Bladderwrack

Bladderwrack can be used to support thyroid function when underactivity of this endocrine gland is caused by an underlying iodine deficiency as a result of insufficient dietary intake (3, 4). Since the widespread introduction of iodised salt, this cause of low-thyroid activity is seen far less commonly than previously when hypothyroidism and goitre were most frequently observed to occur in inland areas with no easily available dietary sources of iodine such as sea-salt, salt water fish or seaweeds (5).

The current main cause of low-thyroid function is auto-immune conditions such as Hashimoto’s disease, which has been seen to be made worse in some individuals as a result of increased iodine intake (5,6,7). For this reason, it is recommended that anyone experiencing symptoms that may be associated with low thyroid function; such as extreme fatigue, unexplained weight gain, brain fog, increased sensitivity to cold, constipation, low mood and dryness of the skin or hair, consults their medical provider for testing to identify the cause of this and seeks the guidance of an experienced herbal practitioner with regard to whether bladderwrack would be indicated as beneficial specific to the diagnosis and cause of their condition.

Bladderwrack may be used for conditions of the digestive system such as indigestion, acid reflux, GORD and gastritis where its soothing, cooling actions make it an effective remedy due to the presence of the polysaccharide alginic acid, a compound used in many over-the-counter remedies for treating indigestion, such as Gaviscon (3,8,9). It may also be used to relieve the symptoms of rheumatic conditions and arthritis both when taken internally or used as an external compress directly applied to painful or swollen joints (3,10).

Bladderwrack is considered to be a herb of protection, particularly for those whose work takes them out to sea, such as sailors. It has also been seen as symbolic of financial abundance resulting in the custom of keeping a little dried bladderwrack in a purse or hung over the door of a dwelling place (11,12).

Energetically the cool, salty qualities of bladderwrack are particularly indicated where there is depletion, a sense of sluggishness or damp stagnation. It can be a valued ally for those who feel weighed down or out of rhythm with life.

Astrologically bladderwrack is associated with both the moon and Saturn connecting it to nourishment and the tides of life alongside structure, boundaries and restoration.

There is evidence of bladderwrack having been used medicinally as early as the first century CE when it was included in a medical text from that time, De Materia Medica, written by the Greek physician Dioscorides who recommended it for inflammation and “gouty afflictions” (11).

In European herbalism, its use in the treatment of thyroid conditions has been documented as far back as the 17th century which followed the observation that cases of goitre were rarely seen among populations living along coastlines who regularly consumed seafoods including seaweed (1).

The Eclectic physicians of the US in the 19th century also acknowledged the value of bladderwrack in treating conditions of the thyroid and considered it to be a specific for  “….both exophthalmic and uncomplicated goitre….” as well as a remedy to support weight loss (12).

It is described in King’s American Dispensatory, a medical and botanical textbook published in 1898, in which its use for directly promoting weight loss is disputed and any subsequent reduction in weight being deduced to be a result of dietary changes recommended to the patient. It is instead hypothesised to influence the processes of elimination and the glandular system through its alterative action, to tone muscle fibres and reduce fatty degeneration of the heart, properties which were further examined in the later work of 1922 by Harvey Felter, The Eclectic Materia Medica, Pharmacology and Therapeutics (13,14,15).

Endocrine

In times past, low thyroid function and goitre were most commonly caused by a lack of iodine and generally seen in inland areas with no available dietary sources, such as sea-salt, salt water fish or seaweeds (5). Due to its rich mineral content, including iodine, bladderwrack has been seen to be of benefit in the treatment of hypothyroid conditions or goitre caused by iodine deficiency (3,6,10,16). In modern practice, underactive thyroid function is more frequently seen to be a result of autoimmune conditions, such as Hashimoto’s disease or other endocrine disorders (of which some cases have been seen to be exacerbated by excess iodine) (7,13,17). Furthermore, high doses of iodine may reduce the synthesis of hormones by the thyroid gland consequently reducing thyroid function further and resulting in a worsening of symptoms. Consequently, it is recommended to be taken under the guidance of an experienced practitioner in endocrine conditions who may include it if appropriate along with other herbs shown to be of benefit in low thyroid function such as ashwagandha (Withania somnifera), guggul (Commiphora mukul) and black seed (Nigella sativa) (18,19,20).

