Benefits of Brown Seaweed

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Brown seaweed can be found in two different types, including Laminaria japonica and Fucus vesiculosus. Both types contain iodine and fucoidan. Iodine is necessary for normal cell metabolism and is a trace mineral. The substance fucoidan is believed to have immune-stimulating properties. There are a variety of purported benefits of brown seaweed, which is sometimes referred to as bladderwrack.

Possible Uses

There are several purported uses. Such uses include: fatigue, cellulite, asthma, stomach ailments, hypothyroidism, menstrual problems, cough, hemorrhoids and headaches. Some believe that it may also be beneficial for the skin and aid in promoting weight loss.

Possible Benefits

It is believed that there are a variety of different benefits of brown seaweed. However, only a few studies have been conducted so there is little to no evidence to fully support these purported benefits. Preliminary research suggests the following possible benefits:

Reduced Inflammation: In a 2007 laboratory study, results showed that all fucoidans possessed anti-inflammatory effects. They also seem to prevent breast cancer cells from sticking to platelets and this suggests that they may help in preventing the spread of cancer.

Cancer Prevention: In 2004, a case report reported that three pre-menopausal women experienced anti-estrogenic effects from dietary intake from bladderwrack. This means that it may help in decreasing the risk of estrogen-related cancers. Further research is needed.

Blood-Thinning Benefits: Test-tube research shows that fucoidan may have some anti-coagulant properties. However, at this time, no human studies have been conducted to support these findings.

Safety Concerns

There is always the chance that it contains high concentrations of iodine. This could worsen or cause some thyroid problems. Dietary iodine has been linked to increased risk of thyroid cancer and with goiter. Those preparing for surgery, who are infertile and those who are breastfeeding or pregnant should avoid brown seaweed.

When discussing the risks of brown seaweed it is important to discuss drug interactions. It may interact antiplatelet or anticoagulant medications and antithyroid medications. Supplements and herbs that may slow clotting may also interact. Some of these include angelica, danshen, feverfew, ginger, Panax ginseng, red clover, clove, fenugreek, garlic, gingko, poplar and turmeric.

There is always the chance that brown seaweed could be contaminated with heavy metals, such as arsenic. Overconsuming iodine could cause disruption of thyroid health, stomach irritation, lowered blood pressure and/or an increased risk of bleeding.

Before using brown seaweed, it is very important to talk to your health care provider. This is especially important for patients with thyroid issues, both past and current.


MedlinePlus. (2010). Bladderwrack. Retrieved on March 29, 2011 from MedlinePlus:

Natural News. (2006). Brown Seaweed Found Remarkably Effective at Breaking Down Fat Cells, Treating Diabetes. Retrieved on March 29, 2011 from Natural News:


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