A Pilot Pre and Post 4 Week Intervention Evaluating the Effect of a Proprietary, Powdered, Plant Based Food on Micronutrient Status, Dietary Intake, and Markers of Health in a Healthy Adult Population.

Background: A "balanced, adequate, and varied diet" is recommended as the basis of nutritionally sound diet by the World Health Organisation and national public health agencies. Huel is a proprietary, on-the-go, powdered, plant based food, providing all 26 essential vitamins and minerals, protein, essential fats, carbohydrate, fibre, and phytonutrients. Objectives: Assessing the effect of solely consuming Huel on micronutrient status, dietary intake and markers of health was achieved through a 4-week intervention of solely Huel powder. Methods: Habitual energy intake was assessed through a one-week lead in period with healthy adult participants (aged 18 or over) logging their food intake, after which only Huel was consumed for 4 weeks. Blood samples and body composition was assessed before and after the lead in week as well the end of the intervention. Thirty participants were recruited with 20 (11 females, median age 31, range 22-44) completing the study, 19 sets of blood samples were collected. 22 blood markers were analysed along with weight, BMI, waist circumference, visceral adipose tissue (VAT), and body composition. All blood micronutrients, except for Thyroid Stimulating Hormone and choline were sent to Royal Victoria Infirmary NHS, Newcastle Laboratory (Newcastle upon Tyne, United Kingdom) for analysis. Results: Fourteen of the parameters significantly changed over the course of the study with circulating haemoglobin, iron, vitamins B12 and D as well as selenium significantly increasing (p < 0.05). HbA1c, total and non-HDL cholesterol, vitamins A and E, potassium, BMI, VAT, and waist circumference all significantly decreased (p < 0.05) post intervention. Conclusion: Although energy intake decreased during the intervention period, the adherence to recommended micronutrient intake, as quantified by the dietary Total Adherence Score, significantly increased which tallies with the preservation or improvement of micronutrient status. This study potentially demonstrates that consuming only Huel for 4 weeks does not negatively affect micronutrient status.

Evaluation of the Proximity of Singaporean Children's Dietary Habits to Food-Based Dietary Guidelines.

Dietary habits in children may not only impact current health status but could also shape future, lifelong dietary choices. Dietary intake data in Singaporean children are limited. The current study aimed to define the overall diet quality of Singaporean children using an existing cross-sectional dataset and to consider how demographic factors (i.e., body mass index (BMI) status, ethnicity, age, and sex) were associated with these scores. Existing, cross-sectional dietary data (n = 561 children aged 6-12 years, collected in 2014-2015) from duplicate 24-h recalls were assessed for diet quality using an index based on the Singaporean Health Promotion Board dietary guidelines. Total diet quality scores were calculated from ten different components (frequencies of rice and alternatives, whole grains, fruits, vegetables, meat and alternatives, dairy and alternatives, total fat, saturated fat, sodium intake, and added sugars). Association with demographic factors and BMI category was evaluated by one-way multivariate ANOVA (MANOVA) tests, with Bonferroni post hoc analyses. Median (interquartile range) total diet quality scores were 65.4 (57.1-73.0). Median scores for whole grains (0.0, 0.0-33.4), fruits (24.1, 0.0-65.3), vegetables (36.5, 10.4-89.8), and sodium (58.4, 0.0-100.0) intake were frequently sub-optimal. Children of Malay ethnic origin had statistically lower total diet quality scores ((55.3, 47.5-60.3) vs. other ethnic groups (combined median 65.4 (57.1, 73.0); p < 0.001). These findings highlight the need for continuing efforts to improve dietary intake in young Singaporeans and for longitudinal dietary monitoring in this group.

Analysis of the Lipolytic Activity of Whole-Saliva and Site-Specific Secretions from the Oral Cavity of Healthy Adults.

