Changes in gut microbiota and lactose intolerance symptoms before and after daily lactose supplementation in individuals with the lactase nonpersistent genotype.

BACKGROUND: Approximately 70%-100% of the Asian adult population is lactase nonpersistent (LNP). The literature shows that many individuals with the LNP-genotype can consume ≤12 g of lactose without experiencing gastrointestinal discomfort. Repetitive consumption of lactose may reduce intolerance symptoms via adaptation of the gut microbiota. OBJECTIVE: This study aimed to assess the effects of daily consumption of incremental lactose doses on microbiota composition and function, and intolerance symptoms. METHODS: Twenty-five healthy adults of Asian origin, carrying the LNP-genotype were included in this 12-wk before and after intervention trial. Participants consumed gradually increasing lactose doses from 3 to 6 g to 12 g twice daily, each daily dose of 6 g, 12 g, or 24 g being provided for 4 consecutive weeks. Participants handed-in repeated stool samples and underwent a 25 g lactose challenge hydrogen breath test (HBT) before and after the 12-wk intervention. Daily gastrointestinal symptoms and total symptom scores (TSSs) during the lactose challenge were recorded. RESULTS: A significant increase from 5.5% ± 7.6% to 10.4% ± 9.6% was observed in Bifidobacterium relative abundance after the intervention (P = 0.009), accompanied by a 2-fold increase (570 ± 269 U/g; P < 0.001) in fecal ß-galactosidase activity compared with baseline (272 ± 158 U/g). A 1.5-fold decrease (incremental area under the curve; P = 0.01) in expired hydrogen was observed during the second HBT (38 ± 35 ppm·min), compared with the baseline HBT (57 ± 38 ppm·min). There was a nonsignificant decrease in TSS (10.6 ± 8.3 before compared with 8.1 ± 7.2 after intervention; P = 0.09). Daily consumption of lactose was well tolerated, with mild to no gastrointestinal complaints reported during the intervention. CONCLUSIONS: Increased levels of Bifidobacterium indicate an adaptation of the gut microbiota upon repetitive consumption of incremental doses of lactose, which was well tolerated as demonstrated by reduced expired hydrogen concentrations during the second 25-g lactose HBT. Bifidobacteria metabolize lactose without gas production thereby potentially reducing intestinal gas formation in the gut of individuals with the LNP-genotype. This increased lactose tolerance possibly lifts the necessity to remove nutrient-rich dairy foods completely from the diet. The trial is registered at the International Clinical Trials Registry Platform: NL9516. The effect of dietary lactose in lactase nonpersistent individuals on gut microbiota.

Anti-hyperglycemic potential and chemical constituents of Aristolochia triangularis Cham. leaves - A medicinal species native to Brazilian forests.

ETHNOPHARMACOLOGICAL RELEVANCE: Aristolochia triangularis Cham. has been used in Brazilian traditional medicine for various therapeutic purposes, including as a leaf-based infusion for diabetes management. AIM OF THE STUDY: This study was designed to chemically characterize an infusion of in natura A. triangularis leaves and evaluate the in vivo anti-hyperglycemic properties of this infusion. MATERIALS AND METHODS: Chemical composition was examined using liquid-liquid extraction procedure, chromatographic methods, NMR, and LC-MS/MS. The in vivo anti-hyperglycemic activity of the freeze-dried infusion of A. triangularis leaves (Inf-L-At) was assessed using oral glucose tolerance test (OGTT). Initially, normoglycemic male rats were pre-treated with orally administered Inf-L-At at doses of 62.5, 125, and 250 mg/kg for two consecutive days. On the day of the OGTT, fasting animals received a glucose load (4 g/kg) 30 min after treatment with Inf-L-At, and the blood glucose levels were verified at 15, 30, 60, and 180 min. Intestinal maltase, lactase, and sucrase activities and muscle and liver glycogen contents were also assessed after the OGTT. RESULTS: Inf-L-At extract led to glycemic reduction with no dose-response at 15, 30, and 60 min comparable to that of the antidiabetic drug glibenclamide and was accompanied by an increase in hepatic and muscle glycogen contents. Additionally, there was a significant statistically decrease in the in vitro activity of disaccharidases. Maltase and sucrase activities were inhibited at all doses, whereas lactase activity was inhibited only at 62.5 and 250 mg/kg. In total, 75 compounds were found in the infusion, including seven new ones, (7S*,8S*,7ꞌS*,8ꞌR*)-4,4ꞌ-dihydroxy-3,3ꞌ-dimethoxy-7,9ꞌ-epoxylignan-7ꞌ-ol; 4ꞌ-hydroxy-3ꞌ-methoxy-3,4-methylenedioxy-7,9ꞌ-epoxylignan-9,7ꞌ-diol; triangularisines A, B, and C; N-ethyl-N-methyl-affineine; and N-methyl pachyconfine, and one previously not described as a natural product, epi-secoisolariciresinol monomethyl ether. CONCLUSION: The results demonstrated the anti-hyperglycemic activity of the infusion from A. triangularis leaves and showed that it is a rich source of lignoids, alkaloids, and glycosylated flavonoids, which are known to exhibit antidiabetic effects and other biological properties that can be beneficial for patients with chronic hyperglycemia, thus certifying the popular use of this herbal drink.

