Spirulina: A miracle nutritional supplement?

Originally Published: September 22, 2006
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What is spirulina? I found some websites that say it's the best thing in terms of nutrition, but I haven't found a source I really trust.

Dear Reader,

Spirulina is a common type of blue-green algae that grows in warm fresh water. Many people tout the nutritional and curative properties of spirulina, and it has been consumed for centuries by many cultures throughout the world.

As a nutritional supplement, spirulina usually comes in the form of pills or powders. It is a source of protein, carbohydrates, vitamins, and minerals. Eating five grams of spirulina provides about 230 percent of the Recommended Daily Allowances (RDAs) of vitamin A and beta carotene, 150 percent of the RDAs of vitamin D and vitamin B12, and 125 percent of the RDA of vitamin K. It's also a rich source of carotenoids, copper, vitamin E, iron, manganese, selenium, and zinc, and studies show that taking spirulina in moderation is not harmful.

Some people believe spirulina may help boost the immune system, prevent allergic reactions, combat certain viruses, lower cholesterol, protect the liver, fight cancer, and even aid in weight loss. So far, studies on animals or in test tubes demonstrate some effectiveness in some of these areas. However, there isn't enough evidence from research with humans to be able to make firm conclusions about its health benefits.

Some people experience side effects or allergic reactions from consistently taking spirulina (at least one gram daily). These may include headache, flushing of the face, sweating, difficulty concentrating, and nausea.

The Food and Drug Administration does not strictly regulate herbs and nutritional supplements the way it does prescription medications; there is no guarantee of the potency, purity, or safety of products such as spirulina. In fact, there may be a risk of contamination by other potentially harmful microorganisms or heavy metals, e.g., mercury. Since there are potential health risks involved, it's a good idea to speak with a health care provider before taking spirulina.