Isocaloric Standard Diet Research Articles

Deleterious Effect of High-Fat Diet on Skeletal Muscle Performance Is Prevented by High-Protein Intake in Adult Rats but Not in Old Rats.

The phenotype of sarcopenic obesity is frequently associated with impaired muscle strength and performance. Ectopic lipid deposition may interfere with muscle anabolic response especially during aging. Evidence is scarce concerning the potential interplay among aging and nutrient imbalance on skeletal muscle functionality. The objective of the present study was to investigate the impact of protein intake in the context of an obesogenic diet on skeletal muscle functional properties and intramuscular lipid infiltration. Two groups of forty-two adult and thirty-seven old male Wistar rats were randomly divided into four groups: isocaloric standard diet (12% protein, 14% lipid, as ST12); isocaloric standard (high-protein) diet (25% protein, 14% lipid, ST25); hypercaloric high-fat (normal-protein) diet (12% protein, 45% lipid, HF12); and hypercaloric high-fat (high-protein) diet (25% protein, 45% lipid, HF25). The nutritional intervention lasted 10 weeks. Total body composition was measured through Echo-MRI. Lipids were extracted from tibialis anterior muscle and analyzed by gas-liquid chromatography. The functional properties of the plantarflexor muscles were evaluated in vivo on an isokinetic dynamometer. Maximal torque was assessed from the torque-frequency relationship in isometric condition and maximal power was evaluated from the torque-velocity relationship in concentric condition. In adult rats high-protein intake combined with high-fat diet determined a lower decrease in relative isometric torque, normalized to either FFM or body weight, compared with adult rats fed a high-fat normal-protein diet. High-fat diet was also detrimental to relative muscle power, as normalized to body weight, that decreased to a larger extent in adult rats fed a high-fat normal-protein diet than their counterparts fed a normal-fat, high-protein diet. The effect of high-fat diet observed in adults, with the enhanced protein intake (25%) conferring some kind of protection against the negative effects of HFD, may be linked to the reduced intramuscular fat in this group, which may have contributed to preserve, at least partly, the contractile properties. A potential role for high-protein diet in preventing ectopic lipid deposition needs to be explored in future research. Detrimental effects of high- fat diet on skeletal muscle performance are mitigated by high- protein intake in adult rats but not in old rats.

Evaluating the effect of an energy-restricted anti-inflammatory diet on weight loss, body composition, cardiometabolic risk factors and immune system response in younger adults with obesity: Study protocol for a randomized controlled trial

IntroductionLow-grade chronic inflammation is associated with obesity and related cardiometabolic disorders, such as cardiovascular diseases, type 2 diabetes, and some types of cancer. A growing body of evidence suggests that a variety of dietary factors can modulate obesity-induced chronic low-grade inflammation and thus the course of obesity-related chronic non-communicable diseases. We are aiming to evaluate the effect of an energy-restricted anti-inflammatory diet on weight loss, body composition, cardiometabolic risk factors, and immune system response among younger adults with obesity. MethodsA two-arm, parallel design randomized controlled trial will be conducted in Croatia among 220 adults with obesity aged 18–50 years. Following baseline assessments, participants will be randomized into the intervention or control group in a 1:1 ratio. A nutritional intervention based on an energy-restricted anti-inflammatory diet (low-glycemic, low in omega-6, rich in omega-3 fatty acids, spices, herbs) will be compared with an isocaloric standard diet (55–60 % carbohydrates, 25–30 % fat, 15–20 % protein). The inflammatory potential of the diet will be assessed with the Dietary Inflammatory Index®. The change in body weight from baseline to the week 24 will be the main outcome measure. Secondary outcomes will include changes in body composition, cardiometabolic parameters, and the impact of the anti-inflammatory diet on immune system response and thyroid function. ConclusionIf the energy-restricted anti-inflammatory diet is found to be effective in the management of obesity, it has the potential to be implemented into management for reducing obesity and related chronic non-communicable disease in younger adults.