Baohe pill decoction for diarrhea induced by high-fat and high-protein diet is associated with the structure of lactase-producing bacterial community.

Background: This study investigated the effects of Baohe pill decoction on the diversity and community composition of lactase-producing bacteria in the intestinal contents of mice with diarrhea induced by high-fat and high-protein diet, which provided an experimental basis for the study on the therapeutic mechanism of Baohe pill decoction. Materials and methods: The Traditional Chinese Medicine Systems Pharmacology (TCMSP), DisGeNET, UniProt, National Center for Biotechnology Information (NCBI), and GeneCards databases were used to collect the potential targets with active ingredients of Baohe pill decoction, diarrhea, and lactase, and then construct correlation networks. Fifteen Kunming mice were randomly divided into the control group (CN), natural recovery group (NR), and Baohe pill decoction treatment group (BHP), with five mice in each group. After constructing a mouse diarrhea model by HFHPD induction, BHP was gavaged with Baohe pill decoction, and the other groups were gavaged with distilled water of equal. The intestinal contents were collected from ileal to jejunal and analyzed using metagenomic sequencing to characterize the intestinal content of lactase-producing bacteria in mice. Results: The core active ingredients related to diarrhea in Baohe pill decoction were quercetin, luteolin, kaempferol, forsythin, and wogonin. And there was no intersection between the potential targets with the active ingredient of Baohe pill, lactase, and diarrhea. After the intervention of Baohe pill decoction, the Observed species, Chao1 index, and Operational Taxonomic Units (OTU) number increased in BHP (P > 0.05), while the Pielous evenness and Shannon index decreased (P > 0.05). In Beta diversity, the community structure of the NR was significantly different from CN and BHP (P < 0.05), and the community structure of the CN was not significant difference from BHP (P > 0.05). Compared to NR, the relative abundance of Bifidobacterium and Amycolatopsis increased, while the relative abundance of Lachnoclostridium, Sinorhizobium, Cedecea, and Escherichia decreased in BHP, but none of the significant differences (P > 0.05). Conclusion: The therapeutic effect of Baohe pill decoction on diarrhea induced by HFHPD does not appear to involve the body's lactase gene targets directly, but is associated with the change of the construction of lactase-producing bacterial communities.

Dairying, diseases and the evolution of lactase persistence in Europe.

In European and many African, Middle Eastern and southern Asian populations, lactase persistence (LP) is the most strongly selected monogenic trait to have evolved over the past 10,000 years1. Although the selection of LP and the consumption of prehistoric milk must be linked, considerable uncertainty remains concerning their spatiotemporal configuration and specific interactions2,3. Here we provide detailed distributions of milk exploitation across Europe over the past 9,000 years using around 7,000 pottery fat residues from more than 550 archaeological sites. European milk use was widespread from the Neolithic period onwards but varied spatially and temporally in intensity. Notably, LP selection varying with levels of prehistoric milk exploitation is no better at explaining LP allele frequency trajectories than uniform selection since the Neolithic period. In the UK Biobank4,5 cohort of 500,000 contemporary Europeans, LP genotype was only weakly associated with milk consumption and did not show consistent associations with improved fitness or health indicators. This suggests that other reasons for the beneficial effects of LP should be considered for its rapid frequency increase. We propose that lactase non-persistent individuals consumed milk when it became available but, under conditions of famine and/or increased pathogen exposure, this was disadvantageous, driving LP selection in prehistoric Europe. Comparison of model likelihoods indicates that population fluctuations, settlement density and wild animal exploitation-proxies for these drivers-provide better explanations of LP selection than the extent of milk exploitation. These findings offer new perspectives on prehistoric milk exploitation and LP evolution.

