Like seen with other minerals, sea vegetables contain more magnesium per gram than just about any other food, with Irish moss and sea lettuce being especially good sources. A 5-gram serving of sea lettuce flakes meets over 25% of the RDA for men.
Seaweeds such as Sea Spaghetti, Dulse and Carrageen have the most magnesium.
Nori is the go-to sea vegetable for sushi, and USDA data shows that the algae has protein and beneficial vitamins like C and K, and compounds (including taurine, which can help prevent gallstones).
Seaweed contains several useful plant nutrients, including nitrogen, potassium, phosphate and magnesium.
Magnesium comprises around 0.7-3% (dry weight) of the seaweeds Laminaria digitata, Fucus serratus, Ascophyllum nodosum, Sargassum muticum, Irish moss and Sea Lettuce.
Seaweeds contain many vitamins, such as A, D, E, C and B, and minerals including calcium, potassium, magnesium and iron.
The best plant sources of magnesium include wholegrain foods (quinoa, wholemeal spaghetti, wholegrain rice, oatmeal or rolled oats and wheat germ), nuts (Brazil nuts, almonds, cashew nuts, hazelnuts, walnuts, pecans, pistachios, peanuts and peanut butter), seeds (pumpkin seeds, sunflower seeds, sesame seeds and tahini ...
“They have so much iodine that consumers are advised to eat it no more than three times per week.” Since the concentration of specific nutrients in seaweed can interact with various medications, check with your doctor if you have a thyroid condition or take blood thinners before going all in.
Nori. This kelp is rich in iodine, iron, and vitamin K and is high in protein. It's also a good source of vitamin C, vitamin A, potassium, magnesium and riboflavin, and is a low-fat food.
May contribute too much iodine
And while iodine is an essential nutrient, there is such a thing as getting too much of it, which can be easy to do if you're eating a lot of sea vegetables daily. Too much iodine can lead to hyperthyroidism and can also interfere with thyroid medications, like Synthroid.
Sea Vegetables
Get to know hijiki, nori, kombu, arame, kelp, dulse, Irish moss, and alaria esculenta, each with its unique taste, look, and texture.
Seafood also proves to be an excellent source of magnesium. Oysters, clams and winkles are the richest, with 410 mg of magnesium in 100 grams of seafood.
Forms of magnesium that dissolve well in liquid are more completely absorbed in the gut than less soluble forms [2,12]. Small studies have found that magnesium in the aspartate, citrate, lactate, and chloride forms is absorbed more completely and is more bioavailable than magnesium oxide and magnesium sulfate [12-16].
Spinach. Many leafy greens contain magnesium, and spinach tops the list at 78 milligrams per 1/2 cup serving of cooked leaves.
Seaweed contains a high amount of potassium, which can be harmful to individuals with kidney disease. Seaweed also contains vitamin K, which could interfere with blood-thinning medications such as Warfarin. Some varieties may have high levels of heavy metals.
“Even with a smaller amount of seaweed, you can get a lot more nutrients out of it than ground vegetables,” Hatanaka says, such as magnesium and iron. Many seaweeds also contain vitamin A, vitamin K, folate and some vitamin B12, though not all types contain B12 that can be digested by humans.
"It is difficult to determine how much seaweed a person should consume to benefit from its good qualities," said Mouritsen. "Five to 10 grams of dried seaweed per day is my estimate." Not that you should need to seek this out or sprinkle it on your breakfast cereal (although you can if you wish).
Magnesium deficiency in healthy people is rare but it can be caused by: a poor diet (especially in elderly people or those who don't have enough to eat) type 2 diabetes. digestive problems such as Crohn's disease.
In their lab at the University of Hawaii, nutritionists studied 13 varieties of popular edible seaweeds, and found that, while many of them are indeed rich in iron, only two types—nori and sea lettuce—provide more bioavailable iron than you'd get from eating the same amount of spinach. Popeye would be pleased.
The nutrition facts for seaweed were based on a serving size double of that of kale's with relatively similar numbers. Therefore in theory seaweed, at least from a nutritional standpoint, is twice the superfood that kale is.
It is possible to eat too much seaweed, especially if it contains large amounts of iodine, which can affect thyroid health. A small 2020 study suggests that consuming seaweed may cause high iodine exposure, which can lead to a thyroid condition. A 2019 review notes that seaweed may also contain heavy metals.