Influence Of Dietary Carbohydrate Research Articles

The impact of macronutrient composition on metabolic regulation: An Islet-Centric view.

The influence of dietary carbohydrates and fats on weight gain is inconclusively understood. We studied the acute impact of these nutrients on the overall metabolic state utilizing the insulin:glucagon ratio (IGR). Following in vitro glucose and palmitate treatment, insulin and glucagon secretion from islets isolated from C57Bl/6J mice was measured. Our human in vivo study included 21 normoglycaemia (mean age 51.9 ± 16.5 years, BMI 23.9 ± 3.5kg/m2 , and HbA1c 36.9 ± 3.3 mmol/mol) and 20 type 2 diabetes (T2D) diagnosed individuals (duration 12 ± 7 years, mean age 63.6 ± 4.5 years, BMI 29.1 ± 2.4kg/m2 , and HbA1c 52.3 ± 9.5 mmol/mol). Individuals consumed a carbohydrate-rich or fat-rich meal (600 kcal) in a cross-over design. Plasma insulin and glucagon levels were measured at -30, -5, and 0min, and every 30 min until 240 min after meal ingestion. The IGR measured from mouse islets was determined solely by glucose levels. The palmitate-stimulated hormone secretion was largely glucose independent in the analysed mouse islets. The acute meal tolerance test demonstrated that insulin and glucagon secretion is dependent on glycaemic status and meal composition, whereas the IGR was dependent upon meal composition. The relative reduction in IGR elicited by the fat-rich meal was more pronounced in obese individuals. This effect was blunted in T2D individuals with elevated HbA1c levels. The metabolic state in normoglycaemic individuals and T2D-diagnosed individuals is regulated by glucose. We demonstrate that consumption of a low carbohydrate diet, eliciting a catabolic state, may be beneficial for weight loss, particularly in obese individuals.

Dietary survey in Japanese patients with type 2 diabetes and the influence of dietary carbohydrate on glycated hemoglobin: The Sleep and Food Registry in Kanagawa study.

Aims/IntroductionThe present study investigated the relationship between the macronutrient energy ratio, dietary carbohydrate and glycated hemoglobin levels in Japanese patients with type 2 diabetes, to generate a potential optimal dietary intake of macronutrients for such patients.Materials and MethodsIn total, 3,032 patients participating in the Sleep and Food Registry in Kanagawa study were evaluated. Their diets were assessed for macronutrient content through a brief self‐administered dietary history questionnaire. Relevant biochemical assays were carried out.ResultsThe mean energy intake (±standard deviation) was 1,711 ± 645 kcal/day. The proportion of energy supplied by protein, fat and carbohydrate were 16.3, 26.8 and 52.3%, respectively. Total fiber intake was 12.6 ± 5.7 g/day. The high glycated hemoglobin (HbA1c) group (HbA1c >8%) had significantly lower protein and higher carbohydrate intake than the low HbA1c group (HbA1c <6.5%). Higher HbA1c levels were positively correlated with unfavorable metabolic factors, including elevated body mass index and excess carbohydrate intake, and negatively correlated with age, protein intake and fiber intake. Multiple regression analysis showed a significant association between HbA1c and carbohydrate intake after adjusting for sex, age and body mass index (0.104, P < 0.0001). Additionally, patients within the uppermost tertile for the percentage of total energy intake from carbohydrate (>60%) were most likely to have high HbA1c levels. HbA1c was significantly correlated with carbohydrate (%E) in all age groups and in patients taking one or two antidiabetic drugs.ConclusionsThe dietary carbohydrate:energy ratio has a positive correlation with HbA1c, suggesting that avoiding excessive carbohydrate intake (>60%) might help foster glycemic control.

Influence of dietary carbohydrate and protein on colonic fermentation and endogenous formation of N-nitroso compounds

Influence of dietary carbohydrate and protein on colonic fermentation and endogenous formation of N-nitroso compounds

Association of Diet-Induced Hyperinsulinemia With Accelerated Growth of Prostate Cancer (LNCaP) Xenografts

