Dietary protein, fat, and minerals in nephrocalcinosis in female rats.

Young female rats fed semipurified diets containing casein or a soy protein isolate had extensive nephrocalcinosis at the junction between the outer and inner stripe of the outer medullary zone after 5 wk on the diets, whereas rats fed a diet containing a lactalbumin concentrate did not. Although the percentages of actual protein and of total ash were similar in all three diets, the concentrations of individual minerals were not, owing to methods used in isolating the proteins. Comparison of the individual mineral contents of these diets with those in other laboratories as compiled from the literature suggested that factors other than minerals, including protein, are also implicated. Dietary fat appeared to be another such factor in a series of experiments in which saturated medium-chain triglycerides and corn oil were included in diets containing soy protein isolate. Although these diets had identical mineral compositions, the rats fed medium-chain triglycerides had less severe lesions.     

Nutritional support of malnourished lactose intolerant African patients.

The effectiveness of two commonly available liquid diets was assessed in 40 severely malnourished black African patients. All patients were shown to have normal xylose absorption. The diets were given according to the manufacturer's recommendations. One diet was lactose containing (LC diet) (150 g/d) and high protein (112 g/d), the other normal protein and lactose free (LF diet) (protein 67 g/d), total energy content being similar. Patients were randomly divided into two equal groups and allocated (blind) to one of the diets. Tolerance and nitrogen balance were assessed over two three day periods on half and then full strength formulations. Severe intolerant symptoms were observed in 50% of patients on half strength and 94% of patients on full strength lactose containing diet with evidence of malabsorption of fluid, nitrogen, and fat. Despite high stool nitrogen losses (3.75 +/- 1.04 g/d), however, positive nitrogen balance was achieved in most patients receiving the full strength LC formulation. On the other hand, the full strength LF diet was generally well tolerated and was associated with significantly lower faecal losses and positive nitrogen balance. The results indicate that high density lactose containing liquid formulae are poorly tolerated by severely malnourished black African patients, while lactose free formulae containing approximately 10 g nitrogen/d are well tolerated and result in positive nitrogen balance.     

Absorption of calcium and magnesium in patients with intestinal resections treated with medium chain fatty acids

BACKGROUND: Steatorrhoea is associated with increased faecal loss of calcium and magnesium. Medium chain C8-C10 triglycerides (MCTs) improve fat absorption in patients with small bowel resections but the effects on intestinal absorption of divalent cations are not clear. AIM: To assess the effect of dietary replacement of long chain triglycerides (LCTs) with MCTs on calcium and magnesium absorption in patients with small bowel resections. PATIENTS: Nineteen adult patients with a remaining small intestine averaging 171 cm (range 50-300). METHODS: In a crossover design, patients were randomised to two high fat diets (10 MJ/day, 50% as fat) for four days each separated by one day of washout. Diets were prepared in duplicate and were based on either LCT (LCT period) or equal quantities of LCT and MCT (L/MCT period). Metabolic balances were calculated during the last three days of each period. RESULTS: Mean stool volume increased significantly with the L/MCT diet and was 336 ml more than that with the LCT diet (95% confidence interval of mean difference, 26-649 ml). There was no significant change in the net absorption of calcium and magnesium between the two diets. On average, percentage calcium absorption was 8.6% with the LCT diet and 12.5% with the L/MCT diet. Mean percentage magnesium absorption was 5.4% with the LCT diet and 2.9% with the L/MCT diet. CONCLUSIONS: Dietary replacement of 50% long chain triglycerides with medium chain triglycerides in small bowel resected patients increased faecal volume significantly. No changes in the intestinal net absorption of calcium and magnesium were demonstrated.     

Effect of the ingestion of dietary fiber on the digestibility of lipids in a sorghum-consuming African population

Digestibility measurements were carried out on 12 men. Their habitual diet, deficient in animal products, is based on sorghum meals which supply between 2.4 and 4.2 g of crude fiber per 100 g of dry matter. Over three 11-day periods, the subjects received 3 successive diets (A, B and C) which supplied respectively 3.3, 4.8 and 5.4 g of crude fiber per 100 g of dry matter. Reduced lipids digestibility was noted, even for diet A which was the poorest in fiber content. No difference was observed between diet A and diet B (92.3 and 91.7% respectively). The apparent digestibility of lipids dropped to 86.1 with diet C. True digestibility of lipids is hidden by poorly digestible dietary lipids. Lipid losses increased more rapidly than nitrogen losses with increasing of fiber content in diets. On these regimens, there were no significant changes in concentrations of fecal fat. Concentration of fecal nitrogen decreases for diets B and C.     