In addition to the iodine content, the flavonoid constituents of bladderwrack, particularly fucoxanthin, have been seen to be of benefit in the treatment of other endocrine conditions, including type 2 diabetes and metabolic system through modulation the inflammatory responses and supporting metabolism (8,20).

Digestive

The role of bladderwrack in promoting weight loss has been generally considered to be associated with its effects on thyroid gland function and clinical evidence of its benefits in the treatment of obesity is varied (6,10). However, more recent research may indicate a more complex mechanisms of action such as improved insulin receptor response, increased breakdown of fats in white adipose tissue and a decreased expression of genes associated with a tendency towards obesity and accumulation of fat through their effects on appetite regulation, metabolism and body fat storage (7,19,21). Through its action on the digestive system including the inhibition of bile acid absorption, it is also seen to have benefits such as lowering cholesterol and triglycerides contributing towards overall improved health outcomes (3)

Bladderwrack is also a rich source of alginic acid that, along with being a mild appetite suppressant, supports the gut microbiota and has a cooling soothing action on the gastrointestinal tract which, along with other herbs known to have mucous membrane protective or restorative properties such as marshmallow (Althaea officinalis) and liquorice (Glycyrrhiza glabra), may be useful in the treatment of acid reflux, GORD, gastritis and peptic ulcers (3,8,9).  

Musculoskeletal

Bladderwrack has traditionally been prescribed for rheumatic conditions including rheumatoid arthritis and may be used both as an internal preparation and applied externally to inflamed joints (4,10,13). Its alterative, nutritive, antioxidant and anti-inflammatory actions have been shown to be of benefit in the treatment of arthritis as well as other inflammatory conditions (3,8,10).

Immune

The antimicrobial, anti-inflammatory, antioxidant, antiangiogenic and antitumour properties of bladderwrack all contribute to its role in supporting immune function. Its antiviral action has been seen to be effective in practice against Herpes simplex virus and shows promising results against HIV in in-vitro testing (3,13). There is also evidence to suggest it may inhibit the growth of some cancer cell lines and it may be used as part of a preventative treatment protocol for individuals at high risk, or in remission from, lymphoma and breast cancer (3,4,8).

Supplementation of elderly Japanese men and women with fucoidan from seaweed increases immune responses to seasonal influenza vaccination

This randomised, double blind placebo-controlled trial from 2013 examined the potential benefits of fucoidan, a polysaccharide constituent found in bladderwrack, in increasing the effectiveness of flu vaccination in the elderly population, a group previously acknowledged to exhibit an inadequate immunological response. Following vaccination with the current seasonal influenza vaccine, the group receiving a fucoidan supplement were seen to have significantly higher levels of antibodies against all three strains of influenza virus contained in the vaccine given when compared with the placebo-control group.

A substantial increase in natural killer cells at around nine weeks was evidenced in the fucoidan supplemented group; in contrast to the control group, within whom no significant increase was seen in natural killer cells around this time. These results offer evidence to suggest that in immunocompromised elderly patients supplementation with fucoidan may increase vaccination induced antibody production, increasing the effectiveness of vaccines in this population (22).

Fucoidan prevents high‐fat diet‐induced obesity in animals by suppression of fat accumulation

The benefits of bladderwrack with regard to promoting weight loss are frequently attributed to its effect on thyroid function. In contrast, this 2014 study examines a possible additional mechanism of action responsible for its effects on obesity in an animal model when this is caused by a high fat diet, focusing on fucoidan, one of the main chemical constituents contained within bladderwrack. After a five week trial it was found that the group who had received supplements of fucoidan had gained significantly less weight and decreased their food efficiency ratios and epididymal and liver fat mass when compared to those in the control group fed an identical high fat diet.