Prior research suggested that energy balance and fat intake influence prostate cancer progression, but the influence of dietary carbohydrate on prostate cancer progression has not been well characterized. We hypothesized that hyperinsulinemia resulting from high intake of refined carbohydrates would lead to more rapid growth of tumors in the murine LNCaP xenograft model of prostate cancer. Athymic mice were injected subcutaneously with LNCaP human prostate cancer cells and, when tumors were palpable, were randomly assigned (n = 20 per group) to high carbohydrate-high fat or low carbohydrate-high fat diets. Body weight and tumor volume were measured weekly. After 9 weeks, serum levels of insulin and insulin-like growth factor 1 (IGF-1) were measured by enzyme immunoassay. AKT activation and the levels of the insulin receptor in tumor cells were determined by immunoblotting. The in vitro growth response of LNCaP cells to serum from mice in the two treatment groups was measured based on tetrazolium compound reduction. All statistical tests were two-sided. After 9 weeks on the experimental diets, mice on the high carbohydrate-high fat diet were heavier (mean body weight of mice on the high carbohydrate-high fat diet = 34 g versus 29.1 g on the low carbohydrate-high fat diet, difference = 4.9 g, 95% CI = 3.8 to 6.0 g; P = .003), experienced increased tumor growth (mean tumor volume in mice on high carbohydrate-high fat diet = 1695 versus 980 mm3 on low carbohydrate-high fat diet, difference = 715 mm3, 95% CI = 608 to 822 mm3; P<.001), and experienced a statistically significant increase in serum insulin and IGF-1 levels. Tumors from mice on the high carbohydrate-high fat diet had higher levels of activated AKT and modestly higher insulin receptor levels than tumors from mice on the low carbohydrate-high fat diet. Serum from mice on the high carbohydrate-high fat diet was more mitogenic for LNCaP cells in vitro than serum from mice fed the low carbohydrate-high fat diet. A diet high in refined carbohydrates is associated with increased tumor growth and with activation of signaling pathways distal to the insulin receptor in a murine model of prostate cancer.

Influence of dietary carbohydrate and fat on LDL and HDL particle distributions

Variations in the size and density distributions of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particles have been related to risk for cardiovascular disease. In particular, increased levels of small, dense LDL particles, together with reduced levels of large HDL and increases in small HDL, are integral features of the atherogenic dyslipidemia found in patients with insulin resistance, obesity, and metabolic syndrome. Increased dietary carbohydrates, particularly simple sugars and starches with high glycemic index, can increase levels of small, dense LDL and HDL, primarily by mechanisms that involve increasing plasma triglyceride concentrations. Low-carbohydrate diets may have the opposite effects. Diets with differing fatty acid composition can also influence LDL and HDL particle distributions.

Influence of dietary carbohydrates and glycaemic response on subjective appetite and food intake in healthy elderly persons

Increased satiety and decreased food intake are reported following the consumption of low glycaemic index (GI) foods, which gradually increase blood glucose. This observation, however, is not uniformly supported and few studies have examined the impact of different GI foods on satiety and intake in the elderly. After an overnight fast, 10 men and 10 women (aged 60-82 years) consumed similar amounts of available carbohydrate as high (glucose drink or potatoes) or low (barley) GI foods or a non-energy placebo drink on four mornings. Blood glucose and subjective appetite were measured throughout a 120 min post-ingestion period, followed by consumption of an ad libitum lunch. Differences in plasma glucose after test food ingestion (glucose > potatoes > barley > placebo; P < 0.03) did not predict subjective appetite or lunch intake. Potatoes increased subjective satiety the most, followed by barley, then glucose, which trended towards greater satiety than placebo. Potatoes led to less hunger than placebo (P = 0.0023) and less prospective consumption than the other three foods (P < 0.0083), and potatoes and barley led to greater fullness than glucose and placebo (P < 0.0001). Lunch intake was decreased, compared with placebo (502 ± 47 kcal, P < 0.031), by potatoes (405 ± 40 kcal) and barley (441 ± 41 kcal); however, only potatoes (41.9 ± 12.3%) led to greater compensation at lunch for test food ingestion compared with glucose (11.9 ± 9.5%, P = 0.016). These results suggest that elderly subjects are sensitive to the effects of different foods on subjective appetite and food intake, and that the GI of the foods tested did not predict their effects on satiety and food intake.

Influence of dietary carbohydrate on antioxidant enzyme activities in liver of Atlantic salmon (Salmo salar L.)

