Possible Risks of Eating Kelp and Seaweed

With all things, there is an element of risk. This goes beyond the normal “if you make any large life choices please consult your general practitioner” type of thing. Seaweed is no different. In some cases, eating seaweed or taken as a supplement can even have negative consequences, so do your research before plunging in.

I’ve been lucky enough not to have any negative effects but there are particular things you need to look out for before considering supplementing your diet with seaweed or consuming large quantities of seaweed as part of your regular diet.

Risks with Seaweed


Iodine deficiency used to be a big thing back in the 70’s, and the government has been supplementing your table salt with iodine to make up for this for quite some time. Sea kelp, like most types of seaweed, has large quantities of iodine built into it because it absorbs most of that nutrient from the ocean. Because of the government programs, most of us in more developed countries do not suffer from iodine deficiencies. However, there is another danger to consider. Some people may be allergic to iodine, or together with your regular salt intake, you might take in too much iodine, should you be heavily relying on seaweed products and supplements as part of your nutritional intake. It’s also important to note that iodine allergy is not the same is a seafood allergy, which is actually reactions to allergens in the seafood itself.

Heavy metals

Seaweed absorbs toxic heavy metals, which is one of the health benefits Seaweed offer. But this benefit can have a darker side. It is a sad fact of our modern world, that some of our oceans are heavily polluted. Seaweed grown in polluted environment absorb quite a lot of the toxic heavy metals present in the water. By eating seaweed from a source that is polluted, you ingest some of these heavy metals which can have dire health consequences for you. Because of that, make sure you can trust the source of your seaweed.


Because many seaweed capsules and seaweed products are listed as supplements, and not as medicine, the FDA does not have a say about the quantities of nutrients present or the quality of the material in the supplement. Companies also do not need to put a lot of information on their bottle wraps, branding, labels, and advertisements. This means that unscrupulous supplement companies can put any old algae into their capsule and call it kelp. Some kelp is not as good for you as others, and some might even have not the best effects on your health. Because of this, make sure you trust the source of your kelp or seaweed if you buy it in supplement from.

By taking these simple measures into consideration, you can get the health benefits from seaweed quite easily without much risk. It might sound dire, but in most cases, if you take the precautions, you can avoid running into trouble. Make sure to keep an eye on how you feel, as well as the dosage of supplements to make sure not to exceed the daily allowance of minerals such as iodine. And of course, as mentioned before, if you’re unsure, ask your general practitioner.

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