Ancient Europeans farmed dairy-but couldn't digest milk.

Giant study of ancient pottery and DNA challenges common evolutionary explanation for lactase persistence.

Detection of ricin activity and structure by using novel galactose-terminated magnetic bead extraction coupled with mass spectrometric detection.

Ricin is a toxic protein derived from the castor bean plant (Ricinus communis) and has potential for bioterrorism or criminal use. Therefore, sensitive and rapid analytical methods are needed for its confirmatory detection in environmental samples. Our laboratory previously reported on the development of a confirmatory method to detect ricin involving antibody capture of ricin followed by mass spectrometric detection of ricin's enzymatic activity and of tryptic fragments unique to ricin. Here, we describe a novel ricin capture method of magnetic beads coated with 4-aminophenyl-1-thiol-ß-galactopyranoside, using ricin's lectin characteristics. The assay has been adapted for use on a simple, benchtop MALDI-TOF MS mass spectrometer common in clinical microbiology laboratories. Validation of the novel assay includes establishment of a limit of detection, and an examination of assay selectivity. The limit of detection of the enzymatic activity method is 8 ng/mL and 500 ng/mL for the confirmatory tryptic fragment assay. The assay is highly selective with no cross-reactivity from near neighbors and highly specific with a panel of 19 cultivars all testing positive. Additionally, there were no interferences found during testing of a panel of white powders. This allows for a confirmatory detection method for ricin in laboratories lacking expensive, sophisticated mass spectrometers.

Nutritional management of lactose intolerance: the importance of diet and food labelling.

Worldwide, 70% of the adult population has limited expression of lactase enzyme with a wide variation among different regions and countries. Lactase deficiency may lead to lactose intolerance (LI). Depending both on the amount of lactose ingested and on the lactase activity, people who suffer from lactose malabsorption might experience numerous gastrointestinal and extra-intestinal symptoms and manifestations. Treatment of LI mainly consists of reducing or eliminating lactose from the diet until the symptoms disappear as well as supplementing lactase, and inducing colon microbiome adaptation by probiotics. Cow's milk is one of the major source of calcium and several other vitamins and minerals. Thus, a complete exclusion of dairy products may favor the development of bone diseases such as osteopenia and osteoporosis. Therefore, the dietetic approach has a crucial role in the management of LI patients. Additionally, the use of lactose and milk-derived products in non-dairy products (e.g., baked goods, breakfast cereals, drinks, and processed meat) has become widespread in the modern industry (the so-called "hidden lactose"). In this regard, a strict adherence to the lactose-free diet becomes challenging for LI patients, forced to continuous check of all products and food labels. In fact, lactose-free product labeling is still controversial. Considering that nowadays a specific cut-off value establishing "lactose-free" labeling policy is lacking and that there is no universal law regulating the production and commercialization of "delactosed" products, identification of specific safe and suitable products with a well-recognized lactose-free logo might help consumers. This narrative review aims to identify the dietary management for lactose intolerant people, avoiding symptoms and nutrients deficiencies, helped by the use of specific labelling to guide them to choose the safer product on the market.

Halloysite nanotube-embedded microparticles for intestine-targeted co-delivery of biopharmaceuticals.

