Spirulina is a genus of blue-green algae used as a nutritional supplement. Blue-green algae, which are microscopic fresh-water organisms, are also known as cyanobacteria. Their color is derived from the green pigment of chlorophyll, and the blue from a protein called phycocyanin. It grows naturally in fresh water ponds and is grown commercially in the US, East Asia and Southeast It is most frequently taken in pill form or sprinkled as flakes or powder over another food.


The average serving size for spirulina is 1 tbsp. This represents an average sprinkle added to food or the content in many commercially produced tablets. One such serving contains 20 calories. Spirulina is about 65% protein by composition. These proteins are complete, in that they contain all essential amino acids. It also has high digestibility and bioavailability of nutrients.

Spirulina is rich in thiamin and riboflavin, delivering more than 10 percent of your daily allowance per serving. It also contains between 1 and 2 percent of your daily vitamins A, C, E, K, B3, B6, B12 and folate.

A serving of spirulina delivers 21 percent of your daily copper, 7 percent of your manganese and 11 percent of your iron. It contains 3 percent each of your daily magnesium, potassium and sodium; and 1 percent each of your calcium, phosphorus, zinc and selenium.


Spirulina has been used as a source of protein and nutrients, particularly beta-carotene, by the World Health Organization (WHO) to feed malnourished Indian children.

There is a high vitamin B12 content in spirulina. For this reason, it has often been recommended as a supplemental source of the vitamin for vegans and other strict vegetarians, who are unlikely to have adequate dietary intake.

Spirulina is a good source of available iron and zinc. A study done in rats found that those consuming spirulina had equivalent or better absorption than those given a ferrous sulfate iron supplement. A small human study of iron-deficient women had good response to iron supplementation with spirulina, although the amounts used were large (4 grams after each meal). Similarly, a study of zinc deficient children found that those taking spirulina had a superior response to those taking zinc sulfate, and had fewer side effects.

A stronger immune system is one claim made by boosters of spirulina. A number of animal studies appear to support stimulation of both antibody and cellular types of immunity. Immune function was markedly improved in children living in the areas surrounding Chernobyl. The measurements were made after 45 days, with each child consuming 5 grams of spirulina per day.

Cholesterol, serum lipids, and low-density lipoprotein (LDL) cholesterol may be lowered by a small but significant percentage by the consumption of spirulina.

Spirulina has the highest concentration of evercetin found in a natural source. Evercetin is a potent antioxidant and anti-inflammatory compound that can be used to alleviate the symptoms of sinusitis and asthma. Phycocyanin, the protein that gives spirulina its blue color, has also been shown to relieve inflammation associated with arthritis and various allergies.

Dr. Sal’s Thoughts: 

I usually add a teaspoon of spirulina to my smoothies, or use spirulina crunches (buy at Whole Foods) to my home-made raw bars or cookies.

It is expensive, so I tend to buy the powder online at Amazon.



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