Recent dietary life involves frequent opportunities for the ingestion of purified, processed food products and preserved foods, and it has been pointed out that the current dietary mineral intake strongly tends toward nutritional imbalance. The Ryukyu Islands yield coral which contains calcium and magnesium in a content ratio of about 2 to 1, with their approximate contents of 20 and 10%, respectively. In this report, the calcium absorption from the ingestion of crackers into which the coral powder was incorporated (coral-added crackers) and that from ingestion of calcium carbonate-added crackers was comparatively assessed. Twelve healthy adult volunteers (6 men and 6 women) ingested coral-added crackers (calcium content: 525mg) and calcium carbonate-added crackers (ditto) once each alternately on a cross-over design with a wash-out period of 3 d between the regimens. The study also included controls receiving neither cracker. The degree of intestinal absorption of calcium from coral-added crackers and that from calcium carbonate-added crackers was evaluated in terms of increment in urinary calcium excretion per dL of glomerular filtrate (GF) (difference between coral calcium and calcium carbonate) and increase in urinary calcium excretion per millgram creatinine (difference from control value). The increment in urinary calcium excretion per dL of GF during the latter half of the observation period after the ingestion of coral-added crackers was significantly greater than that during the latter half of the observation period after ingestion of calcium carbonate-added crackers (p=0.039, paired t-test). A significant difference (from control value) in the increase of urinary calcium excretion per milligram creatinine was also observed (p=0.0008). The present data, though from a relatively few study subjects, suggest that the calcium of coral origin is better absorbed from the intestine than calcium of calcium carbonate origin on the average.
Using 351 one-day weighed diet records, we selected foods providing vitamins, minerals and dietary fiber according to contribution analysis (CA) and multiple regression analysis (MRA). Vitamin C was supplied by various vegetables and fruits, and carotene was specifically derived from green-yellow vegetables based on MRA as well as CA. Vitamin A was provided by green-yellow vegetables, fruits, chicken egg and milk (whole) according to CA; whereas chicken liver and pork liver were major sources according to MRA. Vitamin E was mainly of vegetable origin as determined by CA, and largely of spinach, safflower oil and pumpkin as determined by MRA. Vitamin D was mainly derived from chicken egg, fish and mushroom based on CA, and particularly from fish based on MRA. Calcium was supplied by milk (whole), soy products and chicken egg as determined by CA; while milk, tofu and various small fishes were the main contributors to variance. Magnesium was provided by soy products, well-milled rice and spinach according to both analyses, and iron by chicken egg, spinach and soy products. Zinc was largely derived from well-milled rice, followed by chicken egg and milk (whole) as determined by CA, and copper was provided by well-milled rice, soy and wheat products. Dietary fiber was supplied by vegetable sources, whether water soluble or insoluble, based on both analytic methods.
A cross-sectional sample of 253 ambulatory elderly Egyptians (99 males and 154 females) of minimal age, 60y, living in the metropolitan Cairo area was investigated. Nutritional status assessment was based on body weight, mid-upper arm circumference and skinfold thickness. Additionally, three nutritional indices, namely body mass index, index of adiposity and index of muscularity, were computed. The oral cavity was examined clinically to evaluate the number and health condition of teeth present. Results showed that the anthropometric nutritional indicators were higher than expected, however, they decreased by age in both sexes. In addition, the values of body mass index and index of adiposity in females were significantly higher than in males, while the reverse was observed in regards to muscularity index (p<0.05). The three nutritional indices in dentate subjects were slightly higher than those in edentulous ones. Moreover, within the dentate groups there was a tendency for increased values of these indices by the increasing number of healthy teeth.
We hypothesized that bone acquisition was affected by the timing of meal intake after resistance exercise training. This was based on the following previous results: 1) Nutrient intake right after exercise resulted in an increase in muscle mass and a decrease in abdominal fat mass as well as muscle protein synthesis when compared to the intake of a meal later after the exercise; and 2) body composition has been proposed to be a good predictor of bone mass. To substantiate our hypothesis, 20 male rats were assigned to either a group fed a meal right after squat exercise (R) or a group fed a meal 4 h after the exercise (L). The 10-wk training program consisted of approximately 70% of one repetition maximum for each animal, 15 repetitions per set, 10 sets per day, 3 d per week. As a result, hindlimb muscle mass in the R group was greater (p<0.05) than that in the L group and abdominal fat mass was less (p<0.01) in the R group as compared to the L group, regardless of there being no significant difference in body weight between the groups. Bone volume in the tibia (p<0.01) and femur (p0.05) were both significantly greater in the R group than in the L group. Bone mineral content index (BMCI) and bone mineral density index (BMDI) in the tibia of the R group were significantly (p0.05) greater than the corresponding values of the L group. The greater BMCI and BMDI in the tibia were positively and significantly (p<0.05) related with hindlimb muscle mass, but not with abdominal fat mass. There was no significant difference in BMCI and BMDI in the femur between the groups. These results suggest that the R regimen may contribute to increased bone acquisition in the tibia as compared to the L regimen, and this effect is partly due to the enlargement of muscle mass in the R group as compared to the L group.
