What is Spirulina

Spirulina is a type of bacteria (blue-green algae) called filamentous cyanobacterium, which is often referred to as blue-green algae, that is incredibly high in protein and a good source of antioxidants, B-vitamins and other nutrients 1), 2), 3).

Spirulina microalgae (Spirulina platensis, Spirulina maxima, Spirulina fusiformis) is considered as a valuable additional food source of some macro- and micronutrients including high quality protein, iron, gamma-linolenic fatty acid, carotenoids, vitamins B1 and B2. When harvested correctly from non-contaminated ponds and bodies of water, it is one of the most potent nutrient sources available.

Spirulina microalgae occur naturally in tropical and subtropical alkaline hot lakes with high pH values and high salt concentrations, like carbonate and bicarbonate. Two species, spirulina platensis and spirulina maxima, are mainly present, the first occurring in Africa, Asia, and South America, whereas the second is confined to Central America. Cultivation of Spirulina on a large scale started 30 years ago in Mexico and China, and later in other parts of the world, owing to the easy conditions for cultivation. Most cultivated Spirulina is produced in open channel raceway ponds, with paddle-wheels used to agitate the water. The largest commercial producers of Spirulina are located in the USA, Thailand, India, Taiwan, China, Bangladesh, Pakistan, Burma (Myanmar), Greece, and Chile. Spirulina is primarily known across the world for its potential nutritional value. There is a concern about toxins produced by cyanobacteria 4). Microcystins, produced by Microcystis sp., were in the news as they caused acute liver failure in more than 100 Brazilian haemodialysis patients. The problem arose due to the use of a contaminated water reservoir, whose filters and carbon adsorption tanks had not been changed for a long time.

Recently, it has experienced a surge in popularity as a dietary supplement. Spirulina is available in capsules, tablets, and powder and has been incorporated in certain foods and beverages such as energy bars, popcorn, and smoothies.

Phycocyanin is an antioxidant substance also gives spirulina its unique blue-green color. Phycocyanin can fight free radicals and inhibit production of inflammatory signalling molecules, providing impressive antioxidant and anti-inflammatory effects.

Spirulina has been shown to lower total cholesterol, LDL cholesterol and triglycerides, while raising HDL (the “good”) cholesterol.

Spirulina may have some anti-cancer properties, especially against a type of precancerous lesion called OSMF (oral submucous fibrosis).

Spirulina supplements have been shown to be effective against allergic rhinitis, helping to reduce various symptoms.


In Spirulina, cells are aggregated into filaments that tend to form spirals. Note the blue-green colour typical of cyanobacteria.

A single tablespoon (7 grams) of dried spirulina powder contains:

  • Protein: 4 grams, though with reduced amounts of methionine, cysteine, and lysine when compared to meat, eggs, and milk, although superior to typical plant protein, such as that from legumes 5), 6), 7), 8).
  • Vitamin B1 (Thiamin): 11% of the RDA.
  • Vitamin B2 (Riboflavin): 15% of the RDA.
  • Vitamin B3 (Niacin): 4% of the RDA.
  • Copper: 21% of the RDA.
  • Iron: 11% of the RDA.
  • It also contains decent amounts of magnesium, potassium and manganese, and small amounts of almost every other nutrient that we need.
  • The American Dietetic Association and Dieticians of Canada, in their position paper on vegetarian diets, state that spirulina cannot be counted on as a reliable source of active vitamin B12 9).

Spirulina is a type of blue-green algae that grows in both salty and fresh water. It may be the single most nutrient-dense food on earth.

spirulina blue green algae after exsiccation

Image of Spirulina algae. Most Spirulina cells, after their exsiccation and transformation into marketed products, are fragmented, but the original characteristics useful for identification are still evident.  (Source 10)).

Spirulina Side Effects

Reported side effects associated with Spirulina consumption are insomnia and gastric problems with uncertain or unlikely causality 11) and only few cases of severe side effects have been reported, including a case of rhabdomyolysis after the consumption of 3 g/day for 1 month 12). Two cases of anaphylaxis caused by Spirulina tablets were reported 13)14) of which one in a 17-year-old male who had a history of atopic dermatitis, asthma, allergic rhinitis, and a possible pollen-food syndrome (oral allergy symptoms to tomato and cucumber) 15). Three cases of autoimmune-mediated skin damage were reported, of which one in a 82-year-old woman 16), whereas the other two cases were observed in subjects consuming Spirulina as ingredient of multicomponent-nutraceuticals (organic cayenne pepper, ethylsulfonylmethane, and the algae Aphanizomenon flos-aquae and Spirulina or Ginseng, Ginkgo biloba, and Spirulina) 17). In this regard, it is well known that plant-food and herbal supplements could have adverse effects, such as hepatotoxicity and autoimmune hepatitis 18). Besides, the two cases described by Lee and Werth 19) involved a 57-year-old man with known pemphigus vulgaris and a 45-year-old woman with a history of hypertension, chronic migraines and fibromyalgia. Furthermore, a case report of hepatotoxicity involved a 52-year-old Japanese man who had a history of hypertension, hyperlipidemia and type 2 diabetes (T2D) and taking medications (amlodipine besilate, simvastatin, and acarbose) 20). In this context, potential food-drug interactions have been hypothesized for Spirulina 21) and for phenolic phytochemicals 22), 23), 24). Therefore, Spirulina should be ingested with caution in subjects with diseases, in particular in patients in treatment with substrates of cytochrome P450 enzymes, such as immunosuppressant, antihypertensive, and lipid lowering drugs 25), 26), 27), 28), 29).

