Re-evaluation of the mechanisms of dietary fibre and implications for macronutrient bioaccessibility, digestion and postprandial metabolism

The positive effects of dietary fibre on health are now widely recognised; however, our understanding of the mechanisms involved in producing such benefits remains unclear. There are even uncertainties about how dietary fibre in plant foods should be defined and analysed. This review attempts to clarify the confusion regarding the mechanisms of action of dietary fibre and deals with current knowledge on the wide variety of dietary fibre materials, comprising mainly of NSP that are not digested by enzymes of the gastrointestinal (GI) tract. These non-digestible materials range from intact cell walls of plant tissues to individual polysaccharide solutions often used in mechanistic studies. We discuss how the structure and properties of fibre are affected during food processing and how this can impact on nutrient digestibility. Dietary fibre can have multiple effects on GI function, including GI transit time and increased digesta viscosity, thereby affecting flow and mixing behaviour. Moreover, cell wall encapsulation influences macronutrient digestibility through limited access to digestive enzymes and/or substrate and product release. Moreover, encapsulation of starch can limit the extent of gelatinisation during hydrothermal processing of plant foods. Emphasis is placed on the effects of diverse forms of fibre on rates and extents of starch and lipid digestion, and how it is important that a better understanding of such interactions with respect to the physiology and biochemistry of digestion is needed. In conclusion, we point to areas of further investigation that are expected to contribute to realisation of the full potential of dietary fibre on health and well-being of humans

Effects of seaweed supplementation on blood glucose concentration, lipid profile, and antioxidant enzyme activities in patients with type 2 diabetes mellitus

The present study was carried out to evaluate the physiological effects of seaweed supplementation on blood glucose levels, lipid profile, and antioxidant enzyme activities in subjects with type 2 diabetes mellitus. Subjects were randomized into either a control group or a seaweed supplementation group. Pills with equal parts of dry powdered sea tangle and sea mustard were provided to the seaweed supplementation group three times a day for 4 weeks. Total daily consumption of seaweed was 48 g. We found that total dietary fiber intake was 2.5 times higher in subjects receiving seaweed supplementation than in the control group. Accordingly, fasting blood glucose levels (p<0.01) and 2-hour postprandial blood glucose measurements (p<0.05) were decreased significantly in those ingesting seaweed. Furthermore, the serum concentrations of triglycerides were decreased and high-density lipoprotein cholesterol was increased significantly in seaweed supplement group (p<0.05). However, the concentrations of total cholesterol and low-density lipoprotein cholesterol were not affected by seaweed supplementation. The level of thiobarbituric acid reactive substances in erythrocytes was significantly lower with seaweed supplementation compared to controls (p<0.05). Catalase and glutathione peroxidase activities with seaweed supplementation were higher than the controls (p<0.05), but superoxide dismutase activity was not affected. We, therefore, conclude that ingestion of seaweed influences glycemic control, lowers blood lipids, and increases antioxidant enzyme activities

Neuropeptides, Trophic Factors, and Other Substances Providing Morphofunctional and Metabolic Protection in Experimental Models of Diabetic Retinopathy

Vision is the most important sensory modality for many species, including humans. Damage to the retina results in vision loss or even blindness. One of the most serious complications of diabetes, a disease that has seen a worldwide increase in prevalence, is diabetic retinopathy. This condition stems from consequences of pathological metabolism and develops in 75% of patients with type 1 and 50% with type 2 diabetes. The development of novel protective drugs is essential. In this review we provide a description of the disease and conclude that type 1 diabetes and type 2 diabetes lead to the same retinopathy. We evaluate existing experimental models and recent developments in finding effective compounds against this disorder. In our opinion, the best models are the long-term streptozotocin-induced diabetes and Otsuka Long-Evans Tokushima Fatty and spontaneously diabetic Torii rats, while the most promising substances are topically administered somatostatin and pigment epithelium-derived factor analogs, antivasculogenic substances, and systemic antioxidants. Future drug development should focus on these

