The origin and disposal of 1,5-anhydro-D-glucitol (AG), one of the main polyols found in the human body, was studied in normal subjects and diabetic patients. AG was detected in various kinds of foods. The mean AG supplement through foods was estimated to be approximately 4.38 mg/day, which was compatible with that calculated in a food analysis (average 0.22 mg AG/100 kcal in Japanese foods) on eight healthy subjects. The mean AG excretion in urine was approximately 4.76 mg/day in these subjects. Excretion into stools was negligible. From observations on the patients without oral supplement of AG, 0.4 mg of daily de novo synthesis of AG was strongly suggested. It was also implied that urinary AG excretion occurred soon after food ingestion and that its amount was closely correlated with daily supplement through foods. Thus the fundamental kinetics of AG were recognized as follows: 1) AG in the body originates mainly from foods and is well absorbed in the intestine, 2) AG is little degraded and metabolized in the body, and 3) an equilibrium exists between oral supplement plus a small but steady amount of de novo synthesis and excretion in urine.
The antioxidant activity of casein calcium peptides in several in vitro assay systems was investigated. Casein calcium peptides were prepared by the microbial enzymic hydrolysis of casein calcium. The main peak of the molecular mass distribution of the peptides was about 3 kDa. Casein calcium peptides showed strong antioxidant activity with the beta-carotene bleaching method, and they also showed scavenging activity against radicals such as superoxide radicals, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, and hydroxyl radicals. Antioxidant activity was increased with an increasing peptide concentration. Casein calcium peptides also showed strong antioxidant activity against lipid oxidation in ground beef homogenates. These results suggest that casein calcium peptides are a suitable natural antioxidant that prevents the lipid oxidation of meat and related food ingredients.
1. A major polyol found in the sera and other tissues of humans, 1,5-anhydro-D-glucitol, is mainly ingested in the diet and is excreted in urine. We compared the influence of the long-term administration of total parenteral nutrition free of 1,5-anhydro-D-glucitol with that of total enteral nutrition on the serum level of 1,5-anhydro-D-glucitol in 46 patients who could not take food by mouth. 2. The serum concentration of 1,5-anhydro-D-glucitol and its kinetics remained unchanged in the group receiving total enteral nutrition (n = 21) over a period of 12 months. However, after 1 month on total parenteral nutrition (n = 25), the serum level of 1,5-anhydro-D-glucitol decreased, falling to about one-sixth the pretreatment level in the 12th month. Because the serum level of 1,5-anhydro-D-glucitol continued to decline, falling below the limit at which its renal reabsorption is normally activated, this decrease did not seem to be caused directly by a nutritional deficiency of this substance. 3. The urinary excretion of 1,5-anhydro-D-glucitol was closely correlated (r = 0.792) with that of N-acetyl-beta-glucosaminidase; but not with the serum creatinine level or of the urinary excretion of microalbumin or of urinary beta 2-microglobulin. We observed no glucosuria, hyperuricuria or changes in serum electrolytes during total parenteral nutrition. 4. The reduction in the serum level of 1,5-anhydro-D-glucitol and the urinary excretion of N-acetyl-beta-glucosaminidase were correlated with the duration of total parenteral nutrition administration.(ABSTRACT TRUNCATED AT 250 WORDS)
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