HEALTHY LIVING

World Health Organization defines healthy ageing as “the process of developing and maintaining the functional ability that enables wellbeing in older age. Maintaining a healthy aging includes healthy and balanced nutrition.  

However, what kind of nutrients can we take to preserve our health capital? 

Microalgae have attracted great interest for their potential applications in nutraceutical as an interesting source of food ingredients with antioxidant, anti-cancer, immunomodulatory, antidiabetic, antihypertensive, and antihyperlipidemic activities (Ref 1).  

One other potential application for bioactive microalgae compounds is the maintenance of body weight. In fact, the scientific literature supplies evidence supporting an anti-obesity effect of several microalgae such as Chlorella vulgaris, or cyanobacteria, such as Arthrospira platensis or Spirulina, commonly referred to as a blue-green alga (Ref 2). 

Spirulina has been consumed for centuries, and to this day it is still considered as a Super Food due to its unique and balanced nutritional profile. Marketed as a dehydrated powder, in capsules, tablets or sometimes fresh, this blue-green filamentous cyanobacterium, is particularly renowned for providing excellent quality proteins. It is an excellent source of iron, and contains vitamins A, E, D, B1, B2, B3, B6, B7, B8 and K as well as minerals and trace elements such as calcium, magnesium, and selenium. Besides, this microalgae contains carbohydrates, essential fatty acids, such as Docosahexaenoic acid and Eicosapentaenoic acid, and pigments.

Chlorella is a green unicellular alga that is commercially produced and distributed worldwide as a dietary supplement. The dominant biochemical component of Chlorella species is protein, which made up to 60% of Chlorella cells, followed by carbohydrates and lipids about 20% each. In addition, fiber, essential fatty acids, pigments, and a full range of vitamins including D and B12, minerals and phytonutrients have also been considered as primary components of Chlorella microalgae (Ref 4).  

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Diet and physical activity play an important role in regulating weight. In recent years use of herbs for weight loss has been dramatically increased, because of fewer side effects of herbal remedies and many supplements have been manufactured in order to decrease obesity and its negative consequences on health. Very limited studies evaluate the anti-obesity effects of Spirulina platensis and Chlorella. However, these algae have recently been considered not only as nutritional compound, but also as bioactive source with various therapeutic effects linked 1) to their role in the prevention of hypercholesterolemia, 2) to their ability to decrease intestinal absorption of cholesterol, 3) to induce the reduction of triglycerides concentrations by inhibiting hepatic fatty acid synthesis (Ref 3). Mehdinezhad et al. (Ref 5) reported that supplementation with Spirulina and Chlorella alone and combined, by limiting insulin secretion, and in addition to their role in improving lipid metabolism, justify the reduction of weight. 

Generally speaking, thanks to their role in improving lipid metabolism, these microalgae can be considered a functional food capable of modulating serum lipids, appetite control, thus reducing weight (Ref 4). They also exert anti-inflammatory properties due to their antioxidant and vitamin content. 

The biological activities of Spirulina and Chlorella vulgaris on weight management and health aging have been attributed to essential fatty acids such as linoleic, arachidonic, and linolenic acids. They play indeed important roles in cellular and tissue metabolism, including regulation of membrane fluidity, oxygen transport, as well as thermal adaptation. Polyunsaturated fatty acids may reduce the risk of coronary heart disease. Spirulina can also induce increased energy expenditure via thermogenesis activation limiting the reduction in body fat accumulation. Reduction in appetite may be due to an improvement in leptin resistance in the arcuate nucleus (Ref 3). A recent study also demonstrated that three months of taking of 2 g.day-1 Spirulina improves Body Mass Index (BMI) and weight as well as blood pressure in overweight patients with hypertension without evidence of cardiovascular disease (Ref 6). These observations were correlated to a significant reduction in serum Total Cholesterol and increase in High-density lipoprotein (HDL), the powerful hypolipidemic effects of this microalgae being reported by previous studies. 

Insulin resistance, or systemic low-grade inflammation are improved by Chlorella vulgaris treatment (Ref 4). Moreover, this microalga contains dietary fiber such as β-glucan that is metabolized to short-chain fatty acids (SCFAs) such as propionate and butyrate, which are known to have beneficial effects on host health, by the gut microbiota (Ref 6). β-Glucans promote the growth of probiotic Lactobacillus and Bifidobacterium (Ref 7), propionate has also beneficial effects, such as anti-inflammatory activity and body weight maintenance.  The prophylactic effect of Chlorella supplementation on weight management was also studied, several studies showing that Chlorella supplementation combined with aerobic exercise training have pronounced effects on the improvement of glycemic control via increased activation of muscle phosphorylation signaling. 

Chlorella is cultivated by more than 70 companies in the world. The annual production of Chlorella biomass exceeds 2,000 tones, mostly used for dietary supplements and nutraceuticals, with a minor share destined to the cosmetic market and aquaculture. 

Chlorella is commercially produced under photoautotrophic conditions, mainly in open ponds (both raceway and circular) or heterotrophically in fermenters.  

Some companies, such as Allmicroalgae, (Portugal) produce autotrophic organic Chlorella and heterotrophic Chlorella and exploit the benefits for food, nutraceutical, feed, agriculture, cosmetic and beyond. 

Depending on the mode of production, 4 types of Chlorella can be produced. 

1. Organic Chlorella vulgaris is grown in a sustainable autotrophic manner, using sunlight and CO2 and producing oxygen.

2. A light-green smooth Chlorella is produced in the dark, inside a fermenter vessel. This allows for the reduction of its chlorophyl content, thus leading to a lighter color and milder taste. 

3. A yellow Chlorella vulgaris, which is obtained through the isolation of lighter strains, under stress conditions. This GMO-free manipulation is commonly used as a way to speed naturally-occurring selection. The final product is a stable strain with similar productivity but lower chlorophyl content, which translates to a milder taste and odor. 

4. White Chlorella vulgaris is obtained through selection of lighter strains, under stress conditions. It is a vegan/vegetarian alternative ingredient with mild taste and odor.. 

Less known than green Chlorella, and because of their growth performance as well as improved organoleptic and nutritional characteristics, white and yellow Chlorella have a high potential for applications in the food and nutraceutical industries for novel products based on microalgal biomass. However, further investigations are needed to evaluate their prophylactic effects on health aging. 

Spirulina and Chlorella vulgaris have single-handedly deliver powerful healthy anti-aging benefits, through their active components which are antioxidant scavengers and anti-inflammatory lipid mediators such as carotenoids and n-3 PUFAs (EPA/DHA), prebiotic polysaccharides, phenolics, antihypertensive peptides, several pigments such as phycobilins and phycocyanin, and some vitamins, such as folate. The currently literature supports the benefits of both these microalgae for reducing body fat, waist circumference, body mass index and appetite. 

Do not hesitate, these two foods allow you to preserve your metabolic capital and therefore your weight! 

EDITH FILAIRE¹          JEAN-YVES BERTHON²        

¹ICARE Group | France

²Greentech SA | France