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At least 19 recordsLinked to original sources
PubMed1975

Influence of quantity of diet on protein synthesis of rats force-fed a threonine-devoid diet.

The influence of the quantity of diet on protein synthesis of rats force-fed a complete diet or one free of threonine for 3 days. Protein synthesis was studied. The results revealed that rats force-fed an adequate amount (6.5 gm. per day) of threonine-devoid diet demonstrated increased hepatic and cardiac protein synthesis and decreased skeletal muscle and splenic protein synthesis in comparison to the results with rats force-fed the complete diet. In contrast, rats force-fed one-half the quantity (3.25 gm. per day) of the diets revealed no or small differences in protein synthesis of the liver, heart, gastrocnemius muscle, and spleen between the rats force-fed the complete and the threonine-devoid diets, although both of the one-half quantity groups had values which were decreased in comparison to those of rats force-fed the adequate quantity of complete diet. The tube feeding of L-threonine (60 mg.) to rats force-fed one-half the quantity of the complete or threonine-devoid diet on the 4th morning 2 hours before killing did not influence the results of organ protein synthesis. Protein synthesis was studied in vivo by measuring 14C-leucine incorporation into organ proteins and in vitro by measuring 14C-leucine incorporation into proteins by using postmitochondrial supernatants or microsomes of livers. Sucrose density gradients of hepatic polyribosomes were studied and revealed that there were more aggregated polyribosomes in rats force-fed adequate quantities of the experimental diets than in those force-fed the control diets. Rats force-fed one-half quantity of the complete and threonine-devoid diets revealed similar polyribosomal patterns which revealed more disaggregation than those in rats ofrce-fed the adequate quantity of complete diet.

Animals↗
PubMed1977

Effect of diet composition on metabolic adaptations to hypocaloric nutrition: comparison of high carbohydrate and high fat isocaloric diets.

The metabolic consequences of two hypocaloric diets were assessed in 10 obese men. The study, performed on a metabolic ward, compared the response of these men to two cholesterol-free liquid formula diets of differing composition (10 kcal/kg per day, 70% carbohydrate, 20% protein, 10% fat versus 70% fat, 20% protein, 10% carbohydrate) but identical in calories. These were administered for 14 days in a random order and each diet was preceded by a 7-day control weight maintenance diet (30 kcal/kg per day, 40% carbohydrate, 20% protein, 40% fat). The low calorie diets were well tolerated by the men and effected similar losses of nonaqueous body weight. Fasting glucose and insulin decreased significantly in these men after they ingested either weight loss diet for 14 days, but the change in each parameter was greater for high fat as compared to high carbohydrate (15% versus 7% and 67% versus 35%, respectively, P less than 0.01). In contrast, fasting glucagon concentration decreased in these subjects to a greater extent in response to the high carbohydrate diet (35% versus 16%, P less than 0.01). This adaptive response thus resulted in a 50% fall in insulin:glucagon molar ratio for high fat and no change for high carbohydrate weight loss. Despite these hormonal alterations no change in glucose tolerance was observed. Fasting serum triglyceride and cholesterol levels declined in these subjects to a greater extent following the high fat compared to the high carbohydrate regimen (45% versus 28%, P less than 0.01 and 8% versus 3%, not significant, respectively). These changes reflected decrements in very low density lipoproteins alone. Despite similar increments in free fatty acid levels, (350% versus 270%, not significant) serum ketone body (beta-hydroxybutyrate and acetoacetate) concentrations increased 7-fold on the high fat diet compared to the high carbohydrate diet, P less than 0.001. The hyperketonemia of these men in response to the high fat, low calorie diet suggested the occurrence of a shift in hepatic free fatty acid metabolism toward ketogenesis rather than triglyceride synthesis. The associated decrease in the insulin: glucagon molar ratio raised the question of a possible role for these hormones in the adaptation.

Adolescent↗
PubMed1976

Variations in the response of the thyroid gland of the rat to different low-iodine diets: correlation with iodine content of diet.

