Toxicological effects of marine seaweeds: a cautious insight for human consumption

Algae as a potential source of protein meat alternatives

With the rise of plant-based meat alternatives, there is a growing need for sustainable and nutritious sources of protein. Alga is a rich protein source, and initial studies show that it can be a good component in developing protein meat alternatives. However, there are certain limitations in their use as the need for efficient and optimal technical process in large-scale protein extraction and purification, as well as overcoming certain negative effects such as potentially harmful compounds, allergenicity issues, or sensorial affections, especially in color but also in textural and flavor characteristics. This review offers a vision of the fledgling research about using alga protein in the development of meat alternatives or supplementing meat products.

Arctic Edible Brown Alga Fucus distichus L.: Biochemical Composition, Antiradical Potential and Human Health Risk

Fucus distichus L. is the dominant canopy-forming macroalga in the rocky intertidal areas of the Arctic and Subarctic. In the present study, the impact of the geographic location of F. distichus collected in the Baffin Sea (BfS), Norwegian Sea (NS), White Sea (WS), and Barents Sea (BS) on the variations in biochemical composition, antiradical properties, and health risk was evaluated. The accumulation of main carbohydrates (fucoidan, mannitol, and alginic acid) varied from 335 mg/g dry weight (DW) in NS to 445 mg/g DW in BS. The highest level of the sum of polyphenols and flavonoids was found in samples of F. distichus from WS and was located in the following ranking order: BS < BfS < NS < WS. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of seaweed is correlated with its phenolic content. It is notable that in most Arctic F. distichus samples, Cd, Cr, Pb, and Ni were not detected or their concentrations were below the limit of quantification. According to calculated targeted hazard quotient and hazard index values, all studied samples of Arctic F. distichus are safe for daily consumption as they do not pose a carcinogenic risk to the health of adults or children. The results of this study support the rationale for using Arctic F. distichus as a rich source of polysaccharides, polyphenols, and flavonoids with important antiradical activity. We believe that our data will help to effectively use the potential of F. distichus and expand the use of this algae as a promising and safe raw material for the food and pharmaceutical industries.

Comparative study of the chemical composition and antifungal activity of commercial brown seaweed extracts

INTRODUCTION

A sustainable agriculture and the great increase in consumers of organic products in the last years make the use of natural products one of the main challenges of modern agriculture. This is the reason that the use of products based on seaweed extracts has increased exponentially, specifically brown seaweeds, including Ascophyllum nodosum and Ecklonia maxima.

METHODS

In this study, the chemical composition of 20 commercial seaweed extract products used as biostimulants and their antifungal activity against two common postharvest pathogens (Botrytis cinerea and Penicillium digitatum) from fruits were evaluated. Data were processed using chemometric techniques based on linear and non-linear models.

RESULTS AND DISCUSSION

The results showed that the algae species and the percentage of seaweed had a significant effect on the final composition of the products. In addition, great disparity was observed between formulations with similar labeling and antifungal effect of most of the analyzed products against some of the tested pathogens. These findings indicate the need for further research.

Current Status and Future Trends in Removal, Control, and Mitigation of Algae Food Safety Risks for Human Consumption

With the rapid development of the economy and productivity, an increasing number of citizens are not only concerned about the nutritional value of algae as a potential new food resource but are also, in particular, paying more attention to the safety of its consumption. Many studies and reports pointed out that analyzing and solving seaweed food safety issues requires holistic and systematic consideration. The three main factors that have been found to affect the food safety of algal are physical, chemical, and microbiological hazards. At the same time, although food safety awareness among food producers and consumers has increased, foodborne diseases caused by algal food safety incidents occur frequently. It threatens the health and lives of consumers and may cause irreversible harm if treatment is not done promptly. A series of studies have also proved the idea that microbial contamination of algae is the main cause of this problem. Therefore, the rapid and efficient detection of toxic and pathogenic microbial contamination in algal products is an urgent issue that needs to be addressed. At the same time, two other factors, such as physical and chemical hazards, cannot be ignored. Nowadays, the detection techniques are mainly focused on three major hazards in traditional methods. However, especially for food microorganisms, the use of traditional microbiological control techniques is time-consuming and has limitations in terms of accuracy. In recent years, these two evaluations of microbial foodborne pathogens monitoring in the farm-to-table chain have shown more importance, especially during the COVID-19 pandemic. Meanwhile, there are also many new developments in the monitoring of heavy metals, algal toxins, and other pollutants. In the future, algal food safety risk assessment will not only focus on convenient, rapid, low-cost and high-accuracy detection but also be connected with some novel technologies, such as the Internet of Things (artificial intelligence, machine learning), biosensor, and molecular biology, to reach the purpose of simultaneous detection.

