Spirulina microalgae stands out for its unparalleled values of high biological value protein. As well as for vitamin, mineral and antioxidant contents. It stimulates the immune system, plays an important role in preventive medicine, and helps with weight loss as well. Brief scientific review.
Spirulina, microalgae extraordinaire
Spirulina is a cyanobacterium, a single-celled organism that converts sunlight into micronutrients. It is one of the earliest forms of life, originated more than 3.6 billion years ago and owes its name to its characteristic spiral shape.
The common name includes several species. In addition to the more common Arthrospira platensis (or fusiformis), the other two strains Arthrospira maxima and Arthrospira indica (or fusiformis sensu) are available.
It grows wild in alkaline freshwater lakes (pH 8-11.5) in intertropical areas (25°C), as well as being grown in tanks under similar conditions. Its discovery in the West is relatively recent, although the Aztecs had been regular consumers of it since at least the 16th century, around Lake Texcoco (present-day Mexico). The microalgae also thrived in Africa, at least since the 1940s, in Lake Chad and those in the Rift Valley (East Africa).
The Kenembus tribe in Chad harvests the microalgae from the lake, dries them and shapes them into a savory cake, dihe, which is very popular with communities living near the lake. A sauce is also made from it, to accompany millet snacks. An FAO study comparing levels of poverty and malnutrition in 10 African countries highlights how precisely because of ‘spirulina pizza’ Chad is the only poor country without malnutrition.
A nutrient powerhouse (but watch out for B12)
Blue-green microalgae contains the highest concentration of nutrients of any plant food. It has an extraordinary protein content (up to 70 percent) with high biological value due to their rich amino acid content. It is also distinguished by the presence of the rare essential fatty acid GLA (gamma-linolenic acid). As well as beta carotene and various substances with antioxidant power, iron and other minerals.
It provides in essence almost all of the vitamins (B1, B2, B3, B6, B9, B12, C, D and E) and minerals (potassium, calcium, iron, magnesium, phosphorus, selenium, sodium, zinc) that the human body needs.
Vegans, however, should be under no illusion that spirulina will fill their vitamin B12 needs. In fact, the valuable microalgae contains it mainly in the form of an ‘inactive analogue,’ so it does not replace foods that are its main source (meat, fish, eggs, dairy products).
Table 1. Nutritional values and functional compounds of Spirulina. V. https://doi.org/10.1155/2017/3247528
The sustainability of spirulina is phenomenal, with an unbeatable protein yield per hectare. 20 times more protein per hectare compared to soybeans, 40 times more than corn, over 200 times more than beef. With a far smaller water and energy footprint than the same plant protein matrices.
An ally of immune system and disease prevention
The benefits are many and varied. In addition to its high nutritional value, spirulina has hypolipidemic, hypoglycemic and antihypertensive properties. Animal studies show its ability to modulate immune function, reducing levels of inflammation. And it is effective in preventing metabolic syndrome, a risk factor for the onset of cardiovascular disease and cancer. Several scientific studies also show that spirulina can contribute to the inhibition of virus replication, including HIV-1 (AIDS virus).
Antimicrobial activity and ability to enhance the growth of probiotics (with improved gut microbiota) are other properties mentioned in the scientific literature. Some in vitro studies show that spirulina is able to:
– Inhibit the growth of some pathogenic bacteria. Gram-negative(Escherichia coli, Pseudomonas aeruginosa and Proteus vulgaris) and Gram-positive(Staphylococcus aureus, Bacillus subtilis and Bacillus pumulis),
– Promote the growth of health-allied lactic acid bacteria(Lactococcus lactis, Streptococcus thermophilus, Lactobacillus casei, Lactobacillus acidophilus and Lactobacillus bulgaricus). It thus prevents dysbiosis and infections that recur in individuals with inflammatory bowel syndromes (IBD) and metabolic and immunologic diseases, among others.
Finally, antioxidant and anti-inflammatory effects have been confirmed in numerous researches on various animal species (mice, fish, goats). In studies, spirulina seaweed plays a protective role against toxicity caused by carbon tetrachloride (CCl4), metals (arsenic, mercuric chloride, chromium, cadmium, and fluoride), the insecticide deltamethrin, and the drugs tilmicosin, gentamicin, and erythromycin. And it acts as an anti-inflammatory on guinea pigs with induced colitis and arthritis.
Contraindications and side effects
Side effects associated with spirulina consumption are rare and generally mild, such as insomnia and stomach upset. But there is no shortage of more serious, if sporadic, cases. The serious adverse reactions that the scientific literature hypothetically associates with spirulina consumption are limited to about ten cases. (1)
Precautions for use,” recalls ANSES(Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail), which published a report on spirulina in 2017, “nevertheless advise against the consumption of spirulina at the occurrence of:
– Presence of disease (unspecified),
– Muscle or liver vulnerability,
– allergic background,
– subjects with phenylketonuria (since spirulina naturally contains the amino acid phenylalanine),
– Treatment with immunosuppressive, antihypertensive, and hypolipidemic drugs.
