blood samples were obtained from both groups before randomization and 3 months later. A sample was also obtained from the remaining 34 patients. RESULTS: Plasma Iso-P, serum amyloid A (S-AA), and plasma intercellular adhesion molecule-1 (ICAM-1) concentrations were higher in patients with high plasma tHcy levels than in patients with low to normal tHcy levels. Plasma levels of P-, L-, E-selectins, MDA, C-reactive protein (CRP), and orosomucoid did not differ between the groups. Vitamin therapy reduced plasma tHcy from 17.4 (15.3/20.1) to 9.2 (8.3/10.3) micromol/L (25th and 75th percentiles in parentheses) (p<0.0001). Plasma levels of Iso-P remained unchanged and, of all inflammatory markers, only the S-AA concentrations were slightly reduced by the vitamin treatment, from 5.3 (2.2/7.0) ng/L at baseline to 4.6 (2.1/6.9) ng/L (p<0.05) after 3 months of vitamin supplementation. CONCLUSION: Patients with CAD and high plasma tHcy levels had elevated plasma levels of Iso-P. The increase remained unaffected by plasma tHcy-lowering therapy, suggesting that homocysteine per se does not cause increased lipid peroxidation. Levels of plasma ICAM-1 and S-AA were increased in patients with high plasma tHcy, suggesting an association between homocysteinemia and low-grade inflammation.     

Impairment of homocysteine metabolism in patients with retinal vascular occlusion and non-arteritic ischemic optic neuropathy.

Mild hyperhomocysteinemia is established as an independent risk factor for atherothrombotic disease, including ocular pathologies such as retinal vascular occlusion and non-arteritic ischemic optic neuropathy (NAION). Low intake or low status of B-vitamins explains elevated total homocysteine (tHcy) concentrations only in part. The underlying cause for disturbed homocysteine metabolism requires further insight. We investigated whether the combined determinations of plasma tHcy, methylmalonic acid (MMA) and cystathionine provide more information on the causes of impaired homocysteine metabolism as compared with vitamin B12, vitamin B6 and folate in patients with ocular ischemic vascular disease. A total of 51 hyperhomocysteinemic (>12 micromol/L) patients with retinal vascular occlusion (n=42) and NAION (n=9) were included. Mild renal dysfunction was an important determinant of tHcy, indicated by the positive correlation between creatinine and tHcy (r=0.47, p=0.001). The assessment of MMA in addition to tHcy identified at least 12 out of 51 patients (23%) who were most likely to have a functional vitamin B12 deficiency. An additional 14 patients (27%) with elevated MMA and cystathionine levels also had slightly elevated concentrations of creatinine, pointing to the need for discrimination between renal dysfunction and vitamin B12 deficiency in this group. In contrast, measurement of cystathionine is very sensitive for renal dysfunction and this marker was strongly related to serum creatinine (r=0.56, p<0.001) and to tHcy (r=0.50, p<0.001). Measurement of the vitamins folate, vitamin B12 and vitamin B6 in plasma did not provide sufficient information on intracellular disturbances in homocysteine metabolism. In conclusion, the metabolites homocysteine, cystathionine and MMA are sensitive indicators and valuable for discrimination of the underlying cause of mild to moderate hyperhomocysteinemia, with implications for therapeutic targeting.     

Coffee consumption is associated with higher plasma adiponectin concentrations in women with or without type 2 diabetes: a prospective cohort study

To test whether the beneficial effects of coffee consumption in metabolism might be explained by changes in circulating levels of adiponectin, we evaluated self-reported habitual coffee and tea consumption and caffeine intake as predictors of plasma adiponectin concentrations among 982 diabetic and 1,058 nondiabetic women without cardiovascular disease from the Nurses' Health Study. Women with and without diabetes who drank >or=4 cups of coffee per day had significantly higher adiponectin concentrations than those who didn't drink coffee regularly (7.7 vs. 6.1 microg/ml, respectively, in diabetic women, P = 0.004; 15.0 vs. 13.2 microg/ml in nondiabetic women, P = 0.04). Similar associations were observed for caffeine intake. We confirm previously reported inverse associations of coffee consumption with inflammatory markers, C-reactive protein, and tumor necrosis factor-alpha receptor II. Adjustment for adiponectin did not weaken these associations, and adjustment for inflammatory markers did not attenuate the association between coffee consumption and adiponectin concentrations. High consumption of caffeine-containing coffee is associated with higher adiponectin and lower inflammatory marker concentrations.     

