Dietary fiber in management of diabetes

Reduction of cat voluntary feed intake in the short-term response to the sugar cane fibre supplementation

Obesity is a well-known syndrome of excessive body fat in cats (Felis catus) that affects the health, welfare and lifespan of animals. Consequently, different diet strategies aiming to reduce voluntary feed intake in cats have been studied. One of these consists in reducing energy intake based on reduction of feed intake. Several clinical studies have demonstrated that dietary fibre inclusion in food reduced efficiently voluntary feed intake (VFI) in dogs. However, little clinical data is available regarding the impact of dietary fibre inclusion on cat’s feeding behaviours and VFI. The aim of the current study was to test the performance of sugar cane fibre included at three different levels in extruded feline diets. The main purpose was to measure the impact of fibre inclusion on the cats’ VFI, while maintaining palatability. Four feline diets were formulated with different inclusion levels of sugar cane fibre expressed on an as fed basis (0% sugar cane fibre (control), 3.7% of sugar cane fibre (SF3.7), 5.5% of sugar cane fibre (SF5.5) and 7.3% sugar cane fibre (SF7.3)). The VFI and palatability were evaluated in two different methods: a new method using 79 cats, called ‘consumption kinetics’ based on the dynamic measure of cat’s daily consumptions in ad libitum conditions providing information about cat’s feeding pattern, and the standard palatability two-bowl (versus) test using more than 30 cats. All foods had identical palatability performance, regardless of sugar cane fibre inclusion level, while the VFI of products containing 5.5% and 7.3% sugar cane fibre decreased significantly compared to the control diet. The level of supplementation of sugar cane fibre was efficient to reduce felines VFI without impairing food palatability level, and may be a useful ingredient to add to feline diets to improve the success of the weight management programs.

A High-Fiber Diet Decreases Postabsorptive Protein Turnover but Does Not Alter Insulin Sensitivity in Men with Type 1 Diabetes Mellitus

BACKGROUND

High-fiber diets (HFDs) are recommended in the diet of persons with diabetes, yet such diets can impair macronutrient digestion and/or absorption, modify insulin sensitivity, and reset metabolism.

OBJECTIVES

We studied the effects of a HFD on the kinetics of whole-body protein, a macronutrient that could be affected by dietary fiber, in type 1 diabetes mellitus (T1DM), under both basal-low insulinemic and hyperinsulinemic conditions.

METHODS

Eight men with T1DM (body mass index range: 21.8-27.8 kg/m2) were studied twice - before and after the addition of guar gum (∼15 g/d) to their usual diet for ∼4 mo. Whole-body protein degradation (i.e., the rate of appearance [Ra] of endogenous leucine), leucine disposal to protein synthesis (PS), deamination, and reamination, were determined before and after the HFD, both in the postabsorptive state and following a euglycemic, hyperinsulinemic, hyperaminoacidemic clamp, using isotope dilution methods.

RESULTS

After the HFD, mean values (± SEs) for postabsorptive leucine Ra decreased by ∼20%: from 2.52 (0.15) to 2.03 (0.16) μmol x kg-1 x min-1, P < 0.049, after vs. before the HFD respectively. PS also decreased, by ∼25%: from 2.03 (0.15) to 1.57 (0.15), P < 0.045. Leucine concentration (P = 0.1) and reamination (P = 0.095) decreased moderately, whereas deamination was unchanged. Following the clamp, plasma amino acid concentrations (P < 0.001), leucine deamination (+ ∼50%, P < 0.00002), reamination (+ ∼30%, P < 0.0007), and PS (+ ∼35%, P < 0.00001) were all increased compared with postabsorptive state values, whereas endogenous leucine Ra was suppressed (by 15%, P < 0.00001, and by 25%, P < 0.001, with the primary or the reciprocal pool models, respectively). No significant differences in these insulin effects before compared with after the HFD were observed. Metabolic control (glycated hemoglobin), daily insulin requirement, and insulin-mediated glucose disposal were unchanged after the HFD.

CONCLUSIONS

A HFD downregulates postabsorptive protein turnover in men with T1DM, by decreasing both protein degradation and synthesis, possibly due to a subtle decrease and/or delay in amino acid absorption. It does not significantly affect the insulin (and amino acid sensitivity) to protein turnover, glucose disposal, and metabolic control.