Effects of dietary fiber on pancreatic enzyme activities of ileostomy evacuates and on excretion of fat and nitrogen in the rat

Ileostomized rats were fed diets with different fiber content. The addition of 5% pectin to the diet caused an increase in the wet weight, fat content, amylase activity per gram, and lipase output of the ileostomy evacuates. Twenty percent wheat bran in the diet increased weight, fat and nitrogen content, and trypsin output of the evacuates. In normal rats pectin added to a meal containing 3H-labeled triolein increased the isotope activity of the feces, indicating an impaired fat absorption. In rats operated on with occlusion of the pancreatic ducts with a tissue glue, the fat absorption was, however, not significantly affected by pectin. The results of the study show that fiber can cause a change in the intestinal enzymatic milieu of ileostomized rats and can cause steatorrhea, which can be explained, at least partly, by malabsorption.     

Enteral nutrition in Crohn's disease: fat in the formula

Enteral nutrition is effective in inducing remission in active Crohn's disease. Speculation on the underlying mechanism of action has moved away from the presentation of nitrogen and towards the fat content of the various enteral feeds. Evidence is accumulating that additional long-chain triglyceride in such feeds impairs the response rate in active Crohn's disease, whereas no deleterious effects of additional medium-chain triglyceride have been identified. It has been proposed that long-chain triglycerides composed from n-6 fatty acids may be the most harmful, since such fatty acids are substrates for inflammatory eicosanoid production. However, recent studies comparing different enteral feeds are not consistent in identifying which additional fatty acids impair response rates to the greatest extent. Despite meta-analyses concluding that polymeric diets (typically containing large amounts of fat) are as effective as elemental diets, it would seem sensible to use enteral feeds with minimal fat content when treating active Crohn's disease.     

Comparison of amino acid v peptide based enteral diets in active Crohn's disease: clinical and nutritional outcome.

Elemental diets are considered an effective primary treatment for active Crohn's disease. This study examined the hypothesis that improvement occurs because of the presence of amino acids or the low fat content, or both. A randomised, controlled trial was undertaken in 40 patients with active Crohn's disease to evaluate clinical and nutritional outcomes after an amino acid based diet containing 3% fat was given by a feeding tube compared with a peptide based diet containing 33% fat. After three weeks' treatment, clinical remission occurred in 84% of patients who were given the amino acid diet and 75% of patients who received the peptide diet (p = 0.38). Plasma linoleic acid concentration was reduced after the amino acid but not the peptide diet. An increase in total body nitrogen was associated with the magnitude of nutritional depletion before treatment and at six months' follow up, only patients who showed gains in total body nitrogen after enteral nutrition had a sustained clinical remission. This study shows that peptide based high fat diets are as effective as amino acid low fat diets for achieving clinical remission in active Crohn's disease. Improved total body protein stores but not essential fatty acid depletion may be an important indicator of a sustained remission.     

Comparison of isocaloric quantities of medium-chain tryglyceride and carbohydrate in promoting weight gain in short bowel rats

Weight gain was studied in short-bowel rats fed diets consisting of rat chow supplemented with isocaloric quantities of long chain triglycerides (LCT), medium-chain triglycerides (MCT) or carbohydrate. Compared with the LCT-supplemented diet, MCT supplementation did not result in a significant weight gain, while a significantly increased weight gain was obtained by the rats on a sucrose- or maltose-supplemented diet. These studies suggest that while the caloric content per gram of disaccharides is only one-half that of MCT, disaccharides were better absorbed than MCT and thus provided as good, if not a better, source of calories for short-bowel rats.Supported by United States Public Health Service Grant 5 RO1 AM13309-02 and University of Minnesota Graduate Research Grant 452-0303-4909-02.     