It is currently unclear how the process of fat digestion occurs in the mouth of humans. This pilot study therefore aimed to quantify the levels of lipolytic activity at different sites of the mouth and in whole saliva. Samples of whole saliva and from 4 discrete sites in the oral cavity were collected from 42 healthy adult participants. All samples were analyzed for lipolytic activity using two different substrates (olive oil and the synthetic 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester (DGGR)). Bland⁻Altman analyses suggested that the two assays gave divergent results, with 91% and 23% of site-specific and 40% and 26% of whole-saliva samples testing positive for lipolytic activity, respectively. Non-parametric multiple comparisons tests highlighted that median (IQR) of lipolytic activity (tested using the olive oil assay) of the samples from the parotid 20.7 (11.7⁻31.0) and sublingual 18.4 (10.6⁻47.2) sites were significantly higher than that of whole saliva 0.0 (0.0⁻35.7). In conclusion, lipolysis appears to occur in the oral cavity of a proportion of individuals. These findings give a preliminary indication that lipolytic agent activity in the oral cavity may be substrate-specific but do not discount that the enzyme is from sources other than oral secretions (e.g., microbes, gastric reflux).

Acceptability of alginate enriched bread and its effect on fat digestion in humans.

Lifestyle interventions and physical activity remain the cornerstone of obesity management, as pharmacological therapies (orlistat) are associated with gastrointestinal (GI) side effects. Combining orlistat with fibers can reduce side effects, improving compliance. Therefore, a fiber that inhibits lipase without side effects could help treat obesity. The aims of the present work were to assess whether alginate enriched bread could inhibit fat digestion, and assess the acceptability of alginate bread and its effect on GI wellbeing. A double-blind, randomised, controlled cross-over pilot study (NCT03350958) assessed the impact of an alginate bread meal on; lipid content in ileal effluent and circulating triacylglycerol levels. This was compared against the same meal with non-enriched (control) bread. GI wellbeing and acceptability of alginate bread was compared to control bread through daily wellbeing questionnaires and food diaries (NCT03477981). Control bread followed by alginate bread were consumed for two weeks respectively. Consumption of alginate bread reduced circulating triacylglycerol compared to control (2% reduction in AUC) and significantly increased lipid content in ileal effluent (3.8 g ±â€¯1.6 after 210 min). There were no significant changes to GI wellbeing when comparing alginate bread to control bread. A significant increase in the feeling of fullness occurred with alginate bread compared to baseline and the first week of control bread consumption. This study showed that sustained consumption of alginate enriched bread does not alter GI wellbeing and can decrease lipolysis, increasing lipid leaving the small intestine. Further studies are required to demonstrate that reduced fat digestion through the action of alginate can reduce fat mass or body weight.

An Overview of Whole Grain Regulations, Recommendations and Research across Southeast Asia.

The Association of Southeast Asian Nations (ASEAN) is a diverse region that is experiencing economic growth and increased non-communicable disease burden. This paper aims to evaluate the current regulations, dietary recommendations and research related to whole grains in this region. To do this, a systematic literature review was carried out and information was collected on regulations and dietary recommendations from each member state. The majority of publications on whole grains from the region (99 of 147) were in the area of food science and technology, with few observational studies (n = 13) and human intervention studies (n = 10) related to whole grains being apparent. Information from six countries (Indonesia, Malaysia, The Philippines, Singapore, Thailand and Vietnam) was available. Wholegrain food-labelling regulations were only noted in Malaysia and Singapore. Public health recommendation related to whole grains were apparent in four countries (Indonesia, Malaysia, The Philippines, Singapore), while recent intake data from whole grains was only apparent from Malaysia, The Philippines and Singapore. In all cases, consumption of whole grains appeared to be very low. These findings highlight a need for further monitoring of dietary intake in the region and further strategies targeted at increasing the intake of whole grains.

Wholegrain Food Acceptance in Young Singaporean Adults.