Microparticles (MPs) with pH-responding macropores have recently proved their significance for the delivery of vulnerable biomolecules for oral drug administration. The previous MP systems were proven to provide enhanced protection against the gastric environment, however, their application is hindered due to insufficient loading efficiencies and deficient penetration capabilities of encapsulated drugs across the mucus barrier. Here, we report a new co-delivery approach based on amine-functionalized halloysite nanotube (HNT)-embedded MPs (amine-HNT-MPs) with pH-responding macropores specifically designed to deal with the mucus barrier at the absorption site. The mean diameter and polydispersity index of the pored MPs were measured by a particle size analyzer to be 37.6 ± 1.3 µm and 1.15, respectively. The drug loading capacity of the co-delivery system was shown to be 50-times higher than previously reported pored MPs. Fluorescence microscopy analysis of sulforhodamine B (into a hollow interior of HNTs)/ fluorescent nanoparticles (into a hollow interior of MPs)-encapsulated MPs confirmed biphasic release behavior due to pH-dependent pore closing/opening in the simulated gastrointestinal (GI) digestive conditions. To verify the protective effect of the co-delivery system, bromelain and lactase were loaded into HNTs and MPs, respectively, and found to exhibit 94.5 ± 3.3% (bromelain) and 70 ± 14.1% (lactase) functional activity in simulated GI tract conditions. The considerable improvement in the stability of the encapsulated enzymes against gastric conditions are attributed to the efficient pore sealing of the co-delivery system after the encapsulation of enzymes and maintenance of these closed pores in the gastric environment. Furthermore, the mucolytic enzyme (i.e. bromelain)-encapsulated co-delivery system was found to enhance mucopenetration of the encapsulated drug from histological analysis using ex vivo porcine intestine tissue. Therefore, the new microencapsulation design proposed in this study provides a promising solution to the major issues hampering the wide-spread application of MPs in the development of oral drug formulations for biopharmaceuticals and vaccines.

Low-molecular-weight chitosan relieves enterotoxigenic Escherichia coli-induced growth retardation in weaned pigs.

The objective of the present study was to evaluate the effects of low-molecular-weight chitosan (LMWC) on the growth performance, immune responses and intestinal health of weaned pigs challenged by enterotoxigenic Escherichia coli (ETEC). A total of 32 weaned pigs were randomly allocated to four treatments: non-challenged (fed with basal diet), ETEC-challenged (fed with basal diet) and ETEC-challenged plus 50 or 100 mg/kg LMWC supplementation, respectively. After 11 days feeding, the non-challenged pigs were infused with sterilised Luria-Bertani culture, while the remaining pigs were infused with 2.6 × 1011 colony-forming units of ETEC. At 3 days post-challenge, all pigs were administered d-xylose at 0.1 g/kg body weight. One hour later, blood samples were obtained, and the pigs then euthanised to collect intestinal samples. Data showed that only 100 mg/kg LMWC supplementation attenuated (P < 0.05) the average daily gain reduction caused by ETEC. Furthermore, besides the decreased (P < 0.05) serum tumour necrosis factor-α and immunoglobulin (Ig) G concentrations detected in ETEC-challenged pigs supplemented with LMWC at 50 or 100 mg/kg, the higher dose (100 mg/kg) also decreased (P < 0.05) the serum IgM concentration and increased (P < 0.05) the villus height and villus height-to-crypt depth ratio in both the jejunum and ileum, and the sucrase activity in the ileal mucosa. Moreover, LMWC supplementation (50 or 100 mg/kg) in ETEC-challenged pigs elevated (P < 0.05) the mRNA levels of jejunal mucosal peptide transporter 1 and ileal mucosal peptide transporter 1, divalent metal transporter 1 and zinc transporter 1, and decreased (P < 0.05) the ileal and caecal E. coli abundances, while 100 mg/kg LMWC additionally elevated (P < 0.05) the ileal Bacillus abundance, and caecal and colonic Bifidobacterium abundances. These results suggest that LMWC helps alleviate ETEC-induced growth retardation in weaned pigs, which could be associated with the inhibition of the immune responses and improved intestinal health.

Oral Administration of miR-30d from Feces of MS Patients Suppresses MS-like Symptoms in Mice by Expanding Akkermansia muciniphila.