Effects of dietary carbohydrates on hepatic antioxidant enzymeactivities were studied in Atlantic salmon (Salmo salarL.), fed diets containing no additional carbohydrate, or a low (15% addition)orhigh (30% addition) concentration of D-glucose or gelatinised potato starch.Addition of free glucose to the feeds resulted in glucose availability being 7and 18% when added at 15 and 30%, while the addition of gelatinised starch didnotseem to reduce starch availability. The dietary treatment groups (nocarbohydrate, 7 and 18% glucose or 15 and 30% gelatinised starch) were providedwith quantities of feed that supplied the same amounts of protein and lipid.There was a positive correlation between tiobarbituric acid-reactive substances(TBARS) in feeds and salmon liver. Liver glycogen concentrations increased withincreasing dietary glucose and starch, and the two higher levels of liverglycogen, found in groups G18 and S30, resulted in decreased activities ofcatalase, superoxide dismutase (t-SOD), and concentrations of glutathione. Thisindicates that there are links between carbohydrate metabolism and antioxidantsystems in salmon liver. There was no correlation between selenium dependentglutathione peroxidase (Se-GPX) activity and dietary carbohydrateconcentrations, but Se-GPX activity increased in response to increased TBARS.Catalase and t-SOD activities did not correlate with either TBARS values orSe-GPX activity.

Influence of dietary carbohydrate on zinc-deficiency-induced changes in oxidative defense mechanisms and tissue oxidative damage in rats.

The aim of this study was to determine the effect of dietary carbohydrate type on the expression of zinc (Zn) deficiency in rats with respect to tissue oxidative damage and defense mechanisms. Rats were fed diets containing adequate (+Zn) or low concentrations (-Zn) of Zn. Both fructose- and glucose-based diets were tested. Pair-fed controls were also studied to evaluate changes in the oxidative defense system which are secondary to Zn-deficiency-induced anorexia. Plasma and liver Zn concentrations and CuZn superoxide dismutase activities were lower in the -Zn rats than in the +Zn rats. Liver glutathione (GSH) and disulfide glutathione concentrations were higher in the -Zn rats than in the +Zn rats; this difference was most pronounced in the fructose groups. Liver and heart selenium glutathione peroxidase (Se-GSH-Px) activities were lower in the -Zn-fructose group than in the +Zn-fructose group. Liver Se-GSH-Px activity was higher in the fructose groups than in the glucose groups. Liver GSH reductase (GSH-Red) activity was lower in the -Zn-fructose group than in its control group. Liver glutamine synthetase activity was lower in the -Zn-glucose group and in the fructose groups than in the glucose control group. Liver thiobarbituric acid reactive substance (TBARS) production was similar among the groups. Collectively, these results support the concept that Zn deficiency can result in an impaired oxidant defense system. Based on the observation that pair-fed control animals also showed evidence of oxidative damage, we suggest that one factor that contributes to the effect of Zn deficiency is the reduction in caloric intake that occurs in these animals. Fructose feeding resulted in increased activities of several of the oxidant defense enzymes. Protein oxidative damage assessed by glutamine synthetase activity was increased by both Zn deficiency and fructose feeding.

Secretion of 13C-Labelled Oligosaccharides into Human Milk and Infant's Urine after an Oral 13C-Galactose Load

Human milk oligosaccharides seem to play an important role in the infant's defense against bacterial and viral infections of the gastrointestinal and the urogenital tract. In this study, we investigated the influence of dietary carbohydrates on the biosynthesis of lactose and oligosaccharides in the human mammary gland and their renal excretion by the human milk-fed infant. For this purpose, a lactating woman was given 27 g galactose (Gal) containing 2 g [13C] Gal (1-13C/99%) immediately after breakfast. In the following 36 h. milk (5–10 ml) was collected before each nursing. Infant's urine was collected over a period of 24 h. 13C-enrichment was measured in total milk, milk fat and protein, in the carbohydrate fraction as well as in urine by isotope ratio mass spectrometry (IRMS). Milk carbohydrates and deproteinized urine samples were fractionated by Sephadex G25 gel nitration and further analyzed by IRMS, high performance thin layer chromatography and and high pH anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). IRMS revealed that in milk a maximal δ13CPDB was reached within 8h after Gal intake which then rapidly declined in the following 8h. The cumulative 13C-elimination over this first peak was 6.9% of the oral 13C-dose. The highest 13C-enrichment was detectable in the carbohydrate fraction, mainly in lactose and neutral oligosaccharides. Compared to the enrichment of human milk, the δ13CPDB of infant's urine was delayed. In urine, the highest amount of 13C was found in the Sephadex G25 fractions which mainly contained lactose, fucosyl-lactose, lacto-N-tetraose (LNT), fucosyl-LNT and difucosyl-LNT. For further characterization, individual components were separated by HPAEC-PAD and subsequently analyzed by fast atom bombardment mass spectrometry and IRMS. The data show, that orally applied Gal is incorporated in milk, especially in lactose and neutral oligosaccharides. Obviously, some of these components were absorbed by the infant and then excreted with urine. There, oligosaccharides may serve as analogous receptors for bacterial or viral adhesion molecules, and, hence, may prevent urogenital infections in breastfed infants.

