Daily ingestion of alginate reduces energy intake in free-living subjects

Advances in oligosaccharides production from brown seaweeds: extraction, characterization, antimetabolic syndrome, and other potential applications

Brown seaweeds are a promising source of bioactive substances, particularly oligosaccharides. This group has recently gained considerable attention due to its diverse cell wall composition, structure, and wide-spectrum bioactivities. This review article provides a comprehensive update on advances in oligosaccharides (OSs) production from brown seaweeds and their potential health applications. It focuses on advances in feedstock pretreatment, extraction, characterization, and purification prior to OS use for potential health applications. Brown seaweed oligosaccharides (BSOSs) are extracted using various methods. Among these, enzymatic hydrolysis is the most preferred, with high specificity, mild reaction conditions, and low energy consumption. However, the enzyme selection and hydrolysis conditions need to be optimized for desirable yield and oligosaccharides composition. Characterization of oligosaccharides is essential to determine their structure and properties related to bioactivities and to predict their most suitable application. This is well covered in this review. Analytical techniques such as high-performance liquid chromatography (HPLC), gas chromatography (GC), and nuclear magnetic resonance (NMR) spectroscopy are commonly applied to analyze oligosaccharides. BSOSs exhibit a range of biological properties, mainly antimicrobial, anti-inflammatory, and prebiotic properties among others. Importantly, BSOSs have been linked to possible health advantages, including metabolic syndrome management. Metabolic syndrome is a cluster of conditions, such as obesity, hypertension, and dyslipidemia, which increase the risk of cardiovascular disease and type 2 diabetes. Furthermore, oligosaccharides have potential applications in the food and pharmaceutical industries. Future research should focus on improving industrial-scale oligosaccharide extraction and purification, as well as researching their potential utility in the treatment of various health disorders.[Figure: see text].

Hypoglycaemic Molecules for the Management of Diabetes Mellitus from Marine Sources

Diabetes mellitus (DM) is a chronic metabolic disorder recognized as a major health problem globally. A defective insulin activity contributes to the prevalence and expansion of DM. Treatment of DM is often hampered by limited options of conventional therapies and adverse effects associated with existing procedures. This has led to a spike in the exploration for potential therapeutic agents from various natural resources for clinical applications. The marine environment is a huge store of unexplored diversity of chemicals produced by a multitude of organisms. To date, marine microorganisms, microalgae, macroalgae, corals, sponges, and fishes have been evaluated for their anti-diabetic properties. The structural diversity of bioactive metabolites discovered has shown promising hypoglycaemic potential through in vitro and in vivo screenings via various mechanisms of action, such as PTP1B, α-glucosidase, α-amylase, β-glucosidase, and aldose reductase inhibition as well as PPAR alpha/gamma dual agonists activities. On the other hand, hypoglycaemic effect is also shown to be exerted through the balance of antioxidants and free radicals. This review highlights marine-derived chemicals with hypoglycaemic effects and their respective mechanisms of action in the management of DM in humans.

Roles of Marine Macroalgae or Seaweeds and Their Bioactive Compounds in Combating Overweight, Obesity and Diabetes: A Comprehensive Review

Obesity and diabetes are matters of serious concern in the health sector due to their rapid increase in prevalence over the last three decades. Obesity is a severe metabolic problem that results in energy imbalance that is persistent over a long period of time, and it is characterized by insulin resistance, suggesting a strong association with type 2 diabetes (T2D). The available therapies for these diseases have side effects and some still need to be approved by the Food and Drug Administration (FDA), and they are expensive for underdeveloped countries. Hence, the need for natural anti-obesity and anti-diabetic drugs has increased in recent years due to their lower costs and having virtually no or negligible side effects. This review thoroughly examined the anti-obesity and anti-diabetic effects of various marine macroalgae or seaweeds and their bioactive compounds in different experimental settings. According to the findings of this review, seaweeds and their bioactive compounds have been shown to have strong potential to alleviate obesity and diabetes in both in vitro and in vivo or animal-model studies. However, the number of clinical trials in this regard is limited. Hence, further studies investigating the effects of marine algal extracts and their bioactive compounds in clinical settings are required for developing anti-obesity and anti-diabetic medicines with better efficacy but lower or no side effects.

