Plant Part Used
Thallus
Active Constituents
Polyphenols (including phloroglucinol); mucopolysaccharides (including algin, fucoidan); (1),(34) sulfuryl-, sulfonyl- and phosphonyl-glycosyl ester diglycerides; sterols (including fucosterol); polar lipids; trace metals, particularly iodine (usually 0.03-1% by weight), (35) vitamins (mainly vitamin C). (2) [span class=alert]
This section is a list of chemical entities identified in this dietary supplement to possess pharmacological activity. This list does not imply that other, yet unidentified, constituents do not influence the pharmacological activity of this dietary supplement nor does it imply that any one constituent possesses greater influence on the overall pharmacological effect of this dietary supplement.[/span]
Introduction
Fucus, or bladderwrack, consists of the entire thallus of the marine plant Fucus vesiculosus, commonly found in the southern Baltic Sea as roughly 90% of the total biomass. This species act as key species and nursery for fish juveniles, gives shelter and offers a foraging place for many other organisms. (31) The survival of bladderwrack is affected by several factors, such as wave exposure and regional differences. The high wave exposure resulting in thinner populations. The life spans of this species at North Sea coast is average three years while at the sheltered areas gave maximum life spans of 4-5 years. In addition, a single frond at Baltic Sea may survive up to 20 years in sheltered areas. (32)
The fronds are dried as soon as possible after collection in preparation for use as dietary supplements. Marine algae have enjoyed a long usage in the materia medica of Europe and Asia (the Chinese have used bladderwrack for at least 4,000 years). Bladderwrack is a rich source of iodine, and is traditionally used in weight loss and hypothyroidism. (3) , (4) , (5) The low incidence of goiter in maritime people has been attributed to the iodine content in bladderwrack. (6) Bladderwrack also contains potassium, magnesium, calcium, iron, zinc, and other minerals. (7) Historically, bladderwrack has been used in the dairy and baking industries, due to the gelling properties of the constituent algin.
The ability of marine plants to accumulate heavy metals and other toxic elements is recognized. Manufacturing should include testing for these and other contaminants – use caution when recommending bladderwrack or other seaweed products that may contain contaminants. Levels of iodine should also be listed on the product label to ensure safety. (8)
Interactions and Depletions
Interactions
- Anticoagulant medications
- Antiplatelet medications
- Thyroid medications
- Free iodine increasing agents
- Diabetic / Hypoglycemic medications
Dosage Info
Dosage Range
300 – 600mg, 1-3 times a day.
Extract: 4 to 8 ml, 3 times daily. (9)
Most Common Dosage
600mg, 2 times a day.
Extract: 4 ml, 3 times daily.
Standardization
[span class=doc]Standardization represents the complete body of information and controls that serve to enhance the batch to batch consistency of a botanical product, including but not limited to the presence of a marker compound at a defined level or within a defined range.[/span]
The most current available medical and scientific literature indicates that this dietary supplement should be standardized to no more than 150mcg of iodine daily.
It is important that levels of iodine be listed on the product label to ensure safety. (10) , (11)
Uses
Frequently Reported Uses
- Antiviral.
- Goiter Prevention
- Weight Management
Other Reported Uses
- Mild Laxative
- Blood Lipid Lowering
- Wound Healing
- Anticancer/anti-tumor/anntimetastatic
- anti-hypertensive activity
- Immune modulating
Toxicities & Precautions
General
Bladderwrack is safe in recommended dosages. However, it has been reported that marine based plants can contain various levels of iodine as well as traces of heavy metals such as arsenic. (12) It is important that the levels of iodine are listed on the product label to ensure safety.
Stop using this dietary supplement for at least 14 days prior to any type of surgery or dental work.
Allergy
There have been reports of seaweed causing contact dermatitis, so caution should be used in sensitive individuals. (13),(33)
Health Conditions
Individuals with thyroid disorders should only use fucus under the supervision of a physician.
Avoid use in individuals with iodine sensitivity.
Based on pharmacology, use with caution in individuals with bleeding disorders.
Side Effects
Overdoses may lead to hyperthyroidism, tremor, increased pulse rate, and hypertension. These effects are likely the result of an iodine overdose. The adult RDA for iodine 150mcg per day with an upper limit for iodine not to exceed 1,100mcg daily. (14)
Pregnancy/ Breast Feeding
Do not use fucus in pregnancy and lactation due to the potential for marine plants to contain heavy metals, such as arsenic. (15)
Age Limitations
Due to the potential for marine plants to contain heavy metals, such as arsenic, (16) concern is warranted when using fucus in young children.
