Superfood or pond scum? In this evidence-based review, you’ll hear about spirulina’s health benefits and the possible side effects you need to know.
What Is Spirulina?
Spirulina is a blue-green alga, which is precisely a cyanobacteria. It occurs in both salt and freshwater.
Already the Aztecs used spirulina as a natural food supplement. Furthermore, NASA astronauts used the alga on space missions several times.
The blue-green alga is called spirulina because its cells form spirals when viewed under a microscope.
Spirulina is harvested, freeze-dried, and mainly sold as powder or pills.
Because the health benefits of spirulina are exceptional and add exciting color to snacks, drinks, and granola, it is trendy in food production.
Additionally, spirulina consists of approximately 60% protein, covering all essential amino acids.
For this reason, many people consider it the best non-animal protein source available.
Is Spirulina Blue or Green?
The spirulina alga is packed with the natural antioxidant phycocyanin, which gives it a bright blue-green color.
This phycocyanin also ensures that the blue-green alga absorbs enough sunlight for photosynthesis.
Due to the color-giving properties of phycocyanin, spirulina is the only naturally blue food colorant.
Therefore, the blue-green alga is also called blue spirulina. Hence, it’s not a different species.
With this in mind, blue-green algae lattes are hyped by wellness gurus, so they have been conquering the menus of coffee shops lately.
Besides, you may have heard of Blue Majik, an extract of phycocyanin, the spirulina dye. In contrast to Blue Majik, spirulina powder is obtained directly from the algae.
With this in mind, in the wellness and superfood, three algae are currently quite large:
- Spirulina (in blue lattes)
- Green span algae (also a cyanobacterium)
- Chlorella (unicellular freshwater algae)
Above all, these algae have high concentrations of nutrients and minerals such as protein, iron, potassium, zinc, calcium, and B vitamins.
Is Spirulina Healthy?
Due to its excellent nutritional value and health benefits, spirulina is often referred to as a superfood.
Because of spirulina’s amino acids, vitamins, and minerals, it is an outstanding natural supplement for vegetarians or vegans.
According to research, you can experience the following health benefits from spirulina:
- Antioxidant and anti-inflammatory
- Immune system boosting
- Triglyceride lowering
- Weight loss promoting
How Much Spirulina per Day?
You will mostly find spirulina in two forms as a more or less natural food supplement:
- Spirulina powder: Inexpensive with an intense taste
- Spirulina capsules: More expensive, portable, and tasteless, but processed a small step further
Although there is no single scientific opinion on how much spirulina you should take per day, here is an overview of the doses research has used:
- 2 grams daily to lower blood sugar (Winter et al. 20011)
- 4.5 grams daily against high blood pressure (Torres-Duran et al. 20072)
- 8 grams daily for the improvement of blood lipid levels (Lee et al. 20083)
Nevertheless, you should remember that spirulina, despite its natural origin, is a kind of dietary supplement.
Therefore, the appropriate dose may depend on age, gender, nutrition, and medical history. Consequently, you should contact your doctor for a personal consultation.
Health Benefits of Spirulina
Although I do not like the term, spirulina lives up to its superfood title.
Accordingly, it is one of the most versatile foods on the planet, even though it may look like blue-green mud.
However, we will now take a closer look at what the research says about the health benefits of spirulina:
1. Nutrient Density
Due to its high concentration of vitamins, minerals, and proteins, spirulina is considered the most nutritious food in many places. Nevertheless, beef liver is still ahead regarding overall nutrient density (*).
However, the term could apply well to a vegetarian or vegan diet. Either way, spirulina provides a unique composition of nutrients (*):
- Proteins: Spirulina is a complete source of essential amino acids. Due to the 58g of proteins per 100g of spirulina, the alga is often compared to eggs. Spirulina has a net protein utilization rate of more than 50%, equivalent to a raw egg. However, cooked eggs bring 90% bioavailability to the plate (Evenepoel et al. 19984).
- Fatty acids: Although rarely mentioned, spirulina is an excellent source of omega-3 fatty acids. 100g of spirulina provides almost a whole gram of omega-3 fatty acids, exceptional for plant-based food. Moreover, its omega-3 to omega-6 ratio of 1:1.5 aligns with the research’s health ideal (Okuyama et al. 19965).
