Seaweed, Kelp, Bladderwrack (Fucus vesiculosus)
  
Seaweed, Kelp, Bladderwrack (Fucus vesiculosus)
Background
Fucus vesiculosus is a brown seaweed that grows on the northern coasts of the Atlantic and Pacific oceans, and the North and Baltic seas. Its name is sometimes used for Ascophyllum nodosum, which is another brown seaweed that grows alongside Fucus vesiculosus . These species are often included in kelp preparations along with other types of seaweed.
Synonyms
Black-tang, bladder, bladder fucus, Blasen-tang, common seawrack, cut weed, Dyers fucus, Fucus, Hai-ts'ao, kelp, kelpware, knotted wrack, Meereiche, Quercus marina, popping wrack, red fucus, rockrack, rockweed, schweintang, sea kelp, sea oak, seetang, seaware, seaweed, sea wrack, swine tang, tang, Varech vesiculeux, vraic, wrack.
Evidence
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Uses based on scientific evidenceGrade*Weight loss
Bladderwrack and other seaweed products are often marketed for weight-loss. Theoretically, thyroid stimulation from bladderwrack may increase metabolism and cause weight loss. However, safety and effectiveness have not been studied in humans.
C
Goiter (thyroid disease)
Bladderwrack contains variable levels of iodine (up to 600 micrograms of iodine per gram of bladderwrack). As a result, it has been used to treat thyroid disorders such as goiter. Although there are case reports of seaweed/kelp products causing hyperthyroidism, there have not been studies of dosing, safety, or efficacy, and there is no widely accepted standardization of iodine content for these products. While the evidence does suggest thyroid activity, there is not enough research to support this use of bladderwrack.
C
Cancer
Several brown algae, including bladderwrack ( Fucus vesiculosus ), appear to suppress the growth of various cancer cells in animal and laboratory studies. However, currently there are no reliable human studies to support a recommendation for use in cancer.
C
Antibacterial/antifungal
Laboratory study suggests antifungal and antibacterial activity of bladderwrack. However, there are no reliable human studies to support use as an antibacterial or antifungal agent.
C
Anticoagulant (blood-thinner)
Laboratory study has found anticoagulant properties in fucans or fucoidans, which are components of brown algae such as bladderwrack. However, there are no human studies to support this use.
C
Antioxidant
Laboratory study suggests antioxidant activity in fucoidans, which are components in some brown algae. However, there are no human studies to support use as an antioxidant.
C
Diabetes
Based on animal research, extracts of bladderwrack may lower blood sugar levels. However, there are no reliable human studies to support a recommendation for use in hyperglycemic conditions, such as diabetes.
C
* Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use (it may not work);
F: Strong scientific evidence against this use (it likely does not work).
Uses based on tradition or theory
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Atherosclerosis, arthritis, benign prostatic hypertrophy (BPH), bladder inflammatory disease, eczema, edema, enlarged glands, fatigue, heart disease, hair loss, heartburn, high cholesterol, kidney disease, laxative, lymphadenoid goiter, malnutrition, menstruation irregularities, obesity, parasites, psoriasis, radiation protection, rheumatism, sore throat, stool softener, stomach upset, swollen or painful testes, ulcer, urinary tract tonic.
Dosing
The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Standardization
Standardization involves measuring the amount of certain chemicals in products to try to make different preparations similar to each other. It is not always known if the chemicals being measured are the "active" ingredients. There is no known standardization for bladderwrack. Because of the potential contamination of bladderwrack with heavy metals, its consumption should always been considered potentially unsafe.
Adults (18 years and older)
General use (by mouth) : Soft capsules (alcohol extract) in doses of 200 to 600 milligrams daily have been used. Tablets have also been used, initially taken 3 times per day and gradually increased to 24 tablets per day. 16 grams of bruised plant mixed with one pint of water has been used, administered in 2 fluid ounce doses 3 times per day, or an alcoholic liquid extract in a dose of 4 to 8 milliliters before meals.
Patch : Bladderwrack and seaweed patches are sold commercially as weight loss products, although there are no commonly accepted or tested doses.
Children (under 18 years old)
There is not enough scientific evidence to recommend safe use of bladderwrack in children. Because of the iodine content and potential for contamination with heavy metals, it may be inadvisable for use in children.
Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Allergies
Allergy/hypersensitivity to Fucus vesiculosus or any of its components, or iodine sensitivity may occur.
Side Effects and Warnings
Most adverse effects appear related to high iodine content, heavy metal or other contamination of bladderwrack preparations, rather than to the seaweed itself. Because of the potential contamination of bladderwrack with heavy metals, its consumption should always been considered potentially unsafe.
Based on the known effects of iodine toxicity, the high iodine content in bladderwrack may lead to abnormal thyroid conditions. There are reports of increased thyroid activity (hyperthyroidism) and decreased thyroid activity (hypothyroidism) from ingestion of seaweed/kelp products. In theory, bladderwrack may increase or decrease blood thyroid hormone levels. In addition, acne-type skin lesions may occur, and there are reports of severe acne exacerbations with use of kelp. Iodine may also cause a brassy taste, increased salivation, and stomach irritation.
Reports of kidney and nerve toxicity have occurred in persons taking seaweed/kelp, attributed to high levels of arsenic. One case report of abnormal bleeding and reduced blood platelet count was attributed to contaminants in a kelp product. Bladderwrack may contain vitamins and minerals, calcium, magnesium, potassium, and sodium, and may increase blood levels.
