Thanks to trendy wellness blogs and so-called health gurus, spirulina has recently skyrocketed in popularity. But long before social “influencers” made it a staple of smoothie bowls and green juices, spirulina has been used as a food source by various cultures for centuries.
Manufacturers and proponents claim that spirulina packs a punch of protein, antioxidants, and other compounds that strengthen the immune system, tame inflammation, aid with digestion, support a healthy cardiovascular system, and regulate energy levels. But do spirulina products—many of which are not regulated by the FDA—actually deliver on their grandiose claims? We spoke with a sports dietitian to cut through the clutter and dive into the health and performance benefits of spirulina.
What Even Is Spirulina?
First, let’s lay out what exactly spirulina is: It is a type of cyanobacteria, which is a family of single-celled microbes that grow in both fresh and salt water and is often referred to as blue-green algae. In fact, it is quite possibly one of the oldest life forms on Earth. After harvesting (most often from man-made spirulina lagoons), the biomass is dried into a powder that can then be used as is, turned into capsules, or incorporated into foods. So it’s a “green” that you won’t find alongside kale and spinach in the produce department of the grocery store, nor is it the same type of seaweed you’ll see on a sushi platter.
What Does The Science Say?
Before you start dusting your oatmeal in the green stuff, you should know that spirulina research is scant. Only a few small studies support some of the overarching health claims.
Some preliminary data suggests that supplementing with spirulina daily can improve blood cholesterol and triglyceride levels along with blood pressure numbers, which could make it an ally in the battle against heart disease. Other research hints at the idea that spirulina may make it easier for people, particularly those with diabetes, to control their blood sugar. Some evidence also suggests that spirulina has anti-cancer properties (though most of this research hails from rodent studies, and we, as humans, are different than lab rats).
But popping an algae pill will likely mostly benefit people who start out with unhealthy cholesterol or blood pressure levels and poor blood sugar control. “It’s easier for a study to look at how a substance like spirulina has an effect on a measurable outcome, like a disease,” says Lori Nedescu, a sports dietitian and founder of Hungry for Results. “It’s much harder to assess how it can prevent an outcome.” So, we still have no idea if a daily spirulina habit can help a healthy runner stay healthy.
Certain antioxidants in spirulina such as phycocyanin, which gives it the unique blue-green hue, may benefit bodies in motion by altering metabolism and protecting muscle cells from damage. “Likely one the biggest benefits of spirulina for runners would be associated with its high antioxidant content,” notes Nedescu. “Athletes who consume more antioxidants can potentially recover their muscles faster, have increased blood flow to muscles, and prevent chronic inflammation; all things that lead to better performance.”
A study in the journal Medicine and Science in Sports and Exercise found that nine fairly fit volunteers who supplemented with 6 grams of spirulina (roughly 2 teaspoons of powder) for a month were able to run longer before fatiguing and burned more fat during a treadmill exercise trial. Still, more large-scale studies are needed before we declare spirulina to be the key to nailing a PR. The aforementioned study is very small and did not do a very good job of controlling for other potential dietary influences.
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What Are the Nutritional Benefits of Spirulina?
Spirulina is relatively high in protein, at least by weight (about 70 percent of its mass is protein). It’s one of the few plant-based foods considered a “complete protein,” meaning that it contains the amino acids your body needs but can’t make on its own. But this does not make spirulina the ultimate muscle-builder. You’d have to eat a lot of spirulina for it to noticeably contribute to your daily protein needs, and that, frankly, would be gross. A one-teaspoon serving of spirulina powder has roughly 2 grams of protein, whereas a single ounce of chicken has about 7 grams. “Spirulina is very nutrient dense, but should not be looked at as a good source of protein,” Nedescu cautions.
Proponents like to trumpet spirulina as being extremely high in chlorophyll, which it makes when it absorbs energy from the sun. However, the claims that this helps detox the body and boost the immune system are not scientifically proven to say the least.
Yet, one benefit of spirulina that is totally legit is its sky-high levels of beta-carotene–a single teaspoon serving ponies up well over twice the daily requirement. “Beta-carotene is very important to us as it plays a role in so many body functions including eye, skin, and lung health,” says Nedescu. Some of this occurs via its ability to be converted to vitamin A in the human body. However, Nedescu points out that you don’t necessarily need to rely on pricey spirulina powders to get what you need since many fruits and vegetables are also loaded with this nutrient.
On top of beta-carotene, the sea green is also a notable source of vitamin K. “Vitamin K is an understated nutrient that plays a big role in blood clotting and bone health, explains Nedescu.
You may have also heard that spirulina can contribute some iron to your diet. But the form of iron in spirulina is not as well as absorbed as that found in meats like beef. Still, one study found that spirulina supplementation can help older individuals overcome anemia, but it’s not known if that would also be the case for runners with low iron status.
Though spirulina is sometimes lauded as a vegan-friendly source of vitamin B12 (used in making red blood cells), Nedescu cautions that it contains a form of pseudo B12 that is not very bioavailable to the human body.
Should You Try Spirulina?
Since spirulina grows in water, there is the risk it can become contaminated with heavy metals and other hazards. A lack of quality control in the supplement industry makes matters worse. As such, do your research to pin down a brand that is transparent in what they are delivering. Some brands are third-party tested to show they are free of contamination and that you are getting what the label says.
If you are interested in trying spirulina, there are a couple of ways to do so. It’s a common ingredient in bottled green juices, where the amount you are actually consuming can vary greatly, but it also comes in capsule form or as a stand-alone powder that can be stirred into water, juice, or smoothies. Some people will also use the powder to bolster the nutrition of homemade energy balls and bars.
These products below make it easy to work spirulina into your diet in a way that doesn’t taste like pond scum.
The Bottom Line
While much more research is needed before we award spirulina with superfood status, Nedescu says that athletes who want to try it for a nutritional boost can do so, “but don’t base your nutrition needs around it,” she says. “Including spirulina in the diet should be considered a supplemental action that could potentially have a small impact on health outcomes and performance on top of an already healthy diet.” In other words, it won’t hurt to try it (except maybe your wallet), but spirulina is not going to be your ultimate panacea.