Welcome!

Welcome to "TSN: The Seaweed Nation" -- a blog on notable therapeutic uses of seaweed, in particular brown or red seaweed.  For your convenience, the five posts listed below (in order of occurrence: history, active components, current uses, adverse effects and sources) are also listed in the tabs above.

From East to West: Seaweed Through History

From East to West: A Brief History of Seaweed

Seaweed usage dates back to 4th and 6th century BC Japan and China, respectively for Laminaria species (Madhusudan, Manjo, Rahul & Rishi, 2010; Wang, Zhang, Zhang, & Li, 2008).  Its oldest medicinal reference is rooted in Traditional Chinese Medicine, TCM (Hetzel, 1989).  However, seaweed origins and use varies according to species and location.

Ancient Chinese medicine.

(Source: chinapedia.chinaassistor.com)

In the history of East Asia, seaweed usage was predominantly nutritional but medicinal uses were also notable.  Wakame (Unnidaria pinnifida) and kombu (Laminaria japonica) remain as Asian nutritional staples (e.g. Iodine content, high fibre).  The Chinese text Materia Medica, outlines the ancient use for treating goiter, phlegm accumulation, and “cleansing heat,” a key principle to restoring balance in TCM (Hsu et al, 1988). 

English carrack (1511).

(Source: hnsa.org)

Seaweed usage in the Western world occurred later, with earliest documentation dating back to Greek and Roman empires, where seaweed mucilage was used to treat rashes and burns (Karleskint, Turner & Small, 2010).  Atlantic wakame (Alaria esculenta) is more commonly found around Ireland/The British Isles (Guiry, 2010).  European uses began at sea, including scurvy treatment and parasite elimination (Karleskint, Turner & Small, 2010).  

Example of a TCM decoction.

(Source: chinese-healing.com)

Administration of seaweed is dependent on species and ailment.  For nutritional purposes (e.g. iodine supplementation) seaweed was ingested raw or cooked, fresh or dried (McHugh, 2003).  Medicinal uses ranged from physical application of seaweed, to herbal extractions/concoctions, e.g. Haizao Yuhu Tang (Sargassum Decoction for the Jade Flask), a concoction including multiple seaweeds utilized for severe goiter treatment (Bensky & Barolet, 1990). 

Phenols, fucoxanthin, and fucoidan--oh my!: Active Components & Preparation

Seaweed's Active Components

Various studies have stated different active components, dependent on the ailment.  Brown seaweeds in particular have a medley of active components.  The most extensively studied thus far include: phlorotannins (phenols), fucoxanthin, and fucoidan.  

Ascophyllum nodosum has the highest phenol content, including pholorotannins/oligomers of “phloroglucinol”/1,3,5-trihydroxybenzene (Audibert et al, 2010).   They are proposed to be antioxidants used in cosmetics and nutraceuticals (Apstolidis & Lee, 2010; Yangthong, Hutadilok-Towatana & Phromkunthong, 2009).  

Phloroglucinol chemical structure.  (Source: Wikipedia.org)

Fucoxanthin, the xanthophyll which gives brown seaweed its colour, has also been extensively studied, especially with regards to obesity treatments (Jeon et al, 2010).

Fucoxanthin.  (Source: Wikipedia.org)

A popular component in current seaweed/drug research is fucoidan (aka: fucan, fucosan), which is a polysaccharide containing L-fucose and sulfate ester groups.  Its structure and its subsequent biological activity vary according to species of brown seaweed (Li, Lu, Wei & Zhao, 2008).  Fucoidan has been implicated in antioxidant, anticoagulant, antithrombitic, antiviral, immune system modulation, and lipid reduction activities (Pomin & Mourao, 2008; Wang et al, 2010; Li et al, 2006; Li et al, 2001).

Fucoidan.  (Source: glycomix.co.uk)

Typical Preparation of Seaweed

(Source: herbsgardenshealth.com)

Typical preparation of herbal treatments (extracts or otherwise) vary per species.  For adults, bladderwrack (Fucus vesiculosus) may be soft capsules containing alcohol extracts (dose: 200-600mg/day).  Tablets are also used, while some preparations require “crude plant mixtures.” (NaturalStandard, 2009; NIH/NLM, 2010). 

Current Uses: What Science Says

Seaweeds and Their Current Therapeutic Value

Precedents categorize seaweed for goiter therapies.  However, newer notable therapies include, but are not limited to: obesity, antioxidants, antiviral and anti-cancer properties (Smith, 2004).  Currently, research has been studying the physiological effects of key compounds in seaweed, such as fucoidan or fucoxanthin.  

Battle to the Death: Fucoidan vs Cancer

With regards to cancer, multiple current studies have underlined brown seaweed in cancer prevention/treatment (Smith, 2004; Li, Lu, Wei & Zhao, 2008).  In an in vitro cancer study, Kim et al (2010) aimed to determine the effectiveness of fucoidan (from Fucus vesiculosus) on human colon cancer cells, HT-29 and HCT116.  The goal was to provide evidence for a natural, low side-effect, prophylactic drug for the fatal colorectal cancer, in which apoptosis is inhibited.  The authors employed an MTT assay and flow cytometry methods to determine cell viability post-fucoidan treatment, a common method used in pre-clinical assessments of lead anti-cancer compounds.  The study noted reduced cancer cell viability and increased apoptosis (i.e. Increased PARP cleavage, reduced survivin protein, increased release of cytochrome c), post-fucoidan (5-20ug/mL).   