Possible risks of contamination
Among the causes of side effects, contamination of the microalgae during production and/or packaging cannot be excluded. However, these risks can be prevented, controlled and verified by proper application ofself-control. It refers specifically to:
– cyanotoxins, produced by cyanobacteria other than spirulina (also a cyanobacterium, as mentioned). This risk is present during inoculum selection and during various stages of production and has been detected in two lakes in Kenya (Krienitz et al. 2003),
– Bacteria other than cyanobacteria. Although the highly basic conditions of spirulina production hinder the development of most pathogenic microorganisms (listeria, salmonella, coliform bacteria, etc.), the risk of contamination during subsequent handling must be kept under control,
– Trace metals (chromium, cadmium, arsenic, lead, mercury, nickel) present in the growing water. Cases of high arsenic content in wild samples collected in Chad, and lead in Burkina-Faso are noted in the literature. (Vicat, Doumnang Mbaigane and Bellion 2014).
Interim conclusions
Microalgae, of which spirulina is a shining example, represent the most practical and sustainable solution available today to address the problem of food security and help improve the public health of populations.
The European research project
ProFuture
– which our team coordinates at the Italian level- therefore aspires to share efficient and sustainable production methods. With attention also paid to the aspects of economics, with the aim of reducing the production costs of microalgae and promoting their ‘democratization’. So that these treasures of nature can be made accessible to broad sections of the population.
Marta Strinati and Dario Dongo
Bibliography
– FAO,
Spirulina: a livehood and a business venture.
– Finamore A, Palmery M, Bensehaila S, Peluso I. Antioxidant, Immunomodulating, and Microbial-Modulating Activities of the Sustainable and Ecofriendly Spirulina. Oxid Med Cell Longev. 2017;2017:3247528. doi:10.1155/2017/3247528
– M.C. Serban, A. Sahebkar, S. Dragan et al, A systematic review and meta-analysis of the impact of Spirulina supplementation on plasma lipid concentrations, Clinical Nutrition, vol. 35, no. 4, pp. 842-851, 2016.
– M. Iyer Uma, A. Sophia, and V. Mani Uliyar, Glycemic and lipemic responses of selected Spirulina supplemented rice-based recipes in normal subjects, International Journal of Diabetes in Developing Countries, vol. 19, pp. 17-22, 1999
– P. V. Torres-Duran, A. Ferreira-Hermosillo, and M. A. Juarez-Oropeza, Antihyperlipemic and antihypertensive effects of Spirulina maxima in an open sample of Mexican population: a preliminary report, Lipids in Health and Disease, vol. 6, article no. 33, 2007
– Abdel-Daim MM, Dawood MAO, AlKahtane AA, et al. Spirulina platensis mediated the biochemical indices and antioxidative function of Nile tilapia (Oreochromis niloticus) intoxicated with aflatoxin B1. Toxicon. 2020;S0041-0101(20)30274-9. doi:10.1016/j.toxicon.2020.06.001
– Mokhbatly AA, Assar DH, Ghazy EW, et al. The protective role of spirulina and β-glucan in African catfish (Clarias gariepinus) against chronic toxicity of chlorpyrifos: hemato-biochemistry, histopathology, and oxidative stress traits. Environ Sci Pollut Res Int. 2020;10.1007/s11356-020-09333-8. doi:10.1007/s11356-020-09333-8
– M. M. El-Sheekh, S. Daboo, M. A. Swelim, and S. Mohamed, Production and characterization of antimicrobial active substance from Spirulina platensis, Iranian Journal of Microbiology, vol. 6, no. 2, pp. 112-119, 2014.
– J. L. Parada, G. Zulpa de Caire, M. C. Zulpa de Mulé, and M. M. Storni de Cano, Lactic acid bacteria growth promoters from Spirulina platensis, International Journal of Food Microbiology, vol. 45, no. 3, pp. 225-228, 1998.
– R. J. Marles, M. L. Barrett, J. Barnes et al, United states pharmacopeia safety evaluation of spirulina, Critical Reviews in Food Science and Nutrition, vol. 51, no. 7, pp. 593-604, 2011
– ANSES – Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail –
AVIS de l’Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail relatif aux ‘risques liés à la consommation de compléments alimentaires contenant de la spiruline
‘ (2017)
Notes
(1) Cases cited include:
– a case of rhabdomyolysis (injury and dissolution of skeletal muscle tissue), reported in Greece (Mazokopakis et al. 2008), but without identification of causation,
– two cases of anaphylaxis in allergic subjects (Le, Knulst and Röckmann 2014 and Petrus, Assih, et al. 2010, Petrus, Culerrier, et al. 2010),
– Three cases of skin damage. In detail, two cases of atopic dermatitis associated with nausea, malaise, headache, and fatigue were observed in Poland. Analysis of consumed products (spirulina and chlorella blends) showed high concentrations of aluminum, cadmium, lead and mercury (Rzymski et al. 2015). In contrast, one case of dermatomyositis was reported in a 45-year-old woman with a history of fibromyalgia (Lee and Werth 2004), and it occurred after consumption of a multingredient supplement (spirulina, Aphanizomenon flos-aquae, cayenne pepper, methyl-sulfonyl-methane). In all cases, causality could not be clearly established.
– Some cases of hepatotoxicity. A case of hepatitis was published in Japan (Iwasa et al. 2002) in relation to a 52-year-old, type 2 diabetic, hyperlipidemic, hypertensive man treated with simvastatin, amlodipine, and acarbose. Recalling that simvastatin causes liver problems, the link with spirulina consumption has not been identified.
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.
Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".