Spirulina and Health Benefits

Numerous studies had reported health benefits of Spirulina in some diseases such as anemia, diabetes, arthritis, cancer and cardiovascular disorders 30). On the other hand, it has been claimed that Spirulina has potential positive effects in therapeutic management of chronic metabolic and non-metabolic disorders 31).

Moreover, despite the fact that Spirulina might represent a functional food with potential beneficial effects on human health, the human interventions used supplements 32), 33), 34), 35), 36), 37), 38), 39), 40), 41), 42), 43), 44), 45), (Ismail M., Hossain M. F., Tanu A. R., Shekhar H. U. Effect of spirulina intervention on oxidative stress, antioxidant status, and lipid profile in chronic obstructive pulmonary disease patients. BioMed Research International. 2015;2015:7. doi: 10.1155/2015/486120.486120. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4320919/()). Although the tested doses (1–20 g/day) in these studies, were not greater than the maximum acceptable percentage (10%) of Spirulina in functional foods, no data are available on the efficacy of Spirulina containing foods. Therefore, the healthy effect of food containing Spirulina should be further evaluated.

  • Impact of daily supplementation of Spirulina platensis on the immune system of HIV patients

This study 46) was performed, to assess the potential effects of 10 grams of daily supplementation of Spirulina platensis with a local balance diet on the level of CD4 cells count and viral load during six months by treatment naïve HIV–infected persons. 169 patients in Cameroon, Africa, aged between 18–65 years, among them 50 men and 119 female HIV–infected naïve to antiretroviral treatment and with CD4 count ≥400 cells/μL were eligible. Patients who had their CD4 below 400 cells/μL during the follow-up were excluded. They were divided into two groups: 87 subjects to the control group (first group) and 82 subjects to the intervention group (second group). The patients of the first group were advised who to take a local balance diet while patients of the second group were asked to add 10 g of S. platensis to their usual diet during the first six months. The S. platensis was given in package of powder doses of 10 grams per day. The next six months were for the follow-up without S. platensis powder. The authors concluded that a daily supplementation with Spirulina platensis to diet combined with a reasonable balanced diet has significantly increased the CD4 cells and reduced the viral load after 6 months. These results showed that spirulina supplementation intake positively and significantly stimulated the immune system and inhibit the replication of viral on HIV-l naïve patients. Further studies are recommended among a large specific group of people infected by the HIV in order to investigate the mechanisms involved on the effect of Spirulina platensis on immune system.

  • Impact of daily supplementation of Spirulina platensis on the weight loss, appetite, lipid profile in obesity

This study 47) was performed, to determine the effects of Spirulina platensis on anthropometric parameters, serum lipids, appetite and serum Vascular Endothelial Growth Factor (VEGF) in obese individuals.

In the current study sixty four obese individuals aged 20–50 years were enrolled and randomly allocated into two groups of intervention and placebo. Intervention group (n = 29) received each 500 mg of the Spirulina platensis a twice-daily dosage while the control group (n = 27) received two pills daily starch for 12 weeks. Anthropometric parameters and serum VEGF and lipid profile were measured in fasting blood samples at the beginning and end of the study period. Dietary intakes were assessed by a 24-h recall method and appetite was measured using standard visual analogue scale.

Diet and physical activity play an important role in regulating weight.As observed in human adipose tissue, one mechanism for an increased inflammatory response may arise through activation of the innate immune system 48). Adipose tissue contains abundant endothelial cells that could secrete angiogenic factors, such as vascular endothelial growth factor (VEGF) 49). Vascular endothelial growth factor (VEGF) is an important angiogenic factor implicated in normal and pathological vessel formation 50), which is an important biomarker in obesity and obesity-related cancer progression 51). Increased serum vascular endothelial growth factor concentrations due to visceral fat accumulation could also influence vascular endothelial function 52).

In this study, the authors mentioned a significant decrease in appetite and consequently weight and BMI (body mass index) in intervention group. The weight reducing effects of Spirulina platensis could be attributed to its appetite reducing effect as observed in the current study. A recent study demonstrated that three months of taking of 2 g/day Spirulina improves BMI and weight as well as blood pressure in overweight patients with hypertension without evidence of cardiovascular disease 53). In the mentioned study, gender and age were considered as parameters with confounding effects and the results were adjusted for these confounders.

In conclusion, the findings of the present study 54) demonstrated that Spirulina platensis supplementation at a dose of 1 g daily was effective in weight regulation, serum total cholesterol and appetite reduction. Several limitations of the current study should also be mentioned; low sample size and short period of treatment could be involved in minor discrepancy of their findings with their hypothesis of change in serum VEGF or other lipids. Although the current study was the first one evaluating the healthful beneficial effects of Spirulina platensis in obesity. Further studies with higher dose, sample sized and study duration are warranted.

  • Hawaiian Spirulina and Blood Pressure

In another study 55), the findings of taking 2 grams of Hawaiian maxima (Spirulina maxima) for three months versus placebo, involving 40 patients with hypertension, showed there was significant reduction in SBP (systolic blood pressure) and SI (stiffness index) was observed. The patients in the spirulina group also showed significant reductions in BMI (26.9 ± 3.1 vs. 25.0 ± 2.7 kg/m2 (placebo), p = 0.0032) and weight loss (75.5 ± 11.8 vs. 70.5 ± 10.3 kg (placebo), p < 0.001). The authors added that spirulina can be used as an adjunctive therapy for hypertension in overweight people. The therapeutic role of spirulina administration needs further investigation. Even though the healthy properties of functional foods and nutraceuticals still need to be fully elucidated, available data suggest that well-designed supplements, containing the better ratio of omega-3 polyunsaturated fatty acids and antioxidants, specific probiotic strains, and selected polyphenols and prebiotics, could be useful in metabolic syndrome prevention and treatment 56).

References   [ + ]

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