Chlorella species of green algae comprise a suite of enduring dietary supplement ingredients that have been touted to have almost panacea-like properties.
Despite its intense green colour (due to the high content of chlorophyll), and not unlike spinach, Chlorella species also harbour robust quantities of the carotenoid lutein.1 Because their growth transpires in a bioreactor rather than in a commercial agriculture field (as for marigolds, the prime biomass for lutein), pesticide and herbicide exposure is non-existent.
New research has blossomed, suggesting promising immune-modulating properties of Chlorella extracts and fractions. The polysaccharide fraction of Chlorella (Sun Chlorella brand, and two other algal species, Spirulina platensis and Aphani-zomenon flos-aquae) was shown in in vitro studies to stimulate human macrophage immune cells.2 The size of the polysaccharides extracted from the algae is large and water-soluble. Animals fed a glycoprotein (carbohydrate-linked protein) extract, derived via hot water extraction from Chlorella vulgaris, show reduced immunity decline following psychological stress, perhaps mediated by the attenuation of a stress-induced increase in glucocorticoids (corticosterone).3
Additional studies using the same C. vulgaris extract (CVE) have shown a reduction in induced casein allergies in mice, possibly by reducing the pro-inflammatory response from antibodies targeted to the casein allergen.4
Activates NK Cells
Complementary in vitro studies by a different group performed with a different Chlorella extract (species not identified) revealed an 'antihistamine' effect in rat mast cells.5 Experiments in mice orally administered CVE and infected with Listeria monocytogenes, a bacterial pathogen and the cause of listeriosis, have shown activation of natural killer (NK) cell function and an increased resistance to infection.6 Clinical studies with Chlorella are very few in number. One placebo-controlled, double-blind, crossover study enrolled 43 subjects with fibromyalgia and reported that daily supplementation with 10g Sun Chlorella tablets and 100ml of a liquid Chlorella preparation (Wakasa Gold) produced some improvements in self-reported symptom scores, but the number of 'responders' did not significantly differ between the groups.7 Unfortunately no objective or immunological markers were measured.
A recent study that appeared in an international patent filing showed that a high molecular weight polysaccharide fraction of Chlorella pyrenoidosa selectively boosted antibody response to influenza vaccinations.8 One hundred and twenty-four subjects older than 50 years took either 200 or 400mg/day of the extract or placebo for 28 days. Only those subjects who were 55 years or younger showed a significantly greater antibody response to the vaccine. Interestingly, those on the lower dose of Chlorella extract reported a significantly greater incidence of fatigue, while those subjects on placebo and over 55 years of age reported a significantly greater incidence of abdominal pain.
Given the voluminous animal and promising clinical research, select Chlorella extracts may harbour substantial promise as immune response modifiers in 'low' and 'high' immune states.
References1. Shi XM, et al. High-yield production of lutein by the green microalgae Chlorella protothecoides in heterotrophic fed-batch culture. Biotechnol Prog 2002;18:723-7.
References2. Pugh N, et al. Isolation of three high molecular weight polysaccharide preparations with potent immunostimulatory activity from Spirulina platensis, Aphanizomenon flos-aquae and Chlorella pyrenoidosa. Planta Med 2001;67:737-42.
References3. Hasegawa T, et al. Chlorella vulgaris culture supernatant (CVS) reduces psychological stress-induced apoptosis in thymocytes of mice. Int J Immunopharmacol 2000;22:877-85.
References4. Hasegawa T, et al. Oral administration of hot water extracts of Chlorella vulgaris reduces IgE production against milk casein in mice. Int J Immunopharmacol 1999;21:311-23.
References5. Price JA and Sanny CG. Analysis of a methanolic extract of the microalgae Chlorella. FASEB J 2001;16:A1240.
References6. Queiroz MLS, et al. Effects of Chlorella vulgaris extract on cytokines production in Listeria monocytogenes infected mice. Immunopharmacol Immunotoxicol 2002;24:483-96.
References7. Merchant RE, et al. Nutritional supplementation with Chlorella pyrenoidosa for fibromyalgia syndrome: A double-blind, placebo-controlled, crossover study. J Musculoskel Pain 2001;9:37-54.
References8. Kralovec JA, inventor; Ocean Nutrition Canada, Ltd., assignee. Chlorella preparations exhibiting immunomodulating properties. WO 02/11746. February 14, 2002.
Anthony Almada, BSc, MSc, is the president and chief scientific officer of IMAGINutrition Inc and has been a co-investigator on more than 60 randomised controlled trials. www.imaginutrition.com