Previous epidemiological evidence suggests that habitual consumption of whole grains is associated with reduction of disease risk. While wholegrain food consumption appears to be increasing in Singapore, it is still low, with more infrequent consumption noted in younger Singaporeans. Therefore, the primary objective of this study is to determine the knowledge of whole grains and barriers to consumption of wholegrain foods. Thirty participants (age range 21-26 year, 19 females) took part in two focus groups separated by a 2-week period in which participants trialled a range of wholegrain foods. Barriers towards whole grain consumption and experiences of products during this familiarization period were discussed during the focus groups and knowledge of whole grains was assessed by questionnaire. Potential barriers such as personal factors, product-specific factors and external factors were identified with sensory and habitual being stronger barriers. The whole grain familiarization period did not alter the taste expectations of the consumers but it did manage to increase acceptance for four of the wholegrain products tested (muesli, cookies, granola bars and wholewheat pasta). These findings suggest existing barriers to wholegrain food consumption should be considered by public health agencies and manufacturing companies.

Energy Expenditure, Availability, and Dietary Intake Assessment in Competitive Female Dragon Boat Athletes.

Dragon boat racing requires high physical activity levels during competition and training. The female athletic triad refers to a number of negative health consequences (e.g., amenorrhoea, low bone mineral density, and low energy availability) that may result from high physical activity in female athletes in parallel with inadequate dietary intake. This study aimed to estimate energy expenditure and dietary adequacy in female competitive dragon boat athletes. Following ethical approval, energy expenditure was assessed by use of SensewearTM armbands (which measure movement as well as galvanic heat loss) on nine dragon boat athletes preparing for the Southeast Asian Games 2013. The mean estimated energy expenditure for the athletes was 2226 ± 711 kJ/day. Mean total energy, recorded using three-day food diaries (6715 ± 2518 kJ/day) and energy availability (99 ± 56 kJ/kg/day), were low. Estimated micronutrient intake (calcium 699.3 ± 328.7 mg/day and iron 10.6 ± 4.7 mg/day) did not meet recommended daily allowances of 800 mg/day and 19 mg/day, respectively. The low intake of energy, calcium, and iron noted within this study could have negative effects on performance and short- and long-term health in female dragon boat athletes.

Whole-grain food consumption in Singaporean children aged 6-12 years.

Public health bodies in many countries are attempting to increase population-wide habitual consumption of whole grains. Limited data on dietary habits exist in Singaporean children. The present study therefore aimed to assess whole grain consumption patterns in Singaporean children and compare these with dietary intake, physical activity and health parameters. Dietary intake (assessed by duplicate, multipass, 24-h food recalls), physical activity (by questionnaire) and anthropometric measurements were collected from a cross-section of 561 Singaporean children aged 6-12 years. Intake of whole grains was evaluated using estimates of portion size and international food composition data. Only 38·3 % of participants reported consuming whole grains during the dietary data collection days. Median intake of whole grains in consumers was 15·3 (interquartile range 5·4-34·8) g/d. The most commonly consumed whole-grain food groups were rice (29·5 %), wholemeal bread (28·9 %) and ready-to-eat breakfast cereals (18·8 %). A significantly lower proportion of Malay children (seven out of fifty-eight; P < 0·0001) consumed whole grains than children of other ethnicities. Only 6 % of all children consumed the amount of whole grains most commonly associated with improved health outcomes (48 g/d). There was no relationship between whole grain consumption patterns and BMI, waist circumference or physical activity but higher whole grain intake was associated with increased fruit, vegetable and dairy product consumption (P < 0·001). These findings demonstrate that consumption of whole grain foods is low at a population level and infrequent in Singaporean children. Future drives to increase whole-grain food consumption in this population are likely to require input from multiple stakeholders.

Alginate as a protease inhibitor in vitro and in a model gut system; selective inhibition of pepsin but not trypsin.

