Spirulina: Is It Worth Trying?

If you have ever gone to buy a smoothie and wondered what makes some of them blue, it is probably the popular supplement, spirulina. Commonly seen mixed into yogurts, smoothies, and juices, spirulina is considered a "superfood" due to its rich source of various nutrients and antioxidants. Increasingly trendy for its pop of color, spirulina is also known for its health benefits. Are the nutrition benefits of spirulina worth adding this supplement to your regimen? A registered dietitian lays out all the science for you.

What Is Spirulina?

Spirulina is a blue-green algae that is believed to be one of the oldest life forms on Earth. It is usually harvested from bodies of water such as lakes or farmed in ponds. The name comes from the genus Arthrospira, "arthro" meaning "joint" and "spira" meaning "spiral" as spirulina is recognized by its spiral shape. The first known people to recognize spirulina's nutritional properties are the ancient Aztecs. Endurance runners used it because it was thought to help them sustain long runs and treat various diseases.

Spirulina is also becoming a part of astronauts' diets due to its high concentration of macronutrients, vitamins, and minerals. It may help ensure that astronauts receive a nutritionally complete diet in high stress and intensity missions. Packed with nutrients and a sky-blue, eye-catching color, it is no wonder that spirulina has made its way into the wellness space.

What Does the Research Say?

Spirulina can grow in both fresh and salt water and research supports many of its health benefits. One tablespoon or 7 grams of dried spirulina powder contains 4 grams of protein, many B vitamins, copper, iron, magnesium, and potassium. Spirulina also contains a source of omega-6 and omega-3 fatty acids important for heart and brain health.

May Protect Against Oxidative Damage

Oxidative damage from the environment can harm cells and contribute to chronic inflammation and cancer. Spirulina is a rich source of antioxidants, which can help protect against oxidative damage. Its main active component is phycocyanin, which when isolated from marine organisms can be used as a functional food. There is evidence for its anti-inflammatory and anti-cancer functions and is even being used in development of a potential anti-cancer drug. Phycocyanin is also what gives spirulina its blue-green color.

May Decrease Risk of Heart Disease

Spirulina may help decrease the risk of heart disease by lowering triglycerides and LDL or "bad" cholesterol and raising HDL or "good" cholesterol. In one study that looked at individuals with high cholesterol, taking one gram of spirulina per day for 12 weeks lowered triglycerides by 16.3% and LDL cholesterol by 10.1%.

May Reduce Blood Sugar

While animal studies show promising results for spirulina's use in lowering blood sugar, there are limited effective studies in humans to date. In humans, a meta-analysis was conducted in 8 studies with individuals with type 2 diabetes. The studies showed a beneficial effect with spirulina supplementation on fasting blood glucose levels, but no significant effect on HbA1C or post prandial blood sugar. Spirulina may play a role in decreasing fasting blood sugar in individuals with type 2 diabetes, but larger and longer-term studies in humans need to be done.

May Improve Muscle Strength and Endurance

Some studies show spirulina's role in improving muscle strength and endurance and it is increasingly used in athletes. One study examined spirulina supplementation in trained cyclists. Fifteen male cyclists consumed 6 grams of spirulina per day or a placebo for 21 days. They completed a one-hour submaximal endurance test followed by a lactate threshold test and repeated sprint performance tests. The individuals in the spirulina supplementation group had significantly lower lactate and heart rate and significantly higher hemoglobin. Spirulina supplementation may be helpful to increase endurance and power in athletes.

While more research needs to be done, spirulina taken in powder or supplement form may have benefits for decreasing the risk of cancer, lowering triglyceride and LDL cholesterol levels, and decreasing fasting blood sugar. It also may be helpful for athletes to increase muscle strength and endurance in addition to providing many necessary macro and micronutrients to support overall health and well-being. Always speak with your healthcare provider before starting any new supplements.

Is Spirulina Harmful?

Although spirulina is generally considered safe, there are some side effects and potential dangers to consider. Additionally, dietary supplements are not regulated by the FDA. When possible, choose a supplement that has been tested by a trusted third party, such as ConsumerLabs, USP, or NSF.

Spirulina may be contaminated with toxins when harvested from the wild. The algae may contain toxins if it grows in bodies of water that are polluted with heavy metals, bacteria, or microcystins. Microcystins are produced by blue-green algae to defend against predators. However, when consumed in high amounts in humans, microcystins are toxic to the liver. Spirulina is grown in controlled environments where scientists can monitor and remove any harmful toxins.

Because spirulina plays a role in boosting the immune system, it may not be recommended for those with autoimmune diseases, such as lupus, multiple sclerosis, and rheumatoid arthritis. This is because, with these conditions, the immune system attacks the body and spirulina strengthens cells in the immune system that are responsible for perceiving a threat. While research on humans is limited, one animal study on shrimp suggests that the immunostimulatory action of spirulina may exacerbate a person's autoimmune condition.

Spirulina is contraindicated in those with bleeding disorders or for those taking blood thinners. Spirulina has an anticoagulant effect, which means that it can thin your blood and increase the amount of time it takes for your blood to clot. Taking spirulina with a blood thinner may be dangerous, causing more bleeding and bruising.

How to Incorporate Spirulina Into Your Diet

While it is always a good idea to get most of your nutrients through food, spirulina can help to fill in some gaps or give you an extra nutrition boost. With a varied diet that contains fruits, vegetables, whole grains, proteins, and fats, supplementation is not generally necessary. However, spirulina contains a number of vitamins, minerals, and antioxidants that are important for health and well-being.

For individuals who struggle to get enough protein, spirulina can be a good addition to the diet. While spirulina will not supplement all of the protein you need in a day, the amount is comparable to that of meat and soybeans. Approximately 5 to 15 grams of spirulina provide about 3 to 9 grams of protein. Mix spirulina powder into yogurts or smoothies to increase your protein intake even more. You can also find spirulina in some top-rated kombuchas.

Some individuals may have a difficult time getting enough iron, particularly vegans and vegetarians. Spirulina may be helpful in boosting iron for those not eating enough food sources of it. In one study, 240 children with iron deficiency anemia were given spirulina supplements or a placebo to take for 6 months. Those who took the spirulina supplements had faster reversal and recovery from iron deficiency anemia compared to the placebo group. Spirulina may play an important role in increasing iron for those who cannot get enough through food.

If you are looking to up your antioxidant intake, spirulina may be a superfood to add to your diet. There is significant evidence for spirulina's antioxidant and anti-cancer effects. It can be taken in supplement form as an addition to a diet rich in a variety of fruits and vegetables.

A Word From Verywell

Spirulina may be a superfood that is worthy of adding to your diet due to its nutrient-packed profile. Always speak with a healthcare professional before adding spirulina into your diet. It may interact with medications you are taking or be contraindicated in certain medical conditions and pregnancy.