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What Are the Benefits of Spirulina Tablets?

author image Joanne Marie
Joanne Marie began writing professionally in 1981. Her work has appeared in health, medical and scientific publications such as Endocrinology and Journal of Cell Biology. She has also published in hobbyist offerings such as The Hobstarand The Bagpiper. Marie is a certified master gardener and has a Ph.D. in anatomy from Temple University School of Medicine.
What Are the Benefits of Spirulina Tablets?
Spirulina tablets spilling from bottle Photo Credit: Vesna Sajn/iStock/Getty Images

You probably know that algae grow in water, but you may be unaware of the possible benefits of a special type called blue-green algae. Actually not algae, blue-green algae are highly specialized bacteria, or Cyanobacteria, that grow naturally in high-salt, alkaline bodies of water. One type, called spirulina, was probably harvested and consumed by the Aztecs, as well as by ancient people who lived near African lakes where the microorganism grows. It is available as a supplement that's highly nutritious, contains vitamins and minerals, and provides compounds that may have significant health benefits.

Packed With Nutrients

Pure protein makes up about 65 percent of the mass of spirulina and includes 22 essential amino acids, which your body is unable to manufacture. Spirulina also provides iron, with about 2 milligrams in each tablespoon, and its iron is easily used by your body, unlike iron from many plant sources. One tablespoon of dried spirulina also contains 8 milligrams of calcium and trace amounts of other important minerals, including manganese, selenium and zinc. Spirulina is also a source of several vitamins, including vitamin A, vitamin K and several B vitamins.

Possible Cancer Prevention

A substantial amount of laboratory research suggests that one or more compounds in spirulina might prevent or slow growth of cancer cells. For example, a study published in 2004 in "Biochemical Pharmacology" found that a protein called C-phycocyanin in spirulina significantly reduced growth of cultured leukemia cells by causing the cells to undergo a type of cell death called apoptosis. In another study published in 2009 in "Cancer Science," researchers found that laboratory animals who consumed spirulina had increased activity of immune cells called natural killer cells that can destroy cancer cells and developed fewer malignant tumors than animals fed a placebo. These findings from laboratory research are promising, but studies of the supplement's possible effects on cancer in human subjects are still needed.

Allergies and Asthma

Consuming spirulina supplements might help suppress nasal allergies and asthma, according to both laboratory and clinical research. In a clinical trial published in 2008 in the "European Archives of Oto-rhino-laryngology," 85 subjects with nasal allergies consumed spirulina supplements, along with 44 who took a placebo. In the treated group, subjects had less sneezing, congestion and itching compared with the placebo group, and researchers concluded that spirulina is clinically effective for this condition. A small study published in 2001 in the "Journal of Neutraceuticals, Functional and Medical Foods" found that subjects with asthma who consumed spirulina supplements had improved lung function equal to that in a group who took medication, but this small study needs confirmation in larger clinical trials.

Safety and Recommendations

Spirulina is available from health-food stores in tablets or as a loose, dried powder. Although it's generally considered a safe supplement, some preparations might be contaminated by a toxic compound called microcystin and might also contain mercury, so only choose products certified free of these contaminants. Avoid taking spirulina if you're pregnant or breastfeeding, because its safety hasn't been studied in these conditions. It might also interact with certain prescription medications, such as immunsuppressives. If you have a condition called phenylketonuria, or PKU, don't consume spirulina, which contains the amino acid phenylalanine. Talk to your family doctor about spirulina to decide if it might be helpful for you.

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