13/06/2020
Q. I read that spirulina is good for your health. What can you tell me about it?
A. Spirulina β classified as a cyanobacteria, or blue-green algae β has been used for centuries as a food source in other countries. Spirulina is available in capsules, tablets, and powder and has been incorporated in certain foods and beverages such as energy bars, popcorn, and smoothies. An Internet search returns hundreds of suppliers from around the world promoting spirulina's supposed health benefits.
Spirulina can grow in extreme conditions inhospitable to most other water-dwelling organisms. It's generally cultivated in manmade or natural lakes, harvested, and freeze-dried. Spirulina boasts a 60% protein content β it's a richer source of protein than most vegetables β and it's also a good source of beta-carotene, various minerals, and gamma linolenic acid, an essential fatty acid.
If claims for spirulina were limited to its high (albeit expensive) nutritional content, we would have fewer concerns about it. But spirulina is also being promoted to prevent, treat, or cure a number of conditions, including high cholesterol, hypertension, diabetes, depression, viral hepatitis, and malnutrition. Moreover, it's said to boost the immune system and improve kidney and liver function. The problem is, there's little or no scientific evidence to back up such claims. A few assertions have been tested, but most trials have been small, poorly designed, or inconclusive.
Like other dietary supplements, spirulina is not regulated by the FDA, so there's no guarantee that the product you buy will be contaminant-free or contain the amount of spirulina promised on the label.
Few side effects have been reported from spirulina when used at recommended doses. But this type of algae theoretically could contain the amino acid phenylalanine and thus should be avoided by people who have phenylketonuria (PKU) β a metabolic disorder in which the body can't metabolize phenylalanine. If you're using spirulina, let your health provider know, as it could interact with other medications you might be taking.
β Celeste Robb-Nicholson, Former M.D.Editor in Chief, Harvard Women's Health Watch