An Overview on Probiotics as an Alternative Strategy for Prevention and Treatment of Human Diseases

Probiotics are viable and useful microorganisms, which are beneficial factors for human and animal health by altering their microbial flora. Most of the probiotics belong to a large group of bacteria in the human gastrointestinal tract. There are several clinical shreds of evidence that show anti-carcinogenic effects of probiotics through altering digestive enzymes, inhibition of carcinogenic agents, and modulating the immune responses in experimental animals. Many studies have been performed to evaluate the potential effectiveness of probiotics in treating or preventing neurological diseases such as MS and novel treatment modality for T1D. The purpose of this study is to have an overview on probiotic microorganisms and to review the previous researches on the effects of probiotics on health through currently available literatures. The study was performed using following keywords; Probiotics, Cancer, Immune system, Multiple Sclerosis (MS) and Diabetes mellitus. PubMed/Medline, Clinicaltrials.gov, Ovid, Google Scholar, and Reaxcys databases used to find the full text of related articles. According to the current available data on probiotics and related health-promoting benefits, it seems that, consumption of probiotics can lead to the prevention and reduction the risk of cancer, diabetes, and multiple sclerosis. Although for the better and more decisive conclusion, there is a need to larger sample size clinical studies with more focus on the safety of these biological agents and their possible beneficial effects on different population.

Can dietary fructans lower serum glucose?

BACKGROUND

Convincing evidence indicates that the consumption of inulin-type fructans, inulin, and oligofructose has beneficial effects on blood glucose changes in animal models, although data in humans have been considered equivocal. As such, a systematic review of available literature on humans was conducted to evaluate the effectiveness of dietary inulin-type fructans on serum glucose.

METHODS

Thirteen eligible randomized controlled trials (RCT), published from 1984 to 2009, were identified using a comprehensive search strategy involving the PubMed, Medline, and Cochrane Library databases. Exclusion criteria, such as the absence of a control group, lack of information on the quantity of inulin-type fructans used, and lack of glucose values at outcome, were established.

RESULTS

Upon review, only four of the 13 trials (31%) showed a decrease in serum glucose concentration and only one of these was statistically significant. The remaining nine trials showed no significant changes in serum glucose concentration.

CONCLUSION

Based on the present systematic review, it does not appear that inulin-type fructans have a significant lowering effect on serum glucose in humans. More RCT are needed to determine whether inulin-type fructans, inulin, and oligofructose have beneficial effects on blood glucose in humans.

Evidence of glycemia-lowering effect by a Cynara scolymus L. extract in normal and obese rats

Several recent preliminary clinical studies have suggested that artichoke (Cynara scolymus L., Asteraceae family) preparations may be capable of lowering post-prandial glycemia. The present study was designed to test this hypothesis in laboratory rats. To this aim, non-selected Wistar and genetically obese Zucker rats were treated acutely with a purified extract of Cynara scolymus flowering heads (500-1500 mg/kg by gavage) immediately prior to 1 h access to a fixed amount of food. Glycemia was recorded 60, 120 and 360 min after food presentation. Treatment with Cynara scolymus flowering head extract resulted in a significant decrease of post-prandial glycemia in both rat strains. The lack of any fiber content in this Cynara scolymus flowering head extract excludes the involvement of dietary fibers in glycemia reduction. The results obtained constitute the first evidence of a hypoglycemic effect of an artichoke preparation in laboratory rodents and confirm previous observations made in humans.

Aqueous extracts of husks of Plantago ovata reduce hyperglycaemia in type 1 and type 2 diabetes by inhibition of intestinal glucose absorption

Plantago ovata has been reported to reduce postprandial glucose concentrations in diabetic patients. In the present study, the efficacy and possible modes of action of hot-water extracts of husk of P. ovata were evaluated. The administration of P. ovata (0.5 g/kg body weight) significantly improved glucose tolerance in normal, type 1 and type 2 diabetic rat models. When the extract was administered orally with sucrose solution, it suppressed postprandial blood glucose and retarded small intestinal absorption without inducing the influx of sucrose into the large intestine. The extract significantly reduced glucose absorption in the gut during in situ perfusion of small intestine in non-diabetic rats. In 28 d chronic feeding studies in type 2 diabetic rat models, the extract reduced serum atherogenic lipids and NEFA but had no effect on plasma insulin and total antioxidant status. No effect of the extract was evident on intestinal disaccharidase activity. Furthermore, the extract did not stimulate insulin secretion in perfused rat pancreas, isolated rat islets or clonal beta cells. Neither did the extract affect glucose transport in 3T3 adipocytes. In conclusion, aqueous extracts of P. ovata reduce hyperglycaemia in diabetes via inhibition of intestinal glucose absorption and enhancement of motility. These attributes indicate that P. ovata may be a useful source of active components to provide new opportunities for diabetes therapy.

Effect of a nutritional liquid supplement designed for the patient with diabetes mellitus (Glucerna SR) on the postprandial glucose state, insulin secretion and insulin sensitivity in healthy subjects

AIM

To identify the effect of a nutritional liquid supplement designed for the patient with diabetes mellitus (Glucerna SR) in single administration on the postprandial glucose state, insulin secretion and insulin sensitivity in healthy subjects.