Marine macroalgae as a feasible and complete resource to address and promote Sustainable Development Goals (SDGs)

Because the world's population is increasing, science-based policies are needed to promote sustainable global development. It is important to maintain and restore the environment and help human society overcome the risks from industrialization and unsustainable exponential growth. In recent years, many studies have highlighted that macroalgae represent a key marine resource for ecological and sustainable living, thus helping to address today's global problems, such as water pollution, ocean acidification, and global warming. Macroalgae show the potential to provide innovative, ecofriendly, and nutritious food sources and natural compounds for various industries, such as biomedical, food, agricultural, and pharmaceutical industries. This review discusses how macroalgae can help us today and how they can promote a more sustainable way of life in the future. It also discusses the potential danger for ecosystems and the global population if these organisms are not part of the solution but part of the problem. Integr Environ Assess Manag 2022;18:1148-1161. © 2022 SETAC.

Properties of Foods That Impact Appetite Regulation in Cats

Overweight and obesity are common in global pet cat populations which makes it important to understand how properties of food affect appetite (food motivation). In four experiments, we studied this by using a model of operant conditioning for assessing appetite in which cats could press a lever for food rewards. There was no effect of protein status on motivation for protein, when evaluated in a cross-over design with cats receiving low protein (LP) or high protein (HP) foods for 14 days. Cats obtained similar numbers of HP and LP rewards, irrespective of whether their daily food was HP or LP (mixed-effects model, P = 0.550 for food × reward, P = 0.151 for reward). High dietary protein reduced food motivation when we regressed protein levels in 12 commercial foods (12.0 to 27.4 g crude protein/MJ metabolizable energy; P = 0.022) fed for 2 days and tested at 5 h postprandially on the third day whereas fiber levels were without effect (3.8 to 17.8 g non-starch polysaccharides/MJ; P = 0.992). Dietary fiber may reduce appetite depending on its physicochemical properties and we tested the effect of a gelling fiber (alginate), viscous fiber (psyllium) and a fermentable fiber (inulin). Cats received test foods as well as control foods for 3 days and were tested on the third day at 3 h (alginate), 5 h (psyllium) or 8 h (inulin) postprandially. Enriching the food with alginate (P = 0.379) or psyllium (P = 0.153) did not affect the number of rewards obtained, but the feeding of the inulin-enriched food did make the cats obtain fewer rewards than when they received the control food (P = 0.001). Finally, cooking or grinding of dietary meat increased the number of rewards obtained by cats, on day 3 at 3 h postprandial, without evidence for additive effects of these treatments (P = 0.014 for grinding × cooking). This study shows that dietary content of protein or fiber, and the grinding or cooking of meat, all affect appetite in cats as expected, though some predicted effects remained undetected and clearly details regarding food properties matter. These and future findings can guide the designing of foods that promote satiety and prevent over-eating in meal-fed cats.

Seaweed Intake and Risk of Cardiovascular Disease: The Circulatory Risk in Communities Study (CIRCS)

AIM

Seaweed contains soluble dietary fibers, potassium, and flavonoids and was recently reported to be inversely associated with the risk of coronary heart disease and mortality from stroke. However, epidemiological evidence on this issue has remained scarce.

METHODS

At the baseline survey of four Japanese communities between 1984 and 2000, we enrolled 6,169 men and women aged 40-79 years who had no history of cardiovascular disease. We assessed their seaweed intake using the data from a 24 h dietary recall survey and categorized the intake into four groups (0, 1-5.5, 5.5-15, and ≥ 15 g/day). We used sex-specific Cox proportional hazards models to examine the association between seaweed intake and risk of cardiovascular disease (stroke, stroke subtypes, and coronary heart disease).

RESULTS

During the 130,248 person-year follow-up, 523 cases of cardiovascular disease occurred: 369 cases of stroke and 154 cases of coronary heart disease. Seaweed intake levels were inversely associated with the risk of total stroke and cerebral infarction among men but not among women. Adjustment for cardiovascular risk factors did not change the associations: the hazard ratios (95% confidence intervals; P for trend) for the highest versus lowest categories of seaweed intake were 0.63 (0.42-0.94; 0.01) for total stroke and 0.59 (0.36-0.97; 0.03) for cerebral infarction. No associations were observed between seaweed intake and risks of intraparenchymal hemorrhage, subarachnoid hemorrhage, or coronary heart disease among men or women.

CONCLUSIONS

We found an inverse association between seaweed intake and risk of total stroke, especially that from cerebral infarction, among Japanese men.

