Evaluation of Iodine Bioavailability in Seaweed Using in Vitro Methods

Modulatory effects of red seaweeds (Palmaria palmata, Porphyra umbilicalis and Chondrus crispus) on the human gut microbiota via an in vitro model

This work investigated the nutritional and mineral composition of three red seaweed species, Palmaria palmata, Porphyra umbilicalis and Chondrus crispus, and an in vitro assay was performed to determinate the effects of the intake of whole red seaweed on gut microbiota, short chain fatty acids production and metabolic pathways. The results obtained showed that 100 g of seaweeds contained essential minerals such as 28-107 % daily needs of Ca, 183-600 % daily needs of Fe and 18-54 % daily needs of Zn, whereas low content were found for Cu and I. Seaweed digestion fermentation showed beneficial effects of gut microbiota, as increases in beneficial species such as Akkermansia muciniphila, and in some seaweed, Bifidobacterium adoslescentis, Bacteroides ovatus or Lactobacillus ruminis. Metabolic pathways did only found little significant differences with respect to inulin fermentation. In view of the results, red seaweed showed prebiotic effects on human gut microbiota.

In Vivo Bioavailability and In Vitro Bioaccessibility of Iodine in Edible Seaweeds: Method Development and Health Implications

Both iodine (I) deficiency and I excess can adversely affect human health. Seaweed consumption is one of the most important natural sources for I. This study assessed I relative bioavailability (RBA) in seaweed using an in vivo mouse model and compared it with I bioaccessibility measured by three in vitro methods (Physiologically Based Extraction Test (PBET), the Solubility Bioaccessibility Research Consortium (SBRC), and the Unified Bioaccessibility Research Group of Europe Method (UBM)). Total I concentrations in 26 seaweed samples from four species ranged from 52.4 to 1322 mg/kg of dry weight. The I RBA varied from 18.5% to 89.0%, significantly influenced by inorganic I percentage (r = 0.50, p < 0.01) and total dietary fiber contents (r = -0.28, p < 0.05) in seaweeds. The I bioaccessibility varied among species and methods and were affected by the pH of gastric solution, as well as the structural changes in seaweed during in vitro extraction. Correlation analysis demonstrated that PBET was the best predictor for I RBA (R2 = 0.64). These results developed an appropriate in vitro method for predicting I bioavailability in seaweeds, which is highly beneficial for the accurate assessment for I dietary intake.

Evaluation of the Bioavailability of Iodine and Arsenic in Raw and Cooked Saccharina japonica Based on Simulated Digestion/Caco-2 Cell Model

Kelp is a traditional healthy food due to its high nutritional content; however, its relatively high contents of iodine and arsenic have raised concerns about its edible safety. This study explored the effects of different cooking treatments on the contents of iodine and arsenic in kelp, evaluated the bioaccessibility and bioavailability of iodine and arsenic in kelp using in vitro digestion, and compared the differences in the transport characteristics of iodine in kelp and KIO3 using a Caco-2 monolayer cell transport model. The results show that the content of target elements that reached systemic circulation could be reduced by cooking and gastrointestinal digestion. The highest reductions in iodine and arsenic were 94.4% and 74.7%, respectively, which were achieved by boiling for 10 min. The bioaccessibility and bioavailability of iodine and arsenic were significantly improved by a cooking treatment. However, the contents of iodine and arsenic decreased significantly, with the bioaccessibility of iodine reducing from 3188.2 μg/L to 317.0 μg/L and that of arsenic reducing from 32.5 μg/L to 18.1 μg/L in the gastric phase after boiling. The findings also show that the efficiency of iodine transport in kelp and KIO3 was positively correlated with the transport time and negatively correlated with the concentration of iodine. With the increase in the iodine concentration, the rate of iodine transport in kelp decreased from 63.93% to 3.14%, but that of KIO3 was stable at around 35%, which indicates that the absorption efficiency of iodine from kelp was limited, even when too much kelp was ingested. In conclusion, the edible safety of kelp is significantly improved after cooking. The risk of excessive iodine and arsenic intake caused by consuming kelp is extremely low, and as an effective iodine supplement source, kelp has higher edible safety compared with KIO3. This study clarifies the safety of algae based on iodine and arsenic contents and also provides a basis for the formulation of food safety standards.

