Magnesium – What Is It and Why Is It Important?

magnesium and seaweed

Magnesium is a laborious, mineral macronutrient found in seaweed that is used in more than 300 biochemical reactions in the human body. Its demand is so high it is literally everywhere in your body.

And seaweed, being great at collecting such precious nutrients, does not disappoint with its magnesium levels.

However, seaweed, in general, contains high mineral content. In fact, anywhere between 8-40% of a seaweed’s dry mass translates into minerals.

Besides magnesium, other macronutrients found in algae include fan-favorites like sodium, calcium, potassium, chlorine, and phosphorus, but also the more alternative iodine, iron, zinc, copper, selenium, molybdenum (whatever that is), fluoride, boron, nickel, and cobalt (Burtin, 2003).

This means that about half of what seaweed is corresponded to minerals and macronutrients necessary to the human body.

How Much Magnesium Do Seaweeds Have?

The amount of magnesium could vary depending on the type of seaweed species, their geographic habitat, and millions of other variables.

However, seaweeds have an average of 90-570 mg of magnesium per 100 g of algae.

What Is the Recommended Nutrient Intake (RNI) for Magnesium?

Interestingly, the average amount of magnesium in a handful of seaweed, 90 to 570 mg, represents up to 100% of the recommended nutrient intake (RNI) of magnesium for an average adult.

In comparison to seaweed, spinach only has 54 mg of magnesium per 100g, while whole milk contains 11 mg per 100 g (MacArtain, et al. 2007).  

What Health Benefits Does Magnesium Intake Have?

As it has been mentioned, the National Institutes of Health in the US has stated that magnesium is needed for more than 300 biochemical reactions in the body (three-freaking-hundred of ‘em!).

Just as a little taste of all it does, here are the proven health benefits to magnesium intake:

  • It helps maintain normal nerve and muscle function
  • It supports a healthy immune system
  • It keeps the heartbeat steady
  • It helps bones remain strong
  • It helps regulate blood sugar, blood pressure, and blood glucose levels
  • It also aids in the production of energy and protein
  • Etc, etc, etc.

There is even ongoing research in regards to the role of magnesium in preventing and managing disorders such as high blood pressure, heart disease, and diabetes.

What Risks Are Associated to Low Magnesium Intake?

Magnesium is basically the working class keeping the system moving forward, so if there is not enough of it, body processes start to suffer in the long term.

Too little magnesium does not produce obvious symptoms immediately, because kidneys help retain magnesium by limiting the amount lost in urine.

But for a long period of time, the lack of magnesium in your system can lead to some medical conditions, like loss of appetite, nausea, vomiting, fatigue, and weakness. Without magnesium, the body tries to run without fuel, and it shows.

Extreme magnesium deficiency can cause numbness, tingling, muscle cramps, seizures, personality changes, and abnormal heart rhythm.

Of course, seeing as we are in modern times, a lot of people’s diets provide less than the recommended amounts of magnesium.

Eating a variety of foods that are rich in this mineral is necessary. Legumes, nuts, seeds, whole grains, green and leafy vegetables (such as spinach), milk and other dairy products all can help provide your daily intake.

Seaweeds are not green and leafy vegetables, but they are an excellent green and leafy source of magnesium.  

As we mentioned before, their magnesium levels are so high they are above other green and leafy stuff like spinach, and much more above than popular guys like milk.

Seaweed is indeed a great option to fuel your body with the much-needed magnesium.



Burtin, P. (2003). Nutritional value of seaweeds. Electronic journal of Environmental, Agricultural and Food chemistry, 2(4), 498-503. 

MacArtain, P., Gill, C. I., Brooks, M., Campbell, R., & Rowland, I. R. (2007). Nutritional value of edible seaweeds. Nutrition reviews, 65(12), 535-543.

National Institutes of Health.

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