Marginal copper and high fat diet produce alterations in electrocardiograms and cardiac ultrastructure in male rats

This study investigated whether a high fat diet in tandem with a marginal copper (Cu) diet exerts deleterious effects on copper status, cardiac morphology, and electrophysiology compared to a low-fat marginal copper diet. Male weanling Long-Evans rats were fed diets containing either marginal copper (42.5 mumol/kg) or adequate copper (97.6 mumol/kg), and low fat (50.0 g/kg) or high fat (150.0 g/kg) diet for 12 wk in a 2 x 2 factorial design. To simulate the western diet, fat was composed of a 1:2 polyunsaturated:saturated fatty acids using a coconut and corn oil mixture. High dietary fat increased liver Cu concentration. Marginal copper diets decreased liver Cu,Zn-superoxide dismutase activity. Dietary copper and fat level had no effect on volume densities of mitochondria and myofibril. However, lower mitochondrial pathologic scores were observed in the rats consuming the high fat diets. Marginal copper high fat diet prolonged atrial electric depolarization (PR) and ventricular electric depolarization and repolarization (QT) intervals. This study provided direct evidence that a high fat diet can exert detrimental effects on cardiac ultrastructure and lead to alterations in electrocardiograms. The combination of marginal copper-high fat diet appears to alter cardiac electric conductivity. Longer term studies should provide information more relevant to clinical situations and morphologic changes.     

Copper and sodium concentration in rat hair as related to dietary intake

The use of hair as an index of mineral status has received some criticism despite its wide use in research and its wider use as a diagnostic tool. This study evaluated the effect of dietary copper and sodium intake upon the concentration of these minerals in hair. Forty-eight Long-Evans rats were divided into 3 groups of 16 at weaning and fed one of three levels of copper; 1) low copper (LC), 2) marginal copper (MC) or 3 mg Cu/Kg feed, and 3) adequate copper (AC) or 8 mg/Kg feed. Rats were fed these diets ad libitum for 6 months. At day 100, half of the rats received 5% NaCl for 1 week followed by 1% NaCl for 11 weeks as drinking water. The other half received deionized-distilled water as drinking water. Results revealed that rats fed the AC diet had higher (p≤0.001) hair copper concentrations than rats fed the MC and LC diets. Rats fed the MC diet had higher (p≤0.001) hair copper concentrations than rats fed the LC diet. Higher hair sodium concentrations were found in rats consuming saline compared to rats consuming deionized-distilled water (p≤0.05). These results support the use of hair as a measure of mineral intake for populations.     

Dietary supplementation with t-butylhydroquinone reduces cardiac hypertrophy and anemia associated with copper deficiency in rats

The effect of dietary supplementation with the antioxidant, t-butylhydroquinone (TBHQ), on some of the cardiovascular consequences of copper deficiency was investigated. Rats were fed copper-deficient (CuD) diet containing 0.3 μg Cu/g of diet that were either nonsupplemented or supplemented with TBHQ (supplied in the dietary safflower oil at a concentration of 0.02%). Control rats were fed copper adequate (CuA) diet containing >5.0 μg Cu/g (CuA) that also were either nonsupplemented or supplemented with TBHQ. After five weeks, rats consuming CuD diet supplemented with TBHQ exihibited plasma copper concentrations, ceruloplasmin activities, and liver and heart copper concentrations that were significantly (P<0.05) lower than those of rats consuming either nonsupplemented or TBHQ supplemented CuA diet, but no different from those of rats consiming nonsupplemented CuD diet. However, rats consuming CuD diet supplemented with TBHQ had significantly (P<0.05) higher growth, hemoglobin concentrations, hematocrits, and red blood cell qistribution widths but lower heart weights than rats consuming nonsupplemented CuD diet. TBHQ supplementation had no effect on these variables in rats fed CuA diet. Thus, while TBHQ did not improve copper status, it did ameliorate the growth reduction, anemia, and cardiac hypertrophy associated with copper deficiency. These findings indirectly support the contention that oxidative damage contributes to the pathophysiological consequences of copper deficiency.     