Iodine biofortification of Swiss chard (Beta vulgaris ssp. vulgaris var. cicla) and its wild ancestor sea beet (Beta vulgaris ssp. maritima) grown hydroponically as baby leaves: effects on leaf production and quality

BACKGROUND

About 35-45% of the global population is affected by iodine deficiency. Iodine intake can be increased through the consumption of biofortified vegetables. Given the increasing interest in wild edible species of new leafy vegetables due to their high nutritional content, this study aimed to evaluate the suitability of Swiss chard (Beta vulgaris ssp. vulgaris var. cicla) and its wild ancestor sea beet (Beta vulgaris ssp. maritima) to be fortified with iodine. Plants were cultivated hydroponically in a nutrient solution enriched with four different concentrations of iodine (0, 0.5, 1.0, and 1.5 mg L-1 ), and the production and quality of baby leaves were determined.

RESULTS

Sea beet accumulated more iodine than Swiss chard. In both subspecies, increasing the iodine concentration in the nutrient solution improved leaf quality as a result of greater antioxidant capacity - the ferric reducing ability of plasma (FRAP) index increased by 17% and 28%, at 0.5 and 1.5 mg L-1 iodine, respectively - the content of flavonoids (+31 and + 26%, at 1 and 1.5 mg L-1 of iodine, respectively), and the lower content of nitrate (-38% at 1.5 mg L-1 of iodine) and oxalate (-36% at 0.5 mg L-1 of iodine). In sea beet, however, iodine levels in the nutrient solution higher than 0.5 mg L-1 reduced crop yield significantly.

CONCLUSIONS

Both subspecies were found to be suitable for producing iodine-enriched baby leaves. The optimal iodine levels in the nutrient solution were 1.0 in Swiss chard and 0.5 mg L-1 in sea beet, as crop yield was not affected at these concentrations and leaves contained enough iodine to satisfy an adequate daily intake with a serving of 100 g. © 2023 Society of Chemical Industry.

Possible molecular exploration of herbal pair Haizao-Kunbu in the treatment of Graves' disease by network pharmacology, molecular docking, and molecular dynamic analysis

Objective

To promote the development and therapeutic application of new medications, it is crucial to conduct a thorough investigation into the mechanism by which the traditional Chinese herb pair of Haizao-Kunbu (HK) treats Graves' disease (GD).

Materials and methods

Chemical ingredients of HK, putative target genes, and GD-associated genes were retrieved from online public databases. Using Cytoscape 3.9.1, a compound-gene target network was established to explore the association between prosperous ingredients and targets. STRING, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes pathway analyses visualized core targets and disease pathways. Additionally, we conducted a refined analysis of the binding interactions between active ingredients and their respective targets. To visualize these findings, we employed precise molecular docking techniques. Furthermore, we carried out molecular dynamics simulations to gain insights into the formation of more tightly bound complexes.

Results

We found that there were nine key active ingredients in HK, which mainly acted on 21 targets. These targets primarily regulated several biological processes such as cell population proliferation, protein phosphorylation, and regulation of kinase activity, and acted on PI3K-AKT and MAPK pathways to treat GD. Analysis of the molecular interaction simulation under computer technology revealed that the key targets exhibited strong binding activity to active ingredients, and Fucosterol-AKT1 and Isofucosterol-AKT1 complexes were highly stable in humans.

Conclusion

This study demonstrates that HK exerts therapeutic effects on GD in a multi-component, multi-target, and multi-pathway manner by regulating cell proliferation, differentiation, inflammation, and immunomodulatory-related targets. This study provides a theoretical foundation for further investigation into GD.

Effect and mechanism of edible oil co-digestion on the bioaccessibility and bioavailability of ursolic acid

Ursolic acid (UA), a pentacyclic triterpenoid, has gained attentions due to its various health-promoting benefits, but exhibits poor bioavailability. This could be enhanced by changing the food matrix of UA in which it is present. In this study, several UA systems were constructed to investigate the bioaccessibility and bioavailability of UA in combination with in vitro simulated digestion and Caco-2 cell models. The results showed that the bioaccessibility of UA was significantly improved after adding rapeseed oil. Caco-2 cell models showed that the UA-oil blend was more advantageous than UA emulsion in total absorption. The results indicate that the location of UA distribution in oil determines the ease of UA release into the mixed micellar phase. This paper brings a new research idea and basis for the design of improving the bioavailability of hydrophobic compounds.