Diagram of colorectal cancer, stages 0 to IV.

(Source: amitbhawani.com)

Results provided enlightenment on fucoidan’s effector mechanisms (i.e. Caspase activation and death-receptor mediation).  The study provided control results, error values, significance values (P<0.05) and a standardized amount of fucoidan, making its usage seem feasible.  However, the authors suggest eating seaweed alone will provide similar amounts of fucoidan.  It is important to note that seaweeds vary, even amongst species, as do substituent ratios (Zimmerman & Delange, 2004).  Additionally, in vitro   studies detract from physiological complexity, thus in vivo models are required. Though further studies are required, fucoidan appears to be a promising anti-cancer contender.

The Fat Battle: Seaweed vs Obesity

Although obesity is not a traditional ailment, its downstream effects are grave.  Studies have attributed seaweed’s weight-management to physical properties of alginate (Paxman, Richardson, Dettmar & Corfe, 2008).  However, recent studies focus on more chemical aspects of seaweed.  Abidov et al (2010) studied xanthigen, a weight-loss product containing pomegranate seed oil (PSO) and fucoxanthin, on obese non-diabetic, premenopausal women.  Obesity has been linked with non-alcoholic fatty liver disease (NAFLD), which may develop into metabolic syndrome.  Overall, NAFLD-women and obese/non-NAFLD women showed significant decreases in body/liver fat as well as waist circumference, in comparison to placebos, with Xanthigen-600/2.4mg supplementation (P<0.05).  Fucoxanthin alone showed increased resting energy expenditure (REE) at 8.0mg/day, an important aspect in weight-loss mechanisms (P<0.05), while PSO alone had no effect.

The effects of excess fat on liver function and disease.

(Source: livercondition.org)

NAFLD increases risk of both diabetes and metabolic syndrome.  Oftentimes, metabolic syndrome is associated with increased waist circumference [woman on left].

(Source: daily-diabetic.com)

Although study rigor was exemplified via a randomized, placebo-controlled, double-blind study on separate components, its small sample size and short time-frame of 16 weeks undermines fucoxanthin’s role in weight loss.  Additionally, the unrealistic dietary restrictions and rigorous check-up makes it difficult to see realistic, successful applications.  Despite sample size, the significant clinical results coupled with positive in vivo results in prior studies makes it difficult to ignore the effects of brown seaweed on obesity (Jeon et al, 2010).

The previous studies only highlight current and progressive research in popular areas (i.e. Cancer and weight-loss), but many other seaweed/disease studies exist.  Other exciting studies display breast cancer prevention, antiviral action vs herpes, and diabetes management (Yang et al, 2010).  However promising results may seem, seaweed studies require greater stringency and homogeneity in species used to gather a more unified consensus on its effects (Zimmerman & Delange, 2004; Smith, 2004).

The ugly, the bad, and the risky: adverse effects, drug interactions and risks

The ugly, the bad and the risky: adverse effects, drug interactions and risks

Although seaweed and its constituents have a promising drug R&D period ahead of them, there are noted adverse/side-effects.  Studies have associated seaweed with the following adverse effects: iodine poisoning (NaturalStandard, 2009); hypothyroidism (Miyai, Tokushige & Kondo, 2008; Crawford et al, 2010); thyrotoxicosis (Bocanegra et al, 2009); organic dust toxic syndrome for external seaweed uses (Holm, Johannesson, Toren & Dahlman-Hoglund, 2009); and high platelet aggregation via high concentrations of fucoidan (de Azevedo et al, 2009).  Of course, it is equally fair to note that side-effects may be due to excessive dosage.

Noted and potential drug (Rx) interactions include: Fucoidan and heparin/anti-coagulants (Zhu et al, 2010); antithyroid drugs such as methenamine mandelate or methimazole; anticoagulant/anti-platelet drugs such as aspirin, warfarin or heparin (NLM/NIH, 2010).  Herbal medication interactions include anti-clotting supplements, such as clove, feverfew and Panax ginseng (NLM/NIH, 2010).

There are cautions to usage of seaweed supplements, pills, and/or extracts.  Dosage and recommended intake varies by species and manufacturing. Pregnant women are cautioned not to take seaweed as an iodine supplement due to lacking purity criteria (Zimmerman & Delange, 2004).  Other cautions include: trace chemicals/heavy metals, e.g. arsenic (Zimmerman & Delange, 2004); infertility; increased thyroid cancer risk (NLM/NIH, 2010); and risk of metabolic syndrome (Shin et al, 2009).

Sources/Links

To minimize clutter, all the sources found in the text (alongside links of interest) can be found on the "Sources" page.