Many studies suggest that a diet supplemented with fish oil concentrates (FOCs) may provide protection against cardiovascular and other diseases. The possible harmful effects of long-term consumption of high doses of FOCs, however, have not been adequately investigated. Corn oil, fish oil (MaxEPA) and various mixtures of the oils were administered by gavage to 120 male and 120 female rats, 5d/wk for 13 wk at the rate of 5mL/kg/d. Although MaxEPA had no effect on prothrombin time or activated partial thromboplastin time, it caused a statistically significant diminution of the total serum cholesterol level. Correlations between relative liver and spleen weights and dose levels were positive but a nega-tive correlation was found between dose levels and serum vitamin E concentration. In female rats, the negative correlations between dose levels and serum iron and triglyceride levels were highly significant. The pathology data showed no remarkable lesions in any of the tissues examined. Results of this study suggest that long-term consumption of high levels of FOCs in rats may reduce serum cholesterol and triglycerides and adversely affect serum iron level and relative liver weight in female rats and relative spleen weights in both sexes.
We studied the effects of the new amino acid solution MRX-III on the nutritional status and nitrogen metabolism of rats with chronic renal failure (CRF) in comparison with those of a general amino acid solution (MPR-F). The essential amino acids/non-essential amino acids ratio was 3.21 for MRX-III and 1.09 for MPR-F. Rats with CRF, induced by 7/8 renal ablation, were divided into 6 groups of 8 rats each receiving total parenteral nutrition (TPN) containing MRX-III or MPR-F at a non-protein calorie/nitrogen ratio (Cal/N) of 300, 600 or 900 for 7 d. The rats were infused with test solutions containing the same amounts of non-protein calories. The cumulative nitrogen balance, as a nutritional index, in the MRX-III group was significantly higher than that in the MPR-F group at the Cal/N of 600 or 900, and the plasma albumin level at the Cal/N of 300. The plasma transferrin levels at the Cal/N of 900 in the MRX-III groups were significantly higher than those in the corresponding MPR-F groups. At all Cal/N, the MRX-III groups showed low levels of blood urea nitrogen and urinary excretion of ammonia and urea nitrogen as compared with the MPR-F groups at the same Cal/N. The plasma amino acid concentration profiles in the MRX-III groups after TPN showed greater similarity to that in the Normal group as compared with the profiles in the corresponding MPR-F groups. No aggravation of renal failure was observed in any TPN groups during TPN. These results indicate that, in rats with CRF undergoing hyperalimenta-tion, the effects of MRX-III on the nutritional status and nitrogen metabolism are superior to those of the general amino acid solution, MPR-F. It is suggested that MRX-III could safely provide adequate amounts of nitrogen during hyperalimentation.
To study whether consumed dietary fat has a linear re-lationship or a threshold with glycemic controls, female C57BL/6J mice were fed different levels of a safflower oil (10, 20, 30, 40, 50, and 60% of total energy) diet ad libitum for 15 wk. Food intake, body weight, parametrial white adipose tissue (WAT) and liver weight were measured, and oral glucose tolerance tests were conducted. Although there was no significant difference in average energy intake, graded increments of safflower oil resulted in graded deterioration of glucose tolerance during 5 and 12-wk feeding, and deterioration of glucose tolerance was more manifested after 12-wk feeding as compared to 5-wk feeding. After 12-wk feeding, a significant deterioration of glucose tolerance was observed in diets of more than 40% fat. Graded increments of body weight and WAT weight were observed, and their weight increases were manifested in diets of more than 30% fat. These data indicated that the amount of dietary fat had an almost linear relationship with glucose tolerance, and significant differences were observed in mice fed diets more of than 40% fat.