New Analytical Strategy for Bioaccessibility Evaluation of Bromine and Iodine from Edible Seaweeds

A strategy for determining the bioaccessibility of bromine and iodine from edible seaweeds was proposed for the first time using microwave-induced combustion (MIC) and ion chromatography coupled to mass spectrometry (IC-MS) after in vitro digestion. The concentrations of bromine and iodine in edible seaweeds using the proposed methods (MIC and IC-MS) were not statistically different from those using MIC and inductively coupled plasma mass spectrometry (p > 0.05). Trueness was assessed by recovery experiments (101-110%, relative standard deviation <10%). Following an in vitro digestion protocol, MIC was proposed as sample preparation for bioaccessible and residual fractions. Using this strategy, the mass balance totaled from 97 to 111%. No statistical difference (p > 0.05) was observed between the total concentration of bromine or iodine and their concentration in bioaccessible and residual fractions for three edible seaweed species, indicating full analyte quantification in the fractions.

Potential prebiotic effect of two Atlantic whole brown seaweeds, Saccharina japonica and Undaria pinnatifida, using in vitro simulation of distal colonic fermentation

Two brown seaweeds (Saccharina japonica and Undaria pinnatifida) were characterized in terms of their nutritional and mineral composition, as well as their potential to modify the human gut microbiota. Nutritional analysis of these seaweeds showed that they comply with the criteria set out in European legislation to be labeled "low fat," "low sugar," and "high fiber." Mineral content analysis showed that 100 g of seaweed provided more than 100% of the daily Ca requirements, as well as 33-42% of Fe, 10-17% of Cu, and 14-17% of Zn requirements. An in vitro human digest simulator system was used to analyze the effect of each seaweed on the human colonic microbiota. The gut microbiota was characterized by 16S rRNA amplicon sequencing and short-chain fatty-acid analysis. Seaweed digestion and fermentation showed beneficial effects, such as a decrease in the phylum Firmicutes and an increase in the phyla Bacteroidetes and Actinobacteria. At the species level, seaweed fermentation increased the proportion of beneficial bacteria such as Parabacteroides distasonis and Bifidobacterium. Regarding of metabolic pathways, no significant differences were found between the two seaweeds, but there were significant differences concerning to the baseline. An increase in short-chain fatty-acid content was observed for both seaweeds with respect to the negative control, especially for acetic acid. Given of the obtained results, S. japonica and U. pinnatifida intake are promising and could open new opportunities for research and application in the fields of nutrition and human health.

Variations in Breast Milk Iodine Concentration over 24 h among Lactating Women in Northern China

BACKGROUND

Adequate breast milk iodine concentration (BMIC) is essential for the growth and cognitive development of exclusively breastfed infants; however, data on variations in BMIC over 24 h are limited.

OBJECTIVE

We aimed to explore in lactating women the variation in 24-h BMIC.

METHODS

Thirty pairs of mothers and breastfed infants aged 0-6 mo were recruited from the cities of Tianjin and Luoyang, China. A 3-d 24-h dietary record, including salt intake, was performed to assess the dietary iodine intake of lactating women. Breast milk samples before and after each feeding for 24 h and 24-h urine samples were collected from the women for 3 d to estimate iodine excretion. A multivariate linear regression model was used to analyze the factors influencing BMIC. A total of 2658 breast milk samples and 90 24-h urine samples were collected.

RESULTS

The median BMIC and 24-h urine iodine concentration (UIC) of lactating women for a mean of 3.6 ± 1.48 mo were 158 μg/L and 137 μg/L, respectively. The interindividual variability of BMIC (35.1%) was higher than that observed within individuals (11.8%). The variation in BMIC showed a "V" shaped curve over 24 h. The median BMIC at 08:00-12:00 (137 μg/L) was significantly lower than that at 20:00-24:00 (163 μg/L) and 00:00-04:00 (164 μg/L). A progressively increasing curve was obtained for BMIC until it peaked at 20:00 and plateaued at a higher concentration from 20:00 to 04:00 than at 08:00-12:00 (all P < 0.05). BMIC was associated with dietary iodine intake (β: 0.366; 95% CI: 0.004, 0.018) and infant age (β: -0.432; 95% CI: -1.07, -0.322).

