Bladderwrack

Alternative names: Sometimes mistakenly written as Bladder Wrack.

Bladderwrack is a type of perennial brown seaweed that grows on the northern Atlantic and Pacific coasts of the United States and on the northern Atlantic coast and Baltic coast of Europe.  The main stem of bladderwrack, known as the thallus, is used medicinally.  It should not be confused with kelp.

History

It has been used for conditions associated with the bladder, although its name is probably derived from the bladder-like vesicles along its fronds.  Bladderwrack has been used historically as a diuretic as well as for cases of cystic irritations and chronic inflammations of the bladder.  Bladderwrack was once thought to help reduce obesity and increase muscle mass.  Recently, this use is being explored once again.  Even though little evidence for its use in obesity exists, more research needs to be done in this area.  Some sources of bladderwrack may be significant sources of iodine.  Bladderwrack is considered "Unapproved" under the German Commission E.

Function; Why it is Recommended

There are three major active constituents in bladderwrack: iodine, alginic acid, and fucoidan.

Fucoidan is a type of dietary fiber in bladderwrack that contains numerous sulfur groups.  According to test tube and animal studies, this appears to give fucoidan several properties, such as lowering LDL cholesterol levels, lowering blood glucose levels, anti-inflammatory activity, possible anticoagulant effects, and antibacterial and anti-HIV activity.  Though it has not been definitively proven, fucoidan is thought to prevent bacteria and viruses from binding to human cells, a necessary step in starting an infection, as opposed to killing the microbes directly.  As at the time of writing, no human clinical trials have been done with fucoidan or bladderwrack to support their use for any of these conditions.

As well as the conditions mentioned below, bladderwrack has traditionally been used for: Diarrhea; gastritis; gastroesophageal reflux disease (GERD); improved wound healing (topical application).  Calcium alginate (the calcium salt of alginic acid) has shown promise as an agent to speed wound healing in animal studies, but has not been demonstrated to be effective in humans.

Bladderwrack's mucilaginous thallus has long been used to soothe irritated and inflamed tissues in the body.  It has also been used to counter obesity, possibly due to its reputation for stimulating the thyroid gland.  Clinical research in this area has failed to confirm that seaweeds like bladderwrack help with weight loss, though more specific research is warranted.

Side-Effects; Counter-Indicators and Warnings

Bladderwrack is generally safe, though there are three potential problems with its consumption: acne, thyroid dysfunction, and heavy-metal contamination.  Bladderwrack and other seaweeds that grow in heavy-metal-contaminated waters may contain high levels of these toxins (particularly arsenic and lead), possibly leading to nerve damage, kidney damage or other problems.  Only bladderwrack known to have been harvested from clean water or labeled to indicate the absence of heavy metals or other contaminants should be consumed.

At the time of writing, there were no well-known drug interactions with bladderwrack.

The safety of using bladderwrack during pregnancy and breast-feeding is unknown.  People who are allergic to iodine may need to avoid bladderwrack.