Low dietary copper increases fecal free radical production,fecal water alkaline phosphatase activity and cytotoxicity in healthy men

One possible dietary factor that may increase susceptibility to colon cancer is inadequate copper intake. The objective of this study was to investigate the effects of low and adequate copper intakes on copper nutriture and putative risk factors for colon cancer susceptibility in healthy men. Seventeen healthy free-living nonsmoking men aged 21-52 y completed a 13-wk controlled feeding study in a randomized crossover design. The basal diet contained 0.59 mg Cu/13.65 MJ. After a 1-wk equilibration period in which the men consumed the basal diet supplemented with 1.0 mg Cu/d, they were randomly assigned to receive either the basal diet or the basal diet supplemented with 2 mg Cu/d for 6 wk. After the first dietary period, the men immediately began to consume the other level of Cu for the last 6 wk. They collected their feces during the equilibration period and during the last 2 wk of the two dietary periods for free radical and fecal water analysis. Low dietary copper significantly (P < 0.01) increased fecal free radical production and fecal water alkaline phosphatase activity. Low dietary copper significantly (P < 0.0001) decreased fecal water copper concentrations but did not affect fecal water volume, pH, iron or zinc concentrations. In contrast to the fecal analysis, hematological indicators of copper status were not significantly affected by the dietary treatments. These results suggest that low dietary copper adversely affects fecal free radical production and fecal water alkaline phosphatase activity, which are putative risk factors for colon cancer.     

Long-term high copper intake: effects on copper absorption, retention, and homeostasis in men

BACKGROUND: Numerous studies have examined the effect of low and adequate intakes of copper on absorption and retention, but little information is available on the regulation of absorption and retention of copper when intake is high. OBJECTIVE: A study was conducted in men to determine the effect of long-term high copper intake on copper absorption, retention, and homeostasis. DESIGN: Nine men were confined to a metabolic research unit (MRU) for 18 d and were fed a 3-d rotating menu containing an average of 1.6 mg Cu/d. They continued the study under free-living conditions for 129 d, supplementing their usual diets with 7 mg Cu/d. They then returned to the MRU for 18 d and consumed the same diet as during the first period, except that copper intake was 7.8 mg/d. The stable isotope (63)Cu was fed to 3 subjects and infused into the other 6 on day 7 of each MRU period, and complete urine and stool collections were made throughout the study. Total copper and (63)Cu were determined by inductively coupled plasma mass spectrometry. Copper absorption, excretion, and retention were calculated on the basis of dietary, urinary, and fecal copper and (63)Cu. RESULTS: Results were as follows when comparing the high copper intake with the usual intake: fractional copper absorption was significantly lower, but the amount absorbed was significantly higher; excretion of the infused (63)Cu was significantly faster; and total retention was significantly higher. CONCLUSIONS: Homeostatic regulation of copper absorption and retention helped to minimize the amount of copper retained with high copper intake but was not sufficient to prevent retention of >0.6 mg Cu/d.     

Dietary selenium and fecal mutagenicity in young men

Fecal mutagenicity, as a possible tool to evaluate risk for colon cancer, was measured in six healthy volunteers (24–33 yr) who consumed diets low in Se (19–24 μg/day) for 45 days followed by 24 days of a selenium repletion diet (203–224 μg/day). Samples were collected at the beginning of the dietary experiment, at the end of the Se-depletion period and at the end of the Se-repletion period. Mutagenic activity with S. typhimurium TA100 and TA98 did not vary significantly among samples taken after the two diet periods. Mutagenicity with TA98 was higher at the beginning of the dietary experiment than at the end of Se-depletion (p<0.01) and at the end of Se-repletion (p<0.1). This effect might be due to the change of the subjects from their habitual diet to the experimental liquid formula diet. Since fecal mutagenicity with both tester strains was the same after the Se-depletion and Se-repletion periods, Se does not appear to be a dominant factor for determining fecal mutagenicity under these experimental conditions.     