Large variations are frequently encountered in the thyroidal responses of rats to commercially available low-iodine diets. The major aim of this investigation was to attempt to correlate these variations with differences in the iodine content of the diets. A method was developed for measuring the iodine content of low-iodine diets which was sufficiently sensitive to discriminate between a diet containing 15-20 ng of iodine per g and one containing 30-40 ng of iodine per g. Large differences were observed between various commercial low-iodine diets in their ability to induce goiter and to affect other indices of thyroid function, and these differences could be correlated with differences in the iodine content. The most severe iodine deficiency occurred in rats that were fed a Remington diet containing 15-20 ng of iodine per g. After 3 months on this diet, thyroid weight increased about 7-fold, thyroid 127I concentration was reduced to about 0.5% of control values, serum thyroxine (T4) was reduced to less than 0.25 mug/100 ml, the ratio of labeled triiodothyronine to labeled T4 was increased to 5.2, and that of labeled monoiodotyrosine to labeled diiodotyrosine was increased to 4.2. Much smaller changes were observed in the rats on the other low-iodine diets, which ranged from 30-40 to about 100 ng of iodine per g. A daily supplement of only 0.2 mug of iodide per day administered to rats on a Remington low-iodine diet produced a significant changes in thyroidal responses. These results suggest that iodine deficiency alone is sufficient to explain the effects of the Remington low-iodine diet and that it is not necessary to postulate the presence of a goitrogen.

Animals↗
PubMed1979

Effect of low protein diets on free amino acids in plasma of young men: effect of wheat gluten diet.

Studies were made on alterations in plasma amino acids in young men fed a diet containing graded levels of wheat gluten. After one week on a standard diet containing 200 mgN/kg of mixed protein (animal protein content 45%), 38 young men were given a wheat gluten diet containing 170, 100, 60, 30, 15 or zero mgN/kg for 2 weeks. Blood samples measuring plasma free amino acids were taken before breakfast at the end of the periods on a standard diet and an experimental diet. In subjects on diets containing 170 to 30 mgN/kg the plasma concentrations of threonine, valine, methionine, leucine, tyrosine, phenylalanine, serine, histidine and arginine fell significantly with decrease in protein intake, but the concentration of alanine increased significantly. On the other hand, in subjects on diets containing 15 or zero mgN/kg, the plasma concentrations of the essential amino acids did not decrease, but increased to slightly more than in subjects on a diet containing 30 mgN/kg, and the alanine and glycine concentrations increased steadily. Values for plasma lysine varied from 146 +/- 22 to 194 +/- 31 mumoles/liter with gluten intakes of 170 to zero mgN/kg, but were comparable with that of 186 +/- 33 mumules/liter in subjects on a standard diet, showing that the plasma lysine concentration did not clearly reflect the dietary concentration of lysine in young men on a wheat gluten diet.

Adult↗
PubMed1977

A comparison of insulin binding by liver plasma membranes of rats fed a high glucose diet or a high fat diet.

The interaction of (125)I-labeled insulin with purified liver plasma membrane from rats fed a high fat (L) diet or a high glucose (G) diet was studied with respect to specific binding, insulin degradation, binding site degradation, and rate of hormone association and dissociation. Scatchard analysis suggested the presence of high and low affinity binding sites for membranes of both G and L diet-adapted rats. However, liver plasma membrane from rats fed the high glucose diet bound 50% more insulin than did membrane from rats fed the high fat diet. Diet did not change insulin binding site degradation. The results suggested that an apparently reduced number of insulin binding sites (G = 10.2 +/- 2.45 x 10(-12) mol/mg membrane protein, L = 4.5 +/- 1.73 x 10(-12) mol/mg membrane protein) associated with fat feeding as compared to glucose feeding was responsible for the reduced insulin binding by membrane from rats fed the high fat diet. The effects of concanavalin A (Con A) on insulin binding to liver plasma membranes were also investigated. Con A enhanced the specific binding of insulin to liver plasma membranes from rats fed either diet at concentrations lower than 50 micro g/ml, whereas at concentrations higher than 50 micro g/ml Con A inhibited insulin binding to these membranes. The stimulatory effect of Con A on insulin binding at low concentrations was greater and inhibition of binding at high concentration was less in the case of membrane prepared from L diet-adapted animals. These results suggested that diet can modify the plasma membrane glycoproteins.

Animals↗
PubMed1979

Influence of meal frequency on diurnal lipid, glucose and insulin levels in normal subjects on a high fat diet; comparison with data obtained on a high carbohydrate diet.

