The mircoalgae spirulina and chlorella are known to many and are used today in various areas as dietary supplements. An interplay of different micro- and macronutrients makes these microalgae so valuable for our nutrition. In the following, the most important micro- and macronutrients found in Spirulina and Chlorella and their function are explained in more detail.
Proteins
Proteins (= proteins) are broken down into amino acids in the gastrointestinal tract after being absorbed through food. These are then transported to the liver, where they are reassembled – depending on the tasks assigned to them. One speaks of a protein only when more than 60 amino acids have come together – it is therefore a very complex structure.
Known sources of protein are meat, sausage, milk and dairy products, all animal products, these are at the same time suppliers of non-healthy dietary components if consumed in excess (e.g. cholesterol). It is therefore recommended that half of all daily protein intake should come from plant sources, e.g. potatoes, legumes, cereals or microalgae such as spirulina. The high protein content of microalgae was demonstrated in analytical data of protein content (8).
Proteins are responsible, for example
- for the regulation of metabolism (they are then called enzymes)
- for the structure formation of cells, organs and cell membranes
- for various transport mechanisms in the body as well as
- the control of hormones and hormone receptors
- for the maintenance of physiological osmolarity in the vessels. A deficiency of the protein albumin can lead to a drop in pressure in the vessels, which is manifested by edema.
- for the defense of the immune system through antibodies and
- Proteins are also important for energy production.
Without protein, therefore, a body cannot exist. It protects itself against deficiencies by breaking down existing protein, e.g. in the muscles, so that it can be used again elsewhere. This phenomenon is observed, for example, in intentional or unintentional weight reduction, where not only fat is lost, but also (undesirable) muscle loss occurs if protein is not consumed. The minimum daily protein requirement is 25.7 g. The German Nutrition Society (DGE) and the WHO recommend a daily protein intake of 0.8 g/kg body weight, i.e. about 60 g for a 70 kg adult.
Text Proteins: Bettina Hees, MD, Source: Schauder P., Ollenschläger G. Nutritional Medicine, Prevention and Therapy. Urban&Fischer Publishing House, 2006
Our organic Spirulina & Chlorella products contain a large amount of protein (min. 58.6% based on dry weight). In comparison, the protein dry weight of, for example, soybeans as a known protein source is significantly lower at approx. 33%.
Amino acids
Amino acids are the building blocks from which the organism builds proteins and obtains energy. Chlorella contains all the amino acids that are essential for humans, i.e. essential for life, which must be supplied in the diet. These are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. They are present in chlorella not only in traces but abundantly.
This can be proven by determining the EAAI, the Essential Amino Acid Index, which is a parameter for the nutritional assessment of protein quality. By determining the protein quality, it is possible to find out whether the protein taken in with the food is at all capable of replacing the broken down body protein. The EAAI takes into account the content of essential, i.e. indispensable, amino acids in the protein being tested and compares this to the content of amino acids in a standard protein such as whole egg protein – the higher the EAAI, the better. For chlorella, the index ranged from 1.35 to 0.92 (9, 10); in comparison, the EAAI for soy protein was only 0.66 (9). These results indicate that the proteins in chlorella are of high or good quality.
Polysaccharides + dietary fiber
Chlorella consists of approximately 17% (dry weight) carbohydrates (8), of which more than 65% of the carbohydrates are indigestible dietary fiber, apparently derived from the chlorella cell walls.
In addition to dietary fiber, other polysaccharides have been found in Chlorella that act as stimulators of algal growth, but also have antioxidant activity, because an alga must also protect itself against free radical attack, and it does this with the help of antioxidants (11-14). In addition, Tabarsa’s research group (15) discovered and described an immune-enhancing water-soluble α-glucan derived from Chlorella vulgaris.
Fat
Chlorella contains a small amount of fats at approximately 11% dry weight (8). These are α-linolenic acid (about 10-16% of total fatty acids) and linoleic acid (about 18% of total fatty acids), but not eicosapentaenoic acid and docosahexaenoic acid (= omega-3 fatty acids) as found in fish or vegan microalgae such as Schizochytrium (10, 16). Approximately 65-70% of the total fatty acids in commercially available chlorella products are polyunsaturated fatty acids (3, 10,16).
Opened (= broken) cell walls
Chlorella algae cannot be digested by humans in their natural state because their cell walls consist of indigestible cellulose. Therefore, it is useful to mechanically break down the cell walls of chlorella. This is achieved very well by means of the high-quality spray drying process. Digestibility could be significantly increased by 80% by using spray drying, which is a good value (18).
Vitamin B12
Chlorella contains mainly vitamins D2 and B12, which are not found in plant foods, as well as larger amounts of folic acid and iron than other plant foods.
Vitamin B12 – also called cobalamin – is found in animal foods such as meat, fish, milk + dairy products (non-pasteurized), eggs and fermented foods such as sauerkraut or beer. The fact that vitamin B12 is found in microalgae such as chlorella is valuable for the diet of, for example, vegetarians and vegans.
The daily amounts of vitamin B12 needed are small and usually well within dietary reach when consuming the foods listed above. The situation is different for vegetarians and vegans and for fully breastfed infants of vegan mothers, who are thus exposed to a high health risk. The supply of vitamin B12 can also become problematic in old age, because age-related atrophic changes in the gastric mucosa can lead to reduced formation and release of vitamin B12. According to research, it can affect up to 43% of people over the age of 60.