Effects of breakfast cereals containing various amounts of beta-glucan fibers on plasma glucose and insulin responses in NIDDM subjects

OBJECTIVE: To determine whether increasing doses (amounts) of beta-glucan present in an extruded breakfast cereal affect the glycemic and insulinemic responses in eight NIDDM subjects, compared with the same responses after a continental breakfast (bread, milk, cheese, ham). RESEARCH DESIGN AND METHODS: Breakfast cereals were produced using various proportions of oat bran enriched in fiber, which contain an unusually high amount of a viscous polysaccharide, called beta-glucan, and oat bran. The carbohydrate load was 35 g. RESULTS: The maximum increases observed in plasma glucose after the breakfast cereal were 67% (P &lt; 0.05), 42% (P &lt; 0.001), and 38% (P &lt; 0.001) with 4.0, 6.0, and 8.4 g beta-glucan, respectively, compared with the continental breakfast. There was a linear inverse relationship between dose of beta-glucan and plasma glucose peak or area under the glucose curve (R2 = 0.94, P &lt; 0.05). Postprandial insulin increase was only 59-67% (P &lt; 0.01) as high as the continental breakfast after all three levels of beta-glucan. CONCLUSIONS: The 50% decrease in glycemic response that was observed after the ingestion of 35 g carbohydrate is estimated to occur with approximately 5 g beta-glucan. This dose of beta-glucan can easily be attained without the loss of taste by incorporating oat bran concentrate in products

An innovative micro optical element assembly robot characterized by high accuracy and flexibility

This paper describes a novel robotic assembly station, named Sixtiff, which has been conceived and realized at the Swiss Institute of Technology (EPFL) in Lausanne, Switzerland. This station was developed in order td actively assemble micro-optical devices with high accuracy along six degrees of freedom. This novel robotic system is a hybrid serial-parallel structure with six degrees of-freedom. The system is very stiff and since it is not affected by any floating, it is able to guarantee high movement accuracy (linear resolution of 0.25 mu m, and angular resolution of 1.7 mu rad). The robot was used to collimate a laser beam with a Doric lens (cylindrical lens with a diameter of 60 mu m and a focal of 45 mu m). The distance between the emitting area of the diode and the lens is about 10 mu m and the alignment was adjusted with an accuracy of 0.5 mu m

An innovative micro optical element assembly robot

Concerns the fabrication of miniaturized optical devices with height attachment precision. For active alignment of micro-optical elements machined with tolerances lower than the intended precision, an accurate 6-DOF robot is needed. This article describes such a structure, which is named Sixtiff. Sixtiff was first developed for the use of a new optical assembly technology, TRIMO-SMD. The robot is a hybrid serial-parallel structure composed of five linear stages and one angular stage. It has a stiff structure, without floatin

Metabolic effect of pre-cooked instant preparations of bean and potato in normal and in diabetic subjects

The effect of a 50 g starch meal prepared with pre-cooked instant bean flakes on glucose and insulin plasma levels and on glucose oxidation rate as measured by continuous indirect calorimetry was assessed in six healthy human volunteers during 4 h following the meal. Comparison was done with the same load of starch as potato flakes to which the fiber and protein content of the bean meal had been added. Thirty minutes after ingestion, plasma glucose and insulin rise was less after beans than after potatoes (0.4 +/- 0.2 vs 2.0 +/- 0.3 mmol . l-1), p less than 0.01, and 8 +/- 2 vs 38 +/- 5 microU . ml-1, p less than 0.001). The elevation of glucose oxidation was markedly less during the 2 h following the ingestion of beans when compared to potatoes. The bean flakes meal gave rise to only moderate elevation of plasma glucose and insulin levels and of glucose oxidation rate when given to four noninsulin-dependent-diabetes mellitus patients. It is suggested that the slow carbohydrate property of legumes is not due to their fiber content, but might be related to the histological structure of the seed