Alginates are widely used in the food and medical industries, including as a Gastro-Oesophagul Reflux treatment. This work investigates the inhibitory effects of alginate on the reflux aggressors trypsin and pepsin and the role of alginate-substrate binding, pH and alginate structure on inhibition. Alginates were shown to reduce pepsin activity by up to 53.9% (±9.5SD) in vitro. Strong positive correlation between alginate mannuronate residue frequency and levels of pepsin inhibition was observed. Limited inhibition of trypsin was shown. Viscometric observations of pH dependent interactions between alginate and protein suggest a mechanism whereby pH dependent ionic interactions reduce substrate availability to enzyme at acidic pH. To understand how dietary protein digestion is affected by alginate, proteolytic digestion was investigated in an in vitro model of the upper digestive tract. Significant inhibition of proteolysis was shown in the gastric phase of digestion, but not the small intestinal phase.

Biological activity of alginate and its effect on pancreatic lipase inhibition as a potential treatment for obesity.

Alginates are classed as a dietary fibre and have been shown to inhibit digestive enzymes in vitro, and therefore could be used as an obesity treatment. The current study aims to assess whether alginate in a bread vehicle maintains its inhibition properties despite cooking and digestion, and may therefore be used as a potential treatment for obesity. After 180 min in a model gut that replicates digestion in the mouth, stomach and small intestines alginate bread (AB), control bread (CB), CB with Manucol® DM alginate, free DM alginate and model gut solution were collected. DM, LFR 5/60 and SF200 were heated at 37 °C and 200 °C, with DM also heated at 50, 100 and 150 °C. Samples from the model gut and heated alginate were assessed for molecular size and inhibition properties using viscosity, gel filtration and a lipase turbidity assay. AB does not significantly increase viscosity in the model gut. Viscosity of alginate reduces beyond 100 °C, although alginate retains its inhibition properties up to 150 °C. Cooking into the bread does not reduce the molecular size of the alginate or affect its inhibition properties. These data demonstrate the robustness of alginates lipase inhibition despite the cooking process and digestion. Therefore adding alginate to a bread vehicle may have the potential in the treatment for obesity.

Whole-grain foods and chronic disease: evidence from epidemiological and intervention studies.

Cereal-based foods are key components of the diet and they dominate most food-based dietary recommendations in order to achieve targets for intake of carbohydrate, protein and dietary fibre. Processing (milling) of grains to produce refined grain products removes key nutrients and phytochemicals from the flour and although in some countries nutrients may be replaced with mandatory fortification, overall this refinement reduces their potential nutritional quality. There is increasing evidence from both observational and intervention studies that increased intake of less-refined, whole-grain (WG) foods has positive health benefits. The highest WG consumers are consistently shown to have lower risk of developing CVD, type 2 diabetes and some cancers. WG consumers may also have better digestive health and are likely to have lower BMI and gain less weight over time. The bulk of the evidence for the benefits of WG comes from observational studies, but evidence of benefit in intervention studies and potential mechanisms of action is increasing. Overall this evidence supports the promotion of WG foods over refined grain foods in the diet, but this would require adoption of standard definitions of 'whole grain' and 'whole-grain foods' which will enable innovation by food manufacturers, provide clarity for the consumer and encourage the implementation of food-based dietary recommendations and public health strategies.

Method for quantifying alginate and determining release from a food vehicle in gastrointestinal digesta.

To assess the efficacy of alginate as a modifier of enzyme activity, a suitable method to quantify its release must be developed. This paper develops and assesses the ability of the Periodic Acid Schiffs (PAS) assay to quantify alginate, and its release from bread during digestion in a model gut. Control and alginate enriched (4% w/w wet dough) bread were used. A model gut replicating the mouth, stomach and small intestines was used. Standard curves were created for alginate in deionised H2O and model gut solutions using a modified PAS to remove interference. The PAS assay quantified alginate with excellent linearity (R(2)=0.99), and optical density range (0.02-0.5). There was a significant difference in alginate release at 180 min compared to 0 and 60 min. The data indicate the modified PAS assay is a simple method for quantifying alginate release and release rate from alginate enriched products.