A semi dynamic in vitro digestion study of milk protein concentrate dispersions structured with different polysaccharides

Hydrocolloids are often added as functional ingredients in foods, to better design the structure of the matrix and ensure food quality and optimal sensory properties. However, much less is known about their influence on the physical and chemical changes during gastric digestion. In this study, semi-continuous in vitro gastric digestion was applied on a model food system, prepared with milk protein concentrate (MPC) (3% w/v) and 1% alginate, pectin, guar gum, as well as a 1:1 mixture of alginate and pectin. The dynamics during simulated gastric digestion were observed by measuring particle size distributions, structuring at various length scales, as well as by evaluating differences in protein breakdown. Immediately after contact with the simulated gastric fluids, all samples showed extensive aggregation and formation of different structures. MPC control dispersions (no polysaccharide) and MPC containing alginate formed large inhomogeneous aggregates. The lack of structural homogeneity affected the simulated gastric emptying: there were marked differences in the type of aggregates present at various times of emptying depending on the hydrocolloid present in the mixture. MPC containing pectin or guar gum formed macroscopically homogeneous dispersion, with rather small protein aggregates showing a large population of particles between 60 and 100 ​μm of diameter, with marked differences in microstructure. Pectin created large coacervates, while guar microscopic phase separated systems. These dispersions showed a higher extent of protein digestion, due to the larger surface area created for enzyme activity compared to the macroscopically phase separated matrices. In all cases, there was a large undigested fraction at the end point of 140 ​min. SDS PAGE demonstrated differences in the casein peptides distribution depending on the type of polysaccharide present during simulated gastric emptying. This in spite of similarities in cumulative protein emptied. It was concluded that in this semi-continuous in vitro gastric digestion model, structuring with polysaccharides has a significant impact on gastric emptying and protein digestion kinetics.

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Protein-hydrocolloid interactions cause differences in structuring during gastrointestinal transit.

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Milk protein concentrates show different proteolysis kinetics during gastric digestion depending on aggregates formed.

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Milk protein concentrates with alginates show a delay in digestion.

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Pectin and guar form homogenous dispersions during gastric digestion.

Functional foods and bioactive ingredients harnessed from the ocean: current status and future perspectives

With an increase in life expectancy and decrease of quality-of-life couple with the high prevalence of diseases, diet is expected to play a key function in sustaining human health. Nutritionists, food technologists and medical experts are working in synergy to cater for the increasing demand of food with associated therapeutic benefits, commonly known as functional food, that may improve well-being and reduce the risk of diseases. Interestingly, the marine ecosystem, due to its abundant and phenomenal biodiversity of marine organisms, constitutes a vital source of a panoply of healthy foods supply for the thriving functional food industry. Marine organisms such as seaweeds, sea cucumbers, sponges, and mollusks amongst others are sources of thousands of biologically active metabolites with antioxidant, anti-parasitic, antiviral, anti-inflammatory and anticancer properties. Given the growing number of research and interest to probe into the therapeutic roles of marine products, this review was designed to provide a comprehensive summary of the therapeutic properties of marine organisms (macroalgae, sea cucumbers and fish among others) which are consumed worldwide, in addition to their potentials and as sources of functional ingredients for developing novel food and fostering wellness. The gap between research development and actual commercialization, and future prospects of marine-based products also summarized to some extent.

Impact of seaweed intake on health

Seaweeds contain minerals, vitamins, soluble dietary fibers, and flavonoids, which are regarded as preventive agents against lifestyle-related diseases. Seaweeds are consumed commonly in East Asian countries including Japan. Thus, intake of seaweeds might contribute to Japanese longevity via prevention of lifestyle-related diseases. Recently, two large Japanese cohort studies have reported the association of seaweed intake with reduced risk of cardiovascular diseases. On the other hand, seaweeds also contain iodine and heavy metals such as arsenic species, which are considered to have adverse effects on health. We here reviewed studies of the association between seaweed intake and mortality from or incidence of cancer and cardiovascular diseases, and their risk factors such as blood pressure or serum lipids. We also summarized the adverse effects of iodine and arsenic species in seaweeds. Although seaweeds have not been widely consumed in Western countries, dietary diversification and an increased proportion of immigrants from East Asia may increase seaweed consumption in those countries. Further epidemiological studies including observational and interventional studies are necessary to clarify the effects of seaweeds on disease and health.

Destructuring and restructuring of foods during gastric digestion

All foods harbor unique length scale-dependent structural features that can influence the release, transport, and utilization of macro- or micronutrients in the human gastrointestinal tract. In this regard, food destructuring and restructuring processes during gastric passage significantly influence downstream nutrient assimilation and feelings of satiety. This review begins with a synopsis of the effects of oral processing on food structure. Then, stomach-centric factors that contribute to the efficacy of gastric digestion are discussed, and exemplified by comparing the intragastric de- and restructuring of a number of common foods. The mechanisms of how intragastric structuring influences gastric emptying and its relationship to human satiety are then discussed. Finally, recently developed, non-destructive instrumental approaches used to quantitively and qualitatively characterize food behavior during gastric destructuring and restructuring are described.

