Postprandial lipolytic activities, lipids, and carbohydrate metabolism are altered in dogs fed diacylglycerol meals containing high- and low-glycemic-index starches

Dietary mannoheptulose does not alter glucose or lipid metabolism in adult Labrador Retrievers

Mannoheptulose (MH), a glycolytic inhibitor, has been preliminarily investigated as a novel functional food ingredient for dogs. This study aimed to determine the effects of dietary MH, delivered as an extract of un-ripened avocados, on fatty acid and glucose kinetics in healthy adult Labrador Retriever dogs (n = 12 dogs). The study was a double-blindcrossover with each dog receiving both dietary treatments, control (CON) and MH (400 mg/kg of diet), in random order. Glucose and glycerol plasma turnover (Ra) and oxidation (Ox) were measured in fasting and in response to repeated meal feeding ("fed") with stable isotope tracers (U-¹³ C-glucose, 1,1,2,3,3-D₅ -glycerol) and indirect calorimetry. Palmitate Ra and Ox were examined during repeated meal feeding only using an oral bolus of U-¹³ C-K₂ -palmitate and indirect calorimetry. MH had no discernible effect on fasting glucose Ra (677, 722 SEM 36 μmol/min, CON, MH) or Ox (107, 109 μmol/min, CON, MH SEM 10 μmol/min) or fed glucose Ra (2913, 3626 SEM 644 μmol/min, CON, MH) or Ox (951, 936 SEM 174 μmol/min, CON, MH). Glycerol Ra, an index of the rate of lipolysis, was not different between dietary treatments (Fast 162, 113 SEM 35 μmol/min CON, MH; Fed 172, 135 SEM 21 μmol/min, CON, MH). Similarly, palmitate oxidation was not impacted by MH feeding (1966, 2276 SEM 79 μmol/min, CON, MH). Together, these findings do not support MH as a novel functional food ingredient at least at the dietary dose tested.

The effect of consuming low- versus high-glycemic index meals after exercise on postprandial blood lipid response following a next-day high-fat meal

Background/Objectives:

Exercise performed shortly before (that is, within half a day of) a high-fat meal is beneficial for stimulating fat oxidation after the meal and reducing postprandial triglycerides (TG). This benefit of exercise is unfortunately negated if the after-exercise food choice to replace the calories expended during exercise is one containing high-glycemic index (HGI) carbohydrates. We determined the effect of consuming low-glycemic index (LGI) carbohydrates after an exercise session on fat oxidation and TG after a subsequent high-fat meal.

Subjects/Methods:

Using a randomized, counterbalanced crossover design, 23 overweight or obese individuals (body mass index ⩾25 kg m⁻²) performed: walking exercise (90 min) at 1800 h followed by no meal (EX); exercise followed by a meal with LGI carbohydrates (that is, lentils, EX-LGI); exercise followed by a meal with HGI carbohydrates (that is, instant potatoes, white bread, EX-HGI); and a control condition with no exercise or meal. After a 10-h overnight fast, participants were given a standardized high-fat meal. Fat oxidation was estimated before and for 6 h after this meal from respiratory gas measures and TG determined from blood samples.

Results:

Fat oxidation (mean±s.d.) was higher with EX (6.9±1.7 g h⁻¹) than EX-HGI (6.3±1.6 g h⁻¹; P=0.007) and Control (5.9±1.7 g h⁻¹; P=0.00002), and EX-LGI (6.6±1.7 g h⁻¹) was higher than Control (P=0.002). TG total area under the curve was 18–32% lower with EX and EX-LGI compared with control (P=0.0005 and P=0.0001, respectively) and EX-HGI (P=0.05 and P=0.021, respectively).

Conclusions:

A meal containing HGI carbohydrates consumed after an evening exercise session cancels the beneficial effect of exercise for stimulating fat oxidation and lowering TG after a subsequent high-fat meal, whereas consuming a post-exercise meal with LGI carbohydrates retains the positive effect of exercise.

Slowly digestible starch--a review

The link between carbohydrate intake and health is becoming increasingly important for consumers, particularly in the areas of glycemic index (GI) and extended energy-releasing starches. From a physiological point of view, slowly digestible starch (SDS) delivers a slow and sustained release of blood glucose along with the benefits resulting from low glycemic and insulinemic response. SDS has been implicated in several health problems, including diabetes, obesity, and cardiovascular diseases (metabolic syndromes). It may also have commercial potential as a novel functional ingredient in a variety of fields, such as nutrition, medicine, and agriculture. The present review assesses this form of digestion by analyzing methods to prepare and evaluate SDS, and factors affecting its transformation, its health benefits, and its applications.