Fecal transfer from healthy donors is being explored as a microbiome modality. MicroRNAs (miRNAs) have been found to affect the microbiome. Multiple sclerosis (MS) patients have been shown to have an altered gut microbiome. Here, we unexpectedly found that transfer of feces harvested at peak disease from the experimental autoimmune encephalomyelitis (EAE) model of MS ameliorates disease in recipients in a miRNA-dependent manner. Specifically, we show that miR-30d is enriched in the feces of peak EAE and untreated MS patients. Synthetic miR-30d given orally ameliorates EAE through expansion of regulatory T cells (Tregs). Mechanistically, miR-30d regulates the expression of a lactase in Akkermansia muciniphila, which increases Akkermansia abundance in the gut. The expanded Akkermansia in turn increases Tregs to suppress EAE symptoms. Our findings report the mechanistic underpinnings of a miRNA-microbiome axis and suggest that the feces of diseased subjects might be enriched with miRNAs with therapeutic properties.

Physicochemical and sensory properties of milk supplemented with lactase microcapsules coated with enteric coating materials.

In this paper, we report the physicochemical and sensory properties of milk supplemented with a powder of microencapsulated lactase. The core material was lactase (ß-galactosidase), the primary coating material was medium-chain triglyceride (MCT), and the secondary (enteric) coating material was either hydroxypropyl methylcellulose phthalate (HPMCP) or shellac, comparing both against market milk as a control. The physicochemical properties of both types of microcapsules were analyzed, including the particle size, zeta potential, and in vitro release behavior. To survey the stability of the microcapsules in milk during storage, we studied the residual lactose content and pH. Furthermore, to determine the properties of milk supplemented with the microcapsules, changes in color and sensory properties were evaluated during storage. The particle sizes (volume-weighted mean; D[4,3]) of the microcapsules coated with HPMCP or shellac were 2,836 and 7,834 nm, respectively, and the zeta potential of the capsules coated with shellac was higher than the zeta potential of those coated with HPMCP. The pH levels of milk supplemented with the lactase microcapsules were similar to those of the control (unsupplemented market milk); however, for milk supplemented with HPMCP-coated microcapsules, the pH was slightly lower. The core material, lactase, was released from the microcapsules during 12-d storage, and 18.82 and 35.09% of lactose was hydrolyzed in the samples for HPMCP- and shellac-coated microcapsules, respectively. The sensory characteristics of milk containing microcapsules coated with HPMCP did not show significant differences from the control, in terms of sweetness or off-taste, until 8 d of storage. However, shellac-coated microcapsules showed significant difference in sweetness and off-taste at d 8 and 6 of storage, respectively. The color of milk containing HPMCP-coated microcapsules did not show a significant difference during storage. However, that containing shellac-coated microcapsules was somewhat higher in color values than others. In particular, it showed significance from 0 to 4 d storage in L* and C* values. In conclusion, a powder of lactase microcapsules coated with HPMCP can be suitable as a supplement for milk.

Effects of ad libitum milk replacer feeding and butyrate supplementation on the epithelial growth and development of the gastrointestinal tract in Holstein calves.

Intensive milk feeding and butyrate supplementation in calves stimulate body growth and affect gastrointestinal development. The aim of the present study was to investigate the synergistic effects of ad libitum milk replacer (MR) feeding and butyrate supplementation of MR on rumen and small intestinal growth and on gene expression in the small intestine related to growth and energy metabolism at weaning. Male Holstein calves (n = 32) received colostrum from birth to d 3 of age and MR either ad libitum (Adl) or restrictively (Res; 6 L of MR/d; 12.5% solids) with (AdlB+, ResB+) or without (AdlB-, ResB-) 0.24% butyrate from d 4 until wk 8 of age. From wk 9 to 10, all calves were weaned and were fed 2 L/d until the end of the trial. Concentrate, hay, and water were freely available. At d 80, calves were slaughtered, volatile fatty acids were measured in rumen fluid, and rumen and small intestine samples were taken for histomorphometric measurements. The expression of mRNA associated with the local insulin-like growth factor (IGF) system and glucose metabolism as well as lactase and maltase activities were measured in the intestinal mucosa. The small intestine was 3 m longer in Adl than in Res. In the atrium ruminis, papilla width was greater in Res than in Adl. Villus circumference, cut surface, and height in the duodenum, proximal jejunum, and ileum were greater in Adl than in Res and in the proximal, mid, and distal jejunum and ileum were greater in calves treated with butyrate. Crypt depth in the duodenum and proximal jejunum was greater in Adl than in Res and in the ileum was smaller in calves treated with butyrate. The villus height:crypt depth ratio was greatest in AdlB+ calves. In the proximal and mid jejunum, IGF1 mRNA abundance was lower in calves treated with butyrate. In the proximal jejunum, INSR mRNA abundance was greater in Res than in Adl. The abundance of PCK2 mRNA was greater in Res than in Adl in the duodenum and was greatest in ResB- in the mid jejunum. Lactase activity tended to be greater in Res than in Adl and after butyrate treatment in the proximal jejunum. The results indicated an elevated growth of the small intestinal mucosa at weaning due to intensive milk feeding and butyrate supplementation, and the local IGF system was involved in intestinal growth regulation. Rumen development was not affected by butyrate supplementation of MR and was slightly delayed due to ad libitum MR feeding.