- Vitamins: The blue algae provides a full charge of thiamine, riboflavin, and niacin. These B vitamins (B1-3) are essential for the functioning of the nervous system and energy metabolism.
- Minerals: Not only do 100g of spirulina exceed the daily requirement of iron, but they also supply three times the need for plant-based copper. Hence, spirulina is incredibly popular among middle-aged women, who suffer from iron deficiency much more often than men due to menstruation (Weinberg 20106).
- Electrolytes: Among other minerals, the blue-green alga provides a balanced composition of the essential electrolytes magnesium, sodium, potassium, and calcium. Therefore, spirulina helps with muscle cramps and ensures the function of the nervous system.
2. Skin and Hair
It’s also the material your body uses to build teeth, joints, connective tissue, skin, hair, and bones. In short, collagen holds the body together.
Accordingly, collagen can slow down skin aging and reduce wrinkles. Studies have shown that collagen supplementation improves skin elasticity (Proksch et al. 20148).
Furthermore, spirulina can promote wound healing and skin cells’ life span (Gunes et al. 20179).
Moreover, spirulina promotes muscle gain. Thus, one tablespoon of spirulina powder corresponds to about six grams of pure protein.
3. Weight Loss and Performance
Those who train intensively induce oxidation, which leads to muscle fatigue.
Spirulina’s antioxidant effect reduces oxidative damage to skeletal muscles and muscle fatigue (Lu et al. 200610).
Further studies have found that spirulina enhances athletic performance and promotes weight loss through fat-burning (Kalafati et al. 201011).
If you are allergic to pollen, dust, or pets, you may know the feeling when the inside of the nose swells up. This process is called allergic rhinitis.
With this in mind, researchers have found that the consumption of spirulina can significantly reduce the following symptoms of allergic rhinitis and increase the patients’ well-being:
- Nasal congestion
- Nasal discharge
Moreover, spirulina algae can reduce inflammation of the nasal mucosa and histamine in the body (Sayin et al. 201313).
Further studies link spirulina with anti-allergy, antiviral, and anticancer effects (Karkos et al. 201114).
5. Anticancer Properties
According to numerous studies, spirulina can be effective against cancer, especially in the mouth (Mathew et al. 199515).
Accordingly, it can counteract changes in connective tissue in the mouth. Not only is it more effective than drugs, but it also causes no side effects (Mulk et al. 201316).
Furthermore, the health benefits of spirulina can reduce tumor growth (Ismail et al. 200917).
6. Blood Glucose Regulation
7. Antioxidant and Anti-Inflammatory Effects
Antioxidants are substances that protect cells from harmful effects. Ideally, you consume antioxidants from natural sources, and spirulina is one of them.
Additionally, phycocyanin gives this alga its blue color.
Furthermore, spirulina is a food with a high oxygen radical absorption capacity (ORAC). This means the ability to neutralize oxygen radicals and prevent oxidative damage to cells.
Therefore, studies show that spirulina can reduce pro-inflammatory cytokines in the body (Gemma et al. 200221).
8. Reduced LDL Cholesterol Oxidation
For LDL cholesterol to become dangerous in the first place, it must acquire oxidative damage.
With this in mind, antioxidants in spirulina can significantly counteract lipid peroxidation (Ismail et al. 201522).
Accordingly, spirulina could reduce oxidative damage and improve blood lipid levels during the day in type 2 diabetes patients (Lee et al. 200823).
9. Antitoxic Properties
One of the primary health benefits of spirulina is its action against heavy metals.
People in Asia and South America still suffer from contaminated drinking water. Researchers have found that spirulina extract is an effective natural treatment for people who have suffered poisoning from drinking water (Misbahuddin et al. 200624).
Moreover, studies suggest that one can even use spirulina clinically against poisoning caused by harmful substances.
Hence, these antitoxic benefits from spirulina can work against the following pollutants in your body (Martinez-Galero 201625):
10. Improved Hypertension
In one study, the oral intake of 4.5 grams of spirulina per day significantly reduced the subjects’ systolic and diastolic blood pressure (Torres-Duran et al. 200726).