Additionally, those supplemented with fucoidan were shown to have reduced total cholesterol, low-density lipoproteins and triglyceride levels. There was also evidence to suggest that fucoidan significantly decreased the expression of genes associated with a tendency towards obesity and accumulation of fat through their effects on appetite regulation, metabolism and body fat storage, which increase an individual’s risk of hyperlipidaemia, insulin resistance and metabolic syndrome (21).

The effect of Fucus vesiculosus, an edible brown seaweed, upon menstrual cycle length and hormonal status in three pre-menopausal women

This case report from 2004 examined whether the variation between the highest rates of oestrogen-dependant cancers reported in Western countries in contrast to the lower incidence rate seen in the East could be attributed to a higher consumption of seaweeds, in addition to greater dietary intake of soy products, included in the traditional diets of these regions such as seen in Japanese populations. This was investigated by administering a daily bladderwrack supplement to a sample group of three women, all of whom were pre-menopausal with a menstrual cycle length considered to be outside of normal parameters along with histories of other menstrual disorders.

In all three subjects included in the study a significant increase in the length of the menstrual cycle was observed of between 5.5 to 14 days within five to seven cycles accompanied by a reduction in heaviness of blood loss and length of menstruation itself. Furthermore, hormone testing of one subject suggested that bladderwrack may possess antioestrogenic and progestogenic actions as results indicated a significant dose-dependant reduction in 17beta-oestradiol levels alongside an increase in mean baseline progesterone levels (23).

A Fucus vesiculosus extract inhibits estrogen receptor activation and induces cell death in female cancer cell lines

This study published in 2016 follows previous work by the same authors into the antioestrogenic action of bladderwrack. It aimed to further investigate the previously evidenced antioestrogenic mechanisms of action along with other potentially beneficial therapeutic indications such as oestrogen-dependant and non-oestrogen-dependant types of cancer, including breast, ovarian and endometrial cancers. Along with the action of a bladderwrack extract on oestrogen receptor activation, aromatase activity was measured in order to assess the effects of bladderwrack extract on the biosynthesis of oestradiol. Analysis included that of cell viability, morphology, membrane integrity, mitochondrial toxicity, induction of apoptotic and autophagic markers, and cell signalling.

Results suggested that bladderwrack extract exhibited potent oestrogen receptor antagonistic effects significantly reducing oestrogen receptor activation and inhibited aromatase activity. The viability of both oestrogen receptor dependant and independent cancer cells was seen to decrease directly correlating with an increased dose of the bladderwrack extract, showing morphological changes indicative of apoptosis and autophagy. This induction of apoptosis and autophagy in cancers of the endometrium, ovaries and breast may potentially indicate anti-tumour properties of bladderwrack independent of its antioestrogenic actions (24).

The botanical name for bladderwrack, Fucus vesiculosus, is derived from the Greek word ‘pykos’ meaning ‘seaweed’ and the Latin term ‘vesiculosus’ which translates as ‘with bladder’ (25).

It has also been used for weather forecasting. Perhaps unsurprisingly, it was said that if bladderwrack is hung up and remains wet then it will soon rain, whereas if it dries out the weather will be fair and sunny (11,12).

During the 19th century, at the time of the Napoleonic wars, seaweeds including bladderwrack were burnt for their ash which is a rich source of potash and soda ash necessary for the production of gunpowder. In more peaceful times, these were both used for the manufacture of glass and by the soap industry of the era (26).

Traditionally it was used as a crop fertilizer in places including Cornwall, Jersey and the Isles of Scotland where it would be gathered from the shoreline and spread directly on the beds containing stable crops such as potatoes .It is still used in organic gardening today albeit more frequently as a liquid crop feed (26,27).

