Bladderwrack is a type of seaweed so named because it stays afloat via air-filled bladders called "thalli," which contain the plant's reproductive organs. Historically, bladderwrack is used in herbal medicine to reduce fat absorption, to promote hormonal balance in women and to address thyroid disorders. Bladderwrack is also attributed with supporting adrenal function, although there is no conclusive evidence of this. Consult your physician before using this herb therapeutically for any reason because of the risk of side effects and drug interactions.
Botanical Profile
Bladderwrack, or Fucus vesiculosus, is also known as "bladder fucus," "rock wrack," "kelp ware," "sea oak" and "Quercus marina." The algae is harvested along the Atlantic, Pacific, Baltic and North Sea coasts at low tide. The “bladder” located on the underside of the fronds is used for food and medicine.
Composition and Actions
Bladderwrack contains mucilage, inorganic iodine salts and a compound called "diiodotyrosine," a form of organically bound iodine that resides in lipids and proteins. Several polysaccharides are also present, including fucane and algin. The latter, according to the National Institutes of Health, acts as a laxative. The “Physicians’ Desk Reference for Herbal Medicines” says that bladderwrack may possess anti-inflammatory and anticoagulant effects and the herb’s polysaccharides may reduce blood levels of LDL cholesterol and triglycerides, although there are no human studies to confirm this. Bladderwrack is used to treat underactive thyroid and enlarged thyroid because it is a source of iodine. Because of its reputed affects on the thyroid, bladderwrack is associated with regulating the activity of another component of the endocrine system -- the adrenal glands.
Effect on the Adrenal Glands
The adrenal glands are triangular-shaped structures that rest atop each kidney and are responsible for the production of steroid hormones, such as cortisol and testosterone. The thyroid gland, located beneath the larynx in the neck, secretes thyroxine and triiodothyronine, iodine-containing hormones that more commonly referred to as "T3" and "T4," respectively. Like the thyroid, the adrenal glands also play a role in metabolism. According to Dallas Clouatre, Ph.D., and William Karneges, co-authors of “Anti-Fat Nutrients: Safe and Effective Strategies for Increasing Metabolism,” if the thyroid doesn’t manufacture enough hormones, then the adrenal glands can’t produce sufficient cortisol. In a study published in the “Journal of Nutrition” in February 2005, scientists from the University of California at Berkeley report that bladderwrack demonstrates anti-estrogenic effects and that its impact on endocrine function may decrease the risk of hormone-related cancers in women.
Safety Considerations
The “Physicians’ Desk Reference for Herbal Medicines” warns that bladderwrack should not be used if you have a thyroid condition because it may cause or worsen an overactive thyroid. Bladderwrack may increase the effects of blood-thinning and diabetes medications and, because it comes from the sea, contamination with heavy metals is possible. This herb should not be used during pregnancy or while nursing.
References
- “Physicians’ Desk Reference for Herbal Medicines”; Thomas Brendler, et al.; 2007
- National Institutes of Health: Bladderwrack
- National Institutes of Health: Adrenal Glands
- University of Maryland Medical Center: Endocrinology Health Guide
- University of Maryland Medical Center: Thyroid Gland
- “Anti-Fat Nutrients: Safe and Effective Strategies for Increasing Metabolism”; Dallas Clouatre, Ph.D., and William Karneges; 2004
- "Journal of Nutrition"; Brown Kelp Modulates Endocrine Hormones in Female Sprague-Dawley Rats and in Human Luteinized Granulosa Cells; C.F. Skibola, et al.; February 2005