Pharmacology
There is limited clinical information on the use of bladderwrack in human subjects. A 60-day trial of obese subjects taking bladderwrack reported a significantly greater weight loss than those taking placebo. (17) Bladderwrack is thought to stimulate the thyroid gland, thus increasing basal metabolism. Bladderwrack may also lower cholesterol levels as reported with in vitro and laboratory animal studies. (18) , (19)
Anti-HIV active polysaccharides and polyphenols have been isolated from bladderwrack. (20) The constituents were reported to inhibit both HIV-induced syncytium formation and HIV reverse transcriptase enzyme activity in vitro. Other studies reported that bladderwrack lowered blood sugar levels in laboratory animals. (21) Another traditional use of bladderwrack is as a laxative. The alginic acid is a hydrophilic colloidal substance that swells to approximately 25-35 times its original bulk in an alkaline environment, and as a result, exerts a bulk laxative action. (22)
As stated, overdoses of iodine may lead to symptoms of hyperthyroidism, including weight loss, fatigue and frequent soft stools. These symptoms were reported in a 72 year old female following six months of ingesting a commercial kelp product. (23) Another report describes a 24 year old woman developing thyroid goiter after taking a proprietary product, which included 0.4-0.5 mg/day of iodine for three months. (24) Products where the iodine content is assayed should be used to avoid potential iodine toxicity problems.
Polysaccharides from an aqueous extract of bladderwrack was reported useful in therapy for irritated mucus membranes in the pharynx region. (25) Results showed the absorption effects of these polysaccharides on mucus membranes, suggesting that this may account, at least in part, for the therapeutic effects of mucilage-containing plants in the treatment of irritated buccal membranes.
In an in vitro model, a proprietary extract of bladderwrack has been reported useful in wound contraction and granulation. (26) The extract promoted gel contraction by increasing the expression of integrin molecules on the fibroblasts surface and increased the relaxation time of the gels.
Fucoidan is a constituent that has been identified in bladderwrack. The structure of this fucoidan has been noted to be identical to that isolated from another algae species, Ascophyllum nodosum. The latter has been noted to have in vitro anticoagulant activity, (27) which may also be represented in bladderwrack. The anticoagulant activity is apparently dependent on the degree of sulfation of the molecule. (28) On a similar note, fucoidan has also significantly increased postischemic renal blood flow in a small rat study, demonstrating potential renoprotective activity. (29)
Bladderwrack may have effects on estrogen in humans. A case report in three women with abnormal menstrual cycles found that consumption of bladderwrack leads to changes in the regulation of the menstrual cycle by lowering the estrogen/progesterone ratio, increasing the length of the cycle and stimulating ovulation in pre-menopausal women. (30)
References
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- Bradley PR, ed. British Herbal Compendium. Dorset, England: Bournemouth;1992:37-39.
- Curro F, et al. Fucus vesiculosis L. nel Trattamento Medico Dell’Obesita e delle Alterazioni Metaboliche Connesse. Arch Med Interna. 1976;28:19-32.
- Newall CA, et al. Herbal Medicines: A Guide for Health Care Professionals. London: The Pharmaceutical Press;1996:124-126.
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- View Abstract: Phaneuf D, Cote I, Dumas P, et al. Evaluation of the Contamination of Marine Algae (Seaweed) from the St. Lawrence River and Likely to be Consumed by Humans. Environ Res. Feb1999;80(2 Pt 2):S175-S182.
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- View Abstract: Norman JA, Pickford CJ, Sanders TW, Waller M. Human intake of arsenic and iodine from seaweed-based food supplements and health foods available in the UK. Food Addit Contam. Jan1987;5(1):103–109.
- View Abstract: Norman JA, Pickford CJ, Sanders TW, Waller M. Human intake of arsenic and iodine from seaweed-based food supplements and health foods available in the UK. Food Addit Contam. Jan1987;5(1):103–109.
- Harrell BL, et al. Kelp diet: A Cause of acneiform eruption. Arch Derm. 1976;112:560.
- PDR for Herbal Medicines, 2nd ed. Montvale, NJ: Medical Economics Company; 2000:107.
- View Abstract: Norman JA, Pickford CJ, Sanders TW, Waller M. Human intake of arsenic and iodine from seaweed-based food supplements and health foods available in the UK. Food Addit Contam. Jan1987;5(1):103–109.
- View Abstract: Norman JA, Pickford CJ, Sanders TW, Waller M. Human intake of arsenic and iodine from seaweed-based food supplements and health foods available in the UK. Food Addit Contam. Jan1987;5(1):103–109.
- Curro F, et al. Fucus vesiculosis L. nel Trattamento Medico Dell’Obesita e delle Alterazioni Metaboliche Connesse. Arch Med Interna. 1976;28:19-32.
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- View Abstract: Beress A, et al. A new procedure for the isolation of anti-HIV compounds (polysaccharides and polyphenols) from the marine alga Fucus vesiculosus. J Nat Prod. Apr1993;56(4):478-88.
- View Abstract: Lamela M, et al. Hypoglycemic activity of several seaweed extracts. J Ethnopharmacol. Nov1989; 27(1-2):35-43.
- Newall CA, et al. Herbal Medicines: A Guide for Health Care Professionals. London: The Pharmaceutical Press;1996:124-126.
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- Christine F.S. The effect of Fucus vesiculosus, an edible brown seaweed, upon menstrual cycle length and hormonal status in three pre-menopausal women: a case report. BioMed Central.Aug2004;4(10)
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