Seaweed’s magical qualities used to be considered a luxury. They are loaded with vitamins and minerals, being some of the most nutrient-dense foods on the planet.

All seaweeds contain all five essential nutrients of a good diet – vitamins, minerals, fibers, protein & fat. They stimulate the metabolism and keep bones, muscles, and the body working properly (read more about how seaweed can benefit you here). All species are also extremely rich in iron and calcium and contain significant amounts of magnesium, potassium, vitamins A, C, and the important B vitamins. Most importantly, seaweed is the world’s richest food in natural organic iodine, a necessary mineral for thyroid and nervous system function.

Did you know? Most people who don’t live near saltwater often don’t get enough iodine!

If you are not already eating seaweed, we hope this article gives you some incentive to get started.

What is Seaweed Made Of?

Seaweed acts like a sponge, absorbing nutrients directly from seawater. Depending on the species, the water content of seaweed is 70-90%, and the remaining content is made up of sugars, proteins, fats, and nutrients. It’s difficult to nail down the nutritional values to exact quantities since there are so many plants and variables. The nutrients vary considerably depending on the water temperature, nearby nutrients, age of the seaweed, depth it grows, and sunlight. Plus the way it’s harvested, stored, and cooked. That said, seaweeds are loaded with vitamins and minerals and are a low-calorie way to get the nutrients your body needs.

Seaweed is a low-calorie way to get nutrients. It is a great addition to diets and can aid weight loss as it contains few calories, filling fiber and protein. All which contribute to increased metabolism.


Seaweed contains many essential amino acids. The amount differs by seaweed type, with some browns having only 5-10% and some reds containing up to 44% protein. Red algae and green algae have the most amino acid proteins with their levels comparable to eating green leafy vegetables, like kale.


Seaweed is an excellent source of fibre, which promotes gut health. There are two types in seaweeds: insoluble fibre, and soluble fibre. Dietary fibre is the most notable, as seaweed contains between 30-60 percent. Fibre is important for a healthy gastrointestinal (GI) system and helps maintain a healthy level of cholesterol. When you eat seaweed the fibre absorbs water from your stomach and expands, helping you feel full and slowing down sugar levels in the blood.

A dietary fibre called Phycocolloids, found only in algae is frequently used in food (and cosmetics) as a thickening agent. As well as an emulsifier and stabilizer as it forms a gelatin-like liquid. The two most recognizable types of Phycololloids are agar and carrageenan which are in many food items, from deli meats to ice creams!


Seaweeds contain relatively little fat. However, the little fat that is found in seaweed (1-5% of its dry weight) is mostly unsaturated and essential fatty acids (EPA); a type of Omega-3 fat that is important for brain health.


Seaweed contains small amounts of vitamins A (retinol), B1 (thiamine), B2 (riboflavin), B3 (niacin), B6 (pyridoxine), C (ascorbic acid), E (alpha-tocopherol) and K (phylloquinone). Vitamins A, C, E, and K are antioxidants that protect your body from cell damage. Whereas the B-vitamins are important for normal brain development and for keeping the nervous system and immune systems healthy. The vitamin makeup of each type of seaweed differs by species and location.

What Minerals Are in Seaweed?

Minerals are essential for good health and the development of the body, there are two types; macrominerals and trace elements. Macrominerals appear in large quantities in the body and are important for your body to stay healthy. Trace elements (or trace metals) are minerals that the body only needs a small amount of, usually less than 0.1% by volume. Your body uses minerals for many different jobs, including keeping your bones, muscles, heart, and brain working properly. The human body cannot naturally make these elements, so it is essential that people consume them through supplements, or better yet – seaweed!

Seaweed Nutrition Facts

Minerals (listed alphabetically)

  • Calcium is associated with healthy bones and teeth. It also helps with blood clotting, heart function, and hormonal balance.
  • Magnesium supports muscle and nerve function and energy production. It’s vital for biochemical reactions in the body.
  • Phosphorus is involved in all bodily processes, most importantly the development of new cells and filtering out waste.
  • Potassium helps maintain normal levels of fluid inside our cells.

Trace Elements (listed alphabetically)

  • Chromium aids in the metabolic foundation.
  • Copper helps form red blood cells and is essential for enzymatic function throughout the body.
  • Fluoride is necessary for strong bones and teeth and prevents oral bacteria.
  • Iodine is essential for thyroid hormones controlling metabolism, growth, and development of the human body. 
  • Iron transports oxygen throughout the body through the blood.
  • Manganese helps the body form connective tissue, bones, blood clotting, and sex hormones.
  • Molybdenum is required for enzymatic functions involved in digestion and excretion. 
  • Selenium detoxifies the body by binding heavy metals. It is an antioxidant that protects against free-radical cells.
  • Zinc aids in cell division, cell growth, tissue repair, and metabolic function. It fights off bacteria and viruses.
seaweed powder, seaweed, laver

Possible Dangers of Eating Seaweed

Seaweed is heavy in Iodine and other minerals, therefore it is not recommended to eat seaweed in unlimited quantities. It is best eaten as a supplement for your diet. For the average consumer, 0.2 to 0.35 ounces of dried seaweed is the ideal amount to add to a daily diet. (Source: Ocean Greens)

 It is important for people to eat seaweed in moderation.

A small 2020 study suggests that consuming seaweed may cause high iodine exposure and notes that seaweed may also contain heavy metals. Though the amounts are usually not toxic, consuming seaweed in large quantities can cause arsenic bioaccumulation.