Frequency of Seaweed Intake and Its Association with Cardiovascular Disease Mortality: The JACC Study

AIM

Seaweed is a popular traditional foodstuff in Asian countries. To our knowledge, few studies have examined the association of seaweed intake with mortality from cardiovascular disease. We examined the association of frequency of seaweed intake with total and specific cardiovascular disease mortality.

METHODS

We examined the association of seaweed intake with mortality from cardiovascular disease among 40,234 men and 55,981 women who participated in the Japan Collaborative Cohort Study for Evaluation of Cancer Risk. Sex-specific hazard ratios for mortality from cardiovascular disease (stroke, stroke subtypes, and coronary heart disease) according to the frequency of seaweed intake were calculated stratified by study area and adjusted for potential cardiovascular risk factors and dietary factors.

RESULTS

During the 1,580,996 person-year follow-up, 6,525 cardiovascular deaths occurred, of which 2,820 were due to stroke, and 1,378, to coronary heart disease. Among men, the multivariable analysis showed that participants who ate seaweed almost every day compared with those who never ate seaweed had hazard ratios (95% confidence interval; P for trend) of 0.79 (0.62-1.01; 0.72) for total cardiovascular disease, 0.70 (0.49-0.99; 0.47) for total stroke, 0.69 (0.41-1.16; 0.11) for cerebral infarction. Among women, the multivariable-adjusted hazard ratios were 0.72 (0.55-0.95; 0.001) for total cardiovascular disease, 0.70 (0.46-1.06; 0.01) for total stroke, and 0.49 (0.27-0.90; 0.22) for cerebral infarction. No associations were observed between seaweed intake and risk of intraparenchymal hemorrhage and coronary heart disease among either men or women.

CONCLUSIONS

We found an inverse association between seaweed intake and cardiovascular mortality among Japanese men and women, especially that from cerebral infarction.

Advances in Research on the Bioactivity of Alginate Oligosaccharides

Alginate is a natural polysaccharide present in various marine brown seaweeds. Alginate oligosaccharide (AOS) is a degradation product of alginate, which has received increasing attention due to its low molecular weight and promising biological activity. The wide-ranging biological activity of AOS is closely related to the diversity of their structures. AOS with a specific structure and distinct applications can be obtained by different methods of alginate degradation. This review focuses on recent advances in the biological activity of alginate and its derivatives, including their anti-tumor, anti-oxidative, immunoregulatory, anti-inflammatory, neuroprotective, antibacterial, hypolipidemic, antihypertensive, and hypoglycemic properties, as well as the ability to suppress obesity and promote cell proliferation and regulate plant growth. We hope that this review will provide theoretical basis and inspiration for the high-value research developments and utilization of AOS-related products.

Seaweed intake and risk of cardiovascular disease: the Japan Public Health Center-based Prospective (JPHC) Study

BACKGROUND

The minerals, vitamins, soluble dietary fibers, and flavonoids of seaweed are protective for preventing cardiovascular diseases. However, the association between seaweed intake and risk of cardiovascular disease has not been established.

OBJECTIVES

We examined the dietary intake of seaweed and its impact upon stroke and ischemic heart disease risk among a Japanese study population.

METHODS

We surveyed 40,707 men and 45,406 women from 2 large cohorts (age range: 40-69 y). Seaweed intake was determined by FFQ at baseline (1990-1994). Incidences of stroke and ischemic heart disease were ascertained until the end of 2009 (Cohort I) or 2012 (Cohort II). Sex-specific cardiovascular disease HRs (95% CIs) were estimated using Cox proportional hazard models after stratification by area and adjustment for cardiovascular disease risk and dietary factors.

RESULTS

During 1,493,232 person-years of follow-up, 4777 strokes (2863 ischemic stroke, 1361 intraparenchymal hemorrhages, and 531 subarachnoid hemorrhages) and 1204 ischemic heart disease cases were identified. Among men, significant multivariable HRs (95% CIs) for almost daily consumption compared with almost no consumption of seaweed were seen in ischemic heart disease [0.76 (0.58, 0.99); P-trend = 0.04] and total cardiovascular diseases [0.88 (0.78, 1.00); P-trend = 0.08]. Among women, such inverse associations were 0.56 (0.36, 0.85; P-trend = 0.006) for ischemic heart disease and 0.89 (0.76, 1.05; P-trend = 0.10) for total cardiovascular diseases. No significant associations were observed between seaweed intake and risk of total stroke or stroke types among either men or women.

CONCLUSIONS

Seaweed intake was inversely associated with risk of ischemic heart disease.