Influence of dietary carbohydrate on blood chemistry, immunity and disease resistance in Atlantic salmon, Salmo salar L.

Abstract. The influence of dietary carbohydrate (CHO) on blood chemistry, immunity and disease resistance was studied in two experiments with Atlantic salmon, Salmo salar L. Moist diets with increasing amounts of digestible CHO ranging from 0 to 30% (dry weight) were used. In the first experiment with adult (0.5 kg) fish, blood haemoglobin concentration was negatively correlated with increasing dietary CHO level, while serum glucose and protein did not differ between the groups. Serum cortisol increased linearly in fish fed from 5 to 30% CHO. Serum haemolytic activity was negatively correlated with dietary levels of CHO. Humoral immune responses elicited after vaccination by intraperitoneal injection or by dip immersion with Vibrio salmonicida showed no differences according to diet 10 and 17 weeks post‐vaccination. Mortality after challenge with live Aeromonas salmonicida by intraperitoneal injection was lowest in fish fed 10% CHO. In the second experiment with juvenile Atlantic salmon (3g), there were minor differences in body and organ weights. Plasma glucose, protein and cholesterol were elevated in fish fed the highest CHO levels. Fish exposed to immersion challenge with different water concentrations of Vibrio anguillarum showed no statistical differences in mortality. The studies indicate that varying dietary levels of CHO affected immunity and resistance to bacterial infections to a minor extent in Atlantic salmon at low water temperatures during freshwater and seawater stages.

The influence of dietary carbohydrate and deferoxamine on developing copper deficiency of rats

The present investigation was conducted to follow the development of copper deficiency in male rats from weaning (day 0) to day 31 of dietary copper deprivation and to correlate changes in tissue sizes with copper and iron concentrations. Male rats were fed for 31 days from weaning copper-deficient or adequate diets containing fructose or starch. Another copper-deficient group of rats that was fed fructose was treated with deferoxamine. Rats were killed at day 0, 8, 16, 24, and 31 of the study. In general, no correlation could be found between the development of heart hypertrophy, pancreatic and thymic atrophy, and tissue copper concentrations in copper-deficient rats fed fructose. In contrast, in the heart and pancreas a negative correlation existed between tissue size and iron concentration. In addition, anemia preceded heart hypertrophy. Deferoxamine lowered hepatic iron concentrations, ameliorated the anemia, and decreased heart size compared with untreated rats. The data of the present study suggest that tissue atrophy and hypertrophy and the severity of copper deficiency are not solely due to tissue concentrations of iron and/or copper.

Effect of intravenous caffeine on muscle glycogenolysis in fasted exercising rats

Caffeine has been reported to enhance performance by increasing fat utilization and by sparing liver and muscle glycogen. The lipolytic effect of caffeine has been reported to be diminished in response to previous carbohydrate loading of the subjects. The present study was designed to investigate the effects of caffeine during submaximal exercise in rats where the influence of dietary carbohydrate was removed by fasting. Rats were fasted overnight and given injection of 25 mg.kg-1 caffeine (CAF) or 0.9% NaCl (SAL) 60 min before exercise. They were run for 15, 30, and 60 min on a rodent treadmill up a 15% grade at 21 m.min-1. Plasma free fatty acids (FFA) were significantly elevated to 0.72 +/- 0.04 mM in CAF as compared to 0.45 +/- 0.03 mM in SAL at the beginning of exercise. During exercise, however, a significant difference in FFA levels between CAF and SAL was seen only at 30 min and not at other time points. No significant decrease in muscle glycogenolysis was observed in the CAF as compared to SAL rats, and the liver cyclic AMP remained the same in both CAF and SAL. Blood lactate (mM) showed an increase due to caffeine only at 15 min of exercise (CAF = 2.4 +/- 0.2; SAL = 1.7 +/- 0.3). Intravenous caffeine during exercise did not alter plasma glucagon or blood glucose. We conclude that caffeine has no effect on muscle glycogen utilization in fasted rats during exercise even though there was an increased FFA in CAF rats at the beginning of exercise.