The effects of various phosphate salts as the dietary phos-phorus sources on the development of nephrocalcinosis and kidney func-tion were examined in rats fed diets containing monophosphate salts (sodium dihydrogenphosphate, NaH2PO4, or potassium dihydrogen-phosphate, KH2PO4) or polyphosphate salts (sodium tripolyphosphate, Na5P3O10, or potassium tripolyphosphate, K5P3O10), at levels represent-ing normal phosphorus (normal phosphorus diet) or high phosphorus (high phosphorus diet) contents for 21d. High phosphorus diet-feeding increased the kidney calcium and phosphorus concentrations. Kidney calcium and phosphorus concentrations were higher in rats fed the high phosphorus diet containing Na5P3O10 or K5P3O10 than in rats fed the high phosphorus diet containing NaH2PO4 or KH2PO4. Nephrocalcinosis was observed in all rats fed a high phosphorus diet, and the degree of nephrocalcinosis was more severe in rats fed Na5P3O10 or K5P3O10 than in rats fed NaH2PO4 or KH2PO4. In rats fed the high phosphorus diet, creatinine clearance was higher in rats fed Na5P3O10 or K5P3O10 than in rats fed NaH2PO4 or KH2PO4. In rats fed Na5P3O10 or K5P3O10, urinary albumin excretion and N-acetyl-β-D-glucosaminidase (NAG) activity in the urine were increased in rats fed the high phosphorus diet. These were higher in rats fed the high phosphorus diet containing Na5P3O10 than in rats fed the high phosphorus diet containing NaH2PO4 or KH2PO4. This study observed that the development of nephrocalcinosis and kidney function in rats fed the high phosphorus diet was influenced by the difference in monophosphate or polyphosphate salts provided as the dietary phosphorus source, while the effects of sodium and potassium salts were not evident. We suggest that the development of nephrocalcinosis and kidney function in rats fed a high phosphorus diet was altered depending on the form of phosphate salts provided as the dietary source of phosphorus. Additionally, the development of nephrocalcinosis and diminished kidney function in rats fed the high phosphorus diet was more severe for polyphosphate salts as compared to monophosphate salts.
We have developed a new noninvasive method of estimating abdominal fat volume in live rats using ultrasonography. By this method, cross sections of perirenal (retroperitoneal) fat tissue, which is an abdominal fat, at the renal vein level could be identified and the area determined. The perirenal fat in Wistar rats (wide body weight range, 111.4 to 497.3g; limited range, 300.1 to 337.9g) measured by ultra-sonography was compared with the actual fat tissue weight. The cross-sectional area of perirenal fat tissue was significantly correlated to the actual whole tissue weight. Using this procedure, we examined the changes of perirenal fat stores during fasting. Consequently, the cross-sectional area of perirenal fat and its actual weight decreased in parallel. Total body electrical conductivity (TOBEC) is currently used to measure fat-free mass (FFM) and indirectly predicts total body fat mass of live laboratory animals. The body fat distribution, that is, the location of adipose tissue in the abdominal region, is closely associated with obesity-related diseases. Therefore, it is important to focus not only on the accumulation of total body fat, but also on that of abdominal fat. The present ultrasonographic method is considered to be useful for repeated noninvasive measurement of abdominal fat in the live rat.
The characteristic cyclic variation in feed intake of rats fed a Zn-deficient diet (Mills et al, Am J Clin Nutr 22: 1240-1249 (1969)) followed a Cosinor curve, as determined by computer analysis (Tamaki et al, Br J Nutr 73: 711-722 (1995)). The values of amplitude for the feed-intake cycle had a positive correlation to their own day-to-day variations and to the correlation value of their own simulated cycles (r2=0, 764, df=50, p<0.001 and r2=0.682, df=50, p<0.001, respectively). The cyclic variation in feed intake was accompanied by a cyclic variation in body-weight change in rats fed the Zn-deficient diet, and cyclic variation in body-weight change occurred similarly in pair-fed control rats. There were no differences in the mesors of body-weight change cycles of Zn-deficient rats and pair-fed control rats (Zn-deficient rats: 2.5±1.0g/d, pair-fed rats: 2.8±1.0g/d, mean±SD, df=18, t=-0.674, ND). Rats fed the Zn-deficient diet were given different amounts of Zn supplementation by daily subcutaneous injection. The amplitude of the feed-intake cycle was decreased with increasing Zn supplementation (r2=0.919, df=5, p<0.001). The concentration of Zn for the appearance of the feed-intake cycle was estimated to be 71.6+6.6μg/d per rat. The Zn level in the serum showed a significant decrease in the Zn-deficient diet groups, but the supplement of Zn did not vary in the Zn-deficient rats injected with up to 47.3μg/d per rat. From these results, an analysis of the feedintake cycle allowed us to estimate the quantitative Zn-deficient status of rats.