Study of the activity of erythrocyte acid phosphatase in chronic renal failure

The vitamin B₆ status of 233 women taking an oral contraceptive agent was assessed by means of the erythrocyte glutamate-oxaloacetate transaminase activation test. 48% were found to have a deficient or marginal status compared with 18% in a control group, irrespective of whether a low-dose (0.05 mg) or a high-dose (0.075–0.1 mg) oestrogen preparation was taken. The daily administration of at least 20 mg pyridoxol hydrochloride appears to be necessary to prevent a biochemical vitamin B₆ deficiency.     

Total plasma homocysteine values among elderly subjects: findings from the Maracaibo Aging Study

OBJECTIVES: The present study generated baseline data for total homocysteine (tHcy) in elderly Caribbeans of Hispanic ancestry, residing in Venezuela, their country of origin. DESIGN AND METHODS: 2106 participants in the Maracaibo Aging Study (MAS), older than 55 years, underwent standardized clinical and laboratory assessments, including measurement of plasma tHcy levels, folate, and vitamin B12 in fasting samples. RESULTS: tHcy concentration in the healthy, normative group ranged from 4.1 to 31.8 micromol/L, with a median of 11.5+/-4.7 micromol/L. tHcy level increased with age, was significantly higher in men than in women, and exhibited inverse correlations with folate and vitamin B12. CONCLUSIONS: tHcy levels of the MAS participants were generally higher than levels previously reported for community-dwelling elderly populations from other countries. The normative centile curves for tHcy can be used in disease risk analysis for this population, and possibly for other Hispanic populations residing in the Caribbean.     

Plasma choline,homocysteine and vitamin status in healthy adults supplemented with krill oil: a pilot study

Abstract

Plasma concentrations of metabolites along the choline oxidation and tryptophan degradation pathways have been linked to lifestyle diseases and dietary habits. This study aimed to investigate how krill oil, a source of ω-3 polyunsaturated fatty acids (PUFAs) with a high phosphatidylcholine content, affected these parameters. The pilot study was conducted as a 28 days intervention in 17 healthy volunteers (18–36 years), who received a supplement of 4.5?g krill oil per day, providing 833?mg ω-3 PUFAs, and 1750?mg phosphatidylcholine. Krill oil supplementation increased fasting plasma choline (+28.4%, p?p?p?p?2-, B₃-, and B₆ vitamers, tryptophan, kynurenines, nicotinamide, vitamin A and vitamin E. In summary, krill oil supplementation influenced choline metabolite levels, but not plasma metabolites of the tryptophan-kynurenine-nicotinamide pathways and vitamins. These observations should be confirmed in a placebo-controlled trial, including an ω-3 PUFA supplement without phospholipids to explore the potential additive effects of the different active ingredients.     

Homocysteine, folic acid and vitamin B12 in relation to pre- and postnatal health aspects.

Studies linking hyperhomocysteinemia (HHCY) and B-vitamin deficiency to some health aspects in children have been accumulating. Low B-vitamin status inearly life, even as early as the time of conception, may endanger the potential for new life and may negatively influence the health of the offspring. Early abortion, pregnancy complications and poor pregnancy outcomes have been linked to elevated concentrations of total plasma homocysteine (tHcy) and low folate or vitamin B12. Maternal vitamin status predicts that of fetuses and neonates. Lactating women are likely to experience low micronutrient status, which might affect breast-milk composition and hence the nutritional status of their breast-fed infants. Elevated concentrations of methylmalonic acid (MMA) is common in infants (age <6 months), which may indicate a transient inadequate vitamin B12 status. Deficiency of B-vitamins might confer deleterious effects on the physical and mental health of the child, such as impaired growth, gross motor function, poor school performance and other adaptive skills. The importance of maintaining adequate B-vitamin status during periods of progressive growth and development should be emphasized because symptoms related to folate and vitamin B12 deficiency are difficult to detect. Serum levels of tHcy and MMA should be estimated in several target groups of children, pregnant and lactating women and those planning for pregnancy. Concentrations of tHcy and MMA are useful indicators of B-vitamin status in the pediatric laboratory. Using these functional markers may facilitate detecting sub-optimal B-vitamin status in children.     