Effect of dietary carbohydrates on bacterial cholyltaurine hydrolase in poultry intestinal homogenates.

The bile salt hydrolase activity in intestinal homogenates reflects composite activities of the gastrointestinal microbial consortia. We have proposed that specific transformations of conjugated bile acids by the intestinal microflora result in the production of metabolites which depress the growth of poultry. The influence of dietary carbohydrates on the physical and kinetic properties of cholyltaurine hydrolase activity, one such bile acid-transforming enzyme in gastrointestinal homogenates of young chickens, was characterized by using a sensitive radiochemical assay. Cholyltaurine hydrolase activity in crude extracts of ileal homogenates was increased twofold by 0.25% Triton X-100 and a freeze-thaw cycle. The pH optimum for cholyltaurine hydrolase from ileal homogenates was very broad and reflected the pH range of poultry intestinal contents (i.e., 5.8 to 6.4). The carbohydrate component of the diet did not affect the apparent temperature optimum (41 degrees C) or stability profile, nor did it affect the apparent Km for taurocholic acid hydrolysis (approximately 0.43 mM). The enzymes in intestinal homogenates were active on all taurine-conjugated bile acids tested. The carbohydrate component of the diet did, however, affect the specific activity of cholyltaurine hydrolase in ileal homogenates from chickens. The levels of cholyltaurine hydrolase activity (rye greater than sucrose greater than corn) in homogenates from birds fed the different diets were directly related to the amount of growth depression (rye greater than sucrose greater than corn) associated with feeding these dietary carbohydrates. These data suggest that intestinal levels of cholyltaurine hydrolase are correlated with the amount of carbohydrate-induced growth depression in poultry.

The influence of dietary carbohydrate on antibody-mediated immunity in copper deficiency

The influence of dietary carbohydrate on antibody-mediated immunity in copper deficiency

Essential Fatty Acid Deficiency during Pregnancy in the Rat: Influence of Dietary Carbohydrates

We investigated the role of gestation in the development of essential fatty acids (EFA) deficiency by comparing four groups of nonpregnant rats and four groups of pregnant rats fed either glucose or sucrose as carbohydrate source (61.5% kJ) and either corn oil (EFA) or hydrogenated coconut oil [saturated fat (SF)] as fat source (5% kJ). Pregnancy was a crucial period for the onset of EFA deficiency in sucrose-fed rats. The arachidonic acid content of plasma lipids and liver microsomes was lower in SF-sucrose pregnant rats than in SF-sucrose nonpregnant rats. The liver microsome Δ6- and Δ5-desaturase activities were higher in sucrose pregnant rats than in sucrose nonpregnant rats. In glucose-fed rats the EFA deficiency was less severe. Δ6 - and Δ5-desaturase activities were higher in SF-glucose rats than in EFA-glucose rats, except for Δ5-desaturase of the pregnant rats, in which activity was high in both glucose-fed groups. This might explain the effect of glucose in preventing the onset of EFA-deficiency in pregnant rats fed an SF diet.

Short term essential fatty acid deficiency in rats. Influence of dietary carbohydrates.

The effects of long term (8-14 wk) essential fatty acid (EFA)-deprived diets in rats are well documented. In the present study, we compared, in weanling rats, the effect of a short term (two wk) hydrogenated coconut oil, EFA-deprived, diet (D) with that of a corn oil, EFA-adequate, diet (A), using either sucrose (SU) or starch (ST) as carbohydrate. After two wk, rats fed the sucrose/hydrogenated coconut oil diet developed some characteristic features of EFA deprivation: slower growth rate, decreases in linoleic and arachidonic acid of plasma phospholipids and an increase in n-9 eicosatrienoic acid of plasma phospholipids. When rats ate the starch/hydrogenated coconut oil diet, there was a similar decrease in linoleic acid of plasma phospholipids, but only a small effect on growth rate and no change in the arachidonic acid content of plasma phospholipids. EFA deprivation and sucrose had opposite effects on plasma triglyceride (TG) levels: deprivation induced a decrease, whereas the sucrose induced an increase in very low density lipoprotein (VLDL) triglycerides. The observed decrease in plasma triglyceride during EFA deprivation might result from an activation of lipoprotein lipase during the early stages of deprivation.