Based on animal study, extracts of bladderwrack may cause lowered blood sugar. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels may need to be monitored by a healthcare provider, and medication adjustments may be necessary.
Based on laboratory study, bladderwrack may have blood-thinning (anticoagulant) properties. Abmormal bleeding, petechiae, and autoimmune thrombocytopenic purpura with dyserythropoiesis have been reported. Caution is advised in patients with bleeding disorders or taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.
Laxative properties have traditionally been attributed to chronic use of bladderwrack and other brown seaweeds, and may be due to the component alginic acid, present in many laxative agents.
Pregnancy and Breastfeeding
Bladderwrack is not recommended during pregnancy or lactation due to lack of reliable scientific information, and because of the presence of high levels of iodine and possible heavy metal contamination.
References
1. Anonymous. Kelp diets can produce myxedema in iodide-sensitive individuals. JAMA 1975;233(1):9-10.
2. Colliec S, Fischer AM, Tapon-Bretaudiere J, et al. Anticoagulant properties of a fucoidan fraction. Thromb Res 1991;64(2):143-154.
3. Clark CD, Bassett B, Burge MR. Effects of kelp supplementation on thyroid function in euthyroid subjects. Endocr Pract 2003;9(5):363-369.
4. Conz PA, La Greca G, Benedetti P, et al. Fucus vesiculosus: a nephrotoxic alga? Nephrol Dial Transplant 1998;13(2):526-527. Criado MT, Ferreiros CM. Selective interaction of a Fucus vesiculosus lectin-like mucopolysaccharide with several Candida species. Ann Microbiol (Paris) 1983;134A(2):149-154.
5. Criado MT, Ferreiros CM. Toxicity of an algal mucopolysaccharide for Escherichia coli and Neisseria meningitidis strains. Rev Esp Fisiol 1984;40(2):227-230.
6. Durig J, Bruhn T, Zurborn KH, et al. Anticoagulant fucoidan fractions from Fucus vesiculosus induce platelet activation in vitro. Thromb Res 1997;85(6):479-491.
7. Eliason BC. Transient hyperthyroidism in a patient taking dietary supplements containing kelp. J Am Board Fam Pract 1998;11(6):478-480.
8. Ellouali M, Boisson-Vidal C, Durand P, et al. Antitumor activity of low molecular weight fucans extracted from brown seaweed Ascophyllum nodosum. Anticancer Res 1993;13 (6A) :2011-2020.
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10. Harrell BL, Rudolph AH. Letter: kelp diet: a cause of acneiform eruption. Arch Dermatol 1976;112(4):560.
11. Hartman AA. [Hyperthyroidism during administration of kelp tablets]. Ned Tijdschr Geneeskd 1990;134(28):1373.
12. Lamela M, Anca J, Villar R, et al. Hypoglycemic activity of several seaweed extracts. J Ethnopharmacol 1989;27(1-2):35-43.
13. Le Tutour B, Benslimane F, Gouleau MP, et al. Antioxidant and pro-oxidant activities of the brown algae, Laminaria digitata, Himanthalia elongata, Fucus vesiculosus, Fucus serratus and Ascophyllum nodosum. J Applied Phycology 1998;10(2):121-129.
14. Maruyama H, Nakajima J, Yamamoto I. A study on the anticoagulant and fibrinolytic activities of a crude fucoidan from the edible brown seaweed Laminaria religiosa, with special reference to its inhibitory effect on the growth of sarcoma-180 ascites cells subcutaneously implanted into mice. Kitasato Arch Exp Med 1987;60(3):105-121.
15. Norman JA, Pickford CJ, Sanders TW, et al. Human intake of arsenic and iodine from seaweed-based food supplements and health foods available in the UK. Food Addit Contam 1987;5(1):103-109.
16. Pye KG, Kelsey SM, House IM, et al. Severe dyserythropoiesis and autoimmune thrombocytopenia associated with ingestion of kelp supplements. Lancet 1992;339(8808):1540.
17. Riou D, Colliec-Jouault S, Pinczon du Sel D, et al. Antitumor and antiproliferative effects of a fucan extracted from ascophyllum nodosum against a non-small-cell bronchopulmonary carcinoma line. Anticancer Res 1996;16(3A):1213-1218.
18. Rocha A, Rache LS, Rhoden CR. [Natural products utilized as alternative treatment for obesity]. Revist Brasil Med 1994;51(10):1454, 1456, 1459-1460, 1464.
19. Shilo S, Hirsch HJ. Iodine-induced hyperthyroidism in a patient with a normal thyroid gland. Postgrad Med J 1986;62(729):661-662.
20. Springer GF, Wurzel HA, McNeal GM, et al. Isolation of anticoagulant fractions from crude fucoidin. Proc Soc Exp Biol Med 1957;94:404-409.
21. Soeda S, Sakaguchi S, Shimeno H, et al. Fibrinolytic and anticoagulant activities of highly sulfated fucoidan. Biochem Pharmacol 1992;43(8):1853-1858.
22. Walkiw O, Douglas DE. Health food supplements prepared from kelp--a source of elevated urinary arsenic. Clin Toxicol 1975;8(3):325-331.
23. Yamamoto I, Nagumo T, Fujihara M, et al. Antitumor effect of seaweeds. II. Fractionation and partial characterization of the polysaccharide with antitumor activity from Sargassum fulvellum. Jpn J Exp Med 1977;47(3):133-140.
January 01, 2004 
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