With this in mind, researchers assume the reduction is due to increased nitric oxide production. This molecule acts as a messenger and signals blood vessels to dilate (Juarez-Oropeza et al. 200927).
Spirulina Side Effects
The blue-green alga made the headline once that humans would have been ill after consuming it.
Nevertheless, the trigger for this seemed to have been much more the genetically modified maltodextrin and soy protein isolate in the blue-green protein bar.
This is another reason to stay away from highly processed foods, even if superfoods like spirulina spice them up.
With this in mind, the U.S. Food and Drug Administration (FDA) states that most people tolerate spirulina well and do not cause significant side effects (Madrigal-Santillán et al. 201428).
However, you must consult your doctor before adding the supplement to your diet, especially if you take prescription medication.
Some of the few known side effects of spirulina include:
Some people may be allergic to spirulina.
Also, the alga may cross-react with other allergens (Le et al. 201429).
2. Blood Clotting
Spirulina has an effect that dilutes the blood and can thus prolong the duration of blood clotting (Majdoub et al. 200930).
Therefore, you should avoid spirulina if you suffer from a bleeding disorder or are taking blood thinners.
Algae can absorb toxins if they grow in water contaminated with heavy metals or bacteria. This way, they can develop high amounts of microcystins (Roy-Lachapelle et al. 201731).
These are toxins used by algae against predators. Like lectins in nightshades, they may not have a noticeable effect in small quantities, but in more significant amounts, they can be harmful.
Because of their effect on the liver, they pose a health risk. However, spirulina, usually grown in controlled environments, contains hardly any microcystins.
4. Autoimmune Diseases
As spirulina strengthens the immune system, it can aggravate autoimmune diseases in which antibodies attack the body’s cells.
In particular, people with multiple sclerosis and rheumatoid arthritis should be cautious with spirulina (Mukhopadhyay 201532).
The consumption of spirulina increases the production of so-called natural killer cells.
Although natural killer cells strengthen the immune system and slow tumor growth, they can also aggravate autoimmune diseases (Witek-Janusek et al. 200733).
If you suffer from an autoimmune disease, you should be particularly careful and avoid various algae supplements.
People suffering from phenylketonuria (PKU) should strictly avoid spirulina.
Since they cannot metabolize the algae properly, people with this rare metabolic disease must avoid them (Mukhopadhyay 201534).
The Bottom Line
Spirulina is a super rare vegan source of collagen. So if you are vegetarian or want to cut down on animal products, spirulina is your go-to source to maintain skin and hair health.
However, there are a lot more handy health benefits of spirulina. Now that we know that health authorities generally consider spirulina safe and side effects are rare.
Nevertheless, due to the ongoing hype around blue algae, it is essential to be careful in your product selection.
Finally, not every supplier tests for toxicity. And one must be careful of contaminated spirulina preparations.
Since the demand is high, there can be dubious suppliers. Therefore, choosing a GMO-free, sustainable, and organic producer is vital to prevent cross-contamination.
Furthermore, I would not buy highly processed spirulina products. For example, cross-contamination has already been detected in soy protein bars.
Frequently Asked Questions FAQ
How much spirulina should I take daily?
There is no single scientific opinion on how much spirulina you should take per day. However, researchers used doses from 2 to 8 grams of spirulina per day in their trials.
What are the side effects of spirulina?
Health authorities consider spirulina to be generally safe. However, side effects may be caused by specific health conditions or by contamination of spirulina.
Why is spirulina good for you?
The alga may improve blood pressure, glucose, and lipid levels. Besides A, C, E, and K, Spirulina contains various B vitamins that support the nervous system and the body’s energy production.
Is spirulina good for skin?
Spirulina comprises about 60% amino acids, which your body can use to produce collagen. Hence, spirulina benefits skin renewal by supplying its primary building block.
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Mag. Stephan Lederer, MSc. is an author and blogger from Austria who writes in-depth content about health and nutrition. His book series on Interval Fasting landed #1 on the bestseller list in the German Amazon marketplace in 15 categories.
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