Selected disorders of malabsorption

Nutrition, Health, and Regulatory Aspects of Digestible Maltodextrins

Digestible maltodextrins are low-sweet saccharide polymers consisting of D-glucose units linked primarily linearly with alpha-1,4 bonds, but can also have a branched structure through alpha-1,6 bonds. Often, maltodextrins are classified by the amount of reducing sugars present relative to the total carbohydrate content; between 3 and 20 percent in the case of digestible maltodextrins. These relatively small polymers are used as food ingredients derived by hydrolysis from crops naturally rich in starch. Through advances in production technology, the application possibilities in food products have improved during the last 20 years. However, since glucose from digested maltodextrins is rapidly absorbed in the small intestine, the increased use has raised questions about potential effects on metabolism and health. Therefore, up-to-date knowledge concerning production, digestion, absorption, and metabolism of maltodextrins, including potential effects on health, were reviewed. Exchanging unprocessed starch with maltodextrins may lead to an increased glycemic load and therefore post meal glycaemia, which are viewed as less desirable for health. Apart from beneficial food technological properties, its use should accordingly also be viewed in light of this. Finally, this review reflects on regulatory aspects, which differ significantly in Europe and the United States, and, therefore, have implications for communication and marketing.

Chronic diarrhea as the presenting feature of primary systemic AL amyloidosis: serendipity or delayed diagnosis?

Background

Chronic diarrhea in adults is a common symptom with a wide range of underlying etiologies. Although various strategies have been proposed for evaluation, there are still cases with undetermined origins even after extensive workup. Amyloidosis with gastrointestinal (GI) involvement is one of the causes that should be considered in adult patients with chronic diarrhea. We report a case of primary systemic amyloid light-chain (AL) amyloidosis, presenting initially as chronic diarrhea and weight loss.

Case presentation

A 43-year-old man with chronic diarrhea and weight loss was referred to our hospital. Prior to his presentation, extensive evaluation including an exploratory laparotomy was carried out and did not yield any valuable findings. An echocardiography performed after repeated episodes of orthostatic hypotension revealed infiltrative cardiomyopathy. Moreover, biopsies of the terminal ileum revealed amyloid deposition confirmed by Congo Red staining. Finally, a diagnosis of systemic AL amyloidosis was made after hematological workup. Anti-plasma cell therapy did ameliorate his GI symptoms.

Conclusion

Although amyloidosis with GI involvement is a rare cause of chronic diarrhea, it should be considered especially in patients with intestinal malabsorption and extra-GI manifestations, such as orthostatic hypotension. The delayed diagnosis in the present case highlights the importance of recognizing clinical “red flags” not seemingly related to one another, and underscores the need to get intestinal biopsies even with normal endoscopic appearance of the mucosa.

The acid tolerant and cold-active β-galactosidase from Lactococcus lactis strain is an attractive biocatalyst for lactose hydrolysis

The gene encoding the β-galactosidase from the dairy Lactococcus lactis IL1403 strain was cloned, sequenced and overexpressed in Escherichia coli. The purified enzyme has a tetrameric arrangement composed of four identical 120 kDa subunits. Biochemical characterization showed that it is optimally active within a wide range of temperatures from 15 to 55 °C and of pH from 6.0 to 7.5. For its maximal activity this enzyme requires only 0.8 mM Fe(2+) and 1.6 mM Mg(2+). Purified protein displayed a high catalytic efficiency of 102 s(-1) mM(-1) for lactose. The enzyme stability was increased by immobilization mainly at low pH (from 4.0 to 5.5) and high temperatures (55 and 60 °C). The bioconversion of lactose using the L. lactis β-galactosidase allows the production of lactose with a high bioconversion rate (98 %) within a wide range of pH and temperature.