Chemical contaminant levels in edible seaweeds of the Salish Sea and implications for their consumption

Despite growing interest in edible seaweeds, there is limited information on seaweed chemical contaminant levels in the Salish Sea. Without this knowledge, health-based consumption advisories can not be determined for consumers that include Tribes and First Nations, Asian and Pacific Islander community members, and recreational harvesters. We measured contaminant concentrations in edible seaweeds (Fucus distichus, F. spiralis, and Nereocystis luetkeana) from 43 locations in the Salish Sea. Metals were analyzed in all samples, and 94 persistent organic pollutants (POPs) (i.e. 40 PCBs, 15 PBDEs, 17 PCDD/Fs, and 22 organochlorine pesticides) and 51 PAHs were analyzed in Fucus spp. We compared concentrations of contaminants to human health-based screening levels calculated from the USEPA and to international limits. We then worked with six focal contaminants that either exceeded screening levels or international limits (Cd, total Hg, Pb, benzo[a]pyrene [BaP], and PCBs) or are of regional interest (total As). USEPA cancer-based screening levels were exceeded in 30 samples for the PCBs and two samples for BaP. Cadmium concentrations did not exceed the USEPA noncancer-based screening level but did exceed international limits at all sites. Lead exceeded international limits at three sites. Because there are no screening levels for total Hg and total As, and to be conservative, we made comparisons to methyl Hg and inorganic As screening levels. All samples were below the methyl Hg and above the inorganic As screening levels. Without knowledge of the As speciation, we cannot assess the health risk associated with the As. While seaweed was the focus, we did not consider contaminant exposure from consuming other foods. Other chemicals, such as contaminants of emerging concern (e.g., PFAS, pharmaceuticals and personal care products), should also be considered. Additionally, although we focused on toxicological aspects, there are cultural and health benefits of seaweed use that may affect consumer choice.

Antidiabetic potential of seaweed and their bioactive compounds: a review of developments in last decade

Diabetes Mellitus is a public health problem worldwide due to high morbidity and mortality rate associated with it. Diabetes can be managed by synthetic hypoglycemic drugs, although their persistent uses have several side effects. Hence, there is a paradigm shift toward the use of natural products having antidiabetic potential. Seaweeds, large marine benthic algae, are an affluent source of various bioactive compounds, including phytochemicals and antioxidants thus exhibiting various health promoting properties. Seaweed extracts and its bioactive compounds have antidiabetic potential as they inhibit carbohydrate hydrolyzing enzymes in vitro and exhibit blood glucose lowering effect in random and post prandial blood glucose tests in vivo. In addition, they have been associated with reduced weight gain in animals probably by decreasing mRNA expression of pro-inflammatory cytokines with concomitant increase in mRNA expression levels of anti-inflammatory cytokines. Their beneficial effect has been seen in serum and hepatic lipid profile and antioxidant enzymes indicating the protective role of seaweeds against free radicals mediated oxidative stress induced hyperglycemia and associated hyperlipidemia. However, the detailed and in-depth studies of seaweeds as whole, their bioactive isolates and their extracts need to be explored further for their health benefits and wide application in food, nutraceutical and pharmaceutical industries.