Decreased plasma enkephalins in copper deficiency in man

Twenty-four male subjects participated in a study in which the effect of feeding diets low in copper (1.03 mg/day) on plasma opiates was determined. The subjects were fed a low-copper diet for 11 wk with either starch or fructose as a major source of carbohydrate. Feeding low-copper diet decreased serum copper level significantly. In addition, plasma leu- and met-enkephalins decreased significantly while beta-endorphin levels rose. On repletion with copper (3 mg/day) for 3 wk, plasma enkephalins increased while beta-endorphin levels decreased to pretest values. These results suggest that feeding low copper decreases plasma enkephalins, which may reflect a copper-dependent process affecting enkephalin biosynthesis and/or release.     

A stable isotope study of copper absorption in young men: effect of phytate and alpha-cellulose

A sixty-three day study was conducted with young men confined to a metabolic unit to study the effects of alpha-cellulose and phytate on copper absorption. Copper absorption was determined with 65Cu, a stable isotope of copper, during each of 3 dietary treatments (basal diet, basal diet + alpha-cellulose, or basal diet + phytate). The addition of alpha-cellulose or phytate to the basal diet did not affect copper absorption. Average copper absorption was 35.0% from the basal diet, 34.1% from the diet with 0.5 g alpha-cellulose per kg body weight added, and 31.4% from the diet with 2.34 g of phytate as sodium phytate added to the diet. Copper absorption was significantly different between subjects and averaged 44.1%, 26.8%, 33.4%, and 29.5% in individual subjects. The results suggest that high levels of either alpha-cellulose or phytate do not have marked effects on copper absorption, but copper absorption differs between individuals.     

Copper status and urinary and salivary copper in young men at three levels of dietary copper

Eleven young men were confined to a metabolic research unit for 90 d to determine the effect of the amount of dietary copper on copper nutriture. The study was divided into three metabolic periods (MP): 1) with an adequate-copper diet (1.68 mg/d) for 24 d, 2) with a low-copper diet (0.79 mg/d) for 42 d, and 3) with a high-copper diet (7.53 mg/d) for 24 d. Three indices of copper status, urinary copper, and salivary copper were determined at intervals throughout the study. Neither copper status, urinary copper, nor salivary copper differed among MPs. Sweat collections from three subjects suggested that losses of copper through sweat were very low and would not contribute significantly to copper balance. These results suggest that an amount of dietary copper slightly less than 0.8 mg/d is adequate to maintain copper status for greater than or equal to 42 d in normal, healthy men and that neither urinary nor salivary copper is affected by the amount of Cu in the diet.     

Effect of zinc intake on copper excretion and retention in men

To determine the influence of zinc intake on copper excretion and retention, nine men consumed diets containing 2.6 mg of copper/day and 1.8, 4.0, 6.0, 8.0, 18.5 or 20.7 mg of zinc/day for one- or two-week periods in a 63-day study. Copper and zinc in the diet and copper in plasma were determined weekly; fecal copper was determined daily and averaged within each week. The weekly mean (+/-SEM) plasma copper concentrations (81 +/- 3.3 to 100 +/- 5.8 micrograms/dl) remained within the normal range throughout the study. Fecal copper and apparent copper retention were influenced by the level of dietary zinc and the duration it was fed. When 18.5 mg of zinc/day was fed for two consecutive weeks following a lower zinc intake, fecal copper was elevated and apparent copper retention was reduced after a one-week lag. Thus, an intake of zinc only 3.5 mg/day above the RDA for men reduced apparent retention of copper at an intake of 2.6 mg/day.     