CONCLUSIONS

Our study shows that the BMIC presents a "V" shaped curve over 24 h. We recommend that breast milk samples be collected between 08:00 and 12:00 for evaluation of the iodine status of lactating women.

Nutritional composition, heavy metal content and in vitro effect on the human gut microbiota of Talitrus saltator, an underutilized crustacean from the Atlantic coast

In this study, an undervalued marine crustacean (Talitrus saltator) was characterized in terms of nutritional and heavy metal composition and its potential to affect human gut microbiota. Nutritional analysis of this crustacean revealed that it complies with the criteria established in European legislation to include nutritional claims in their labeling, such as "source of fiber," "low in fat," "low in sugars" and "high in protein." The analysis of the heavy metal content did not reveal any risk derived from the presence of Cd, Hg, or Pb, whereas essential metals contained in 100 g exceeded the minimum daily requirements recommended in Europe for Zn (19.78 mg/kg), Cu (2.28 mg/kg), and Fe (32.96 mg/kg). Using an in vitro system, the effect of T. saltator on the human colonic microbiota shows some beneficial effects, such as fermentation-maintained populations of Bifidobacterium or Lactobacillus, did not increase Firmicutes phylum counts, decreased the Firmicutes/Bacteroidetes ratio, and stimulated 11 metabolic pathways with respect to baseline. These results are unusual in a high protein content-food. However, negative effects were also found in gut microbiota relative proportions, such as an increase in the Proteobacteria phylum and especially some opportunistic bacteria from this phylum, probably due to the antimicrobial effect of chitin on other groups more sensitive to its effect. This work shows for the first time the effect of T. saltator on human colonic microbiota using and in vitro system. The presence of chitin in its composition could provide some beneficial effects by modulating the microbiota, but as T. saltator is a high-protein food, more studies should be carried out showing these benefits.

Evaluation of the potential prebiotic effect of Himanthalia elongata, an Atlantic brown seaweed, in an in vitro model of the human distal colon

Until now, although different studies have shown the potential prebiotic effect of seaweed carbohydrates, no studies with the whole seaweeds have been carried out. In addition, the prebiotic effect throughput sequencing remains poorly investigated since most of the published works used qPCR or FISH to estimate bacterial changes. In this work, an in vitro model of the human distal colon was used to determine, for the first time, the potential prebiotic effect of a brown whole seaweed Himanthalia elongata. The whole seaweed was characterized in basis of its nutritional and mineral composition and submitted to the entire gastrointestinal digestion. The prebiotic effect was evaluated by the microbial modulation through 16S rRNA amplicon sequencing, qPCR and short-chain fatty acid analysis. The obtained results indicated that the colonic fraction of H. elongata was used selectively by the Bacteroides genus, more specifically by the specie Bacteoides ovatus, whereas inulin was used mainly by the Parabacteroides genus, being Parabacteroides distasonis the most abundant identified specie. Selective use of inulin by P. distasonis is, therefore, reported by the first time. qPCR analysis shown no significative differences in Bifidobacterium population and a decrease in Lactobacillus along the fermentation assays with both substrates. Regarding to the short-fatty acid production, maximal concentration, 56.11 ± 20.48 mM, was achieved for H. elongata, at 24 h of fermentation whereas for inulin total acid production was 93.66 ± 21.82 mM at 48 h of assay. The metabolic pathways associated with bacterial genera were not significantly different between the two tested substrates. Although more studies are necessary to elucidate the prebiotic character of H. elongata, the results presented in this work are promissory and could open new opportunities of research and application in the area of Nutrition and Food Chemistry.

Maternal Iodine Intake and Neurodevelopment of Offspring: The Japan Environment and Children's Study

Inadequate maternal iodine intake affects thyroid function and may impair fetal brain development. This study investigated the association between maternal iodine intake during pregnancy and neurodevelopmental delay in offspring at 1 and 3 years of age using a nationwide birth cohort: the Japan Environment and Children’s Study. We assessed dietary iodine intake during pregnancy using a food frequency questionnaire and child neurodevelopment using the Japanese translation of the Ages and Stages Questionnaire, Third Edition. The risk of delay (score below the cut-off value) for fine motor domain at 1 year of age was increased in the lowest quintile iodine intake group compared with the fourth quintile iodine intake group. The risk of delay for problem-solving at 1 year of age was increased in the lowest and second quintile iodine intake group and decreased in the highest quintile iodine intake group. The risk of delay for communication, fine motor, problem-solving, and personal–social domains at 3 years of age was increased in the lowest and second quintile iodine intake group compared with the fourth quintile iodine intake group, while the risk of delay for fine motor and problem-solving domains was decreased in the highest quintile iodine intake group. Low iodine intake levels in pregnancy may affect child neurodevelopment.