METHODS

A randomized, single-blind, cross-over, clinical trial was carried out in 14 young, healthy, non-obese, volunteers. A basal metabolic profile, which included glucose level, insulin, total cholesterol, high-density lipoprotein and low-density lipoprotein cholesterol, triglycerides, creatinine, and uric acid, was measured. Subjects received a single administration of 300 kcal, gauged with water at 350 ml, of each of the following (at least 3 days apart): glucose 75 g, polymeric supplement (Ensure high calcium) 315 ml or Glucerna SR 323 ml. At the beginning of each administration and 30, 60, 90 and 120 min later, glucose and insulin concentrations were measured. Areas under the curve of glucose and insulin were calculated. First-phase and total insulin secretions and insulin sensitivity were also estimated.

RESULTS

Glucose level at 120 min was significantly lower after receiving Ensure high calcium or Glucerna SR. Administration of Glucerna SR resulted in a significant reduction in the areas under the curve of glucose and insulin, as well as in total insulin secretion with a tendency to be lower in their first phase. Insulin sensitivity was increased.

CONCLUSIONS

A single administration of Glucerna SR to healthy subjects decreased the postprandial glucose and insulin states, as well as the insulin secretion; insulin sensitivity increased.

Postprandial hyperglycemia and diabetes complications: is it time to treat?

Increasing evidence suggests that the postprandial state is a contributing factor to the development of atherosclerosis. In diabetes, the postprandial phase is characterized by a rapid and large increase in blood glucose levels, and the possibility that the postprandial "hyperglycemic spikes" may be relevant to the onset of cardiovascular complications has recently received much attention. Epidemiological studies and preliminary intervention studies have shown that postprandial hyperglycemia is a direct and independent risk factor for cardiovascular disease (CVD). Most of the cardiovascular risk factors are modified in the postprandial phase in diabetic subjects and directly affected by an acute increase of glycemia. The mechanisms through which acute hyperglycemia exerts its effects may be identified in the production of free radicals. This alarmingly suggestive body of evidence for a harmful effect of postprandial hyperglycemia on diabetes complications has been sufficient to influence guidelines from key professional scientific societies. Correcting the postprandial hyperglycemia may form part of the strategy for the prevention and management of CVDs in diabetes.

Inulin-type fructans modulate gastrointestinal peptides involved in appetite regulation (glucagon-like peptide-1 and ghrelin) in rats

The hypothesis tested in the present study is that dietary fructans are able to modulate gastrointestinal peptides involved in the control of food intake, namely glucagon-like peptide (GLP)-1 (7-36) amide and ghrelin. After 3 weeks of treatment with a standard diet (control) or the same diet enriched with 100 g fructans varying in their degrees of polymerization (oligofructose (OFS), Synergy 1 (Syn) or long chain inulin)/kg, male Wistar rats were deprived of food for 8 h before sample collection. Dietary energy intake throughout the experiment was significantly lower (P<0.05) in fructans-fed rats than in control rats, leading to a significant decrease (P<0.01) in epidydimal fat mass at the end of the treatment in OFS- and Syn-treated rats. GLP-1 (7-36) amide concentration in portal vein serum was higher in OFS- and Syn-fed than in control rats. Both GLP-1 (7-36) amide concentration and proglucagon mRNA concentrations were significantly greater (P<0.05) in the proximal colonic mucosa of fructans-fed rats v. controls. Normally active ghrelin concentration in plasma increases during food deprivation and rapidly falls during a meal. In the present study, after 8 h of food deprivation, active ghrelin in the plasma remained significantly lower (P<0.05) in OFS and Syn-fed than in control rats. These results are in accordance with the modifications of dietary intake and fat-mass development in short-chain fructans-treated rats and demonstrate the potential modulation of GLP-1 (7-36) amide and ghrelin by fermentable fibres such as fructans, which are rapidly and extensively fermented in the proximal part of the colon.

Diet composition and the risk of type 2 diabetes: epidemiological and clinical evidence