Text Vitamin B12: Dr. med. Bettina Hees, Source: Schauder P., Ollenschläger G. Ernährungsmedizin, Prävention und Therapie. Urban&Fischer Publishing House, 2006
EFSA assessment on vitamin B12
Vitamin B12 is involved in important metabolic processes in the organism as a coenzyme. In addition to folic acid (also contained in chlorella), vitamin B12 is enormously important for lowering the homocysteine content of the blood and thus reducing the risk of vascular calcification. The immune system, energy balance and nervous system also benefit from a balanced vitamin B12 supply.
The EFSA (European Food and Safety Authorisation) has taken this into account and approved the following tested and scientifically proven effects of vitamin B12 as health claims:
Iron
Iron is a trace element that – as the name suggests – is present in the body in trace amounts. However, this in no way diminishes its importance for a healthy metabolism, on the contrary. Iron is important and (vital) for many bodily functions.
Iron is found in every cell of the body; it is also an important cofactor for numerous important enzymes. In hemoglobin, the red blood pigment in erythrocytes, the red blood cells, iron plays a central role in oxygen transport in the body. Therefore, hemoglobin also stores the main mass of iron (2500 mg*), followed by storage iron in all cells of our body (500 to 1,000 mg*, half in women) and myoglobin in muscles (150 mg*). The enzymes require between 6 and 8 mg*. (*All values refer to iron distribution in a 70 kg man).
Although iron is one of the most common metals outside our bodies and our bodies use their iron reserves very sparingly, iron deficiency is still one of the most common deficiency symptoms. It is estimated that up to 1/3 of the world’s population has a suboptimal iron supply, with women up to menopause, children and adolescents in the growth phase and pregnant women being particularly affected. Iron deficiency can occur when there is too little iron in the diet, when there is increased loss (e.g. due to menstrual bleeding) or when the demand is increased (e.g. during pregnancy). Through the intestines, the body loses an additional 1 mg of iron per day, which must be replaced through the diet. Menstruation can further increase this loss by 0.6 to 1.5 mg/day, depending on the intensity of bleeding.
- Yan, N. et al. The potential for microalgae as bioreactors to produce pharmaceuticals. Int. J. Mol. Sci. 2016, 17, 962.
- Barkia, I. et al. Microalgae for high-value products towards human health and nutrition. Mar. Drugs 2019, 17, 304.
- Bito, Tomohiro et al. Potential of Chlorella as a Dietary Supplement to Promote Human Health. Nutrients, 2020.
- Beijerinck, M.W. Culture experiments with zoo chlorellae, lichen gonidia and other lower algae. Botanical Journal 1890, 47, 725-739.
- Montoya, E.Y.O. et al. Production of Chlorella vulgaris as a source of essential fatty acids in a tubular photobioreactor continuously fed with air enriched with CO2 at different concentrations. Biotechnol. Prog. 2014, 30, 916-922.
- Rani, K. et al. A comprehensive review on chlorella – its composition, health benefits, market and regulation scenario. Pharma Innov. J. 2018, 7, 583-589.
- Ru, I.T.K. et al. Chlorella vulgaris: A perspective on its potential for combining high biomass with high value bioproducts. App. Phycol. 2020, 1, 2-11.
- Becker, E.W. Micro-algae as a sourse of protein. Biotechnol. Adv. 2007, 25, 207-210.
- Waghmare, A.G. et al. Concentration and characterization of microalgae proteins from Chlorella pynenoidosa. Bioresour. Bioprocess. 2016, 3, 16.
- Kent, M. et al. Nutritional evaluation of Australian microalgae as potential human health supplements. PLoS ONE 2015, 1.
- Olaitan, S.A.; Northcote, D.H. Polysaccharides of Chlorella pyrenoidosa. Biochem. J. 1962, 82, 509-519.
- Sui, Z.; Gizaw, Y.; BeMiller, J.N. Extraction of polysaccharides from a species of Chlorella. Carbohydr. Polym. 2012, 90, 1-7.
- Yu, M. et al. Preparation of Chlorella vulgaris polysaccharides and their antioxidant activity in vitro and in vivo. Int. J. Biol. Macromol. 2019, 137, 139-150.
- El-Naggar, N.E.A. et al. Production, extraction and characterization of Chlorella vulgaris soluble polysaccharaides and their applications in AgNPs biosynthesis and biostimulation of plant growth. Sci. Rep. 2020, 10, 3011.
- Tabarsa, M. et al. An immune-enhancing water-soluble a-glucan from Chlorella vulgaris and structural characteristics. Food Sci. Biotechnol. 2015, 24.
- Ötles, S.; Pire, R. Fatty acid composition of Chlorella and Spirulina microalgae species. J. AOAC Int. 2001, 84, 1708-1714.
- Komaki, H. et al. The effect of processing of Chlorella vulgaris: K-5 on in vitro and in vivo digestibility in rats. Anim. Feed Sci. Technol. 1998, 70, 363-366.
- Richmond, A. Handbook of microalgal culture. Biotechnology and applied Phycology. Blackwell Science Ltd, 259 (2004).