Influence of copper intake and inflammation on rat serum superoxide dismutase activity levels

Serum superoxide dismutase (SOD) activity concentrations, though small compared to tissue levels, could contribute to extracellular superoxide radical detoxification and act as indicators of copper status. The present study identified the response of rat serum SOD activity contents to marginal and deficient copper intakes and to inflammation. Rats fed copper-deficient diet (less than 0.2 mg/kg Cu) for 5 wk displayed serum SOD activity contents that were only about 20% of those found in rats fed copper-supplemented diet (6.0 mg/kg Cu). Activities in rats fed a marginal diet (1.5 mg/kg Cu) were about 55% of those in the adequate rats. Turpentine-induced inflammation lowered serum SOD in rats within each dietary group. However, the change in the marginal group was not statistically significant. Based on chromatographic characterizations and inhibitor studies, rat serum SOD activity seemed to result primarily from a copper protein other than ceruloplasmin, Cu-Zn SOD or the recently discovered tissue extracellular SOD. In conclusion, low copper intake and inflammation may compromise extracellular defenses against superoxide. In addition, serum SOD activities could provide a non-ceruloplasmin-related means of assessing copper status, but nondietary variables can also affect these SOD values.     

Some magnesium status indicators and oxidative metabolism responses to low-dietary magnesium are affected by dietary copper in postmenopausal women

OBJECTIVE: A study with human volunteers was conducted to ascertain whether a low intake of copper (Cu) would exacerbate the response to a deficient intake of magnesium (Mg). METHODS: Nineteen postmenopausal women, age 47 to 78 y, completed a metabolic unit study as designed. For 162 d, nine women were fed a diet containing 1.0 mg of Cu/2000 kcal and 10 women were fed 3.0 mg of Cu/2000 kcal. Diets contained 99 or 399 mg of Mg/2000 kcal for 81 d in a randomized, double-blind, crossover design. Differences were considered significant when statistical analysis yielded P 相似文献   

Long term effects of dietary copper and sodium upon blood pressure in the long-evans rat

Forty-eight male Long-Evans rats were divided into three groups of 16 and assigned to one of the following levels of dietary copper at weaning: 1) low copper (LC), no added copper; 2) marginal copper (MC), 3 mg Cu/kg feed; 3) adequate copper (AC), 8 mg Cu/kg feed. At 100 days of age, half of the rats in each group were fed 5% NaCl in their drinking water for 1 week, followed by 1% NaCl for an additional 11 weeks. The other half were fed deionized-distilled water for the same time period. Systolic blood pressure was measured biweekly from day 100 until the rats were 6 months old. The copper deficiency of rats in the LC group was confirmed by a decrease in growth rate, a decrease in hematocrit and hemoglobin levels, and an increase in serum cholesterol levels. Copper deficient rats also had higher levels of serum triglycerides and glucose, but lower high density lipoprotein cholesterol as a percentage of total cholesterol than AC and MC animals. The results from this study also indicated that LC and MC rats had lower blood pressure than AC rats. The addition of 5% NaCl to drinking water increased blood pressure whereas 1% NaCl did not have the same effect.     

Abnormal motor function persists following recovery from perinatal copper deficiency in rats

What are the biochemical and behavioral consequences of perinatal copper deficiency? Pregnant Holtzman rats were fed a modified AIN-76A diet low in copper (0.34 mg Cu/kg and 42 mg Fe/kg) starting on gestation d 7. Seven rats received copper in their drinking water (20 mg Cu/L) (+Cu) and 7 drank deionized water (-Cu). Treatments did not affect litter size or pregnancy outcome. Compared with +Cu dams and a sample of +Cu male weanling [postnatal day (P)21] offspring, -Cu rats exhibited signs consistent with copper deficiency. P21 males were switched to a nonpurified copper-adequate diet and sampled biochemically after 3 mo and behaviorally after 3 and 6 mo of repletion (CuR). Compared with controls, CuR rats had lower brain copper and iron levels 3 and 6 mo after repletion; other biochemical differences were not detected. Behavioral assessments after 5 mo of repletion indicated a persistent impairment in motor function of CuR compared with control rats as evaluated by the accelerating rotorod procedure. These results suggest that permanent impairment to motor function can persist after long-term recovery from perinatal copper deficiency.     