Is vitamin D-fortified yogurt a value-added strategy for improving human health? A systematic review and meta-analysis of randomized trials

Yogurt is a good source of probiotics, calcium, and proteins, but its content of vitamin D is low. Therefore, yogurt could be a good choice for vitamin D fortification to improve the positive health outcomes associated with its consumption. The primary aim of this systematic review and meta-analysis was to investigate the effect of vitamin D-fortified yogurt compared with plain yogurt on levels of serum 25-hydroxy vitamin D (25OHD). The secondary aim was to evaluate the effect of fortified yogurt on parathyroid hormone, anthropometric parameters, blood pressure, glucose metabolism, and lipid profile. We searched PubMed, Scopus, and Google Scholar for eligible studies; that is, randomized controlled trials (RCT) that compared vitamin D-fortified yogurt with control treatment without any additional supplement. Random-effects models were used to estimate pooled effect sizes and 95% confidence intervals. Findings from 9 RCT (n = 665 participants) that lasted from 8 to 16 wk are summarized in this review. The meta-analyzed mean differences for random effects showed that vitamin D-fortified yogurt (from 400 to 2,000 IU) increased serum 25OHD by 31.00 nmol/L. In addition, vitamin D-fortified yogurt decreased parathyroid hormone by 15.47 ng/L, body weight by 0.92 kg, waist circumference by 2.01 cm, HOMA-IR by 2.18 mass units, fasting serum glucose by 22.54 mg/dL, total cholesterol by 13.38 mg/dL, and triglycerides by 30.12 mg/dL compared with the controlled treatments. No publication bias was identified. Considerable between-study heterogeneity was observed for most outcomes. Vitamin D-fortified yogurt may be beneficial in improving serum 25OHD, lipid profile, glucose metabolism, and anthropometric parameters and decreasing parathyroid hormone level in pregnant women and adult and elderly subjects with or without diabetes, prediabetes, or metabolic syndrome.

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 ± 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.

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Alginate can be incorporated into a highly acceptable loaf at 4%.

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Sustained (two weeks) consumption of alginate bread did not affect GI wellbeing.

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Consumption of alginate bread decreases circulating triglyceride after the meal.

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Consumption of alginate bread increases lipid leaving the ileum after the meal.

The specific use of alginate from Laminaria japonica by Bacteroides species determined its modulation of the Bacteroides community

Accumulating studies showed that the beneficial actions of polysaccharides were closely associated with an improvement of the gut microbiota, but mechanisms that link polysaccharides and gut microbiota alterations are ill defined. Alginate from Laminaria japonica (LJP-A) can avoid being digested by the upper digestive tract and reach the colon where it can improve the gut microbiota community. LJP-A increased the relative abundance of some Bacteroidaceae members, e.g. Bacteroides species. The distribution of Bacteroides species in the gut is specific to the individual, and the specific use of LJP-A by Bacteroides species can determine LJP-A-induced alterations of the intestinal Bacteroides community, in which carbon source-based syntrophic interactions occur in Bacteroides species of the human gut microbial ecosystem. Compared to other species, Bacteroides finegoldii responded more positively to LJP-A intervention, and its properties may have a close connection with the bioactivities of LJP-A. This study provides a rationale for personalized treatment with dietary polysaccharides that were optimally fermented within a particular individual.

Risks and benefits of consuming edible seaweeds

Recent interest in seaweeds as a source of macronutrients, micronutrients, and bioactive components has highlighted prospective applications within the functional food and nutraceutical industries, with impetus toward the alleviation of risk factors associated with noncommunicable diseases such as obesity, type 2 diabetes, and cardiovascular disease. This narrative review summarizes the nutritional composition of edible seaweeds; evaluates the evidence regarding the health benefits of whole seaweeds, extracted bioactive components, and seaweed-based food products in humans; and assesses the potential adverse effects of edible seaweeds, including those related to ingestion of excess iodine and arsenic. If the potential functional food and nutraceutical applications of seaweeds are to be realized, more evidence from human intervention studies is needed to evaluate the nutritional benefits of seaweeds and the efficacy of their purported bioactive components. Mechanistic evidence, in particular, is imperative to substantiate health claims.