Diurnal levels of serum triglyceride (TG) were measured in six normal persons consuming a fixed solid 65% fat diet under steady state conditions in a metabolic unit. The food was divided into either three or eight similar portions, differently spaced over the day and night. The diurnal TG-profiles on this diet were practically identical to those found under comparable conditions on a 65% carbohydrate diet [1]. Mean diurnal TG values did not significantly differ with varying meal frequency. Free fatty acid levels, however, were significantly higher on a high fat diet. Post-prandial glucose and insulin reponses did not significantly differ whether a high fat diet or a high carbohydrate diet was consumed. We conclude that the composition of the diet is of little importance in determining diurnal TG patterns when the diet consists of normal food stuffs, but that these patterns are dependent on meal frequency and distribution.

Blood Glucose↗
PubMed1978

[Behavior of certain parameters of lipid and energy metabolism. 5. Effects of high-fat and low-fat diets on certain biochemical parameters in rat livers before and after change of diet].

Typical metabolic patterns are detectable in the livers of growing rats after feeding diets with high (25%) or low (2%) fat contents. In view of the elucidation of problems related to the regulation of the metabolic processes, it is of interest to know in what way these metabolic patterns change after short-time change from the one diet to the other and if there are hierarchies. Within 2 days after change of diet, the enzymes glucose-6-phosphate dehydrogenase, NAD-malate dehydrogenase, lactate dehydrogenase, citrate synthase and fatty acid synthase were affected, only the 3'.5'-c AMP-splitting phosphodieterase showed no change. The metabolites lactate and pyruvate also changed, inversely to lactate dehydrogenase activity, the lactate-pyruvate ratio remaining almost constant. Acetyl CoA also responded in a characteristic manner. The single parameters were differently affected by the kind of the change of diet (from high-fat to low-fat diet or inversely). For example, glucose-6-phosphate dehydrogenase responded very rapidly to the change from the high-fat to the low-fat diet, malate dehydrogenase behaved inversely, and citrate synthase responded to both changes. Consequently, the regulatory processes after change of diet start from different sides. It is thinkable that this behaviour is related to the different roles of the determined parameters in fat and energy metabolism.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1978

Comparative effects of a protein deprived diet on the weight, lymphocyte content and the number of DNA-synthesizing and dividing cells in the lymphoid organs of the rat. Influence of the diet on the stimulating action of phytohemagglutinin and the inhibitory action of cortisone.

The changes induced in adult male rats by a protein deprived (PD) diet lasting 7 weeks were investigated from the viewpoint of the cell contents of the popliteal lymph nodes (PLN), spleen and thymus; the levels of DNA-synthesizing lymphocytes counted on cell smear autoradiographs, and the levels of mitoses. The stimulating effect of a subplantar injection of phytohemagglutinin (PHA) and the inhibitory action of cortisone (3 mg/100 g per day for 5 days) were also determined in normal and PD rats. The PD diet significantly reduced the cell contents, primarily in the thymus, as well as the number of labeled cells and mitoses per mg of tissue and per entire organ. When expressed on the basis of 10(3) cells, the levels of both cell groups were also reduced in the spleen but not in the PLN's where they were already very low with a balanced diet. In the thymus, the sharp drop in the mitotic index (M.I.) contrasted with unchanged levels of labeled cells and an important increase in the labeling density per cell. PHA increased the M.I. to a great extent in the PLN's and spleen in normal rats but not in PD rats. In contrast, the labeling index (p. 10(3) cells) in the spleen, as well as the number of labeled cells per mg and per organ, increased in PLN's and the spleen after PHA to a much greater extent with a PD diet than with a normal diet. These results suggest a premitotic block of the cell cycle after protein deprivation. Also, the mitotic index appears to be a more reliable test, than the labeling index, of the lymphostimulating action of PHA and of its inhibition following protein removal from the diet. The effects of cortisone in normal rats resembled to a large degree those of a protein-free diet. If the hormone was administered to PD rats, the residual lymphocytes of the atrophic thymus were still more cortisone-sensitive than those of normal rats. On the contrary, DNA synthesizing cells in the PLN's and spleen, and mitoses in the spleen resisted cortisone in PD rats, while they were partly destroyed by the hormone in the controls. This suggests that primarily the cortisone-resistant lymphocytes of these organs are capable of synthesizing DNA after prolonged protein deprivation. The results are in agreement with the hypothesis of an intervention of endogenous glucocorticoid hormones in the protein lack-induced lymphoid involution.