The modulation of pancreatic lipase activity by alginates.

Alginates are comprised of mannuronic (M) and guluronic acid (G) and have been shown to inhibit enzyme activity. Pancreatic lipase is important in dietary triacylglycerol breakdown; reducing pancreatic lipase activity would reduce triacylglycerol breakdown resulting in lower amounts being absorbed by the body. Lipase activity in the presence of biopolymers was assessed by enzymatic assay using natural and synthetic substrates. Alginate inhibited pancreatic lipase by a maximum of 72.2% (±4.1) with synthetic substrate (DGGR) and 58.0% (±9.7) with natural substrate. High-G alginates from Laminaria hyperborea seaweed inhibited pancreatic lipase to a significantly higher degree than High-M alginates from Lessonia nigrescens, showing that inhibition was related to alginate structure. High-G alginates are effective inhibitors of pancreatic lipase and are used in the food industry at low levels. They could be included at higher levels in foods without altering organoleptic qualities, potentially reduce the uptake of dietary triacylglycerol aiding in weight management.

Aspiration and allograft injury secondary to gastroesophageal reflux occur in the immediate post-lung transplantation period (prospective clinical trial).

OBJECTIVES: To provide novel pilot data to quantify reflux, aspiration, and allograft injury immediately post-lung transplantation. BACKGROUND: Asymptomatic reflux/aspiration, associated with allograft dysfunction, occurs in lung transplant recipients. Early fundoplication has been advocated. Indications for surgery include elevated biomarkers of aspiration (bile salts) in bronchoalveolar lavage fluid (BALF). Measurements have been mostly documented after the immediate posttransplant period. We report the first prospective study of reflux/aspiration immediately posttransplantation to date. METHODS: Lung transplant recipients were recruited over 12 months. At 1 month posttransplantation, patients completed a Reflux Symptom Index questionnaire and underwent objective assessment for reflux (manometry and pH/impedance). Testing was performed on maintenance proton pump inhibitor. BALF was assessed for pepsin, bile salts, interleukin-8 and neutrophils. RESULTS: Eighteen lung transplant recipients, median age of 46 years (range: 22-59 years), were recruited. Eight of 18 patients had abnormal esophageal peristalsis. Five of 17 patients were positive on Reflux Symptom Index questionnaire. Twelve of 17 patients had reflux. Three patients exclusively had weakly acid reflux. Median acid exposure was 4.8% (range: 1%-79.9%) and median esophageal volume exposure was 1.6% (range: 0.7-5.5). There was a median of 72 reflux events (range: 27-147) per 24 hours. A correlation existed between Reflux Symptom Index score and proximal reflux (r = 0.533, P = 0.006). Pepsin was detected in 11 of 15 BALF samples signifying aspiration (median: 18 ng/mL; range: 0-43). Bile salts were undetectable, using spectrophotometry and rarely detectable using dual mass spectrometry (2/15) (levels 0.2 and 1.2 µmol/L). Lavage interleukin-8 and neutrophil levels were elevated. A correlation existed between proximal reflux events and neutrophilia (r = 0.52, P = 0.03). CONCLUSIONS: Lung transplant recipients should be routinely assessed for reflux/aspiration within the first month posttransplant. Reflux/aspiration can be present early postoperatively. Pepsin was detected suggesting aspiration. Bile salts were rarely detected. Proximal reflux events correlated with neutrophilia, linked to allograft dysfunction and mortality. These results support the need for early assessment of reflux/aspiration, which may inform fundoplication.

The impact of a 16-week dietary intervention with prescribed amounts of whole-grain foods on subsequent, elective whole grain consumption.

