Short answer
Seaweed isn’t bad for you unless you have a thyroid condition.
Very healthy and numerous health benefits. Harmful qualities may be associated, but aren't usually serious.
View Full Grading System
Category 'A'
Very healthy and numerous health benefits. Side effects are rare. Things rated an 'A+' are typically necessary for survival (for example, water).
Very healthy and numerous health benefits. A few harmful qualities may be associated, but only under certain circumstances such as an allergic reaction.
Very healthy and numerous health benefits. Harmful qualities may be associated, but aren't usually serious.
It is important to note that even the best things in life can become bad in immoderate amounts. So, although something may be rated an 'A+', overconsumption/overdoing can bring unwanted effects.
Category 'B'
Very beneficial to your health. Things rated a 'B+' may have a few harmful qualities to pay attention to.
Overall beneficial to your health. Things rated a 'B' may have some harmful qualities to pay attention to.
More beneficial to your health than not. However, harmful qualities are most likely associated and shouldn't be overlooked.
The main difference between category 'A' and category 'B' is the harmful qualities typically present in 'B' items. Serious side effects are usually uncommon, but are still possible and should be taken note of.
Category 'C'
Both beneficial and harmful qualities associated. Things rated a 'C+' are typically a bit more on the beneficial side. Still, moderation is important.
A fairly even ratio of beneficial and harmful qualities. Moderation is important. Very general topics that can lean towards both sides of the spectrum will be placed here as well. Rice, for example, can be good or bad depending on the type.
More harmful than beneficial. Side effects are common, especially when consumed/done excessively. Moderation is very important.
Category 'C' usually denotes to both good and bad qualities. When it comes to this category, it is important to keep this word in mind: moderation.
Category 'D'
Harmful to your health. Although benefits may be associated, the bad most likely outweighs the good. Moderation is very important.
Harmful to your health. A few benefits may be associated, but the bad outweighs the good. Moderation is extremely important.
Harmful to your health. Very few, if any, benefits are present. Things in this category should be avoided as much as possible.
Category 'D' is typically for things that are more harmful than beneficial. While consuming/doing something unhealthy once in a blue moon shouldn't hurt, we definitely recommend eliminating 'D' items as a regular part of your routine/diet.
Category 'F'
Category 'F' is for things that fail to bring anything beneficial to the table, and are very harmful to your health. We recommend completely avoiding anything in this category. Long-term side effects of 'F' items are usually very serious.
Category 'N'
'N' stands for neutral. Things placed into this category are generally (a) neither good nor bad for you, or (b) lack the necessary evidence to reach any conclusions.
Long answer
There's a lot to recommend about seaweed. It's low in calories. It's got peptides that can improve the health of your heart. Seaweed comes with a whole mess of important vitamins. It's fibrous and can improve the health of your gut. Many seaweed products are lightly processed. According to the Guardian, there's also some evidence that it has antioxidant properties and can mop up certain chemicals in the body.
Is there such a thing as too much seaweed? Maybe. Seaweed is rich in iodine. Really rich in iodine - some varieties can pack multiple times your recommended daily intake in a single serving. Iodine in moderation is good: you need it to keep your thyroid functioning. Too much iodine, however, and you may aggravate your thyroid - especially if you have an underlying condition.
Talk to your doctor if you think the amount of seaweed you eat is interfering with your thyroid. Unless you've got a pre-existing condition or are eating large amounts of Kombu seaweed - one of the varieties with the most iodine - you should be alright. Boiling seaweed in soup helps to reduce the bioavailability of iodine content. Ditto if you prepare the seaweed with vegetables that are goitrogenic - that is, vegetables that interfere with the absorption of iodine. Certain kinds of seaweed are also goitrogenic themselves, which helps to soften the blow of their high iodine content.
Another concern about seaweed is that it sucks up some of the worst of the ocean - heavy metals and radiation - and then delivers it to our bodies. There's not much evidence to support that claim, though. One study conducted in Egypt looked at heavy metal accumulation in a range of seaweeds. It found that levels of heavy metals and other bioaccumulative toxins were well within the safety limits set by the World Health Organization and the governments of those countries in which the seaweed was harvested or consumed.
Concerns about radiation in seaweed are similarly overblown. Kelp Watch took samples up and down the Pacific after the meltdown at Fukushima - from Alaska to California to Hawaii. They found no detectable levels of radioactive isotopes in kelp or seaweed tissue. Other studies found minuscule levels of radioactive isotopes from Fukushima. Emphasis on minuscule - when looking for the isotope 134, they found amounts that were thousands of times less than the radiation you're exposed to during a standard x-ray. So while there are detectable levels of radiation in the Pacific, it's nowhere near the levels needed to be dangerous; it's less than the background radiation you're exposed to when you step outside. And it's not messing up your seaweed.
Possible short-term side effects
- aggravate existing thyroid conditions
Benefits
- great source of protein
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great source of vitamin c
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high mineral content
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one of the richest plant sources of calcium
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natural source of iodine, which promotes thyroid health
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anti-viral, anti-bacterial, anti-inflammatory properties
Our favorite seaweed snacks
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