Effect of enteral diet enriched with eicosapentaenoic acid, gamma-linolenic acid, and antioxidants in patients with sepsis-induced acute respiratory distress syndrome

BackgroundIn this study, the effects of an enteral diet enriched with eicosapentaenoic acid (EPA), γ-linolenic acid (GLA), and antioxidants were compared with a standard enteral diet in critically ill patients with sepsis-induced acute respiratory distress syndrome (ARDS).MethodsThis study was a single-center, prospective, randomized, single-blind, controlled trial in our Advanced Critical Care Center. Patients were randomized to receive a continuous EPA, GLA, and antioxidant-enriched diet (study group), or an isocaloric standard diet (control group).ResultsTwenty-three of 46 patients were in the study group, and the other 23 were in the control group. Duration of mechanical ventilation, incidence of new nosocomial infections, changes over time in Sequential Organ Failure Assessment (SOFA) scores, and 60-day mortality were not significantly different between the two groups. The ratio of partial pressure of oxygen to fraction of inspired oxygen on day 7 was significantly higher in the study group (233.0 [185.5–282.8] vs. 274.0 [225.5–310.8], p = 0.021). Duration of ICU stay was significantly shorter in the study group than in the control group (24.0 [20.0–30.0] vs. 15.0 [11.0–24.0], p = 0.008).ConclusionsAn enteral diet enriched with EPA, GLA, and antioxidants did not improve duration of mechanical ventilation, SOFA score, incidence of new nosocomial infections, or mortality but did favorably influence duration of ICU stay in critically ill patients with sepsis-induced ARDS.Electronic supplementary materialThe online version of this article (doi:10.1186/s40560-015-0087-2) contains supplementary material, which is available to authorized users.

Effects of Raspberry on Biomarkers of Diabetes, Cardiovascular Disease (CVD) and Oxidative Stress in Obese Diabetic (db/db) Mice

Diabetes and its complications are considered major health problems worldwide. Oxidative stress associated with diabetes increases the risk of developing CVD. Red raspberry contains bioactive compounds such as polyphenols which may prevent and treat these diseases. The study investigated the effects of raspberry (Wakefield red raspberries) on diabetes, cardiovascular risk factors and oxidative stress in db/db mice. Thirty male db/db mice were divided into two groups and fed ad libitum for 8 weeks with standard diet (control group) and isocaloric standard diet containing 10% freeze dried raspberry (raspberry group). At the end of the study mice were euthanized; tissue and blood were collected and analyzed using standard techniques. Results indicate that raspberry consumption did not decrease significantly (p>0.05) the blood triglycerides and total cholesterol; though abdominal fat decreased by 38% (p > 0.05). Raspberry increased the plasma high density lipoprotein cholesterol by 1.5‐fold, whereas low density lipoprotein cholesterol decreased by 0.3‐fold. Moreover, the insulin tolerance test showed a trend to increase insulin sensitivity in the raspberry group; this was accompanied by a 19% decrease in reactive oxygen species measured in blood erythrocytes. These findings may suggest the potential role of raspberry in decreasing cardiovascular risk in diabetics.

A high-fat diet impairs cardiac high-energy phosphate metabolism and cognitive function in healthy human subjects

High-fat, low-carbohydrate diets are widely used for weight reduction, but they may also have detrimental effects via increased circulating free fatty acid concentrations. We tested whether raising plasma free fatty acids by using a high-fat, low-carbohydrate diet results in alterations in heart and brain in healthy subjects. Men (n = 16) aged 22 ± 1 y (mean ± SE) were randomly assigned to 5 d of a high-fat, low-carbohydrate diet containing 75 ± 1% of calorie intake through fat consumption or to an isocaloric standard diet providing 23 ± 1% of calorie intake as fat. In a crossover design, subjects undertook the alternate diet after a 2-wk washout period, with results compared after the diet periods. Cardiac (31)P magnetic resonance (MR) spectroscopy and MR imaging, echocardiography, and computerized cognitive tests were used to assess cardiac phosphocreatine (PCr)/ATP, cardiac function, and cognitive function, respectively. Compared with the standard diet, subjects who consumed the high-fat, low-carbohydrate diet had 44% higher plasma free fatty acids (P < 0.05), 9% lower cardiac PCr/ATP (P < 0.01), and no change in cardiac function. Cognitive tests showed impaired attention (P < 0.01), speed (P < 0.001), and mood (P < 0.01) after the high-fat, low-carbohydrate diet. Raising plasma free fatty acids decreased myocardial PCr/ATP and reduced cognition, which suggests that a high-fat diet is detrimental to heart and brain in healthy subjects.

