Effect of phytic acid on postprandial serum uric acid level in healthy volunteers: a randomized, double-blind, crossover study.

Phytic acid, a constituent of various plants, has been related to health benefits. Phytic acid has been shown to inhibit purine nucleotide metabolism in vitro and suppress elevation of plasma uric acid levels after purine administration in animal models. This study investigated the effect of phytic acid on postprandial serum uric acid (SUA) in humans. This randomized, double-blind, crossover design study included 48 healthy subjects with normal fasting SUA. Subjects consumed a control drink and a phytic acid drink with purine-rich food, and serum and urine uric acid levels were measured for 360 min after purine loading. Phytic acid lowered the incremental area under the curve (0-360 min) and incremental maximum concentration of SUA after purine loading (p < 0.05); tended to lower cumulative urinary uric acid excretion (0-360 min) after purine loading (p < 0.10); and suppressed postprandial SUA in this clinical study. Altogether, our findings suggest that phytic acid may play a beneficial role in controlling postprandial SUA.

Evaluation of the 24-hour profiles of physiological insulin, glucose, and C-peptide in healthy Japanese volunteers.

BACKGROUND: Some studies have demonstrated the benefit of blood glucose control as close as possible to physiological conditions. Not enough reports have investigated in detail the 24-h plasma profiles of insulin/glucose/C-peptide. Here we investigated the 24-h plasma profiles of physiological insulin/glucose/C-peptide in healthy Japanese adults. METHODS: In order to evaluate the 24-h profiles of physiological insulin/glucose/C-peptide profiles, 42 blood samples were taken from each subject in our group of healthy Japanese volunteers to measure the 24-h profile with three standardized meals. RESULTS: Plasma glucose and insulin increased rapidly followed by a rapid decrease after each meal with little variation at night. The average peak values of insulin after each meal were as follows: 426.20 pmol/L (breakfast), 373.75 pmol/L (lunch), and 410.28 pmol/L (dinner). The average times to peak insulin were 0.651 h (breakfast), 0.677 h (lunch), and 0.689 h (dinner). The corresponding average maximum postprandial plasma glucose levels were 8.39 mmol/L (breakfast), 8.77 mmol/L (lunch), and 8.74 mmol/L (dinner). The average times to peak glucose were 0.738 h (breakfast), 0.650 h (lunch), and 0.625 h (dinner). The average maximum postprandial C-peptide levels were 2.64 nmol/L (breakfast), 2.55 nmol/L (lunch), and 2.67 nmol/L (dinner). No major differences were found in these parameters between the Caucasian and Japanese populations. CONCLUSIONS: This is the first investigation to measure the 24-h profiles of insulin/glucose/C-peptide in healthy Japanese volunteers with standardized meals. It is hoped this information will provide useful reference for future research and clinical management.

Pharmacodynamic effects and kinetic disposition of rabeprazole in relation to CYP2C19 genotypes.

BACKGROUND: S-mephenytoin 4'-hydroxylase (CYP2C19) catalyses the metabolism of rabeprazole to some extent. Based on the metabolic and pharmacokinetic differences among other proton pump inhibitors such as omeprazole, lansoprazole and pantoprazole, rabeprazole appears to be the least affected proton pump inhibitor by the CYP2C19-related genetic polymorphism. AIM: To determine whether the pharmacodynamic effects of rabeprazole on intragastric pH and serum gastrin levels, and its pharmacokinetics depend on the CYP2C19 genotype status. METHODS: Eighteen healthy subjects, whose CYP2C19 genotype status was previously determined, participated in the study. They consisted of six each of homozygous extensive metabolisers (homo EMs), heterozygous extensive metabolisers (hetero EMs), and poor metabolisers (PMs). Helicobacter pylori status was determined by serology. After a single oral dose of 10 mg or 20 mg rabeprazole or water only (baseline data), intragastric pH values were monitored for 24 h. Plasma levels of rabeprazole and serum gastrin were also measured for 24 h post-dose. RESULTS: Five homo EM, six hetero EM and four PM subjects were H. pylori-negative. After rabeprazole administration, significant differences in intragastric mean pH values, serum gastrin AUC(0-24) and plasma levels of rabeprazole were observed among the three different genotype groups. CONCLUSION: The pharmacodynamic effects of rabeprazole and its pharmacokinetics depend on the CYP2C19 genotype status.