In the last 10 years nutritional research on diabetes has improved dramatically in terms of both number of studies produced and quality of methodologies employed. Therefore, it is now possible to attempt to provide the evidence on which nutritional recommendations for the prevention of type 2 diabetes could be based. We therefore performed a literature search and, among the papers published in indexed journals, we selected relevant epidemiological (mostly prospective) and controlled intervention studies. Lifestyle factors that have, so far, been consistently associated with increased risk of type 2 diabetes are overweight and physical inactivity. However, recent evidence from epidemiological studies has shown that the risk of type 2 diabetes is also associated with diet composition, particularly with: (1) low fibre intake; (2) a high trans fatty acid intake and a low unsaturated:saturated fat intake ratio; (3) absence of or excess alcohol consumption. All these factors are extremely common in Western populations and therefore the potential impact of any intervention on them is large: indeed, >90 % of the general population has one or more of these risk factors. The ability to correct these behaviours in the population is estimated to reduce the incidence of diabetes by as much as 87 %. Recent intervention studies have shown that type 2 diabetes can be prevented by lifestyle changes aimed at body-weight reduction, increased physical activity and multiple changes in the composition of the diet. Within this context, the average amount of weight loss needed is not large, about 5 % initial weight, which is much less than the weight loss traditionally considered to be clinically significant for prevention of type 2 diabetes. In conclusion, new emphasis on prevention by multiple lifestyle modifications, including moderate changes in the composition of the habitual diet, might limit the dramatic increase in incidence of type 2 diabetes envisaged worldwide.

Effect of macronutrient intake on the development of glucose intolerance during pregnancy

BACKGROUND

Dietary intake influences glucose tolerance status, yet the relation between macronutrient intake and the development of glucose intolerance during pregnancy has not been adequately examined.

OBJECTIVE

We examined the relation between macronutrient intake early in pregnancy and the development of glucose intolerance.

DESIGN

Data are from 1698 women in the Pregnancy, Infection, and Nutrition Study. Dietary intake during the second trimester was assessed with a food-frequency questionnaire. Women were classified into 1 of 3 glucose categories: gestational diabetes mellitus (GDM), impaired glucose tolerance (IGT), and normal glucose tolerance. Multivariate logistic regression was used to calculate the relative risk of IGT and GDM, with adjustment for potential confounders. A series of models were specified to test alternate hypotheses about the relation of diet to risk of IGT or GDM.

RESULTS

The overall prevalences of IGT and GDM in the cohort were 2.6% and 5.2%, respectively. The addition model showed that adding 100 kcal from carbohydrates to the diet was associated with a 12% decrease in risk of IGT and a 9% decrease in risk of GDM. The substitution model showed that substituting fat for carbohydrates (per each 1% of total calories) resulted in a significant increase in risk of both IGT and GDM [relative risk = 1.1 (95% CI: 1.02, 1.12) and 1.1 (1.02, 1.10), respectively]. Predicted probabilities of IGT and GDM were reduced by one-half with a 10% decrease in dietary fat and a 10% increase in carbohydrate.

CONCLUSIONS

This study found an association between increased fat intake and the development of glucose abnormalities in pregnancy.

Whole grains protect against atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular disease (ASCVD) is the most common cause of death in most Western countries. Nutrition factors contribute importantly to this high risk for ASCVD. Favourable alterations in diet can reduce six of the nine major risk factors for ASCVD, i.e. high serum LDL-cholesterol levels, high fasting serum triacylglycerol levels, low HDL-cholesterol levels, hypertension, diabetes and obesity. Wholegrain foods may be one the healthiest choices individuals can make to lower the risk for ASCVD. Epidemiological studies indicate that individuals with higher levels (in the highest quintile) of whole-grain intake have a 29 % lower risk for ASCVD than individuals with lower levels (lowest quintile) of whole-grain intake. It is of interest that neither the highest levels of cereal fibre nor the highest levels of refined cereals provide appreciable protection against ASCVD. Generous intake of whole grains also provides protection from development of diabetes and obesity. Diets rich in wholegrain foods tend to decrease serum LDL-cholesterol and triacylglycerol levels as well as blood pressure while increasing serum HDL-cholesterol levels. Whole-grain intake may also favourably alter antioxidant status, serum homocysteine levels, vascular reactivity and the inflammatory state. Whole-grain components that appear to make major contributions to these protective effects are: dietary fibre; vitamins; minerals; antioxidants; phytosterols; other phytochemicals. Three servings of whole grains daily are recommended to provide these health benefits.

Nutrition and diabetes control: advice for non-dietitians

Diabetes mellitus affects 2-4% of the UK population and its prevalence is predicted to double by 2010. It has been widely acknowledged that dietary therapy can reduce the risk of complications in people with diabetes. However, as there are insufficient diabetes specialist dietitians to deliver dietary advice to all people with diabetes, the burden of care will fall on the primary care team. Dietary advice given to people with diabetes by healthcare professionals needs to be consistent. As recommendations change with new evidence, professionals have a duty to update their knowledge. This article reviews current nutritional recommendations from the UK, Europe and the USA and offers suggestions for translating dietary theory into practice. It emphasizes the importance of an individual approach, taking into account usual eating patterns, lifestyle, age, culture and medication.

Effect of dietary insoluble fiber on control of glycemia in cats with naturally acquired diabetes mellitus

OBJECTIVE

To evaluate effects of dietary insoluble fiber on control of glycemia in cats with naturally acquired diabetes mellitus.