Previous (mainly population-based) studies have suggested the health benefits of the elective, lifelong inclusion of whole-grain foods in the diet, forming the basis for public health recommendations to increase whole grain consumption. Currently, there is limited evidence to assess how public health recommendations can best result in longer-term improvements in dietary intake. The present study aimed to assess the impact of a previous 16-week whole-grain intervention on subsequent, elective whole grain consumption in free-living individuals. Participants completed a postal FFQ 1, 6 and 12 months after the end of the whole-grain intervention study period. This FFQ included inputs for whole-grain foods commonly consumed in the UK. Whole grain consumption was significantly higher (approximately doubled) in participants who had received whole-grain foods during the intervention (P< 0.001) compared with the control group who did not receive whole-grain foods during the intervention. This increased whole grain consumption was lower than whole grain intake levels required by participants during the intervention period between 60 and 120 g whole grains/d. Aside from a significant increase (P< 0.001) in NSP consumption compared with control participants (mean increase 2-3 g/d), there were no obvious improvements to the pattern of foods of the intervention group. The results of the present study suggest that a period of direct exposure to whole-grain foods in non-habitual whole-grain food consumers may benefit subsequent, elective dietary patterns of whole grain consumption. These findings may therefore aid the development of future strategies to increase whole grain consumption for public health and/or food industry professionals.

Are the enzymatic methods currently being used to measure bronchoalveolar lavage bile salt levels fit for purpose?

BACKGROUND: Microaspiration after gastroesophageal reflux has been implicated in the chronic loss of allograft function in lung transplant patients. Bronchoalveolar lavage fluid (BALF) assessment for pepsin and bile salts is a common method to document reflux and aspiration. Clinically used methods for bile salt analysis include tandem mass spectrometry and diagnostic enzymatic kits designed to measure bile salts in serum. In clinical research, the enzymatic kits have been commonly used for BALF assays in lung transplant recipients, with reports of detection limits of 0.2 µmol/liter, and the levels used to inform clinical decisions. This study assessed the sensitivity of detection by 2 enzymatic assay kits compared with tandem mass spectrometry. METHODS: These 2 kits were used to measure (1) the absorbance changes for 0 to 50 µmol/liter bile salts, (2) levels in gastric juice (10-10,010 µmol/liter), and (3) bile salt levels of 40 BALF samples that were also measured using tandem mass spectrometry (0.01-1.19 µmol/liter). Measurements of pH/impedance were done in 14 of 15 patients. RESULTS: Neither kit had detection limits as low as claimed in previous BALF studies. The kits could be made more sensitive with a longer incubation time, (5 µmol/liter). All patients had detectable lavage bile acids using mass spectroscopy, 71% had pathologic distal gastroesophageal reflux, and 43% had pathologic proximal reflux. CONCLUSIONS: The enzymatic kits are not sensitive enough for use in situations where bile salt levels are much below 5 µmol/liter, which is the case in BALF. In addition, reports in the literature of levels significantly below 5 µmol/liter need reassessing. Tandem mass spectrometry with a lower limit of detection of 0.01 µmol/liter should be the method of choice.

WHOLEheart study participant acceptance of wholegrain foods.

This qualitative study explored the concept of acceptance of wholegrain foods in an adult population in the UK. Data was generated via focus groups with volunteers from a randomised controlled wholegrain based dietary intervention study (the WHOLEheart study). WHOLEheart volunteers, who did not habitually eat wholegrain foods, were randomised to one of three experimental regimes: (1) incorporating 60 g/day whole grains into the diet for 16 weeks; (2) incorporating 60 g/day whole grains into the diet for 8 weeks, doubling to 120 g/day for the following 8 weeks; (3) a control group. Focus groups to examine factors relating to whole grain acceptability were held one month post-intervention. For participants incorporating whole grains into their diet, acceptance was dependent upon: (a) 'trial acceptance', relating to the taste, preparation and perceived impact of the wholegrain foods on wellbeing, and (b) 'dietary acceptance' which involved the compatibility and substitutability of whole grains with existing ingredients and meal patterns. Barriers to sustained intake included family taste preferences, cooking skills, price and availability of wholegrain foods. Although LDL lowering benefits of eating whole grains provided the impetus for the WHOLEheart study, participants' self-reported benefits of eating wholegrain foods included perceived naturalness, high fibre content, superior taste, improved satiety and increased energy levels provided a stronger rationale for eating whole grains.