Cholecystokinin-8S levels in discrete hypothalamic nuclei of weanling rats exposed to maternal protein malnutrition

Perinatal malnutrition and growth retardation at birth are suggested to be important risk factors for the development of overweight and syndrome X in later life. Underlying mechanisms are unknown. Body weight and food intake are regulated, e.g. by hypothalamic neuropeptidergic systems which are thought to be highly vulnerable to persisting malorganization due to perinatal malnutrition. To investigate possible consequences for hypothalamic cholecystokinin-8S (CCK-8S) in the offspring, pregnant Wistar rats were fed an 8% protein diet during pregnancy and lactation (low-protein group; LP) while control mothers (CO) received a 17% protein isocaloric standard diet. LP offspring displayed underweight at birth ( P<0.05) and during suckling ( P<0.001), while leptin levels were not altered. At weaning, under basal conditions CCK-8S was decreased in LP offspring in the paraventricular hypothalamic nucleus and arcuate hypothalamic nucleus ( P<0.05), as well as in the dorsomedial hypothalamic nucleus, lateral hypothalamic area and ventromedial hypothalamic nucleus ( P<0.01). In summary, these data indicate (1) an inhibition of the satiety peptide CCK-8S in main regulators of body weight and food intake in low-protein malnourished newborn rats; (2) no direct relationship of hypothalamic CCK-8S to circulating leptin at this age; and (3) no neurochemical signs of hypothalamic CCKergic dysregulation in this animal model at the age of weaning.

Imbalance between Jejunum and Ileum in the Response of Brush Border Hydrolases to Oral Feeding after Intravenous Alimentation in Rats

The effect of oral refeeding after total parenteral nutrition (TPN) on brush border hydrolases was measured in the proximal jejunum and ileum of adult rats. The animals received intravenously for 4 days a mixture of Intralipid 10% and Vamine-Glucose. At the end of TPN, oral feeding was reinstituted and the rats were fed with an isocaloric standard diet (60% carbohydrate, 17% protein, 3% lipid). Sucrase, isomaltase, lactase, and aminopeptidase N activities were measured at the end of TPN and at 1, 3, and 5 days after TPN. Sham-operated rats nourished orally with the standard diet were used as controls. In both intestinal segments, lactase activity showed no significant changes at the end of TPN or during oral realimentation. Isomaltase, and especially sucrase activities, exhibited an important drop at the end of TPN. After TPN, a complete restoration of isomaltase and sucrase activities was obtained in the jejunum only. During oral refeeding a 40% deficit in sucrase activity persisted in the ileum throughout the experimental period, whereas normal isomaltase activity was restored in this segment. Aminopeptidase N activity was lowered by TPN and recovered normal values within a few hours after oral realimentation. Thus, reinstitution of oral feeding after TPN should take into account that the intestine is capable of digesting normal amounts of dietary protein but has a reduced tolerance for carbohydrates.

High density lipoprotein subfractions during semistarvation in obese women.

The influence of a very low caloric diet (VLCD) on high density lipoproteins (HDL) is controversial. This study was designed to evaluate the influence of a VLCD on lipids and lipoproteins, especially on HDL subfractions (HDL2, HDL3) in obese women. After a 4-day period of isocaloric standard diet, 30 women at least 50% above ideal body weight were switched for 15 days on a protein-sparing modified diet providing 1.57 MJ per day. Mean body weight reduction was 5.6 +/- 0.7 kg. After the VLCD, total, very low density lipoproteins (VLDL), low density lipoproteins (LDL) and HDL cholesterol significantly decreased in all the subjects (p less than 0.01). Both HDL subfractions were depressed after the VLCD (p less than 0.01) but the reduction occurred predominantly in the HDL2 subfraction, thus inducing a decrease in the HDL2 to HDL3 cholesterol ratio (p less than 0.01). The VLCD was associated with a slight but not significant increase in the LDL to HDL cholesterol ratio. This increase was due mostly to the rise in the LDL to HDL2 cholesterol ratio (p less than 0.01). Further studies are needed to evaluate the long-term changes of HDL subfractions during weight-reducing regimens.