Newborn infants are generally thought to be in a vitamin E-deficient state due to their low plasma tocopherol levels and increased hemolysis of red blood cells (RBCs) induced by hydrogen peroxide (HPT). However, the tocopherol in plasma lipids of newborn infants is within an acceptable range because of the low plasma lipids in neonates. In addition, RBC tocopherol levels in the majority of newborn infants, even if they have a very low birth weight, showed a normal vitamin E status immediately after birth, despite the increased susceptibility of their RBCs to HPT. The incresed susceptibility of RBC ghosts in cord blood to oxidant stress was studied using an azo-compound. After vitamin E was exhausted in the ghosts, the oxygen uptake rate was faster in cord ghosts than in adult ghosts, resulting from the fact that the cord ghosts had a higher bisallylic hydrogen content. This finding indicates a relative deficiency of vitamin E in neonatal biomembranes with a sufficient vitamin E content. In addition, vitamin E concentrations in leukocytes, platelets and buccal mucosal cells, othe than those in plasma and RBCs, showed a lower tocopherol level in cord blood cells, as compared with those in older children. The above finding indicates that a higher amount of vitamin E is required by neonates. Wilson's disease and homocystinuria were further investigated. Copper unassociated with ceruloplasmin and a large amount of homocystein both generated superoxide in association with SH groups and ferrous iron, respectively. The generated free radicals induced from superoxide were thought to initiate cell membrane damage in RBC from patients with Wilson's disease, whereas they were found to produce modified LDL in the reaction of homocystein with ferric iron. These changes seem to be related to the development of hemolytic crisis in Wilson's disease and the early onset of atherosclerosis in patients with homocystinuria. Oxidation of LDL resulting from homocysteine and ferric iron will be prevented by a high concentration of tocopherol in LDL, while oxidative stress due to non-ceruloplasmin Cu will be inhibited by zinc ion.

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α-amylase inhibitor (α-AI), which has an activity of about 40, 000units/mg·dry matter, was purified from commercial wheat powder. We investigated the specificity of its inhibitory effects on various carbohydrolases, such as α-amylase, β-amylase, maltase and invertase, and studied the clinical effects of α-AI on healthy subjects. 1) The inhibitory activity of α-AI on α-amylase from human saliva, human pancreatic juice and mouse pancreatic extract was between 70% and 90%, and that on microbial β-amylase, maltase and invertase was between 30% and 50%. 2) Increases in postprandial blood glucose levels were markedly suppressed by treatment with α-AI (30mg). 3) When α-AI (30mg/day) was administered for one month without any dietary or physical exercise restrictions, the contents of total cholesterol and triglyceride in the serum were slightly decreased. 4) Both male and female body mass indices were decreased by about 0.3-0.4 after administration of α-AI (30mg/day) after meals for one month without any dietary or physical exercise restrictions; under a mild physical exercise load, the body mass indices of male and female subjects were decreased by 1.5±0.3 and 1.3±0.15, respectively.

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Food intake and eating habits affecting dietary fiber intake were investigated in 51 female patients with chronic constipation. According to three-day records of food intake kept by the patients, the following five eating patterns were classified and used for analysis: 1) completeness of each meal with a staple, main dish and side dish, 2) regularity of meal times, 3) eating-out, 4) taking snacks between meals, and 5) not having three meals a day. The results obtained were as follows: 1) Food and nutrient intake was generally less than the RDA. In particular, the mean intake of dietary fiber was as low as 13.3g. 2) There was a significantly strong correlation between daily food intake weight and intake of dietary fiber (γ=0.797, ρ<0.001). 3) Those who took a staple, main dish and side dish at each meal for three days showed the highest dietary fiber intake (18.0g). 4) Multivariate analysis revealed that the daily food intake weight and completeness of each meal are the main factors affecting the intake of dietary fiber in patients with chronic constipation.

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The concentration of N-acetylneuraminic acid (NeuAc) in human milk was determined in 2, 727 samples collected from 2, 434 mothers living in various districts of Japan from 3 to 482 days after delivery, in the winter and summer of 1989. The total amount of NeuAc decreased from about 150mg/100ml (3-5 days postpartum) to about 32mg/100ml (121-240 days postpartum), and thereafter it remained constant. NeuAc concentrations in samples taken in summer were lower than those found in samples collected in winter; however, there was no significant difference in the NeuAc concentrations in human milk collected at different locations. The ratio of NeuAc in defatted milk to that in whole milk decreased from 96-99% to 88% during lactation. The ratio of NeuAc in the 12% TCA-insoluble fraction to that in whole milk decreased from 24% to 15% during lactation, whereas, in the 12% TCA-soluble fraction the ratio of NeuAc remained constant at 72-77% during lactation. The present data suggest that it is necessary to distinguish the forms of NeuAc when attempting to determine the physiological role of human milk NeuAc in infants.