Influence of dietary carbohydrates upon the metabolism of lipids and minerals in rabbits

Rabbits were fed purified diets containing either corn starch, sucrose, glucose or fructose as 39.5% of the caloric content, or were fed a commercial diet. At the end of the 12-week trial period, glucose tolerance tests did not reveal a difference by treatment, and males had a lower tolerance than females. The serum cholesterol concentrations of the various density lipoproteins varied by treatment as determined weekly; often the HDL cholesterol was higher in the rabbits fed corn starch, and the VLDL cholesterol was higher in the rabbits fed corn fructose. Cholelithiasis at the end of the trial was prevalent in rabbits fed sucrose, glucose or fructose, was infrequent in the rabbits fed corn starch, and was absent in the rabbits fed the commercial diet. Lipid and cholesterol concentrations in the liver were greater in the rabbits fed the purified diets than in those fed the commercial diet. Cholesterol concentration in the thoracic aorta was greater in the rabbits fed the commercial diet than in those fed the purified diet. Analyses of liver and kidneys for Cr, Mn, Cu and Zn revealed treatment differences only in the case of the kidneys where Cr concentration was greater in the kidneys when the commercial diet was fed.

Influence of Dietary Carbohydrate on the Induction of Diabetes in C57BL/KsJ-db/db Diabetes Mice

Genetically diabetic C57BL/KsJ-db/db and normal littermate mice of both sexes were fed one of nine defined diets from weaning. The objective was to study dietary carbohydrate interaction with the diabetogenic genes through isocaloric substitution of protein for carbohydrate (either sucrose or dextrin starch) at concentrations of 0, 8, 24, and 60%. In addition, at 60% concentration, the effect of type of carbohydrate (e.g., glucose, fructose, sucrose or dextrin starch) on the deterioration of endocrine pancreatic structure and function was analyzed. The carbohydrate-free diet produced the greatest survival to 1 year of age and allowed the expression of an obesity syndrome uncomplicated by severe hyperglycemia or by extensive necrosis of pancreatic beta cells and islet atrophy. Those diets containing intermediate levels of carbohydrate (8 or 24% of sucrose or dextrin), or 60% dextrin starch, in comparison to diets containing 60% refined carbohydrates, extended life span and produced a more protracted pathogenesis, but were unable to circumvent eventual severe hyperglycemia and islet destruction. The diets containing 60% glucose, fructose, or sucrose all led to the rapid induction of diabetes. Thus, pathogenesis entails an interaction between dietary carbohydrate, the db gene, and other diabetes-predisposing genes in the genome.

The influence of dietary carbohydrate and fat on kidney calcification and the urinary excretion ofN-acetyl-β-glucosaminidase (EC3.2.1.30)

1. Male Sprague-Dawley rats were fed on diets containing either sucrose or starch as the carbohydrate component. In one experiment, the diets also contained 200 g either butter or polyunsaturated margarine/kg; in a second experiment, the diets contained less fat in the form of 20 g maize oil/kg.2. Over a period of 11 months assays were made in the urine of several ions and of the activity of the enzymeN-acetyl-β-glucosaminidase (β-2-acetamido-2-deoxy-β-D glucoside acetamidodeoxygluco-hydrolase;EC3.2.1.30); at 13 months, examination was made of some of the abdominal viscera, especially of the kidneys.3. In rats fed on the higher amount of fat, dietary sucrose produced a higher activity of the enzyme than did dietary starch, and a greater excretion of inorganic phosphate.4. With both the higher and lower amounts of dietary fat, sucrose led to an increase in the weight of the liver and of the kidneys, and an increase in the concentration of calcium and of phosphate in kidney tissue. With the higher amount of fat, sucrose also produced an increase in the concentration of magnesium in the kidney. There was no difference in the concentration of any of the ions assayed in the plasma or, apart from inorganic phosphate, in the urine.5. The kidneys of the sucrose-fed rats showed nephrocalcinosis, mostly in the cortico-medullary region, and basophilic deposits in the tubules. Attention is drawn to this unusual occurrence of nephrocalcinosis in male rats.

Influence of dietary carbohydrate on copper, iron, and zinc status of the rat.

Rats were fed diets containing starch, sucrose, glucose, or fructose as the carbohydrate source, and the influence of these carbohydrates on copper, iron, and zinc status was determined. It was found that copper absorption was reduced in animals receiving glucose. This reduction was exaggerated when a high level of iron was present in the diet, indicating a possible antagonism between iron and copper at the site of absorption. Iron and zinc status of the animals also appeared to be influenced to some extent by dietary carbohydrate.