Fecal Fat Measurement in the Presence of Long- and Medium-Chain Triglycerides and Fatty Acids Comparison of Three Methods

Background: It has been suggested that some of the limitations of the Van de Kamer method for fecal fat measurement could be overcome with the Jeejeebhoy method or the near-infrared reflectance assay. Methods: To test this hypothesis, a fecal fat test was carried out with the three methods, adding butter or MCT oil to the diet of four steatorrhoic patients. An in vitro recovery study of long- and medium-chain triglycerides was also performed. Results: The Jeejeebhoy method measured long- and medium-chain fats more accurately than the Van de Kamer method. It found consistently higher steatorrhea values. Mean results of the near-infrared reflectance analysis resembled those of the Van de Kamer method, but with wide discordance of individual data. Conclusion: The Jeejeebhoy method is more accurate than the Van de Kamer method for fecal fat measurement. The difference may be clinically relevant when most fecal fatty acids derive from medium-chain triglycerides. Near-infrared reflectance may be a viable proposition only when a greater degree of approximation is acceptable.     

The effects of dietary fat and protein levels fed to Syrian hamsters early in life,on blood chemistry throughout life

Nine experimental diets, composed of three levels of protein as casein (9, 18 and 36 g/385 Kcal) and three levels of fat as corn oil (4.5, 9.0, and 18.0 g/385 Kcal), were fed to weanling Syrian hamsters from 3–8 weeks of age. The control diet, consisting of the medium levels of casein and corn oil, was fed for the remainder of life. Blood was collected at 0, 1, 3, 6, 12, and 18 months for analysis of several indicators of nutritional status. Whole blood hemoglobin rose between 0 and 3 months, and then declined. Female values were lower than those of males, and the high fat diet increased hemoglobin at 6 months (5 months after the diet change). High protein diets increased hemoglobin values at 1 month, and decreased hemoglobin at 18 months. Serum triglycerides declined with age to 12 months. Feeding high protein diets resulted in the highest circulating triglycerides at 1 month and the lowest at 18 months. Feeding the high fat diets resulted in elevated triglycerides at 1 and 3 months. Plasma glucose levels increased between weaning and 6 months, then declined to 12 months. High fat diets led to elevated plasma glucose at 1, 3 and 6 months in animals fed the high protein levels, but at only 1 and 6 months in animals fed the low levels of protein. Serum albumin was consistently higher in male hamsters, and serum globulins in the females. Changes in the serum protein fractions with age differed for each of the fractions. Serum alpha one globulins increased with dietary protein, and serum beta globulins increased with dietary fat at 1 month.     

Energy balance trials with a diet rich in fats in the human

The effects of two diets equal in protein content (12% of energy) but different in carbohydrates (80% of energy) or in fat (68% of energy) were studied in a changeover trial with 6 healthy young subjects. Each person was 2 weeks on each diet. Under the conditions of slight undernutrition and neutral temperature the balances of nitrogen, carbon and energy were assessed in 7-day collection periods, and according to 48-hour measurements of gaseous exchange (carbon-nitrogen balance method) by the procedures of indirect calorimetry. At isocaloric supply of metabolizable energy no differences were found in the retention of N, C and energy. The heat production calculated by indirect calorimetry was not significantly different with both diets. The lower body weight during the high-fat diet was due to higher sodium and water excretion. The high-fat diet resulted in lower fecal and higher urine excretion of nitrogen, but because of a compensative response no difference in nitrogen retention was observed between the two dietary regimens. The plasma concentrations of cholesterol, glucose and uric acid were higher with fat-rich diet; those of triglycerides were higher with carbohydrate-rich diet. The results demonstrate that the composition of the diet did not influence the energy balance.     

High-fat diet in a short bowel syndrome

A patient with only 137 cm of jejunum suffereing from excessive jejunostomy losses was studied on three isocaloric liquid formula diets (3850 kcal/24 hr) differing only in carbohydrate and fat content. An increase in dietary fat from 64 g to 200 g per 24 hr and a reciprocal decrease in dietary carbohydrates resulted in a linear increase in the amount of fat absorbed, from 44 g to 133 g and in a 2.5-fold decrease in ostomy fluid bile acids. No undesirable side effects were noted on the 200-g fat diet: the ostomy fluid dry weight was lower than on 64 g of fat and the ostomy fluid output was lowest of all diets. Compared to healthy adults, the patient had higher fasting blood insulin and pancreatic glucagon. Meal-stimulated insulin, glucagon, gastrin, and GIP were also more than two standard errors above mean responses observed in healthy subjects. Smallest meal-stimulated increase in insulin, gastrin and GIP was noted on the 200-g fat diet. This diet induced the highest levels of glucagon. In a hormonally hyperactive individual after massive resection of the distal intestine favorable effects of a high-fat diet consist of increased absorption of dietary fat and bile acids and reduced release of gastroenteropancreatic hormones with the exception of glucagon.     