Maternal Lactase Polymorphism (rs4988235) Is Associated with Neural Tube Defects in Offspring in the National Birth Defects Prevention Study.

BACKGROUND: The risk of neural tube defect (NTD)-affected pregnancies is reduced with adequate folic acid intake during early pregnancy. However, NTDs have been observed among offspring of women with adequate folic acid intake. Some of these women are possibly not absorbing enough folic acid. Because lactase deficiency can lead to poor nutrient absorption, we hypothesized that lactase-deficient women will be at increased risk of having offspring with NTDs. OBJECTIVE: We examined the association between maternal rs4988235 (a lactase deficiency genetic marker) and NTDs in offspring. METHODS: We conducted a case-control study using data from the National Birth Defects Prevention Study, United States, 1997-2009, restricting to non-Hispanic white (NHW) and Hispanic women. Cases were women with an offspring with an NTD (n = 378 NHW, 207 Hispanic), and controls were women with an offspring without a birth defect (n = 461 NHW, 165 Hispanic). Analyses were conducted separately by race/ethnicity, using logistic regression. Women with the CC genotype were categorized as being lactase deficient. To assess potential effect modification, analyses were stratified by lactose intake, folic acid supplementation, dietary folate, and diet quality. RESULTS: Among NHW women, the odds of being lactase deficient were greater among cases compared with controls (OR: 1.37; 95% CI: 1.02, 1.82). Among Hispanic women, the odds of being lactase deficient were significantly lower among cases compared with controls (OR: 0.50, 95% CI: 0.33, 0.77). The association differed when stratified by lactose intake in NHW women (higher odds among women who consumed ≥12 g lactose/1000 kcal) and by dietary folate in Hispanic women (opposite direction of associations). The association did not differ when stratified by folic acid supplementation or diet quality. CONCLUSIONS: Our findings suggest that maternal lactase deficiency is associated with NTDs in offspring. However, we observed opposite directions of effect by race/ethnicity that could not be definitively explained.

Effects of dietary leucine and phenylalanine on gastrointestinal development and small intestinal enzyme activities in milk-fed holstein dairy calves.

This study was investigated the effects of dietary supplementation of leucine and phenylalanine on the development of the gastrointestinal tract and the intestinal digestive enzyme activity in male Holstein dairy calves. Twenty calves with a body weight of 38 ± 3 kg at 1 day of age were randomly divided into four groups: a control group, a leucine group (1.435 g·l-1), a phenylalanine group (0.725 g·l-1), and a mixed amino acid group (1.435 g·l-1 leucine plus 0.725 g·l-1 phenylalanine). The supplementation of leucine decreased the short-circuit current (Isc) of the rumen and duodenum (P<0.01); phenylalanine did not show any influence on the Isc of rumen and duodenum (P>0.05), and also counteracted the Isc reduction caused by leucine. Leucine increased the trypsin activity at the 20% relative site of the small intestine (P<0.05). There was no difference in the activity of α-amylase and of lactase in the small intestinal chyme among four treatments (P>0.05). The trypsin activity in the anterior segment of the small intestine was higher than other segments, whereas the α-amylase activity in the posterior segment of the small intestine was higher than other segments. Leucine can reduce Isc of the rumen and duodenum, improve the development of the gastrointestinal tract, and enhance trypsin activity; phenylalanine could inhibit the effect of leucine in promoting intestinal development.