Changes in pancreatic enzyme specific activities of rats fed a high-fructose, low-copper diet

This study describes the progressive changes in exocrine pancreatic enzyme specific activities from rats provided with a diet containing either 62% starch (S) or fructose (F) with 6.0 ppm copper (+Cu) or 0.6 ppm (-Cu) from 21 to 61 days of age. Copper-deficient rats had significantly reduced pancreatic weight and DNA, RNA, protein and copper content and superoxide dismutase (SOD) activity after consuming diet for 39 days. These reductions were far more severe in F-Cu than in S-Cu rats. Copper deficiency significantly reduced pancreatic amylase and lipase specific activities, but the effect was more severe in the F-Cu dietary group. Chymotrypsinogen and trypsinogen specific activities were reduced only in the F-Cu dietary group and the CHO x Cu interaction was significant. High dietary fructose and low dietary copper in combination interact to produce severe reductions in pancreatic amylase, lipase, chymotrypsinogen, and trypsinogen specific activities which could not be explained by either copper deficiency or by an increase in dietary fructose alone.     

Dietary copper, manganese and iron affect the formation of aberrant crypts in colon of rats administered 3,2'-dimethyl-4-aminobiphenyl

Aberrant crypt foci (ACF) are preneoplastic lesions for colon cancer. Altered amounts of copper-zinc (CuZnSOD) and manganese (MnSOD) superoxide dismutases have been implicated in multistage carcinogesis of both rodents and humans. Dietary factors are potential modulators of both CuZnSOD and MnSOD activity. The purpose of this study was to investigate the interactive effects of dietary copper, manganese, and iron on 3,2'-dimethyl-4-aminobiphenyl (DMABP)-induced ACF and superoxide dismutase activities in weanling rats fed low or adequate copper (0.8 or 5.1 microg Cu/g diet), low or adequate manganese (0.6 or 17 microg Mn/g diet), and adequate or high iron (37 or 140 microg Fe/g diet). Twelve rats were allowed free access to each of these eight diets for 3.5 wk prior to DMABP administration and for an additional 8 wk after the first DMABP injection. Rats fed low dietary copper had 105% (P < 0.0001) higher formation of DMABP-induced ACF than those fed adequate dietary copper. Rats ingesting low rather than adequate dietary manganese had 23% higher formation of ACF, and rats ingesting high rather than adequate dietary iron had 18% higher formation of ACF. Heart total superoxide dismutase activity was significantly correlated with the number of ACF (r = -0.43, P < 0.0001) in rats administered DMABP. These results suggest that dietary alterations that affect superoxide dismutase activity may affect cancer susceptibility.     

Dietary fructose but not starch is responsible for hyperlipidemia associated with copper deficiency in rats: effect of high-fat diet

OBJECTIVE: To test the hypothesis that copper deficiency in rats may be hyperlipidemic only when the diets consumed contain nutrients which contribute to blood lipids such as fructose and high fat. METHODS: Weanling male Sprague Dawley rats were fed diets which contained either starch or fructose as their sole carbohydrate source. The diets were either inadequate (0.6 microg Cu/g) or adequate (6.0 microg Cu/g) in copper and contained either high (300 g/kg) or low (60 g/kg) fat. At the end of the 4th week the rats were killed. Livers were analyzed for copper content. Plasma was analyzed for cholesterol and triglyceride concentrations. RESULTS: High-fat diet did not increase blood lipids in rats fed a copper-deficient diet containing starch. In contrast, the combination of high-fat diet with fructose increased blood triglycerides and fructose with copper deficiency resulted in a significant increases in blood cholesterol. CONCLUSIONS: Hyperlipidemia of copper deficiency in rats is dependent on synergistic effects between dietary fructose and copper deficiency and fructose and amount of dietary fat. Hyperlipidemia does not develop if starch is the main source of dietary carbohydrate in a copper-deficient diet even if a high-fat diet is fed.     

