What is spirulina?

Spirulina is an edible cyanobacterium, a small blue-green alga. It can be eaten by humans and other animals, and it's been around for about 3 billion years. The name actually means “tiny spring”. This is because its simple cells form long strands that look similar to a coiled spring. There are several different species of spirulina , but two of the most well-known and more extensively researched are Arthrospira platensis and Arthrospira maxima[1].

Today, spirulina is cultivated worldwide and consumed by millions of people around the world for its great nutritional value and numerous health benefits. It is supported as an ideal food and dietary supplement for the 21st century by the FAO (Food and Agriculture Organization) of the   United Nations[2].                                                                              

Historical Use of Spirulina

Spirulina was much appreciated by the Aztecs. It grew wild in the great lakes of Central Mexico. Small cakes of spirulina were sold in the marketplace in Tenochtitlan (Mexico City) and were highly prized[3]. The Aztecs called them tecuitlatl. They collected it from the surface of the lakes using nets and then they left the wet paste in the sun to dry. According to the conquistadors travel journals, tecuitlatl was made into a kind of bread and tasted something like cheese. They didn't care for it much themselves, but the Aztecs found it delicious.


Spirulina may have also been used as a source of nutrition by the Toltecs and the Mayas. There is evidence that the Mayas cultivated it in the same waterways they used for crop irrigation[4].


The Kanembu tribe, who live along the shores of Lake Chad in north-central Africa, have harvested and eaten the microalga for centuries. It is one of their main sources of protein. After it is collected and dried, it turns in a form of biscuit called dihé [5]. This is used in many dishes and is also eaten by pregnant women in order to protect their unborn child from evil magic.

Aztecs' Spirulina
Credit: Wikimedia Commons (PD-Art)

Spirulina's Nutritional Profile and Health Benefits

Protein and amino acids

Spirulina's nutritional profile is quite impressive. First of all, it is full of protein, a rare occurrence in plants. Spirulina contains about 60% (51-71%) of protein. This is a complete protein which means it contains all of the essential amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine). It also provides 10 non essential amino acids (alanine, arginie, cystine, glutamic acid, aspartic acid, glycine, proline, serine and tyrosine).

Fatty acid content

Spirulina is rich in gamma-linolenic acid (GLA) and it also contains, among others, alpha-linolenic acid (ALA), linoleic acid (LA), stearidonic acid (SDA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA)[1].  Fatty acids can't be produced in our body so we have to take them from food sources. Our body needs them for many different fuctions and they are essential for cell health, brain and nerve function, and heart health. 


It also has a high vitamin content, including vitamin A (in the form of b-carotene), a great deal of vitamin K, vitamin D, E, the very important vitamins B1, B2, B3 and B6. It contains pseudovitamin B12, which is similar to the actual B12, but it is biologically inactive in humans[6].  


Spirulina has a substantial mineral content with a respectable amount of calcium and iron, as well as phosphorus, magnesium, zinc, selenium and manganese. 

Spirulina also provides biotin, an important enzyme related to some complex B vitamins. Spirulina is also a rich source of other enzymes, RNA, DNA, sulfolipids, glycogen and other nutrients that could be beneficial for us.

            Spirulina Tablets


A substantial amount of phytonutrients can be found in spirulina. Chlorophyll gives it the characteristic dark green colour. There is also a unique blend of carotenoids, zeaxanthin, superoxide dismutase (SOD), polyphenols and, most importantly, phycocyanin.

Antioxidant Protection

Phycocyanin is the major antioxidant costituent in spirulina[7]. There are several antioxidant mechanisms in this amazing microalga. One of them is scavenging the free radicals that move around and cause damage in various tissues (liver, lung, brain). In addition, it can inhibit lipid peroxidation, a chemical process that damages cell membranes. Sprirulina also modulates various enzymes with metabolizing, detoxifying and antioxidant properties.

Spirulina can counter the oxidative damage caused in the heart and kidneys by some drugs through the free radical generation mechanism[7]. It can also protect against metal induced oxidative damage. In one study, the use of spirulina prevents skeletal muscle damage caused by physical exercise[8].

Spirulina's Antiviral Activity and Immune Boosting

Spirulina contains several biological active molecules which have been shown to inhibit several viruses such as HIV-1, HSV-1, HSV-2, HCMV, influenza type A, measles, etc[9]. Spirulina's compounds intefere with the viruses' ability to bind to particular cell receptors and infect them.

In studies carried out in vitro (test tubes) and in animals it has been shown that spirulina is able to stimulate a variety of immune functions. It can help with the production of antibodies and inhibit inflammation[7]. Other preliminary studies show that spirulina has the ability to inhibit histamine release which causes allergic rhinitis[10].

More in vivo studies are needed in order to fully understand the effects of spirulina in human health, but what we know so far looks promising.

Spirulina and Weight Loss

Spirulina offers great assistance in weight management. Taken before meals, it can help you feel fuller without overeating and not as hungry between meals. It is a natural whole food with no conservatives or synthetic ingredients, a much better choice than diet pills.

Spirulina curbs our hunger by keeping our blood glucose and amino acid levels stable. It is easily digested, since it doesn't have the hard cell wall that other plants have. What's more, it is low-fat, low-calorie and very low in cholesterol.

Spirulina offers the body the nutrients it needs to operate properly. It boosts our energy levels, and this also help us exercise, a necessary part of a weight loss programme. Spirulina can be a great asset in a healthy and balanced diet.

How to use spirulina

Green Smoothie

Spirulina can be used as a whole food as well as a dietary supplement. It comes in the form of tablets, capsules, flakes and powder. Make sure you follow the recommended dosage at all times. In my personal experience, you can feel the effects of this amazing food even with smaller dosages, so take it easy at first. You can have too much of a good thing after all.

The powder is especially useful because it can be used in numerous ways. Spirulina can be added in a variety of recipes of salads dips and sauces. It is an excellent addition to your green smoothies! You can also use it in various homemade snack bars, wraps and spring rolls. You can of course use it in facial treatments. In most recipes, one tablespoon of spirulina powder is enough.

A raw food spirulina recipe

One example of an excellent healthy way to enjoy spirulina in your food.

Spirulina and Contraindications

As of 2003 Arthospira platensis has been granted GRAS status ( generally regarded as safe) by the US Food and Drug Administration (FDA). Spirulina can be consumed by healthy individuals of any age. Always buy certified organic spirulina from a reputable source.

People who suffer from a rare metabolic condition called phenylketonuria (PKU) should avoid taking it because it contains the amino acid phenylalanine which they can't metabolize. Spirulina stimulates the immune system and could theoretically be harmful to people who have an autoimmune disease (multiple sclerosis, rheumatoid arthritis, lupus, etc). Finally, in the case of pregrancy or lactation you should always consult your physician before taking spirulina.