Animals↗
PubMed1978

Diet-induced atherosclerosis and experimental hypertension in stumptail macaques (Macaca arctoides). Effects of antihypertensive drugs and a non-atherogenic diet in the evolution of lesions.

This study was carried out to determine the evolution of atherosclerotic lesions during a therapeutic period during which regression might be appreciated. We produced aortic and coronary atherosclerosis in 27 young adult stumptail macaques (Macaca arctoides) by feeding a diet supplemented with 2% cholesterol and 25% fat. Hypertension was produced by bilateral or unilateral narrowing of the renal artery. After six months of this regimen, four monkeys were killed (group 1) and 23 monkeys were divided into three groups: group 2 received unsupplemented diet; group 3 received the same diet as group 2 and drug treatment for hypertension; group 4 was continued on the atherogenic diet and received antihypertensive drug treatment. The results indicate that deleting the atherogenic diet leads to a decrease in the lipid content of the lesions and a transformation of the lipid laden atherosclerotic plaques into lipid-poor, fibro-collagenous lesions, with a decrease in the amount of coronary luminal narrowing. Partial control of systolic hypertension by antihypertensive drugs did not accelerate the involution of the atherosclerotic lesions over the relatively short period of this study. No statistically significant correlation by regression analysis was observed between the level of blood pressure elevation, the plasma renin activity, or the degree of the drug response, and the severity and extent of the atherosclerotic lesions. Furthermore, severe arterial hypertension without an atherogenic diet (group 5) produced arteriosclerosis of the aorta, and intensified branch cushions in the coronary arteries, without inducing lipid deposition in either vascular bed.

Animals↗
PubMed1976

[Potatoe egg diet and mixed low protein diet: subjective evaluation (author's transl)].

Earlier own studies concerning nutritional state (protein metabolism) have shown a superiority of mixed low protein diet - combined with essential amino acids (EAA) - to potatoe egg diet (PE). As a sequal to these studies now the subjective evaluation of the two kinds of diet was investigated. The following results are obtained: Compliance with mixed low protein diet is easier though drug intake is increased. Contrary to potatoe egg diet it seldom causes psychic stress (93 to 33% respectively). Therefore it probably can be strictly adhered to for a longer time and is subjectively told to cause an improvement of the physical condition. For that reason in future the mixed low protein diet in combination with EAA should be preferred in the phase of predialysis or transplantation. A successful treatment presumes a relative constancy of the residual glomerular filtration.

Amino Acids, Essential↗
PubMed1978

Low-fat diet versus low-carbohydrate diet in the treatment of type IV hyperlipoproteinaemia.

The response to dietary management was studied in 24 hypertriglyceridaemic out-patients. Fourteen patients were kept on a diet low in fat and cholesterol and high in polyunsaturated fatty acids; 10 of these patients subsequently followed a period of low-carbohydrate diet. At the end of the first period a significant decrease of serum triglyceride, cholesterol and beta-lipoproteins was observed; after the second feeding period no substantial change of serum lipoprotein pattern occurred. Ten patients were given a low-carbohydrate diet that produced a significant fall of the levels of triglycerides and pre-beta-lipoproteins. Six of these subjects continued the experiment with the low-fat diet; during this period a further trend toward reduction of serum triglyceride, cholesterol and beta-lipoproteins was observed which, however, was not statistically significant. We conclude that serum triglyceride levels can be lowered both by a low-carbohydrate diet and by a low-fat diet, but the latter has the advantage of also producing a significant fall of serum cholesterol and beta-lipoproteins.

Adult↗
PubMed2026

Long-term microbiome and clinical effects of a microbiome-guided personalized diet versus low-FODMAP diet in irritable bowel syndrome: A 12-month follow-up randomized controlled trial.