Recommendations for characterization and reporting of dietary fibers in nutrition research

Dietary fiber (DF) comprises a wide range of naturally occurring and modified materials with substantial variations in physical and chemical properties and potential physiologic effects. Although nutrition studies testing the effects of DF usually provide extensive detail on the physiologic responses, many still fail to adequately report the type and properties of the DF itself. This weakens the ability to directly replicate and compare studies and to establish structure-function relations. We outline the factors that affect DF functionality and provide 4 overarching recommendations for the characterization and reporting of DF preparations and DF-containing foods in nutrition research. These relate to 1) undertaking characterization methods that reflect the study hypothesis; 2) adequate reporting of DF source, quantity, and composition; 3) measurement of DF rheological properties; and 4) estimation of the DF fermentation rate and extent. Importantly, the food matrix of the test products should also be considered, because this can influence DF functionality and hence the apparent DF efficacy for health-relevant outcomes. Finally, we point out differences in DF functionality to be considered in acute and longer-term trials, the need to design the control treatment according to the research question, and the importance of reporting the amount and type of DF in the background diet.

Effects of isolated soluble fiber supplementation on body weight, glycemia, and insulinemia in adults with overweight and obesity: a systematic review and meta-analysis of randomized controlled trials

Background: There is strong epidemiologic evidence that dietary fiber intake is protective against overweight and obesity; however, results of intervention studies have been mixed. Soluble fiber beneficially affects metabolism, and fiber supplementation may be a feasible approach to improve body composition and glycemia in adults with overweight and obesity.Objective: We evaluated randomized controlled trials (RCTs) of isolated soluble fiber supplementation in overweight and obese adults on outcomes related to weight management [body mass index (BMI; in kg/m²), body weight, percentage of body fat, and waist circumference] and glucose and insulin metabolism (homeostasis model assessment of insulin resistance and fasting insulin) through a systematic review and meta-analysis.Design: We searched PubMed, Web of Science, Cumulative Index to Nursing and Allied Health Literature and Cochrane Library databases. Eligible studies were RCTs that compared isolated soluble fiber with placebo treatments without energy-restriction protocols. Random-effects models were used to estimate pooled effect sizes and 95% CIs. Meta-regressions were performed to assess outcomes in relation to the intervention duration, fiber dose, and fiber type. Publication bias was assessed via Begg's and Egger's tests and funnel plot inspection.Results: Findings from 12 RCTs (n = 609 participants) from 2 to 17 wk of duration are summarized in this review. Soluble fiber supplementation reduced BMI by 0.84 (95% CI: -1.35, -0.32; P = 0.001), body weight by 2.52 kg (95% CI: -4.25, -0.79 kg; P = 0.004), body fat by 0.41% (95% CI: -0.58%, -0.24%; P < 0.001), fasting glucose by 0.17 mmol/L (95% CI: -0.28, -0.06 mmol/L; P = 0.002), and fasting insulin by 15.88 pmol/L (95% CI: -29.05, -2.71 pmol/L; P = 0.02) compared with the effects of placebo treatments. No publication bias was identified. Considerable between-study heterogeneity was observed for most outcomes.Conclusions: Isolated soluble fiber supplementation improves anthropometric and metabolic outcomes in overweight and obese adults, thereby indicating that supplementation may improve fiber intake and health in these individuals. However, the interpretation of these findings warrants caution because of the considerable between-study heterogeneity. This trial was registered at clinicaltrials.gov as NCT03003897.

An Alginate/Cyclodextrin Spray Drying Matrix to Improve Shelf Life and Antioxidant Efficiency of a Blood Orange By-Product Extract Rich in Polyphenols: MMPs Inhibition and Antiglycation Activity in Dysmetabolic Diseases

Alginate and β-cyclodextrin were used to produce easily dosable and spray-dried microsystems of a dried blood orange extract with antidysmetabolic properties, obtained from a by-product fluid extract. The spray-dried applied conditions were able to obtain a concentrate dried extract without the loss of AOA and with TPC and TMA values of 35–40% higher than that of the starting material. They were also effective in producing microparticles with 80–100% of encapsulation efficiency. The 2% sodium alginate was capable of improving the extract shelf life, while the beta-cyclodextrin (1 : 1 molar ratio with dried extract) prolonged the extract antioxidant efficiency by 6 hours. The good inhibition effect of the dried extract on the AGE formation and the MMP-2 and MMP-9 activity is presumably due to a synergic effect exerted by both anthocyanin and bioflavonoid extract compounds and was improved by the use of alginate and cyclodextrin.

The role of alginates in regulation of food intake and glycemia: a gastroenterological perspective

Regulation of food intake through modulation of gastrointestinal responses to ingested foods is an ever-growing component of the therapeutic approaches targeting the obesity epidemic. Alginates, viscous and gel-forming soluble fibers isolated from the cell wall of brown seaweeds and some bacteria, are recently receiving considerable attention because of their potential role in satiation, satiety, and food intake regulation in the short term. Enhancement of gastric distension, delay of gastric emptying, and attenuation of postprandial glucose responses may constitute the basis of their physiological benefits. Offering physical, chemical, sensorial, and physiological advantages over other viscous and gel-forming fibers, alginates constitute promising functional food ingredients for the food industry. Therefore, the current review explores the role of alginates in food intake and glycemic regulation, their underlying modes of action and their potential in food applications.