Iodine from brown algae in human nutrition, with an emphasis on bioaccessibility, bioavailability, chemistry, and effects of processing: A systematic review

Brown algae are becoming increasingly popular as a food source and dietary supplement in Europe and other Western countries. As they are highly rich in iodine, they represent a potential new dietary iodine source. Iodine deficiency has been re-emerging in Europe, and it is important to ensure adequate intake through one's diet. However, macroalgae, and especially brown algae, may contain very high amounts of iodine, and both iodine deficiency and excessive iodine may increase the risk of negative health effects. The iodine content of algae or foods containing algae is currently not regulated in the European Union. The aim of this paper is to review the literature to determine the chemical species of iodine in brown algae, the loss of iodine during processing, and the bioavailability and bioaccessibility of iodine. A systematic search of the literature was performed in April 2021, via the databases Web of Science and PubMed. The review includes studies of iodine in brown macroalgae in relation to bioavailability, bioaccessibility, processing and speciation. A meta-analysis was conducted in relation to the following topics: (i) the correlation between total iodine and iodide (I- ) content in brown algae; (ii) the correlation between the loss of iodine during processing and the I- content; and (iii) the correlation between bioavailability and the I- content. The bioavailability of iodine from brown algae was generally high, with in vivo bioavailability ranging from 31% to 90%. The in vitro bioavailability of iodine (2%-28%) was systematically lower than in vivo bioavailability (31%-90%), indicating an inadequate in vitro methodology. Processing may reduce the iodine content of brown algae, and a higher I- content was positively correlated with increased iodine loss during processing. Although processing strategies may reduce the iodine content of brown algae significantly, the iodine content may still be high after processing. These findings may be used in food safety evaluations of brown algae as well as in the development of macroalgae-containing foods with iodine contents suitable for human consumption. Further research on processing techniques to reduce the iodine content in brown macroalgae are warranted.

Seaweed Components as Potential Modulators of the Gut Microbiota

Macroalgae, or seaweeds, are a rich source of components which may exert beneficial effects on the mammalian gut microbiota through the enhancement of bacterial diversity and abundance. An imbalance of gut bacteria has been linked to the development of disorders such as inflammatory bowel disease, immunodeficiency, hypertension, type-2-diabetes, obesity, and cancer. This review outlines current knowledge from in vitro and in vivo studies concerning the potential therapeutic application of seaweed-derived polysaccharides, polyphenols and peptides to modulate the gut microbiota through diet. Polysaccharides such as fucoidan, laminarin, alginate, ulvan and porphyran are unique to seaweeds. Several studies have shown their potential to act as prebiotics and to positively modulate the gut microbiota. Prebiotics enhance bacterial populations and often their production of short chain fatty acids, which are the energy source for gastrointestinal epithelial cells, provide protection against pathogens, influence immunomodulation, and induce apoptosis of colon cancer cells. The oral bioaccessibility and bioavailability of seaweed components is also discussed, including the advantages and limitations of static and dynamic in vitro gastrointestinal models versus ex vivo and in vivo methods. Seaweed bioactives show potential for use in prevention and, in some instances, treatment of human disease. However, it is also necessary to confirm these potential, therapeutic effects in large-scale clinical trials. Where possible, we have cited information concerning these trials.