DESIGN

Randomized controlled crossover trial.

ANIMALS

16 cats with naturally acquired diabetes mellitus.

PROCEDURE

Cats were fed a diet high in insoluble fiber (HF) containing 12% cellulose (dry-matter basis) or a diet low in insoluble fiber (LF) for 24 weeks; they were fed the other diet for the subsequent 24 weeks. Caloric intake and insulin treatment were adjusted to maintain stable body weight and control of glycemia, respectively. Cats were allowed an adaptation period of 6 weeks after initiation of a diet, after which control of glycemia was evaluated at 6-week intervals for 18 weeks. Variables assessed included serum glucose concentration measured during the preprandial state, blood glycated hemoglobin concentration, serum glucose concentration measured at 2-hour intervals for 12 hours beginning at the time of the morning insulin injection, 12-hour mean serum glucose concentration, and mean fluctuation in serum glucose concentration from the 12-hour mean serum glucose concentration.

RESULTS

Mean daily caloric intake, body weight, or daily insulin dosage did not differ significantly between cats when fed HF and LF diets. Mean preprandial serum glucose concentration, most post-prandial serum glucose concentrations, and the 12-hour mean serum glucose concentration were significantly lower when cats consumed the HF diet, compared with values when cats consumed the LF diet.

CONCLUSIONS AND CLINICAL RELEVANCE

These results support feeding a commercially available diet containing approximately 12% insoluble fiber (dry-matter basis) to cats with naturally acquired diabetes mellitus.

Carbohydrates, dietary fiber, and incident type 2 diabetes in older women

BACKGROUND

Dietary carbohydrates may influence the development of type 2 (non-insulin-dependent) diabetes, for example, through effects on blood glucose and insulin concentrations.

OBJECTIVE

We examined the relations of baseline intake of carbohydrates, dietary fiber, dietary magnesium, and carbohydrate-rich foods and the glycemic index with incidence of diabetes.

DESIGN

This was a prospective cohort study of 35988 older Iowa women initially free of diabetes. During 6 y of follow-up, 1141 incident cases of diabetes were reported.

RESULTS

Total grain, whole-grain, total dietary fiber, cereal fiber, and dietary magnesium intakes showed strong inverse associations with incidence of diabetes after adjustment for potential nondietary confounding variables. Multivariate-adjusted relative risks of diabetes were 1.0, 0.99, 0.98, 0.92, and 0.79 (P for trend: 0.0089) across quintiles of whole-grain intake; 1.0, 1.09, 1.00, 0.94, and 0.78 (P for trend: 0.005) across quintiles of total dietary fiber intake; and 1.0, 0.81, 0.82, 0.81, and 0.67 (P for trend: 0.0003) across quintiles of dietary magnesium intake. Intakes of total carbohydrates, refined grains, fruit and vegetables, and soluble fiber and the glycemic index were unrelated to diabetes risk.

CONCLUSION

These data support a protective role for grains (particularly whole grains), cereal fiber, and dietary magnesium in the development of diabetes in older women.

Effects of psyllium on glucose and serum lipid responses in men with type 2 diabetes and hypercholesterolemia

BACKGROUND

Water-soluble dietary fibers decrease postprandial glucose concentrations and decrease serum cholesterol concentrations. This study examined the effects of administering psyllium to men with type 2 diabetes.

OBJECTIVE

The objective was to evaluate the safety and effectiveness of psyllium husk fiber used adjunctively to a traditional diet for diabetes in the treatment of men with type 2 diabetes and mild-to-moderate hypercholesterolemia.

DESIGN

After a 2-wk dietary stabilization phase, 34 men with type 2 diabetes and mild-to-moderate hypercholesterolemia were randomly assigned to receive 5.1 g psyllium or cellulose placebo twice daily for 8 wk. Serum lipid and glycemic indexes were evaluated biweekly on an outpatient basis and at weeks 0 and 8 in a metabolic ward.

RESULTS

In the metabolic ward, the psyllium group showed significant improvements in glucose and lipid values compared with the placebo group. Serum total and LDL-cholesterol concentrations were 8.9% (P < 0.05) and 13.0% (P = 0.07) lower, respectively, in the psyllium than in the placebo group. All-day and postlunch postprandial glucose concentrations were 11.0% (P < 0.05) and 19.2% (P < 0.01) lower in the psyllium than in the placebo group. Both products were well tolerated, with no serious adverse events related to treatment reported in either group.

CONCLUSION

The addition of psyllium to a traditional diet for persons with diabetes is safe, is well tolerated, and improves glycemic and lipid control in men with type 2 diabetes and hypercholesterolemia.