Functional food microstructures for macronutrient release and delivery

There is a need to understand the role of fat, protein and carbohydrate in human health, and also how foods containing and/or structured using these macronutrients can be designed so that they can have a positive impact on health. This may include a reduction in fat, salt or sugar, the protection and targeted release of micronutrients or active ingredients from/to particular parts of the digestive system, improvement of gastrointestinal health or satiety enhancing properties. Such foods can be designed with various macro- and microstructures that will impact on macronutrient release and delivery. These include simple and double emulsions, the use of Pickering particles and shells, nanoparticles, liposomes, gelled networks, fluid gels and gel particles, foams, self-assembled structures, and encapsulated systems. In order to design foods that deliver these benefits understanding of how these structures behave in the gastrointestinal tract is also required, which should involve utilising both in vitro and in vivo studies. This review aims to draw together research in these areas, by focusing on the current state of the art, but also exciting possibilities for future research and food development.

Sodium alginate decreases the permeability of intestinal mucus

In the small intestine the nature of the environment leads to a highly heterogeneous mucus layer primarily composed of the MUC2 mucin. We set out to investigate whether the soluble dietary fibre sodium alginate could alter the permeability of the mucus layer. The alginate was shown to freely diffuse into the mucus and to have minimal effect on the bulk rheology when added at concentrations below 0.1%. Despite this lack of interaction between the mucin and alginate, the addition of alginate had a marked effect on the diffusion of 500 nm probe particles, which decreased as a function of increasing alginate concentration. Finally, we passed a protein stabilised emulsion through a simulation of oral, gastric and small intestinal digestion. We subsequently showed that the addition of 0.1% alginate to porcine intestinal mucus decreased the diffusion of fluorescently labelled lipid present in the emulsion digesta. This reduction may be sufficient to reduce problems associated with high rates of lipid absorption such as hyperlipidaemia.

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There are no specific interactions between alginate and intestinal mucus.

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Mucus rheology was hardly altered by small additions of alginate.

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Alginate freely diffused into mucus and reduced diffusion of 500 nm beads.

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Intestinal mucus permeability was decreased by a factor of two.

Potential Bioactive Compounds from Seaweed for Diabetes Management

Diabetes mellitus is a group of metabolic disorders of the endocrine system characterised by hyperglycaemia. Type II diabetes mellitus (T2DM) constitutes the majority of diabetes cases around the world and are due to unhealthy diet, sedentary lifestyle, as well as rise of obesity in the population, which warrants the search for new preventive and treatment strategies. Improved comprehension of T2DM pathophysiology provided various new agents and approaches against T2DM including via nutritional and lifestyle interventions. Seaweeds are rich in dietary fibres, unsaturated fatty acids, and polyphenolic compounds. Many of these seaweed compositions have been reported to be beneficial to human health including in managing diabetes. In this review, we discussed the diversity of seaweed composition and bioactive compounds which are potentially useful in preventing or managing T2DM by targeting various pharmacologically relevant routes including inhibition of enzymes such as α-glucosidase, α-amylase, lipase, aldose reductase, protein tyrosine phosphatase 1B (PTP1B) and dipeptidyl-peptidase-4 (DPP-4). Other mechanisms of action identified, such as anti-inflammatory, induction of hepatic antioxidant enzymes’ activities, stimulation of glucose transport and incretin hormones release, as well as β-cell cytoprotection, were also discussed by taking into consideration numerous in vitro, in vivo, and human studies involving seaweed and seaweed-derived agents.

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.

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Alginate in bread is undigested and recoverable in an in-vitro model gut.

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Alginate molecular size appears unaffected by cooking, digestion and extraction.

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Alginate retains its inhibition properties despite being heated at 37, 50, 100 and 150 °C.

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Alginate extracted from the model gut retains its inhibition properties.

Use of viscous fibres in beverages for appetite control: a review of studies

Dietary fibres, particularly viscous fibres appear to be more effective for appetite control (reduce subjective appetite, energy intake and/or body weight). Three types of viscous fibres, pectin, alginate and cereal beta-glucan, were identified as potential satiety-enhancing ingredients. The aim of this review was to collect evidence from human intervention studies evaluating pectins, alginates and beta-glucans in beverages, liquid preloads and liquid test meals for their satiety effects. Our focused, narrative review of several satiety studies shows an overall consistent result on the effectiveness of pectin, alginate and beta-glucan for appetite control. Beverages or liquid test meals are probably the better delivery mode for these fibres, as their effect on satiety is affected by their physico-chemical properties. Most, if not all, of these reviewed studies gave little or no consideration to the potential effects of common food processing (e.g. pasteurisation, ultra-high temperature process) on the physico-chemical properties of these fibre-containing beverages. This is one of the research gaps we have identified warranting further work, which is likely to be of significance from the industry and consumer perspective.