Biopersistence rate of metallic nanoparticles in the gastro-intestinal human tract (stage 0 of the EFSA guidance for nanomaterials risk assessment)

The European Food Safety Authority has published a guidance regarding risk assessment of nanomaterials in food and feed. Following these recommendations, an in vitro gastrointestinal digestion has been applied to study the biopersistence of TiO₂ and Ag NPs in standards, molluscs and surimi. TiO₂ NPs standards and TiO₂ NPs/ TiO₂ microparticles from E171 were not found to be degraded. Ag NPs proved to be more degradable than TiO₂ NPs, but the biopersistence rates were higher than 12%, which means that Ag NPs are also biopersistent. Findings for seafood are quite similar to those obtained for TiO₂ NPs and Ag NPs standards, although the calculation of the biopersistence rate proposed by the EFSA was not found to be straightforward for foodstuff (the use of the NPs concentration in the sample instead of the NPs concentration at initial time (sample mixed with the gastric solution before enzymatic hydrolysis) has been proposed.

Study on the bioaccessibility and bioavailability of perchlorate in different food matrices in vitro

Perchlorate, a persistent pollutant, interferes with iodine uptake by the thyroid. Perchlorate exposure mainly occurs through ingested food; understanding the bioaccessibility and bioavailability of perchlorate in foods facilitate more accurate human health risk assessments. An in vitro digestion/Caco-2 cell model was used for this research. The bioaccessibility of perchlorate in the control group, lettuce, rice and formula was 93.45%, 70.14%, 70.25%, and 63.68%, respectively. The bioavailability of perchlorate was as follows: control group, 43.45%; rice, 37.17%; lettuce, 35.13%; and formula, 30.72%. The absorptive apparent permeability coefficient (Papp) of the control, lettuce, rice, and formula was 30-101 nm/s, 32-65 nm/s, 54-161 nm/s, and 41-88 nm/s, respectively. The results suggested that the risk from perchlorate was overestimated only when considering the content of perchlorate in foods and that the presence of food matrices reduced perchlorate bioavailability by differing degrees.

The Effects of Halogenated Compounds on the Anaerobic Digestion of Macroalgae

The urgent need to replace fossil fuels has seen macroalgae advancing as a potential feedstock for anaerobic digestion. The natural methane productivity (dry weight per hectare) of seaweeds is greater than in many terrestrial plant systems. As part of their defence systems, seaweeds, unlike terrestrial plants, produce a range of halogenated secondary metabolites, especially chlorinated and brominated compounds. Some orders of brown seaweeds also accumulate iodine, up to 1.2% of their dry weight. Fluorine remains rather unusual within the chemical structure. Halogenated hydrocarbons have moderate to high toxicities. In addition, halogenated organic compounds constitute a large group of environmental chemicals due to their extensive use in industry and agriculture. In recent years, concerns over the environmental fate and release of these halogenated organic compounds have resulted in research into their biodegradation and the evidence emerging shows that many of these compounds are more easily degraded under strictly anaerobic conditions compared to aerobic biodegradation. Biosorption via seaweed has become an alternative to the existing technologies in removing these pollutants. Halogenated compounds are known inhibitors of methane production from ruminants and humanmade anaerobic digesters. The focus of this paper is reviewing the available information on the effects of halogenated organic compounds on anaerobic digestion.

Growth performance, bioavailability of toxic and essential elements and nutrients, and biofortification of iodine of rainbow trout (Onchorynchus mykiss) fed blends with sugar kelp (Saccharina latissima)

Aquaculture production is demanding novel feed ingredients that reflect natural marine nutrient levels, that are also essential to humans. In this regard, biofortification through addition of iodine-rich sugar kelp in feed formulations was assessed in a 12 week rainbow trout trial. Yttrium inclusion in feed allowed determinations of apparent absorption coefficients of essential and potentially toxic elements and apparent digestibility coefficient of nutrients. E.g. apparent absorption coefficients in trouts fortified feed with 1-4% dw kelp were 67-61% As, 32-40% Cd, <5% Fe; 80-83% I; 66-58% Se. Iodine concentrations in feed up to 239 mg/kg (~4% kelp) was proportional to iodine accumulation in trout fillets (R2 = 1.00) with 0.5% transfer ratio. Feed iodine concentrations up to 117 mg/kg (~2% kelp) did not affect growth performance negatively, but increased significantly protein efficiency ratio after eight weeks feeding. However, 4% kelp meal inclusion affected final growth and hepato somatic index, and caused histomorphological changes in the intestine. All fillets had low toxic element concentrations (As, Cd, Hg, Pb). The potential applicability of Saccharina latissima as feed ingredient to tailor iodine concentration in farmed fish is evident. Consuming of a 160 g fillet (2% kelp) contributes ~60% of recommended daily iodine intake for adults.