Nutrition in the exercising elderly

When making nutrition recommendations to the exercising elderly population, four important areas should be taken into consideration: (1) the changing needs that occur with age; (2) the changing needs that occur with exercise; (3) the presence of any chronic illnesses or diseases; and (4) whether one is exercising for fitness, recreation, or competition. For the most part, these four areas have been researched separately, and recommendations for elderly athletes need to be synthesized from this information. The nutrients for which food consumption is often inadequate and has the largest impact on the exercising elderly population include vitamin B6, vitamin B12, calcium, and vitamin D. The exercising elderly population needs to be aware of their bodies changing needs with exercise and should focus on maintaining energy balance while selecting a wide variety of foods high in complex carbohydrates. When adequate dietary intakes cannot be obtained, supplementation with a multivitamin of no more than 100% of the RDA is recommended.

A physiological level of rhubarb fiber increases proglucagon gene expression and modulates intestinal glucose uptake in rats

Previous work demonstrated that a high fiber diet upregulates proglucagon mRNA and secretion of glucagon-like peptide-1 [GLP-1(7-37)] and insulin compared with an elemental fiber-free diet. This study examined whether similar intakes of fibers differing in physiochemical and fermentative properties alter the expression of intestinal hormones and intestinal absorptive properties. Sprague-Dawley rats were fed either a 50 g/kg cellulose or rhubarb fiber diet for 14 d. Ileal proglucagon mRNA levels were significantly higher in rats fed rhubarb fiber than in those fed cellulose fiber (9.3 +/- 0.9 vs. 6.2 +/- 1.0 densitometer units). Proglucagon mRNA in the colon did not differ between diet treatments. Plasma c-peptide concentrations were significantly higher 30 min after an oral glucose tolerance test in the rhubarb vs. cellulose group (1627 +/- 67 vs. 1290 +/- 71 pmol/L). Passive permeability, measured by the uptake of L-glucose, was significantly higher in the jejunum of rats fed cellulose compared with those fed rhubarb fiber. Adjusting total glucose uptake for passive permeability and unstirred water layer resistance resulted in a higher Km being calculated for the jejunum and ileum of the cellulose fiber group. Jejunal and ileal carrier-mediated uptakes (Vmax) were not altered by diet and reflected the lack of difference between groups in sodium-dependent glucose cotransporter (SGLT-1) and sodium-independent glucose transporter (GLUT2) mRNA levels. Replacing cellulose fiber with rhubarb fiber in a diet upregulated ileal proglucagon mRNA and resulted in a reduced passive permeability but did not affect glucose transport of the small intestine. This work establishes the importance of dietary fiber fermentability in modulating intestinal proglucagon expression and possibly glucose homeostasis.

Postprandial serum glucose, insulin, and lipoprotein responses to high- and low-fiber diets

The effects of high-fiber (HF) and low-fiber (LF) meals on postprandial serum glucose, insulin, lipid, lipoprotein, and apolipoprotein concentrations of 10 hypercholesterolemic men were examined using a random-order, cross over design. HF and LF meals provided 15% of energy as protein, 40% as carbohydrate, and 45% as fat, 200 mg cholesterol/1,000 kcal, and 25 g fiber/1,000 kcal for HF or 3 g fiber/1,000 kcal for LF. Responses over a 15-hour period after multiple meals (MM) and over a 10-hour period after a single meal (SM) were compared. HF meals were associated with a significant reduction in postprandial serum glucose (P < .0005 after SM) and insulin (P < .0005 after SM). Serum free fatty acid (FFA) levels decreased significantly after MM and SM, but differences between HF and LF meals were insignificant. Although serum triglyceride responses did not differ significantly (ANOVA) between HF and LF meals, values were higher at 2 and 3 hours after a HF SM than after a LF SM and at 16 hours after HF MM than after LF MM. Although serum cholesterol values did not differ significantly (ANOVA) between HF and LF meals, values were higher after a HF SM than after a LF SM. Other subtle differences in responses of high-density lipoprotein (HDL) cholesterol, HDL2, and HDL3 concentrations were noted. These studies indicate that large increases in dietary fiber intake are accompanied by small changes in postprandial serum lipoprotein concentrations.