Metabolic effects induced by long-term feeding of medium-chain triglycerides in the rat

Energy intake, weight gain, carcass composition, plasma hormones and fuels, hepatic metabolites and the activities of phosphoenolpyruvate carboxykinase (PEPCK), malic enzyme, and glucose 6-phosphate dehydrogenase (G6P-DH) were examined in adult rats during a 44-day period of low fat, high carbohydrate (LF) feeding or of consumption of one or two high (70% metabolizable energy) fat diets composed of 63% (metabolizable energy) long-chain (LCT) or medium-chain (MCT) triglycerides. Energy intake was similar in the LCT and MCT groups but was less than that of LF group. The weight gain of rats fed MCT diet was 30% less than that of rats fed LF or LCT diets. Energy retention was less when the diet provided MCT than LCT or LF, and that resulted in a 60% decrease in the daily lipids deposition. Plasma glucose, free fatty acids, glycerol, and insulin/glucagon ratio were similar in the three groups. Blood ketone body (KB) concentrations in rats fed the high fat diets were extremely elevated, particularly in the MCT group, but declined throughout the experiment and by the 44th day hyperketonemia decreased by 50% but remained higher than in the LF diet. The blood beta-hydroxybutyrate/acetoacetate (B/A) ratio remained slightly elevated in rats fed the high fat diets. Similar changes were observed in liver KB concentration and in the B/A ratio. Liver lactate/pyruvate ratio elevated in the LCT and MCT groups at the initiation of the diets decreased by 50% at the end of the experiment. The consumption of high fat diets led to a 1.5-fold increase in liver PEPCK activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Tissue factor expression is decreased in monocytes obtained from blood during Mediterranean or high carbohydrate diets

BACKGROUND: Mediterranean and high carbohydrate diets play a dominant role in the prevention of atherosclerosis as a result of their lipid lowering effect. However, diets can also have a protective effect in other ways, such as modulating tissue factor expression in circulating monocytes. METHODS AND RESULTS: Forty-one subjects participated in this randomised crossover study consisting of three dietary periods: a saturated fat enriched diet (SFA), a low fat and high carbohydrate diet (CHO), and a Mediterranean diet. Plasma levels of total cholesterol, triglycerides, low density lipoprotein (LDL-C) and high density lipoprotein (HDL-C) were determined at the end of each dietary period, as was the expression of tissue factor (TF) in circulating monocytes isolated from blood samples. Total cholesterol, LDL-C, HDL-C and TF expression were lower after the Mediterranean and high carbohydrate diets than after the SFA diet, and there was a positive correlation between LDL-C levels and monocyte TF expression. CONCLUSIONS: High carbohydrate and Mediterranean diets reduce the expression of TF in circulating monocytes.     

Influence of dietary composition on energy expenditure during recovery of body weight in the rat: Implications for catch-up growth and obesity relapse

The influence of dietary composition on whole-body energetics was examined during the first 2 weeks of isocaloric refeeding after low food intake in a rat model. The high energetic efficiency and energy partitioning toward fat accretion characteristic of this refeeding period were unaltered by (1) dietary fat levels varying between 6% and 30% of energy intake; (2) protein levels between 15% and 40%; (3) carbohydrate types (glucose v fructose v sucrose v starch v unrefined carbohydrate); and (4) diets containing 30% fat but differing in fatty acid composition (long-chain triglycerides [LCT] v medium-chain triglycerides [MCT] v oleic v linoleic v alpha-linolenic metabolites eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA] omega-3 fatty acids). Changes were only observed for extreme diets, ie, those deficient in protein or very high in fat. Low-protein diet was the only condition in which the high metabolic efficiency characteristic of the refeeding period was partially suppressed, and this occurred despite a lack of concomitant reduction in body fat deposition. On the contrary, with high-fat diets (> 30% of dietary energy consumption) the elevated efficiency was further increased, an effect that was only partially accounted for by the lower energy cost of body fat gain from high-fat diets. These studies indicate that during body weight recovery, the mechanisms underlying the adaptive increase in metabolic efficiency favoring the replenishment of body fat stores override any effect of food type on thermogenesis, and suggest some convergence in the controlling neural pathway. The implications of these findings vis-a-vis nutritional rehabilitation (catch-up growth) and obesity relapse are discussed.     