Intra-individual and inter-individual variations in iodine intake and excretion in adult women: implications for sampling

Iodine intake and excretion vary widely; however, these variations remain a large source of geometric uncertainty. The present study aims to analyse variations in iodine intake and excretion and provide implications for sampling in studies of individuals or populations. Twenty-four healthy women volunteers were recruited for a 12-d sampling period during the 4-week experiment. The duplicate-portion technique was used to measure iodine intake, while 24-h urine was collected to estimate iodine excretion. The mean intra-individual variations in iodine intake, 24-h UIE (24-h urinary iodine excretion) and 24-h UIC (24-h urinary iodine concentration) were 63, 48 and 55 %, respectively, while the inter-individual variations for these parameters were 14, 24 and 32 %, respectively. For 95 % confidence, approximately 500 diet samples or 24-h urine samples should be taken from an individual to estimate their iodine intake or iodine status at a precision range of ±5%. Obtaining a precision range of ±5% in a population would require twenty-five diet samples or 150 24-h urine samples. The intra-individual variations in iodine intake and excretion were higher than the inter-individual variations, which indicates the need for more samples in a study on individual participants.

Health benefits and bioavailability of marine resources components that contribute to health - what's new?

The strict connection between nutritional intake and health leads to a necessity of understanding the beneficial and protective role of healthy nutrients and foods. The marine environment is a source of a plethora of many organisms with unique properties, extremely rich in bioactive compounds and with remarkable potential for medical, industrial and biotechnological applications. Marine organisms are an extreme valuable source of functional ingredients such as polysaccharides, vitamins, minerals, pigments, enzymes, proteins and peptides, polyunsaturated fatty acids (PUFA), phenolic compounds and other secondary metabolites that prevent or have the potential to treat several diseases given their cardiovascular protective, anti-inflammatory, anti-hypertensive, anti-oxidant, anti-coagulant, anti-proliferative and anti-diabetic activities. This review provides an overview on the current advances regarding health benefits of marine bioactive compounds on several diseases and on human gut microbiota. In addition, it is discussed a crucial factor that is related to the effectiveness of these compounds on human organism namely its real bioavailability.

Arsenic in edible macroalgae: an integrated approach

Arsenic is a metalloid naturally present in marine environments. Various toxic elements including arsenic (As) are bioaccumulated by macroalgae. This metalloid is subsequently incorporated as arsenate into the organism due to similarity to phosphate. In recent decades, the use of macroalgae in food has increased as a result of their numerous benefits; however, As consumption may exert potential consequences for human health. The objective of this review was to discuss the articles published up to 2019 on As in seaweed, including key topics such as speciation, toxicity of the most common species in marine macroalgae, and their effects on human health. Further, this review will emphasize the extraction methods and analysis techniques most frequently used in seaweed and the need to develop certified reference materials (CRMs) in order to support the validation of analytical methodologies for As speciation in macroalgae. Finally, this review will discuss current legislation in relation to the risk associated with consumption. The number of articles found and the different approaches, biological, analytical and toxicological, show the growing interest there has been in this field in the last few years. In addition, this review reveals aspects of As chemistry that need further study, such as transformation of organic metalloid species during digestion and cooking, which necessitates analytical improvement and toxicological experiments. Taken together our findings may contribute to revision of current legislation on As content in edible seaweed relating to human health in a growing market.

Brown Macroalgae as Valuable Food Ingredients

Due to the balanced nutritional value and abundance of bioactive compounds, seaweeds represent great candidates to be used as health-promoting ingredients by the food industry. In this field, Phaeophyta, i.e., brown macroalgae, have been receiving great attention particularly due to their abundance in complex polysaccharides, phlorotannins, fucoxanthin and iodine. In the past decade, brown algae and their extracts have been extensively studied, aiming at the development of well-accepted products with the simultaneous enhancement of nutritional value and/or shelf-life. However, the reports aiming at their bioactivity in in vivo models are still scarce and need additional exploration. Therefore, this manuscript revises the relevant literature data regarding the development of Phaeophyta-enriched food products, namely those focused on species considered as safe for human consumption in Europe. Hopefully, this will create awareness to the need of further studies in order to determine how those benefits can translate to human beings.

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.