High viscosity hydroxypropylmethylcellulose reduces postprandial blood glucose concentrations in NIDDM patients

The ability of high viscosity hydroxypropylmethylcellulose (HPMC) to reduce postprandial glucose concentrations was assessed in patients with non-insulin-dependent diabetes (NIDDM) and healthy volunteers. The study design consisted of a two-way crossover, single-dose administration of 10 g prehydrated high viscosity HPMC, or placebo, with a standard carbohydrate-rich meal. In patients with NIDDM, HPMC reduced blood glucose concentrations at the 60-, 75-, 90-, 120- and 150-min sampling intervals, with an average reduction in the maximum postprandial blood glucose concentration, Cmax, of 24% (P < 0.05). The time at which the maximum concentration was reached, Tmax, remained unchanged. The area under the blood concentration versus time plot, AUC0-6h, was reduced by an average of 15% (P < 0.05). The blood concentration profile of insulin followed that of glucose. Concentrations were significantly lower than in the placebo phase only at the 120-min sampling time, while pharmacokinetic parameters (Cmax, Tmax and AUC0-6h) were unchanged. These results suggest that alterations in the blood glucose profile are mediated by luminal events rather than by changes in hormonal response. In contrast to the NIDDM patients, neither the pharmacokinetic parameters nor the blood glucose concentrations at specific sampling times were significantly affected by the co-administration of HPMC in healthy volunteers. Overall, the results of this study suggest that HPMC may be a useful adjunct in the management of NIDDM.

Effect of protein intake on glycaemic control and renal function in type 2 (non-insulin-dependent) diabetes mellitus

Recent clinical investigations have suggested that dietary protein intake may modulate the progression of diabetic nephropathy and influence glycaemic control in Type 2 (non-insulin-dependent) diabetes mellitus. Twelve normotensive Type 2 diabetic patients with microalbuminuria took part in a randomized cross-over trial of a 3-week high protein diet (2.0 g/kg.desirable weight per day) and a 3-week moderate protein diet (0.8 g/kg desirable weight per day) to test the simultaneous effect of protein intake modulation on glycaemic control and renal function. Both diets were isoenergetic and the moderate protein diet was supplemented with calcium and phosphate. Renal function and glycaemic control were evaluated at the beginning and at the end of each diet. The moderate protein diet reduced the urinary albumin excretion rate, glomerular filtration rate, creatinine clearance, and proteinuria without adversely affecting glycaemic control; fasting glycaemia and the ratio of fructosamine to proteins were significantly reduced. The high protein diet induced similar improvements in glycaemic control but small changes in renal function.

Nutrition management of insulin-dependent diabetes mellitus in adults: review by the diabetes care and education dietetic practice group

Insulin-dependent diabetes mellitus (IDDM) is a chronic disease in which insulin production from the pancreas is diminished or absent. Insulin-dependent diabetes mellitus is most often diagnosed in childhood, but it also occurs in adults. Treatment requires the use of exogenous insulin coordinated with food intake and physical activity. Management goals for IDDM are to attain metabolic control of glucose and lipid levels and to prevent or delay the onset of medical complications associated with diabetes. Because the type and amount of food consumed directly affect blood glucose levels, meal and snack planning, along with an appropriate insulin regimen and physical activity program, is necessary to achieve management goals. Nutrition assessment, initial education, implementation of a meal plan, and ongoing nutrition education and counseling are part of the process of nutrition management of diabetes. The registered dietitian who has a working knowledge of nutrition and diabetes management serves as an integral part of the diabetes health care team.

Reduced postprandial blood glucose levels in recently diagnosed non-insulin-dependent diabetics secondary to pharmacologically induced delayed gastric emptying

In a previous study we demonstrated that patients with recently diagnosed non-insulin-dependent diabetes mellitus (NIDDM) had significantly increased gastric emptying rates of glucose solutions compared with those of nondiabetic sex- and age-matched controls. This finding of rapid gastric emptying contrasts with the delayed gastric emptying often exhibited as a late manifestation of diabetes mellitus that is attributed to autonomic neuropathy. The purpose of this study was to determine, in seven of the patients previously studied, whether (1) an intravenous infusion of cholecystokinin-8 (CCK-8) would delay the gastric emptying of a liquid glucose meal and, if so, (2) whether the delay in gastric emptying would result in reduced postprandial blood glucose concentrations due to prolongation of the absorption of the glucose in the liquid meal. Each patient underwent two separate gastric emptying studies, one during a saline infusion and one during a CCK-8 infusion. Blood samples were obtained at 15-min intervals for measurement of glucose, insulin, CCK-8, and gastric inhibitory polypeptide (GIP) concentrations. The average gastric half-emptying time was 41 min with the saline infusion and 94 min with the CCK-8 infusion (P = 0.0042). The average glucose concentration over the 2-hr period following glucose ingestion was 17.1 mmol/liter with the saline infusion and 14.0 mmol/liter with the CCK-8 infusion (P = 0.0073). The average glucose excursion value over the 2-hr period was reduced from 5.6 mmol/liter to 3.7 mmol/liter with the CCK-8 infusion (P = 0.0550).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of various enteral feeding products on postprandial blood glucose response in patients with type I diabetes