Chondracanthus teedei var. lusitanicus: The Nutraceutical Potential of an Unexploited Marine Resource

Presently, there is a high demand for nutritionally enhanced foods, so it is a current challenge to look at new raw food sources that can supplement beneficially the human diet. The nutritional profile and key secondary metabolites of red seaweeds (Rhodophyta) are gaining interest because of this challenge. In this context, the possible use of the red seaweed Chondracanthus teedei var. lusitanicus (Gigartinales) as a novel nutraceutical source was investigated. As a result, we highlight the high mineral content of this seaweed, representing 29.35 g 100 g⁻¹ of its dry weight (DW). Despite the low levels of calcium and phosphorus (0.26 and 0.20 g 100 g⁻¹ DW, respectively), this seaweed is an interesting source of nitrogen and potassium (2.13 and 2.29 g⁻¹ DW, accordingly). Furthermore, the high content of carbohydrates (56.03 g 100 g⁻¹ DW), which acts as dietary fibers, confers a low caloric content of this raw food source. Thus, this study demonstrates that C. teedei var. lusitanicus is in fact an unexploited potential resource with the capability to provide key minerals to the human diet with promising nutraceutical properties.

Trace and major elements in food supplements of different origin: Implications for daily intake levels and health risks

As the use of food supplements increases, voices are being raised questioning the safety of these products. As a contribution to understanding the trace and major elemental composition of food supplements and their potential health risks, this study presents concentrations of 71 elements in 138 supplements, categorised into synthetic products and three groups of products with natural ingredients. Concentrations were converted into average daily doses (ADDs) and compared to tolerable daily intakes (TDIs). For elements where we found significant ADDs relative to the TDI a comparison was also made to the normal dietary intake. Our main findings are that: 1) Most elements display highly variable concentrations in food supplements; more so than in normal foodstuff; 2) For ten of the analysed elements some products rendered ADDs > 50 % of the TDI. Half of the elements were essential (Fe, Mn, Se, Mo, Zn), and as such motivated in food supplements. The other half (As, Pb, Cd, Al, Ni) represent non-essential and highly toxic elements, where the occurrence in food supplements ought to be viewed as contamination. Although none of these toxic metals were declared on any product's table of content, several products gave high ADDs - in several cases even exceeding the TDIs; 3) The risk of reaching high ADDs for the toxic elements is strongly associated with products that contain marine ingredients (e.g. algae, mussels etc), and to some degree products of terrestrial plant-based origin. The health of consumers would benefit if food regulatory frameworks were updated to better address the risks of food supplements occasionally being contaminated with different toxic metals, for example by setting maximum permissible concentrations for a longer list of elements.

On the Health Benefits vs. Risks of Seaweeds and Their Constituents: The Curious Case of the Polymer Paradigm

To exploit the nutraceutical and biomedical potential of selected seaweed-derived polymers in an economically viable way, it is necessary to analyze and understand their quality and yield fluctuations throughout the seasons. In this study, the seasonal polysaccharide yield and respective quality were evaluated in three selected seaweeds, namely the agarophyte Gracilaria gracilis, the carrageenophyte Calliblepharis jubata (both red seaweeds) and the alginophyte Sargassum muticum (brown seaweed). It was found that the agar synthesis of G. gracilis did not significantly differ with the seasons (27.04% seaweed dry weight (DW)). In contrast, the carrageenan content in C. jubata varied seasonally, being synthesized in higher concentrations during the summer (18.73% DW). Meanwhile, the alginate synthesis of S. muticum exhibited a higher concentration (36.88% DW) during the winter. Therefore, there is a need to assess the threshold at which seaweed-derived polymers may have positive effects or negative impacts on human nutrition. Furthermore, this study highlights the three polymers, along with their known thresholds, at which they can have positive and/or negative health impacts. Such knowledge is key to recognizing the paradigm governing their successful deployment and related beneficial applications in humans.

