Spirulina is a type of algae considered to be one of the Earth's oldest forms of life that grows in fresh or salt water. It comes as a supplement, in tablet or powder form. People use it for its health benefits, as it is rich in nutrients and has antioxidant properties.
Spirulina is packed with nutrients. A single tablespoon (tbsp), or 7 grams (g), of dried spirulina powder, contains: Protein: 4 g Thiamin: 14% of the Daily Value (DV) Riboflavin: 20% of the DV Niacin: 6% of the DV Copper: 47% of the DV Iron: 11% of the DV It also contains small amounts of magnesium, potassium, and manganese. In addition, the same amount contains only 20 calories and less than 2 g of carbohydrates. Spirulina also provides a small amount of fat — around 1 g per tbsp (7 g) — including both omega-6 and omega-3 fatty acids in an approximately 1.5 to 1 ratio.
The main component of spirulina is called phycocyanin, which is an antioxidant that also gives it its unique blue color. Phycocyanin can help fight oxidative stress by blocking the production of molecules that promote inflammation and providing impressive antioxidant and anti-inflammatory effects.
Spirulina can help total cholesterol, low-density lipoprotein (LDL) or bad cholesterol, and triglycerides, while also increasing high-density lipoprotein (HDL) or good cholesterol, which are all risk factors for heart disease. According to one review, spirulina was able to significantly improve these markers in people with metabolic syndrome and related disorders.
Fatty structures in your body are susceptible to oxidative damage. This is known as lipid peroxidation a key driver of many serious diseases.Research found that the antioxidants in spirulina may be particularly effective at reducing lipid peroxidation.In fact, one small study showed that spirulina supplementation was able to reduce exercise-induced lipid peroxidation, inflammation, and muscle damage in 17 rugby players.
While more studies are needed, some evidence suggests that spirulina has anti-cancer properties. Research in animals indicates that it may help reduce cancer occurrence and tumor size in various cancers.
One review of five studies found that taking 1-8 g of spirulina per day could significantly reduce both systolic and diastolic blood pressure, especially for people with high blood pressure levels. This reduction is thought to be driven by an increased production of nitric oxide, a signaling molecule that helps your blood vessels relax and dilate.
Spirulina is a popular alternative treatment for symptoms of allergic rhinitis, and there is evidence that it can be effective. For instance, one study found that spirulina was more effective than cetirizine, an antihistamine used to treat allergies, in improving symptoms of allergic rhinitis and decreasing inflammation.
Anemia is fairly common in older adults, leading to prolonged feelings of weakness and fatigue. A 2020 study found that taking spirulina may improve anemia in pregnant people during the second trimester. In 2021, researchers also found it may also improve iron deficiency in young children.
Exercise-induced oxidative damage is a major contributor to muscle fatigue. Spirulina may help reduce this, as research points to improved muscle strength and endurance. In another study, spirulina supplementation was able to improve oxygen uptake during an arm cycling exercise, with researchers noting that it could act as an ergogenic aid to enhance athletic performance.
Animal research suggests that spirulina could help lower blood sugar levels. However, according to one review of eight studies on humans, spirulina supplementation in doses ranging from 0.8-8 g daily could significantly reduce fasting blood sugar levels in people with type 2 diabetes. However, there was no significant effect on blood sugar levels after eating or levels of hemoglobin A1c, which is used to measure long-term blood sugar control.