Effect of ingestion of fat on ileostomy effluent.

Infusion of fat into the ileum slows small bowel transit and increases absorption of a carbohydrate meal. Paired studies were undertaken to investigate the effect of adding fat to the diet on gastrointestinal transit and absorption in eight people with terminal ileostomies. Each subject ate a daily diet that contained either low or high levels of fat but equivalent amounts of carbohydrate, protein, and fibre. Solid and liquid markers were added to the food to measure transit times. The ileostomy outputs after the meals were analysed for protein, fat, carbohydrate, polyethylene glycol, and the delivery of solid markers. All subjects produced more ileal effluent while taking the high fat diet compared with the low fat diet. Fat and protein outputs were significantly higher on the high fat days, but a greater proportion of the fat was absorbed during the high fat diet compared with the low fat diet. The output of carbohydrate on the two diets was not significantly different. The incorporation of fat in the diet produced no significant differences in the transit times of the first marker, but a slight prolongation of the transit time of the second marker. Increasing the fat content of the diet did not slow small bowel transit or increase nutrient absorption. The increase in protein and water output could be explained by an increased secretion of pancreatic enzymes.     

Influence of carbon chain length of dietary fat on intestinal alkaline phosphatase in chylous ascites

The long-term effects of chain length of dietary fat on intestinal lymphatic transport of alkaline phosphatase were investigated in two patients with chylous ascites due to leakage of intestinal lymph into the peritoneal cavity. Substitution of a medium-chain triglyceride diet for long-chain triglyceride resulted in a parallel fall in triglyceride and the intestinal isoenzyme of alkaline phosphatase in chylous ascites. The concentrations of lymph triglyceride were linearly related to lymph intestinal alkaline phosphatase levels, suggesting a positive relation between absorption of long-chain triglycerides and transport of mucosal alkaline phosphatase into lymph.     

Dietary fiber prevents carbohydrate-induced hypertriglyceridemia

Plant foods rich in carbohydrate and dietary fiber have many health benefits. One concern often expressed about higher carbohydrate, lower fat diets is that they may increase fasting serum triglycerides. Recently the importance of hypertriglyceridemia as an independent risk factor for coronary heart disease has been reaffirmed. For 40 years, clinicians have noted “carbohydrate-induced hypertriglyceridemia” when persons were fed high-carbohydrate, low-fiber diets. The role of fiber in protecting from carbohydrate-induced hypertriglyceridemia has not been discussed by many reviewers. Systematic review of the literature documents that high fiber intakes clearly protect from carbohydrate-induced hypertriglyceridemia. These are reviewed. Thus, recent and earlier research indicates that use of a higher carbohydrate, higher fiber diet compared with a lower carbohydrate, higher fat diet is associated with a small reduction in fasting serum triglyceride values.     

Effects of a Low-Fat Diet on Mineral Absorption in Small-Bowel Disease

The absorption of calcium, magnesium, and zinc was studied by the metabolic balance technique at two fat intake levels in nine patients with fat malabsorption. The net absorption of all three minerals was significantly higher from the 40-g fat diet than from the 100-g fat diet. The data indicate that the lower fat content was the main reason for the increased mineral absorption, although the low-fat diet contained larger amounts of the minerals studied than did the high-fat diet.     

Effects of a low-fat diet on mineral absorption in small-bowel disease

The absorption of calcium, magnesium, and zinc was studied by the metabolic balance technique at two fat intake levels in nine patients with fat malabsorption. The net absorption of all three minerals was significantly higher from the 40-g fat diet than from the 100-g fat diet. The data indicate that the lower fat content was the main reason for the increased mineral absorption, although the low-fat diet contained larger amounts of the minerals studied than did the high-fat diet.