Effects of varying dietary iron on the expression of copper deficiency in the growing rat: anemia, ferroxidase I and II, tissue trace elements, ascorbic acid, and xanthine dehydrogenase

The effect of dietary iron on the development of copper-deficiency anemia in the growing rat was investigated. For up to 80 d, female rats (75 g) were fed purified diets containing adequate, marginal or low levels of iron, and either 0.7 or 10 ppm copper. Hemoglobin levels and factors postulated to affect liver iron mobilization, including ferroxidase (Fox) I and II, ascorbate and liver xanthine dehydrogenase (XDH) were assayed. By d 7, Fox I activity in the copper-deficient groups was 10% that of the copper-sufficient groups; thereafter, Fox I activity remained low, and was not affected by dietary iron. Fox II activity in the copper-deficient groups after d 28 was 50-75% of values from rats adequate in copper. On d 49, hemoglobin levels in the copper-deficient groups were lower than in the copper-sufficient groups fed low and marginal levels of iron, but were similar to those fed adequate iron. Liver iron was similar in both groups fed adequate iron, but was higher in the copper-deficient than in the copper-sufficient rats fed low or marginal levels of iron. Copper deficiency tended to result in slightly lower ascorbate levels on d 80 at all levels of iron. Liver XDH activity tended to be lower in the copper-deficient groups than in the copper-sufficient groups on d 28 and 49. These results show that copper deficiency may impair liver iron mobilization in the growing rat if dietary iron is low. Possible mechanisms include decreased Fox activity and/or decreased iron reduction by ascorbate or XDH.     

Effect of dietary copper intakes on biochemical markers of bone metabolism in healthy adult males.

OBJECTIVE: To investigate the effects of changing from a medium (1.6 mg Cu/d) to a low (0.7 mg Cu/d) or a high (6.0 mg/d) Cu intake on biochemical indices of bone turnover in healthy adult males. DESIGN: A longitudinal intervention trial. SETTING: The study was conducted at the Institute of Food Research, Norwich, UK. SUBJECTS: Eleven healthy adult males aged 20-59 y were recruited from Norwich Research Park. INTERVENTION: Subjects were given medium (1.6 mg/d), low (0.7 mg/d) and high (6.0 mg/d) intakes of Cu, in that order, over consecutive 8 week periods with a minimum of 4 week washout periods. On the last d of each dietary period fasting first void urine and blood were collected. RESULTS: Serum caeruloplasmin or Cu (indices of Cu status), serum osteocalcin (biomarker of bone formation), urinary creatinine (Cr) were unaffected by dietary Cu intake. Urinary Pyr/Cr and Dpyr/Cr (biomarkers of bone resorption) were significantly increased (P < 0.05) (by 30% and 25%, respectively), when subjects were switched from the medium to the low Cu diet and were significantly decreased (P < 0.05) (by 30%) and 22% respectively), when subjects were switched from the low to the high Cu diet. CONCLUSION: The findings of the present study could have implications for bone health in individuals with marginal Cu intakes. Thus, further studies are warranted to better define the relationship of marginal Cu intakes to bone health.     

Dietary copper influences reproduction in cats

The objective of this study was to determine the copper requirement of female cats (queens) for gestation. Cuproenzyme activities were evaluated to identify a noninvasive indicator of copper status. This study used a depletion-repletion model. Specific pathogen-free queens (n = 28) were adapted to a purified diet; after consuming a copper-depletion diet (0.8 mg Cu/kg diet) for 4 mo, they were randomly allocated to three dietary treatment groups receiving copper sulfate at 4.0, 5.8 or 10.8 mg Cu/kg diet. Four queens underwent liver biopsies at two time points during the study. Plasma samples were analyzed for copper concentrations, extracellular superoxide dismutase, ceruloplasmin and diamine oxidase activities. Only liver copper concentrations were responsive to dietary copper intake. The dietary concentration of copper had a significant effect on the time taken for queens to conceive (P = 0.04). There was a negative linear relationship between dietary copper (x = Cu mg/kg diet) and the mean time (y = days) for queens to conceive (y = 43.38-2.87x; R(2) = 0.97). The current NRC recommendation of 5 mg/kg diet copper for cats appears marginal for optimal reproduction.