Spirulina: The Missing Component of Freediving Nutrition?


  • Spirulina is a blue green algae that grows in both fresh and salt water.

  • It is cultivated worldwide and consumed as both a whole food and supplement.

  • Spirulina contains more bio-available iron than any other food.

  • Spirulina also contains more calcium than milk.

  • Has 2 to 3 times more protein than meat or fish by mass.

  • Spirulina may help formation of Red Blood Cells (RBCs).

  • Spirulina is an excellent supplement for freedivers (especially vegetarians).

In this article we discuss spirulina, it’s potential health benefits and application to a freediver’s nutrition. All numbers are based on an intake of 10 gram daily.

We do not dispense any medical advice. Consult a physician prior to using any supplements.

Health benefits

Minerals and Trace Metals

This is the bombshell, so let’s start here:

Spirulina has the highest source of iron (by weight) in a form that is easily assimilated by the human body. 10 grams (two tea spoons) of spirulina can contain 5 to 18 mg of iron, or 36 to 125% of daily requirement. Iron helps hemoglobin formation, which facilitates oxygen transport in the blood. Iron is considered a “limiting factor” for freedivers.

Source: Les Vertues de la Spiruline

Spirulina contains many of the trace metals the body requires. These include boron, calcium, chromium, cobalt, copper, iron, magnesium, manganese, phosphorous, potassium, sodium and zinc.

These elements are all highly absorbable in the body because of spirulina’s cellular structure. This is far more effective than taking each element individually.

Spirulina contains more calcium than milk (25 to 140 mg per 10g), 3 to 18% of the daily requirement per dose. It also provides 5 to 11% of the daily dose of magnesium, which aids in energy transport, as well as metabolizing calcium and Vitamin C. Magnesium also helps to fend off cramps.


Spirulina comes only second to beer yeast when it comes to Vitamin Bs (Vitamins B1, B2, B3, B5, B6, B8, B9 and B12).

Vitamin B12 plays a role in the growth and formation of red blood cells (RBCs). This fact made my friend and national record holder Sheena McNally very happy, as Guinness beer contains a lot of B12. Sheena is a vegetarian freediver and loves Guinness Beer, especially the night before her deep dives.

There are, of course, predictable issues with using Guinness as source of Vitamin B, such as dehydration, hangovers and bad attempts at an Irish accent.

Spirulina comes only second to beer yeast when it comes to Vitamin Bs (Vitamins B1, B2, B3, B5, B6, B8, B9 and B12). Unfortunately most of the vitamin B12 in spirulina is present as pseudovitamin B12. This is essentially the same chemical formula but a different structure. So for your vitamin B12, maybe keep drinking that Guinness.

Spirulina is also rich in Beta-Carotene, a precursor for Vitamin A production. It’s known for its properties as an antioxidant, which in turn reduces free radicals. This is yet another benefit, as free radicals cause oxidative damage in the tissue during freediving (read also about nitric oxides here).

Spirulina also contains 10 to 15 times more beta-Carotene than carrots. Two tea spoons of spirulina contain 875% to 2500% of the daily recommended dose of beta-Carotene.

Source: Les Vertues de la Spiruline

Vitamin E is an antioxidant, protects RBCs and helps to prevent cardiovascular diseases. One daily dose can provide 4 to 16% of required Vitamin E, which is more than wheat germ. Vitamin K promotes coagulation and calcium fixation for bone development. Like spinach, spirulina is one of the highest sources of Vitamin K, with 266% of daily requirement met per dose.

Proteins & Amino Acids

Spirulina contains 60% to 70% (by dry weight) of protein. It contains twice as much protein as soy, and 2 to 3 times more protein than meat and fish. Proteins are essential for athletes as they contribute to recovery, especially after deep and taxing dives.

We need a variety of different amino acids, and spirulina contains all the essentials (proteins are made of amino acids). Not every protein is made of the same amino acids. Spirulina is one of those wonder proteins that contains all the amino acids that we can’t make ourselves (ones we need to ingest) and a little extra.

The miracle of spirulina is in its biological structure. Spirulina lacks a rigid cellulose wall (unlike many vegetables we can’t digest). This allows for easy digestion and absorption of its nutrients.

Source: Les Vertues de la Spiruline

Phycocyanin and Chlorophyll

Phycocyanin is a blue pigment specific from cyanobacterias. It is studied for its importance in immune system stimulation, as well as its anti-oxidative and anti-inflammatory capacities. It can be extracted from spirulina and used as a separate supplement (Laval-Legrain, G. et Legrain, B. Les vertues de la spiruline. 3rd Edition. Editions Jouvence. 2013.)

Similarly, chlorophyll is the green pigment that gives spirulina its green colour. In our bodies, chlorophyll helps to maintain acid/base equilibrium and to eliminate heavy metals.

Spirulina in its raw form provides the highest nutritional value of iron, minerals, anti-oxidants and vitamins. Courtesy of “Spiruline de Nicolas”.

Vegetarian Freedivers and Anemia

Freedivers, vegetarians and vegetarian freedivers have particular eating habits. We also eat irregularly due to our diving schedules. Spirulina is helps stimulate digestion and regulate appetite due to the presence of phenylalanine.

Freedivers with naturally low RBCs counts and hematocrit concentrations could (with the consent of their physician) consider spirulina supplementation. This is especially true if you’re a vegetarian with an irregular diet.

Several users of spirulina include women prone to anemia, especially during pregnancy. Anemia occurs when you have a low amount of healthy red blood cells (RBCs) in your body.

The high bio-availability of iron in spirulina has shown to improve blood quality in anemic and pregnant women. This availability in spirulina is considered to be superior to iron found in beef.

Source: Les Vertues de la Spiruline

Environmental Benefits

Spirulina is an ancient cyanobacteria which has existed for more than 3.5 billion years. Spirulina is one of many micro-algae responsible for producing oxygen in the atmosphere. It does so through photosynthesis, and uses carbon dioxide in the process.

Spirulina yields 20 times more protein per hectare compared to soy production. Furthermore, it is produced year-round.

Source: Les Vertues de la Spiruline


We would like to thank Nicolas Hoffman from “Spiruline de Nicolas” for providing the spirulina and information to write this article. Nicolas runs one of the top artisanal spirulina farms in Rahon, France.

He produces a high quality product at his small-scale farm. 100% sustainable, natural, GMO-free and with no pesticides used.

To get in contact with Nicolas please visit www.spirulinedenicolas.com.


  • Laval-Legrain, G. et Legrain, B. Les vertues de la spiruline. 3rd Edition. Editions Jouvence. 2013.

  • Falquet, J. Spiruline Aspects Nutritionels. Antenna Technologies. 1996.

  • Jourdan, J.P. Cultiver votre spiruline: manuel de culture artisanale de la spiruline. Antenna Technologies. 1998.

  • M.C. Carty M.F. et al. Genistein and phycocyanobilin may prevent hepatic fibrosis by suppressing proliferation and activation of hepatic stellate cells. Medical Hypotheses 72 (2009) 330-332.

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