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The contents of 3′-sialyllactose and 6′-sialyllactose in human milk were determined by high-performance liquid chromatography in 2, 279 specimens of human milk collected between 3 and 482 days postpartum from 2, 434 mothers living in various districts of Japan in the winter and summer of 1989. The content of 3′-sialyllactose remained at between 10 and 17mg/100ml during lactation, whereas that of 6′-sialyllactose decreased from 77.8mg/100ml to 12.8mg/100ml in summer milk, and from 75.9mg/100ml to 9.6mg/100ml in winter milk. The 6′-sialyllactose content at the end of lactation was about 14-17% of that in colostrum. The total amount of 3′-sialyllactose and 6′-sialyllactose decreased from 85-90mg/100ml (3-15 days postpartum) to 25mg/100ml (241-482 days postpartum). The ratio of NeuAc in total sialyllactose to that in whole milk increased from 28.6% (3-5 days postpartum) to 46.0% (121-240 days postpartum). The ratio of NeuAc in sialyllactose to that in the 12% TCA-soluble fraction increased from 39.2% (6-10 days postpartum) to 63.3% (121-240 days postpartum). The data presented here indicate that sialyllactose is the most abundant NeuAc-containing oligosaccharide in human milk and an important source of sialic acid for infants.

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Experiments were conducted to determine the influences of low and high saturation of dietary lipids on the levels of liver triacylglycero1 (TG) and phospholipids (PL) and their fatty acid composition in fasted rats, and the effect of oral administration of linoleic acid during fasting. The level of liver TG and its proportion of linoleic acid in rats fed a 5% corn oil diet were increased during fasting to a greater degree than those in rats fed a 5% beef tallow diet. Linoleic acid of liver PL was slightly increased in both dietary groups. Liver TG levels and the proportions of linoleic acid in both liver TG and PL were markedly increased by oral administration of linoleic acid during fasting. Administration of oleic acid during fasting slightly increased the level of liver TG and its proportion of oleic acid. These findings suggest that supply of linoleic acid during fasting stimulates the accumulation of liver TG enriched with linoleic acid.

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The influence of refeeding either a 5% corn oil, or 5% or 30% beef tallow diet after a 48-h fast on the levels of liver triacylglycerol (TG), serum free fatty acids (FFA) and their fatty acid composition was determined. Glucose-6-phosphate dehydrogenase (G6PDH) activity was higher in fasted-refed rats than in fasted rats. Inversely, levels of serum FFA and liver TG were lowered during refeeding. Refeeding a high fat diet suppressed the changes in these parameters. Levels of liver TG and the proportion of linoleic acid were increased during fasting and decreased during refeeding the low-fat diets. The proportion of linoleic acid in liver TG of rats refed the high-fat diet was decreased to a smaller extent than that of rats refed the low-fat diets. G6PDH activity was inversely related to the proportion of linoleic acid in liver TG. Changes in liver lipogenesis might affect the relative proportion of polyunsaturated fatty acids in liver TG.

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This study examined the absorption rate of D-phenylalanine (Phe) and L-Phe across the small intestine of rats, and the influence of intestinal wall cells and microbes on the degree of conversion of D-Phe to L-Phe using the stable isotope tracer technique. D-Phenyl (d₅) alanine (D-Phe (d₅)) was prepared by the hydrogendeuterium exchange method, and mixed in equimolar proportions with commercial L-Phe (d₈). The mixture was administered to two groups of rats by intraperitoneal injection (I.P.) and oral ingestion (Or.), respectively. 1) Blood Phe (d₅) and Phe (d₈) levels were determined by the GC-MS-SIM method. (a) The concentration curve after I.P. showed that the half-life of the D-form (Phe (d₅)) was 30min and that of the L-form (Phe (d₈)) was 15min. (b) The curve after Or. suggested that the D-form was absorbed more slowly than the L-form. 2) L-Phe (d₅) /D-Phe (d₅) ratios in the blood were determined by the LC-MS-SIM method. L-forms converted from D-forms accounted for about 10% of the total available D-forms for both I.P. and Or. These results show that the participation of both intestinal microbes and the process of absorption through intestinal wall cells may be disregarded in the conversion of D-Phe to L-Phe.