Heavy metals and potential risks in edible seaweed on the market in Italy

The seaweed food has always been important in Asia, but recently increased in the Western diet. Superfood known for health benefits and rich in essential elements, can also accumulate high contents of heavy metals and iodine from the environment, becoming a health hazard. In particular for iodine, an appropriate labelling of seaweed is needed to warn the consumer of the potential risks. The aim of the study was to analyze the content of 20 heavy metals in seaweeds, distributed in Italy, by ICP-MS, also determining iodine and arsenic (total and inorganic fraction). A total of 72 samples of European and Asian seaweed of 8 genera were analyzed and the results correlated the content of heavy metals to genus, geographical origin and type of sample; 8.33% of the products lacked in the label of the indications of allergens, while 9.72% had irregularities in the label language. The highest concentration of elements was found in the Rhodophyta. The Aluminum level was the highest in the mixed seaweed (165.39 mg/kg) and for the Cadmium in the Asian seaweed (1.16 mg/kg). The amounts of Iron, Zinc and Magnesium, was highest in the Asian seaweed. The values of Arsenic (total and inorganic contents) were compared with the limits: 2.78% exceeds France and USA limits for inorganic, while higher content of total was found in Phaeophyta, which also showed the highest Iodine content (6770.80 mg/kg) that can be dangerous if not reported correctly in the label.

Invasive Seaweeds in the Iberian Peninsula: A Contribution for Food Supply

The introduction of exotic organisms in marine ecosystems can lead to economic and ecological losses. Globally, seaweeds represent a significant part of these non-indigenous species (NIS), with 407 introduced algal species. Furthermore, the presence of NIS seaweeds has been reported as a major concern worldwide since the patterns of their potential invasion mechanisms and vectors are not yet fully understood. Currently, in the Iberian Peninsula, around 50 NIS seaweeds have been recorded. Some of these are also considered invasive due to their overgrowth characteristic and competition with other species. However, invasive seaweeds are suitable for industrial applications due to their high feedstock. Hence, seaweeds' historical use in daily food diet, allied to research findings, showed that macroalgae are a source of nutrients and bioactive compounds with nutraceutical properties. The main goal of this review is to evaluate the records of NIS seaweeds in the Iberian Peninsula and critically analyze the potential of invasive seaweeds application in the food industry.

Quantitative PCR assay for the simultaneous identification and enumeration of multiple Karenia species

Quantitative PCR (qPCR) is the method of choice for specific detection and quantification of harmful algal bloom (HAB) species. Development of qPCR assay for simultaneous enumeration of species that frequently co-exist in HABs is required. A high sensitivity TaqMan qPCR assay, using probe and primers, located at ITS1-5.8S-ITS2 rDNA region, detecting, specifically, Karenia selliformis, K. bidigitata, and K. mikimotoi, was designed. ITS1-5.8S-ITS2 rDNA region copy numbers per Karenia cell genome were estimated to 217.697 ± 67.904, allowing cell quantification. An application of the designed methodology in field samples has been conducted, and it showed high sensitivity (detection of around 10^-1 cell/100 mg of bivalve mollusk tissue, equivalent to about 20 copies of the target sequence). We suggest that the optimized method could contribute to early detection of three closely related Karenia species in seafood cultivating areas to promote control quality, guarantee a fast and effective intervention, and improve public health prevention.

Seaweed's Bioactive Candidate Compounds to Food Industry and Global Food Security

The world population is continuously growing, so it is important to keep producing food in a sustainable way, especially in a way that is nutritious and in a sufficient quantity to overcome global needs. Seaweed grows, and can be cultivated, in seawater and generally does not compete for arable land and freshwater. Thus, the coastal areas of the planet are the most suitable for seaweed production, which can be an alternative to traditional agriculture and can thus contribute to a reduced carbon footprint. There are evolving studies that characterize seaweed's nutritional value and policies that recognize them as food, and identify the potential benefits and negative factors that may be produced or accumulated by seaweed, which are, or can be, dangerous for human health. Seaweeds have a high nutritional value along with a low caloric input and with the presence of fibers, proteins, omega 3 and 6 unsaturated fatty acids, vitamins, and minerals. Moreover, several seaweed sub-products have interesting features to the food industry. Therefore, the focus of this review is in the performance of seaweed as a potential alternative and as a safe food source. Here described is the nutritional value and concerns relating to seaweed consumption, and also how seaweed-derived compounds are already commercially explored and available in the food industry and the usage restrictions to safeguard them as safe food additives for human consumption.