Effects of oatmeal and corn flakes cereal breakfasts on satiety, gastric emptying, glucose, and appetite-related hormones

OBJECTIVE

The extent to which different types of breakfasts affect appetite and food intake is unclear. To assess the satiety effects of a high-fiber cereal, we compared oatmeal, isocaloric corn flakes, and water.

SUBJECTS/METHODS

Thirty-six subjects (18 lean, 18 overweight) were assigned to three conditions in a randomized sequence on different days. Ratings of hunger and fullness were obtained concurrently with blood samples for measuring concentrations of glucose, insulin, glucagon, leptin, and acetaminophen (gastric emptying tracer). Appetite was assessed by calculating the area under the curve (AUC) for fullness and hunger, and by measuring food intake of an ad libitum lunch meal at 180 min.

RESULTS

Lunch meal intake was lowest after consuming oatmeal (p < 0.00001), which was lower for overweight subjects than lean subjects (p = 0.007). Fullness AUC was greatest (p = 0.00001), and hunger AUC lowest (p < 0.001) after consuming oatmeal. At 180 min, blood glucose was lowest after the corn flakes (p = 0.0001). Insulin AUC was greater for both cereals than water (p < 0.00001). Leptin AUC and glucagon AUC values did not differ between conditions. Acetaminophen concentrations peaked latest after consuming oatmeal (p = 0.046), reflecting slower gastric emptying.

CONCLUSIONS

Satiety was greater and ad libitum test meal intake lower after consuming oatmeal than after corn flakes, especially in the overweight subjects.

The role of seaweed bioactives in the control of digestion: implications for obesity treatments

Seaweeds are an underutilised nutritional resource that could not only compliment the current western diet but potentially bring additional health benefits over and above their nutritional value.

Designing food structures for nutrition and health benefits

In addition to providing specific sensory properties (e.g., flavor or textures), there is a need to produce foods that also provide functionality within the gastrointestinal (GI) tract, over and above simple nutrition. As such, there is a need to understand the physical and chemical processes occurring in the mouth, stomach, small intestine, and large intestine, in addition to the food structure-physiology interactions. In vivo techniques and in vitro models have allowed us to study and simulate these processes, which aids us in the design of food microstructures that can provide functionality within the human body. Furthermore, it is important to be aware of the health or nutritional needs of different groups of consumers when designing food structures, to provide targeted functionality. Examples of three groups of consumers (elderly, obese, and athletes) are given to demonstrate their differing nutritional requirements and the formulation engineering approaches that can be utilized to improve the health of these individuals. Eating is a pleasurable process, but foods of the future will be required to provide much more in terms of functionality for health and nutrition.

Pharmaceutical, cosmeceutical, and traditional applications of marine carbohydrates

Marine carbohydrates are most important organic molecules made by photosynthetic organisms. It is very essential for humankind: the role in being an energy source for the organism and they are considered as an important dissolve organic compound (DOC) in marine environment's sediments. Carbohydrates found in different marine environments in different concentrations. Polysaccharides of carbohydrates play an important role in various fields such as pharmaceutical, food production, cosmeceutical, and so on. Marine organisms are good resources of nutrients, and they are rich carbohydrate in sulfated polysaccharide. Seaweeds (marine microalgae) are used in different pharmaceutical industries, especially in pharmaceutical compound production. Seaweeds have a significant amount of sulfated polysaccharides, which are used in cosmeceutical industry, besides based on the biological applications. Since then, traditional people, cosmetics products, and pharmaceutical applications consider many types of seaweed as an important organism used in food process. Sulfated polysaccharides containing seaweed have potential uses in the blood coagulation system, antiviral activity, antioxidant activity, anticancer activity, immunomodulating activity, antilipidepic activity, etc. Some species of marine organisms are rich in polysaccharides such as sulfated galactans. Various polysaccharides such as agar and alginates, which are extracted from marine organisms, have several applications in food production and cosmeceutical industries. Due to their high health benefits, compound-derived extracts of marine polysaccharides have various applications and traditional people were using them since long time ago. In the future, much attention is supposed to be paid to unraveling the structural, compositional, and sequential properties of marine carbohydrate as well.

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.