Prolonged depletion of dietary n-3 fatty acid induces a neurological disturbance. To ascertain the deficit of neurotransmission at the time of n-3 deficiency, the concentrations of cAMP and inositol triphosphate, and the activities of protein kinases A and C were examined in vitro in rat hippocampus. Furthermore, the saturation binding study of [3H]quinuclidinyl benzilate, a specific antagonist to muscarinic cho-linergic receptor, was performed. Rats were fed a safflower oil diet as the deficient group and a soybean oil diet as the control group. Hippocampi were obtained from rats in the 3rd generation in the deficient group and in the 2nd generation in the control group. Dietary effect was not observed in the parameters except for the concentration of cAMP, which was significantly higher in the deficient group than in the control group.
The effects of allylthiamindisulfide, an allyl derivative of thiamin, and related compounds on thermogenesis were investigated by measuring noradrenaline and adrenaline secretion and the temperatures of interscapular brown adipose tissue (IBAT) and rectum in rats. In Experiment 1, the effects of the administrations of allylthiamindisulfide and related compounds on noradrenaline and adrenaline secretion were evaluated as compared to thiamin in anesthetized rats. The administration of allylthiamindisulfide significantly increased the plasma concentrations of noradrenaline and adrenaline. These increases were dose dependent, while that of thiamin was not. Four synthetic compounds related to allylthiamindisulfide also increased the plasma adrenaline and noradrena-line concentrations. In Experiment 2, the effects of allylthiamindisulfide on thermogenesis were investigated by the direct measurement of tem-peratures in the IBAT and rectum in anesthetized rats, and compared to the effects induced by thiamin and diallyldisulfide. The temperatures in the IBAT and rectum were significantly increased by the administration of allylthiamindisulfide and diallyldisulfide, while there was no significant increase as the result of thiamin administration. These results suggest that allylthiamindisulfide and related compounds enhance thermogenesis by increasing noradrenaline and adrenaline secretion in rats.
We previously found that docosahexaenoic acid (DHA) intake prevented aggression from increasing at times of mental stress. In the present study, we investigated whether DHA intake modified the plasma catecholamines and cortisol of medical students during a 9-wk period of final exams. We also investigated the effects of DHA intake on a 75g oral glucose tolerance test (oGTT). Fourteen medical students participated in the present study. They were randomly allocated to either control or DHA group in a double-blind manner. Subjects in the control group (4 males and 3 females) took 10 control capsules/d, each capsule containing 280mg of mixed plant oil, and those in the DHA group (4 males and 3 females) took 10 DHA capsules/d containing 1.5g DHA for 9 wk, during which subjects underwent more than 20 stressful final exams. At the start and end of the study, plasma catecholamines (epinephrine, norepinephrine (NE) and dopamine) and cortisol were measured; a 75g oGTT was also performed. There were no intra- or intergroup differences in plasma glucose concentrations. However, NE concentrations were significantly reduced after DHA administration (-31%, p<0.03). The other catecholamines and cortisol did not change significantly. The plasma ratio of epinephrine to NE increased in every DHA subject (+78%, p<0.02), and intergroup differences were sig-nificant (p<0.03). We conclude that these effects of DHA may be applied to people under long-lasting psychological stress to prevent stress-related diseases.
We previously demonstrated that plasma glucose concentra-tion was higher while plasma insulin concentration was lower in rats fed a high-fat diet. In the present study, we examined the effects of high-fat diet on glucose uptake in central and peripheral tissues in non-obese rats. Forty male Sprague-Dawley rats were fed high- or low-fat diets for 4 wk. Body weight and body fat accumulation were not different between the two diet groups after 4 wk. Glucose uptake in the skeletal muscles and adipose tissues, estimated by the 2-deoxy-D-glucose method, was lower in the rats fed the high-fat diet than that in the rats fed the low-fat diet, whereas uptake in the liver and pancreas did not differ between the two groups. Glucose uptake in the hypothalamus and cortex was higher in the high-fat diet group as compared with that in the low-fat diet group. These results suggest that increased plasma glucose levels in rats fed the high-fat diet were caused by a decrease in glucose uptake in the skeletal muscles and adipose tissues. Reduced plasma insulin level in the high fat diet group with no difference in glucose uptake in the pancreas may be due to increased sympathetic activity in the pancreas resulting from the increased glucose uptake in the brain regions involved in autonomic functions.