What is kelp good for?
Kelp is a type of seaweed that grows in shallow seas and oceans in what are called kelp forests, and it is also cultivated commercially in underwater kelp farms, a practice that originated in Japan hundreds of years ago. Kelp is in fact a staple in many Asian cuisines.
Not a plant!
Although we often picture it as such, kelp is not actually a plant, but rather what is called a stramenopile.
Stramenopiles are fundamentally different from plants in the sense that they do not have roots, and neither do they have a vascular system for absorbing nutrients from the ground and circulating them through the stem, branches and leaves. Instead, they absorb nutrients directly from the water that surrounds them. Now you have a new fact to impress your friends with!
Kelp's nutritional value
Nutritionally, kelp is densely packed with antioxidants, vitamins, and several minerals, with kelp's iodine content in particular being one of its main selling points as a supplement.
Research shows that kelp may help reduce the risk of cancer, slow the spread of existing cancers, improve cardiovascular health, reduce inflammation, and protect against many of the chronic diseases that are caused by inflammation. Kelp may also have potential for treating or preventing diabetes, although research in this area is still in its infancy.
Kelp also contains a natural fiber called alginate, which is known to help prevent the digestive tract from absorbing fat, specifically by blocking lipase, an enzyme that digests fat. This is precisely why alginates are often found in the ingredient list for weight loss products.
Excessive iodine intake
One important thing to remember when considering taking kelp supplements is that an excess of iodine can be just as harmful as a deficiency in iodine.
Kelp is a rich source of iodine, which means that frequently consuming kelp supplements or other concentrated sources of iodine can introduce too much iodine into your body, resulting in an overstimulated thyroid gland, a condition known as hyperthyroidism. This in turn can have negative consequences on several other aspects of your health.
Because of this, it is a good idea to check with your trusted doctor to see if you would benefit from taking any supplementary form of iodine, or to otherwise simply take your kelp supplements periodically.
Kelp's propensity to absorb heavy metals
One additional aspect to factor into your supplementation is the fact that kelp, and seaweed in general, has the capacity to absorb toxic heavy metals, such as lead, cadmium and arsenic, to much higher concentrations than what is found in the water surrounding it. It is therefore important to ensure the kelp supplement you are taking has been sourced responsibly in waters that do not have elevated levels of heavy metals.
When should I take kelp?
Kelp supplementation can potentially be quite energizing, so it is recommendable to take kelp supplements in the morning, with breakfast, to avoid any potential disturbances to your sleep schedule.
It can be taken on an empty stomach, however some people may experience stomach upset when taking kelp supplements without food.
What should I avoid taking kelp with?
Avoid taking kelp with multivitamin
As we know, kelp is a rich source of iodine, and it is probable that your multivitamin supplement also contains a generous amount of iodine. This means that additional iodine supplementation on top of your kelp supplement could be excessive. Always check the ingredients on your multivitamin, just to be sure.
Who should avoid taking kelp supplements?
People with thyroid conditions
As mentioned above, kelp supplements are a concentrated source of iodine, which is one of the main reasons why people take them. However, people that suffer from thyroid conditions, such as hypothyroidism or hyperthyroidism, should check with their trusted doctor first before taking any kelp supplements, as such a high dose of iodine may not be beneficial for either condition.
Kelp data sources & further reading
Last updated by Asklepios on 30th January, 2025