脊髓亚急性联合变性的临床和神经电生理特征分析

目的:探讨脊髓亚急性联合变性(subacute combined degeneration of spinal cord,SCD)患者的临床及神经电生理特点.方法:回顾性分析2018年1月至2020年3月复旦大学附属中山医院厦门医院收治的12例SCD患者的临床表现、实验室检查结果、神经电生理特点、磁共振表现及随访结果....     

Homocysteine,vitamin B12, folate and cognitive functions: a systematic and critical review of the literature

Elevated serum homocysteine, decreased folate and low vitamin B₁₂ serum levels are associated with poor cognitive function, cognitive decline and dementia. Despite evidence of an epidemiological association, randomised controlled trials did not provide any clear evidence so far that supplementation with vitamin B₁₂ and/or folate improves dementia or slows cognitive decline, even though it might normalise homocysteine levels. In this report, we review the current knowledge on the relationship between homocysteine, folate and vitamin B₁₂ levels and the way their disruption influences cognitive function in adults.     

Relation of coffee consumption and serum liver enzymes in Japanese men and women with reference to effect modification of alcohol use and body mass index

Abstract

Objective. Previous studies have shown that coffee consumption is inversely related to serum levels of liver enzymes such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT), but few have addressed the relation in women and effect modifications of alcohol use and obesity. We examined the association of coffee and green tea consumption with serum activities of liver enzymes in free-living Japanese men and women, focusing on sex difference and effect modifications of alcohol and obesity. Material and methods. The data were derived from the baseline survey of the Kyushu University Fukuoka Cohort Study, and included 12,020 Japanese men and women aged 49–76 years who were free of chronic liver diseases. Results. There was an inverse association between coffee consumption and elevated ALT in men, and the association between the two was weaker in women. In the analyses stratified by aminotransferases category, inverse associations of coffee consumption with serum activities of liver enzymes were observed in both men and women within the whole range and among those with aminotransferases within the reference range (ALT/AST ≤40 IU/L for men and ALT/AST ≤30 IU/L for women). Inverse associations of coffee with liver enzymes were more evident in those with high alcohol consumption and in those with low body mass index. Conclusions. Coffee drinking probably confers protection against alcohol-related increase in liver enzymes.     

Plasma homocysteine—a marker of vascular disease in elderly patients with mental illness

BackgroundTotal plasma homocysteine (tHcy) concentration is elevated in elderly patients with mental illness, and patients with vascular disease have higher plasma tHcy concentration than patients without vascular disease.MethodWe investigated the influence of cobalamin/folate status and renal function on the association between plasma tHcy levels and vascular disease.ResultsThere was a similar degree of significant difference in plasma tHcy levels between patients with and without vascular disease in all enrolled patients and in a group of patients where all those with signs of cobalamin/folate deficiency and/or impaired renal function had been excluded. Furthermore, logistic regression analysis showed that the age-adjusted plasma tHcy was the main predictor of vascular disease in both groups of patients.ConclusionThe findings suggest that the presence of vascular disease itself is associated with elevated levels of plasma tHcy. Plasma tHcy might be a marker of vascular disease in elderly patients with mental illness.     

Caffeine and high energy drink use and knowledge by nurses in three countries

AimThe purpose of this study was to examine nurses' use and knowledge of caffeine and high energy drinks (HED) in three countries.MethodsNurses in each country completed a survey on caffeine and HED use and knowledge.ResultsIn a sample of 182 nurses, caffeine use was high with 92% of nurses in Korea, 90.8% in Italy and 88.1% in the United States (US) having at least one cup of coffee a day while 64% of Koreans and 11.9% of those in the US had at least one HED per day. In Korea 68% of nurses (Italy 63.1% and 35.8% US) had at least one cup of caffeinated tea per day. Most agreed there is a need to educate nurses about HED, which contain high amounts of caffeine. Over half of nurses in Korea (58%) and the US (56.7%) said their colleagues consume HED at work.ConclusionFindings of this study indicate many nurses are consuming caffeine at work and there is a need for education. It is unclear how caffeine affects nurses' clinical performance, which raises the issue of patient safety. Further research is needed regarding safe amounts of caffeine while nurses are on the job as well as an understanding of how HED additives may affect the well-being and clinical care of nurses.