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An investigation was conducted on the bioavailability of milk calcium prepared from rennet casein (milk Ca preparation), in comparison with soluble calcium mixed at the same ratio as that found in milk (calcium from Ca₃ (C₆H₅O₇) 2·4H2O, 56%; CaCl₂, 30%; Ca₃ (PO₄) ₂, 14%: soluble Ca preparation), and CaHPO₄. Eight-week-old SD rats were randomly divided into three groups and given the milk Ca preparation, soluble Ca preparation, or CaHPO₄. All the rats received the same amount of calcium (0.52%), phosphate (0.40%), and magnesium (0.05%). Calcium balance, plasma calcitonin level, and femur calcium gain (difference in femur calcium content between 14-week-old and 8-week-old rats) in each group were determined. No significant differences in serum calcium levels, food efficiency, or body weight gain were found among the three groups. However, the milk Ca group showed significantly higher levels of urinary calcium excretion and plasma calcitonin concentration than the CaHPO₄ group. In the milk Ca group, femur calcium gain was larger than that in the other two groups. These results imply that the milk Ca preparation is absorbed well and increases bone calcium content efficiently, in comparison with the soluble Ca preparation and CaHPO₄.

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Polyamines are thought to play an essential role in cell growth, proliferation and hypertrophy. Ornithine decarboxylase (ODC), the first and rate-limiting enzyme in the polyamine biosynthesis pathway, has the shortest half-life of all mammalian enzymes studied so far, and increases rapidly in response to various growth stimuli. We investigated whether myocardial ODC activity was affected by dietary protein in rats adapted to meal-feeding. Myocardial ODC was induced significantly by feeding a casein diet but not by feeding a non-protein or a zein diet. Essentially the same results were obtained for isoproterenol-induced myocardial ODC activity, which was significantly higher in the casein-fed rats than in the starved or non-protein-fed rats. These results suggest that protein nutrition plays an important role in cardiac growth under both normal and increased sympathetic activity.

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The effects of Spirulina platensis on ethanol metabolism were studied in rats. Male Wistar rats aged 5 weeks were fed on a basal diet or a Spirulina-containing diet for 28 days. The blood ethanol level at 30min after intraperitoneal injection of ethanol (200mg/100g body weight) was decreased by Spirulina feeding. To determine whether Spirulina affects ethanol metabolism, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activities were measured in rats fed ethanol plus Spirulina for 21 days. Spirulina feeding decreased the K_m value of ALDH to acetaldehyde from 0.91mM to 0.70mM. On the other hand, Spirulina feeding did not alter ADH activity. These results suggest that Spirulina may accelerate ethanol metabolism, resulting in rapid clearance of ethanol from blood into the liver.

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Japanese quail were fed different types of dietary fat in combination with chalesterol, and then data on serum and liver lipid concentration and the fatty acid camposition of dietary fats were subjected to principal component analysis to evaluate the degree of atherogenicity. Scores of the first principal component were well correlated with the atherosclerotic index of the dietary fat (r=-0.71, ρ<0.01), and enabled us to evaluate the atherogenicity of the fat. Inspection of factor loading far fatty acids in the first principal component revealed that polyunsaturated or medium-chain fatty acids were anti-atherogenic, whereas oleic acid was atherogenic.

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The effect of corn bran hemicellulose (CBH) on lipid metabolism was studied in ovariectomized rats (OVX-rats) fed a cholesterol-free 20% casein diet with no added fiber (FF diet). OVX rats were fed either the FF diet or the FF diet supplemented with 5% CBH (CBH diet) and pair-fed with rats given a shamoperation and fed the FF diet. In rats fed the FF diet, the plasma cholesteral concentration (p-chol) was higher in OVX rats than in rats given a shamoperation although the difference was not significant. When compared with OVX rats fed the FF diet, OVX rats fed the CBH diet had: (1) lower p-chol, (2) higher liver cholesterol, (3) higher excretion of bile acid into feces. The mechanism of the hypocholesterolemic effect of CBH remains to be elucidated.

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