The regulatory effects of resistant starch on glycaemic response in obese dogs

The purpose of this study was to examine the inhibitory effects of resistant starch on postprandial glycaemic response in obese dogs. The changes in blood glucose concentrations and glycaemic index (GI) were chronologically determined after the administration of resistant and normal starches by nasal feeding. Resistant starch contained indigestible dextrin (IDD) and β-cyclic dextrin (β-CD). Soluble starch (SS) served as a control starch. Glucose concentrations reached their maximum 15 min after the administration of SS solutions, and decreased gradually during the experimental period. In contrast, after the administration of IDD solutions, increased glucose concentrations rapidly decreased to the initial values. After the administration of β-CD solutions, glucose concentrations remained unchanged during this study. GI levels remained constant in the following order: β-CD < IDD < SS. GI levels of dogs receiving IDD and β-CD solutions were significantly lower as compared with those animals receiving SS solutions. In this study, nasal tube feeding was an effective method for evaluating glycaemic responses to various starches accurately. The present data revealed that resistant starches were useful materials in controlling nutritionally glucose concentrations in obese dogs. These results raise the possibility that resistant starches are valuable for dietetic treatment of diabetes and obesity in dogs.

Metabolic and Hormonal Alterations with Diacylglycerol and Low Glycemic Index Starch during Canine Weight Loss

Obesity increases insulin resistance and disregulation of glucose homeostasis. This study investigated low glycemic index starch (LGIS)/diacylglycerol (DAG) diet on plasma insulin and circulating incretin hormones during canine weight loss. Obese Beagle dogs were fed one of four starch/oil combination diets (LGIS/DAG; LGIS/triacylglycerol (TAG); high glycemic index starch (HGIS)/DAG; and HGIS/TAG) for 9 weeks during the weight loss period. At weeks 1 and 8, fasting plasma insulin, glucose, nonesterified fatty acid (NEFA), glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide-1 (GLP-1) were determined. Weight loss did not affect fasting insulin, glucose, and NEFA, but fasting GIP increased and GLP-1 decreased. LGIS affected postprandial insulin at both times and glucose was similar to insulin, except 60 min postprandially with DAG at week 8. NEFA lowering was less with the LGIS diets initially but not thereafter. At 60 min postprandially on week 8, GIP was significantly elevated by DAG, while GLP-1 was increased only with the HD diet. LGIS suppressed insulin and glucose responses up to 180 min postprandially at both sample times. DAG increased incretin hormones as did the DAG/HGIS combination but only at week 8. This latter finding appeared to be related to the glucose response but not to insulin at 60 min.

Nutritional care for aging cats and dogs

Veterinarians need to be prepared to provide nutritional advice for healthy pets as well as for pets that are ill. Before instituting a dietary change in any patient, especially an older dog or cat, a nutritional evaluation should be completed. This should include an evaluation of the patient, the current diet, and feeding management. Diets should be appropriate to the unique needs of the individual patient. Many diseases in senior pets are “diet-sensitive” meaning that diet can play a role in managing the effects of the disease. Common examples discussed include cognitive dysfunction of aging, osteoarthritis, and obesity.

Companion Animals Symposium: Obesity in dogs and cats: What is wrong with being fat?

Few diseases in modern pets are diet induced. One possible exception to this is obesity, which is ultimately caused by consuming more calories than needed by the dog or cat. Although fat is the most concentrated and efficiently stored source of calories, and protein least so, an excess of calories from any source will contribute to adiposity. Obesity is an excess of body fat sufficient to result in impairment of health or body function. In people, this is generally recognized as 20 to 25% above ideal BW. This degree of excess is important in dogs as well. A lifelong study in dogs showed that even moderately overweight dogs were at greater risk for earlier morbidity; these dogs required medication for chronic health problems sooner than their lean-fed siblings. The average difference in BW between groups was approximately 25%. Obese cats also face increased health risks, including an increased risk of arthritis, diabetes mellitus, hepatic lipidosis, and early mortality. The risk for development of diabetes increases about 2-fold in overweight cats and about 4-fold [corrected] in obese cats. Altered adipokine secretion appears to be an important mechanism for the link between excess BW and many diseases. Once considered to be physiologically inert, adipose tissue is an active producer of hormones, such as leptin and resistin, and cytokines, including many inflammatory cytokines such as tumor necrosis factor-α, IL-1β and IL-6, and C-reactive protein. The persistent, low-grade inflammation secondary to obesity is thought to play a causal role in chronic diseases such as osteoarthritis, cardiovascular disease, diabetes mellitus, and others. For example, tumor necrosis factor-α alters insulin sensitivity by blocking activation of insulin receptors. In addition, obesity is associated with increased oxidative stress, which also may contribute to obesity-related diseases. Management of obesity involves nutritional modification as well as behavioral modification. Increased protein intake combined with reduced calorie intake facilitates loss of body fat while minimizing loss of lean body mass. Limiting treats to 10% of calorie intake and increasing exercise both aid in successful BW management.