Bladderwrack is found growing along the shoreline of coastal environments throughout most of the northern hemisphere. It is commonly seen along the shores surrounding the UK along with the more northern-eastern waters of the United States, the Baltic sea, the Atlantic coasts of parts of Europe and the North sea coast of Denmark and the Netherlands (3,34,36).

Although it prefers more protected areas of the shoreline, such as those found between low and high tide marks, it can tolerate moderate wave exposure and varying levels of salinity. Its natural habitat is upon the rocks and pebbles of these environments but will attach itself and grow on any solid base including artificial humankind-made structures (34,36).

Bladderwrack is not featured on the IUCN redlist or TRAFFIC and its conversation status is listed as common by other sources (36,37,38). However, in some regions it has been seen to be in decline since the 1980s in places where it had previously formed extensive belts. Studies of the south-west coast of Finland showed a reduction of bladderwrack belts from eleven to six by 2007, with populations severely declining and observed to be struggling to survive.

Along with concerns for this species itself, its loss would consequently affect the plant and seawater creature populations associated with it. Predicted changes in global climate may result in an additional impact on the environments previously seen to be abundant sources of bladderwrack (39).

Habitat loss and over-harvesting from the wild are two of the biggest threats faced by medicinal plant species. There are an increasing number of well-known herbal medicines at risk of extinction. We must, therefore, ensure that we source our medicines with sustainability in mind.

The herb supplement industry is growing at a rapid rate and until recent years a vast majority of medicinal plant produce in global trade was of unknown origin. There are some very real and urgent issues surrounding sustainability in the herb industry. These include environmental factors that affect the medicinal viability of herbs, the safety of the habitats that they are taken from, as well as the welfare of workers in the trade.

The botanical supply chain efforts for improved visibility (transparency and traceability) into verifiably sustainable production sites around the world is now certificated through the emergence of credible international voluntary sustainability standards (VSS). 

Read our article on Herbal quality & safety: What to know before you buy and Sustainable sourcing of herbs to learn more about what to look for and questions to ask suppliers about sustainability.

Herbal medicines are often very safe to take; however, their safety and efficacy can be jeopardised by quality issues. So, it is important to buy herbal medicines from a reputable supplier, from sources known to test their herbs to ensure there is no contamination, adulteration or substitution with incorrect plant matter, as well as ensuring that recognised marker compounds are at appropriate levels in the herbs.

Some important quality assurances to look for are certified organic labelling, the correct scientific/botanical name, and the availability of information from the supplier about ingredient origins. A supplier should be able to tell you where the herbs have come from, what contaminants are not in the herb, and what the primary compounds are.

Bladderwrack can be wild harvested from clean seawater from around April onwards and throughout the summer months in the UK although in parts of the Atlantic and Pacific oceans surrounding North America the harvesting season may be longer, lasting from March through to October (2). It should only be harvested from healthy, abundant communities and the fronds cut above the point of growth.

As with the wild harvesting of any plant source, sustainable and responsible gathering is essential including harvesting only by hand, collecting less than one third of each individual plant, rotating the harvesting areas and avoiding disturbing resident wildlife, such as shore dwelling birds and other marine creatures (40). It is increasingly essential to ensure that the environment in which bladderwrack, along with any other seaweed, is being gathered is free from contaminates such as sewage, heavy metals and microplastics (41,42).

Seaweed pickle

This seaweed pickle makes a delicious and nutritious addition to salads and other savoury dishes.

Ingredients

• 1 cup apple cider vinegar
• 1 cup water
• 1 tablespoon salt
• 1 tablespoon sugar
• Fresh bladderwrack, best gathered in early spring

How to make seaweed pickle with bladderwrack

• Bring the liquids to the boil.
• Add salt and sugar.
• Sit until dissolved and allow to cool.
• Rinse the bladderwrack and loosely fill a pickling or Kilner jar.
• Cover with the liquid.
• Allow to sit in a cool dark place for a few weeks before use.

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