Minerals from Macroalgae Origin: Health Benefits and Risks for Consumers

Seaweeds are well-known for their exceptional capacity to accumulate essential minerals and trace elements needed for human nutrition, although their levels are commonly very variable depending on their morphological features, environmental conditions, and geographic location. Despite this variability, accumulation of Mg, and especially Fe, seems to be prevalent in Chlorophyta, while Rhodophyta and Phaeophyta accumulate higher concentrations of Mn and I, respectively. Both red and brown seaweeds also tend to accumulate higher concentrations of Na, K, and Zn than green seaweeds. Their valuable mineral content grants them great potential for application in the food industry as new ingredients for the development of numerous functional food products. Indeed, many studies have already shown that seaweeds can be used as NaCl replacers in common foods while increasing their content in elements that are oftentimes deficient in European population. In turn, high concentrations of some elements, such as I, need to be carefully addressed when evaluating seaweed consumption, since excessive intake of this element was proven to have negative impacts on health. In this regard, studies point out that although very bioaccessible, I bioavailability seems to be low, contrarily to other elements, such as Na, K, and Fe. Another weakness of seaweed consumption is their capacity to accumulate several toxic metals, which can pose some health risks. Therefore, considering the current great expansion of seaweed consumption by the Western population, specific regulations on this subject should be laid down. This review presents an overview of the mineral content of prevalent edible European macroalgae, highlighting the main factors interfering in their accumulation. Furthermore, the impact of using these marine vegetables as functional ingredients or NaCl replacers in foods will be discussed. Finally, the relationship between macroalgae’s toxic metals content and the lack of European legislation to regulate them will be addressed.

Assessing bioaccessibility of Se and I in dual biofortified radish seedlings using simulated in vitro digestion

Selenium (Se) and iodine (I) are essential elements for humans, and biofortification of vegetables with these elements is an effective way to amend their deficiencies in the diet. In this study, the distribution and transformation of Se and I species were investigated in radish seedlings that were simultaneously supplemented with these two elements; the fate and the bioaccessibility of Se and I species were dynamically surveyed in the oral, gastric and intestinal phases using a simulated in vitro digestion method. The radish seedlings were cultivated in hydroponic conditions with Se (IV), Se (VI), I^- and IO₃^- (each 1 mg L^-1). The results revealed that Se-methylselenocysteine (MeSeCys), selenocystine (SeCys₂), selenomethionine (SeMet) and Se (VI) were present in radish, and MeSeCys was the dominant species in both gastric and intestinal extracts, comprising 32.7 ± 1.5% and 39.6 ± 1.1% of the total content, respectively. I^- was also the dominant species, which accounted for 57.1 ± 2.1%, 46.6 ± 1.5% and 68.8 ± 1.8% of the total digested content respectively in the oral, gastric and intestinal extracts. Meanwhile, IO₃^- was absent and organic I accounted for approximately 20%. The bioaccessibility of Se and I in the intestinal phase reached 95.5 ± 2.5% and 85.8 ± 0.9%, respectively; although after dialysis through membranes, the data reduced to 60.1 ± 2.8% and 39.6 ± 0.8%, respectively. Contents of MeSeCys and I^- increased from the oral to intestinal phase and the bioaccessibility of both Se and I in radish was above 85%. So radish is suitable as a potential dietary source of Se and I with biofortification.

Iodine content in bulk biomass of wild-harvested and cultivated edible seaweeds: Inherent variations determine species-specific daily allowable consumption

This study represents a large-scale investigation into iodine contents in three commercially important and edible seaweed species from the North Atlantic: the brown algae Saccharina latissima and Alaria esculenta, and the red alga Palmaria palmata. Variability among and within species were explored in terms of temporal and spatial variations in addition to biomass source. Mean iodine concentration in bulk seaweed biomass was species-specific: Saccharina > Alaria > Palmaria. Iodine contents of Saccharina biomass were similar between years and seasons, but varied significantly between sampling locations and biomass sources. In Alaria and Palmaria, none of the independent variables examined contributed significantly to the small variations observed. Our data suggest that all three species are rich sources of iodine, and only 32, 283, or 2149 mg dry weight of unprocessed dry biomass of Saccharina, Alaria, or Palmaria, respectively, meets the recommended daily intake levels for most healthy humans.