Dietary effects of diacylglycerol rich mustard oil on lipid profile of normocholesterolemic and hypercholesterolemic rats

Several recent studies have established that diacylglycerol (DAG) rich oils significantly reduce the body weight. The present study was conducted to evaluate the dietary effects of DAG- rich mustard oil on normal and hypercholesterolemic rats. DAG- rich mustard oil (45.5% DAG) was prepared in the laboratory by enzymatic glycerolysis process. For the feeding experiment, 32 rats were taken and divided into four groups (average body weight 130 g) and body weight gain, food efficiency ratio, lipid profile of plasma, liver, mesentery and erythrocytes membrane (EM), HMG Co-A reductase activity and plasma leptin content were measured and compared with the normal TAG-rich diet. The dietary DAG rich mustard oil significantly decreased body weight and FER compared to TAG rich mustard oil both in normal and hypercholesterolemic rats. The total cholesterol content was decreased with significant increase in HDL- cholesterol by feeding DAG rich diet. Total lipid and TAG content of both liver and mesentery were significantly decreased in DAG diet group compared to control group. Liver HMG CoA: mevalonate ratio was also found to be significantly decreased in the DAG group. Blood leptin level significantly reduced with DAG rich diet compared to the TAG rich dietary groups.

Postprandial lipid-related metabolites are altered in dogs fed dietary diacylglycerol and low glycemic index starch during weight loss

In this study, we investigated a combination of a low glycemic index starch (LGIS) and diacylglycerol (DAG) on lipid, lipoprotein (LP) metabolism, and weight management. Obese, intact female adult Beagle dogs were assigned to 1 of 4 starch/oil combination diets [LGIS/DAG (LD); LGIS/triacylglycerol (TAG); high glycemic index starch (HGIS)/DAG; and HGIS/TAG (HT)] and fed for 9 wk (n = 6/group) using an incomplete 4 × 4 Latin square design. Each dog was fed 1 of 2 opposite starch/oil combination diets (e.g. LD and HT). At wk 1 and 8, postprandial blood was collected for plasma triacylglycerol (TG), β-hydroxybutyrate (BHB), total cholesterol (TC), and LP analyses. During the same week, dogs were overnight feed-deprived and post-heparin blood was collected for LP lipase and hepatic lipase activity determinations. At wk 1, 4, and 8, blood was drawn from overnight feed-deprived dogs for plasma TG, BHB, TC, LP, leptin, and adiponectin measurements. Feces were collected at wk 3 for digestibility calculations. The LGIS diets resulted in lower carbohydrate, protein, total tract dry matter digestibilities, and metabolizable energy compared with the HGIS diet groups (P < 0.05). Thus, the LGIS groups lost more body weight (P = 0.001), which was positively correlated with plasma leptin concentrations (r(2) = 0.427; P < 0.001). Moreover, the LGIS diet lowered TC concentrations in combination with DAG. The DAG diet groups decreased postprandial TG and increased BHB concentrations (P < 0.05). Starch/oil types did not alter lipase activities or adiponectin concentrations. In conclusion, the LGIS diet demonstrated potential as a weight management tool in dogs by decreasing postprandial TG and increasing BHB in combination with DAG.

Effects of a 1,3-diacylglycerol oil-enriched diet on postprandial lipemia in people with insulin resistance

Postprandial hypertriglyceridemia is common in individuals with insulin resistance, and diets enriched in 1,3-diacylglycerol (DAG) may reduce postprandial plasma triglycerides (PPTGs). We enrolled 25 insulin-resistant, nondiabetic individuals in a double-blind, randomized crossover trial to test the acute and chronic effects of a DAG-enriched diet on PPTG. Participants received either DAG or triacylglycerol (TAG) oil, in food products, for 5 weeks. Fasting lipids, and two separate postprandial tests, one with DAG oil and one with TAG oil, were performed at the end of each 5 week diet period. We found no acute or chronic effects of DAG oil on PPTG. Thus, neither the DAG oil PPTG (h/mg/dl) on a chronic TAG diet [area under the curve (AUC) = 503 +/- 439] nor the TAG oil PPTG on a chronic DAG diet (AUC = 517 +/- 638) was different from the TAG oil PPTG on a chronic TAG diet (AUC = 565 +/- 362). Five weeks of a DAG-enriched diet had no acute or chronic effects on PPTG in insulin-resistant individuals. We suggest further studies to evaluate the effects of DAG on individuals with low and high TG levels.