Plasma alkylresorcinols as a biomarker of whole-grain food consumption in a large population: results from the WHOLEheart Intervention Study.

BACKGROUND: Small-scale, short-term intervention studies have suggested that plasma alkylresorcinol (AR) concentrations may be biomarkers of whole grain (WG) wheat and rye intakes. OBJECTIVE: The objective was to determine whether plasma AR concentrations reflect self-reported WG food intake in a 16-wk WG intervention study and to establish which phenotypic characteristics influence plasma AR concentrations. DESIGN: In a randomized parallel-group dietary intervention study, 316 overweight and obese participants with a WG intake of <30 g/d were recruited and randomly assigned to 1 of 3 groups: control (no dietary change), intervention 1 (60 g WG/d for 16 wk), or intervention 2 (60 g WG/d for 8 wk followed by 120 g WG/d for 8 wk). Fasting blood samples were collected at baseline, 8 wk, and 16 wk for the measurement of plasma lipids and ARs. RESULTS: Plasma samples from 266 study completers were analyzed. Total plasma AR concentrations increased with the WG intervention and could be used to distinguish between control subjects and those who consumed 60 or 120 g WG, but not between those who consumed 60 and 120 g WG. Plasma AR concentrations were higher in men, were positively associated with plasma triglyceride concentrations, and were negatively associated with nonesterified fatty acids. CONCLUSIONS: Plasma AR concentrations were correlated with WG intake and could be used to distinguish between low- and high-WG consumers. Sex and plasma lipid concentrations independently influenced plasma AR concentrations, although plasma triglycerides may explain higher concentrations in men. This trial is registered as ISRCT no. 83078872.

The interaction of large bowel microflora with the colonic mucus barrier.

The colonic mucus barrier is the first line of defence that the underlying mucosa has against the wide range of potentially damaging agents of microbial, endogenous, and dietary origin that occur within the colonic lumen. The functional component of mucus is the secreted, polymeric glycoprotein mucin. The mucus barrier can either act as an energy source or a support medium for growth to the intestinal microflora. The mucus barrier appears to effectively partition the vast number of microbial cells from the underlying epithelium. The normal functionality and biochemistry of this mucus barrier appears to be lost in diseases of the colorectal mucosa. Germ-free animal studies have highlighted the necessity of the presence of the colonic microflora to drive the maturation of the colonic mucosa and normal mucus production. A number of by-products of the microflora have been suggested to be key luminal drivers of colonic mucus secretion.

Physiological parameters governing the action of pancreatic lipase.

The most widely used pharmacological therapies for obesity and weight management are based on inhibition of gastrointestinal lipases, resulting in a reduced energy yield of ingested foods by reducing dietary lipid absorption. Colipase-dependent pancreatic lipase is believed to be the major gastrointestinal enzyme involved in catalysis of lipid ester bonds. There is scant literature on the action of pancreatic lipase under the range of physiological conditions that occur within the human small intestine, and the literature that does exist is often contradictory. Due to the importance of pancreatic lipase activity to nutrition and weight management, the present review aims to assess the current body of knowledge with regards to the physiology behind the action of this unique gastrointestinal enzyme system. Existing data would suggest that pancreatic lipase activity is affected by intestinal pH, the presence of colipase and bile salts, but not by the physiological range of Ca ion concentration (as is commonly assumed). The control of secretion of pancreatic lipase and its associated factors appears to be driven by gastrointestinal luminal content, particularly the presence of acid or digested proteins and fats in the duodenal lumen. Secretion of colipase, bile acids and pancreatic lipase is driven by cholecystokinin and secretin release.