Dietary therapy is central to irritable bowel syndrome (IBS) management, yet the long-term durability of the low-FODMAP diet (LFD), and of microbiome-guided personalization, remains unclear. We assessed the long-term clinical and gut-microbiome effects of a microbiome-guided personalized diet (PD) compared with a standard LFD in adults meeting Rome IV criteria for IBS. In this multicenter, open-label randomized controlled trial with blinded outcome assessment, participants who completed a 6-week dietary intervention (PD or LFD) were followed at 6 and 12 months without further dietary intervention. Outcomes included the IBS Severity Scoring System (IBS-SSS), IBS Quality of Life (IBS-QOL), and the Hospital Anxiety and Depression Scale (HADS); gut microbiota were profiled by 16S rRNA sequencing. Longitudinal changes were evaluated using linear mixed-effects models, responder analyses, PERMANOVA, and PERMDISP. Both diets reduced IBS-SSS at 6 weeks. PD maintained symptom improvement at 6 and 12 months (-82.0 and -78.3 points from baseline), whereas LFD benefits regressed by 12 months (+29.3 points; between-group p&#x2009;=&#x2009;0.001). At 12 months, IBS-SSS responder rates were higher with PD than LFD (62.5% vs 34.5%; absolute risk difference&#x2009;+28.0%, 95% CI 4.2-47.7; Fisher p&#x2009;=&#x2009;0.029), and IBS-QOL, HADS-anxiety, and HADS-depression showed more favourable trajectories with PD. PD was associated with sustained Shannon alpha-diversity gains (+0.488 at 6 weeks;&#x2009;+0.205 at 12 months; both p&#x2009;<&#x2009;0.01). A modest between-group beta-diversity difference at 6 months (R2&#x2009;=&#x2009;0.035; p&#x2009;=&#x2009;0.011) was not significant at 12 months. This hypothesis-generating follow-up suggests more durable benefit with PD; larger trials powered for long-term clinical and microbiome outcomes are warranted.

Humans↗
PubMed1975

Effect of a low protein diet and isoenergetic amounts of a high protein diet in the weanling rat on the free amino acids of the brain.

Giving weanling rats a low protein diet for 56 days retarded the growth of the brain, whereas giving isoenergic amounts of a high protein diet did not. The low protein diet resulted in higher concentrations of aspartic acid, glycine, alanine and histidine in the plasma and of glycine and histidine in the brain. The concentration of methionine was unchanged in the plasma, but raised in the brain. Isoenergetic amounts of the high protein diet did not change the concentration of plasma amino acids, but resulted in some changes in brain amino acids. On rehabilitation the plasma and brain amino acids of the low protein animals returned to normal.

Alanine↗
PubMed1977

The effect of a protein-free diet, a sugar diet and of carbon tetrachloride administration on the toxicity and rate of metabolism of dimethylnitrosamine in different rat strains.

A Porton and a hooded rat strain showed a raised LD50 for dimethylnitrosamine (DMN) when pre-conditioned on a protein-free and/or a sugar diet. Little or no such differential toxicity between normal and diet-fed animals was found for rats of the Wistar, BDIX and CFY strains. Pre-treatment with CCl4 did not alter significantly the toxicity of DMN in the Wistar strain. All 5 rat strains treated by diet or CCl4 administration metabolized DMN at a very much slower rate than did the controls, the rates for the different strains being quantitatively similar. It is concluded that the toxicity of DMN is not necessarily related to its rate of metabolism and that the effect of diet or CCl4 treatment of DMN toxicity is dependent on the strain of rat used.

Animals↗
PubMed1975

The replacement of some of the soybean meal by the first limiting amino acids in practical broiler diets. I. The value of special supplementation of chick diets with methionine and lysine.

1. Three trials were carried out in order to determine the amount by which dietary protein concentration can be reduced while maintaining the dietary concentrations of the first two limiting amino acids, methionine and lysine. 2. In all trials growth rate and food utilisation declined as the protein concentration of a well-balanced standard chick diet was lowered by replacing soybean meal with sorghum grain (milo), but this trend could be partly or completely prevented when methionine or methionine and lysine levels were restored. 3. Addition of 0-06 to 0-07% methionine, above that considered to be normal, is sufficient to replace approximately 0.9% soybean protein. 4. In diets containing approximately 3 percentage units less soybean protein than required, a supplementation of about 0.15% each of methionine and lysine can replace nearly 2-0% soybean protein, but cannot bring about chick performance equal to that obtained on the control ration, indicating an insufficiency of a third, or third and fourth, limiting amino acid in such low-protein diets.

Animal Feed↗