These studies were performed to evaluate the postprandial blood glucose responses to a variety of differently formulated enteral feeding products in patients with type I diabetes. Eleven subjects with type I diabetes were evaluated in three studies, all using a Biostator (artificial endocrine pancreas) that delivered a small, basal amount of insulin and measured blood glucose levels. Subjects consumed 20 mL of the assigned formula every 15 minutes for the 240 minutes of the study. Study 1 evaluated the response to each of five products: Glucerna, Enrich, Ensure HN, Pulmocare, and Compleat Modified. When the postprandial blood glucose response to Glucerna was greater than when its research formulation (EN-8715) had been tested in 1988, studies 2 and 3 were undertaken to assess why this discrepancy occurred. Study 2 compared stored EN-8715 to Glucerna and study 3 compared frozen and thawed vs nonfrozen EN-8715, because of a concern that the original product had been frozen during shipping. In study 1 the glucose response (assessed as area under the glucose curve) correlated with the grams of carbohydrate present in the enteral feeding formula (r = .58, p = .002). The presence or absence of fiber, in the form of soy polysaccharide, did not affect the glucose response. Glucerna produced a significantly lower blood glucose response than did Enrich, Ensure HN, or Compleat Modified, although this response was greater than the response to EN-8715 in 1988. However, in study 2 no differences were found between stored EN-8715 and Glucerna and in study 3, freezing and thawing was not found to significantly alter the glucose response.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of the metal associated with the insulin degrading enzyme

Insulin degrading enzyme (IDE) is a thiol-dependent metalloendoprotease that is responsible for initiation of cellular insulin degradation. However, its exact mode of action and the factors controlling it are poorly understood. Since IDE is a metal requiring enzyme, we have examined which metal(s) is(are) endogenously associated with it. Using neutron activation analysis, we studied the metal content of a partially purified enzyme from three different tissues: rat skeletal muscle, rat liver, and human placenta. Our results indicate that zinc and manganese are associated with the enzyme with approximately 10 times more zinc as manganese being present. These results suggest that one or both of these two metals are endogenously associated with this enzyme and are a means of controlling the enzyme's activity.

Metabolic effects and clinical value of beet fiber treatment in NIDDM patients

In the present study a randomized cross-over design was used to determine the clinical usefulness of adding 16 g of beet fiber to the ordinary diet of non-insulin dependent diabetic (NIDDM) out-patients. In addition, fiber effects on the gastrointestinal hormone responses to a standardized test meal were evaluated. The study included five patients treated with diet alone and eight patients treated with diet and sulphonylurea (SU). Beet fiber supplementation resulted in a 10% reduction (P less than 0.01) of serum cholesterol in SU-treated patients. No differences were found for fasting blood glucose, glycated hemoglobin, serum triglycerides or body weight. In the diet-treated patients, fasting plasma somatostatin was elevated during the fiber period. However, postprandial responses of insulin, C-peptide, glucagon, gastric inhibitory peptide and somatostatin were not influenced by an increased fiber intake in any group. All patients experienced mild gastrointestinal discomfort during the fiber period. In view of the limited metabolic benefit of beet fiber treatment we conclude that there is little use for this type of dietary fiber in the routine treatment of patients with NIDDM.

Dietary fiber in foods: options for diabetes education

Diet therapy for the treatment of diabetes often dictates that individuals limit their intake of foods high in fats or sugars. The addition of fibrous foods may be appealing to this population. During the past two decades, clinical investigations have attempted to characterize the benefits of dietary fiber for diabetes. Interpretation of the data and implications for practical application have sometimes been controversial. As results of more clinical trials appear in the literature, a convergent validity is emerging. Evidence that soluble dietary fibers are a food component associated with health benefits is supported by recent investigations. A flexible approach for inclusion of dietary fiber in the diets of individuals with diabetes may be used.

New perspectives in nutrition management of diabetes mellitus

Diet remains the cornerstone in the management of diabetes mellitus. A prudent nutrition plan reduces the exaggerated risk for atherosclerotic heart disease and metabolic complications of diabetes by improving lipid and glycemic control. The current consensus diabetes diet recommends 55 to 60 percent of energy as carbohydrate, 12 to 20 percent as protein, and less than 30 percent fat. Total cholesterol intake should be less than 300 mg per day. Fiber appears to have distinct benefits in improving glucose and lipid levels; therefore, an intake of up to 40 g per day or 15 to 25 g/1,000 kcal of food is recommended. Other considerations in meal planning for diabetes include alternative sweeteners, salt intake, alcohol consumption, and vitamin and mineral needs. Individualized and flexible nutrition plans, designed within established guidelines, promote adherence. Persons with diabetes can change their eating patterns and closely adhere to a diet plan if the entire health care team is enthusiastic, supportive, and instructive.