Analysis of lactase in lactose intolerance supplements.

Lactase is the enzyme responsible for the digestion of the disaccharide lactose, and deficiency in this enzyme causes the prevalent medical condition lactose intolerance. Management of lactose intolerance can be achieved through the administration of lactase supplements. Lactase is an appropriate platform for advanced enzymatic study because its medical application is a motivator for student learning. The following is an upper-level biochemistry laboratory sequence that integrates student inquiry and exposure to advanced laboratory techniques. Students investigate three different lactase supplements through experimentation that includes the Bradford assay, SDS-PAGE, continuous and discontinuous kinetic assays, and zymography. Upon completion of this project, students compile their results and conclusions in a scientifically formatted paper comparing supplement protein content and activity. This safe and inexpensive laboratory project enriches student understanding of key biochemical concepts while mirroring work performed in a realistic research setting. © 2018 International Union of Biochemistry and Molecular Biology, 46(6):652-662, 2018.

Application of a commercial digestive supplement formulated with enzymes and probiotics in lactase non-persistence management.

Strategies to avoid lactose malabsorption, which affects 70% of the world's population, are focused on the restriction of milk and dairy products or the use of non-human ß-galactosidases or probiotics endowed with ß-galactosidase activity added at mealtime. Our evaluation of a commercial blend of probiotics and enzymes (protease, lactase, lipase and amylase) and its potential application in lactase non-persistence management is described in this work. Recommended amounts (460-1000 mg) of the commercial probiotics-enzyme blend were shown to be adequate for performing in vitro lactose hydrolysis in standard solutions (0.25-5%) and commercial dairy products, namely milks (5% lactose) and yogurts (3% lactose), reaching hydrolysis values between 44 and 96%. According to these percentages, the use of the enzymatic preparation would guarantee the intake of less than 12 g, the recommendation of the EFSA for lactose intolerance. Furthermore, formation of prebiotic galactooligosaccharides was also detected, increasing the potential benefits of the enzymatic preparation in the gastrointestinal system.

Inhibition of the glycaemic response by onion: a comparison between lactose-tolerant and lactose-intolerant adults.

This pilot study compared inhibition of the glycaemic response to glucose by a dietary source of quercetin glucosides (onion) in lactose-tolerant adults (n=12) and lactose-intolerant adults (n=12). We hypothesised that lactose-intolerant people (who do not express lactase) will retain intact quercetin glucosides that can inhibit glucose uptake via the glucose transporter SGLT1, whereas lactose-tolerant people (who do express lactase) will hydrolyse quercetin glucosides to free quercetin that does not inhibit glucose uptake. In a glucose tolerance test, reduction in peak glucose levels by an onion meal was higher in lactose-intolerant people than in lactose-tolerant people (44.2 versus 19.3%, P=0.04). Incremental area under the blood glucose curve was reduced more in lactose-intolerant people, but was not statistically significant (54.5 versus 42.1%, P=0.42). A diet containing quercetin glucosides may be of greater benefit for glycaemic control in lactose-intolerant people than in lactose-tolerant people.

Occupational sensitization to lactase in the dietary supplement industry.

Aerogen lactase exposure carries a risk for the development of allergic asthma and rhinitis; only a few occupationally affected patients have been reported. The authors report the results of allergy testing with employees of a lactase tablets manufacturing plant. The survey involved 13 workers, including a questionnaire, spirometry, basophil activation test (BAT), and skin prick tests (SPTs) with lactase and a panel of common aeroallergens. Furthermore, lactase-specific immunoglobulin E (IgE) antibodies were analyzed. Sensitization to lactase could be proven for 9 workers by SPT and BAT; specific IgE antibodies could be detected in serum samples of all sensitized. However, IgE levels ≥0.35 kU/L were only found in 4 sera. These data confirm that occupational exposure to lactase can induce IgE-mediated respiratory sensitization resulting in allergic diseases. Protective measures should thus be obligatory when working with lactase.