Herbs & Supplements

Should I take it?

Spirulina species include a few of the hundreds of species collectively known as blue-green algae. Algae are tiny organisms that usually grow in water. Because so many different kinds of algae exist, they are grouped by their general color--blue-green, green, yellow-green, red, or brown. Algae do not have leaves, stems, or roots like plants, but most of them contain chlorophyll, the pigment needed by plants to turn sunlight into food energy. Like plants, they also remove carbon dioxide from the air and release oxygen. Like animals, however, algae make proteins and sugars. They multiply rapidly, sometimes making them a nuisance on ponds where they are not wanted. Unlike other algae which are mostly flat or round, spirulina are shaped like springs or corkscrews.

Wild algae provide food for fish, birds, and water animals. Humans have also collected them for both animal and human food at various times and in various parts of the world. Records left by the Spanish explorers of South America, for example, show that Aztec people were harvesting what appears to be some type of blue-green algae from lakes as early as the 16th century. Spirulina's popularity as a food source has been inconsistent, though, with most use in cultures that have few field crops. During the 1970s, researchers rediscovered spirulina as a plentiful and economical source of minerals, proteins, and vitamins. It also contains a polyunsaturated omega-6 fatty acid known as gamma-linolenic acid (GLA). Fatty acids such as GLA are known as essential fatty acids because the human body needs them to regulate activities that include heart function, insulin utilization, and mood balance. Humans cannot produce essential fatty acids, so they must be taken in the diet or as supplements.

Presently, commercial cultivation of spirulina and other types of algae is well-established in several parts of the world. Farmers in warm weather areas of Africa, Japan, North America, and South America cultivate several types of algae crops, including spirulina, in artificial ponds that have controlled nutrient supplies. In cool countries such as Belgium, Britain, and the Netherlands, algae are grown in large, flooded greenhouses warmed by waste heat produced by power generation. Insects do not usually attack algae, so pesticides are not needed and most algae can be grown organically--even outside. Harvested essentially all year, spirulina is collected and cleaned. It is then blended into a thick bluish green liquid, which is fast-dried into a powder. Spirulina powder may then be made into capsules or tablets, or it may be left as a powder to be added to foods.

In a closed environment such as a space station, spirulina and other types of algae may serve as both a food source and an air purification system. Because they are rich sources of nutrients, algae are used extensively for poultry and animal feed in some countries and they have also been used to fertilize crops. Some evidence from recent studies shows that they can be used to remove lead and other contaminants from polluted water. Commercially pure spirulina and other algae provide coloring agents that are used in manufacturing and pharmaceuticals. As an antioxidant, spirulina may be added to cosmetics for potential anti-aging effects or to foods and chemicals as a preservative.

Dosage and Administration

Typically, supplemental spirulina is available in oral dosage form--most commonly as 500 mg or 750 mg tablets. Powdered spirulina is also available. One tablespoon of spirulina powder is about 7,000 mg (7 grams) and directions for taking it usually indicate that it can be mixed into liquids, such as fruit juice, or soft foods, such as yogurt. Doses used in the few human studies that have been conducted varied from about 1,000 mg (one gram) per day to more than 5,000 mg (5 grams) per day. If spirulina is taken, the directions on the package that is bought should be followed for the condition being treated.

Summary

A source of protein for human or animal diets, spirulina also contains antioxidants and chemicals that may increase immune function. Therefore, spirulina may be useful for preventing and treating allergies and cancer. Additionally, it may have antiviral effects and it may help to lower the amounts of sugar and cholesterol in the blood.

Risks

Dermatomyositis, pemphigus vulgaris, and phenylketonuria may be worsened by taking spirulina. Contamination with other types of blue-green algae has resulted in liver damage among individuals using spirulina.

Side Effects

Although no side effects have been identified for spirulina, other types of blue-green algae may cause liver damage.

Interactions

Spirulina is not known to interfere with drugs, other dietary supplements, herbals, or foods.

Last Revised October 19, 2007