First I will present the method for mass cultivation. The Spirulina used for cultivation is different than wild-types because certain desirable traits are screened for, while algae with undesirable traits are weeded out. Some of these desirable traits include response to diurnal fluctuations, resistance to photo inhibition, amount of dark respiration, sensitivity to increased oxygen levels, and sensitivity to osmotic stress. Also, to properly cultivate, a pure strain must be obtained so that the culture doesn't become contaminated by other types of microalgae that contain toxins, or don't have the high nutritional content from biomass as Spirulina does (Becker 49).
The selected strain is grown in shallow raceway ponds with paddlewheels that constantly turn the water, thus ensuring proper mixing of nutrients ("Indian Journal of Microbiology" 4). Some also bubble in carbon dioxide because the algae remove this at a rate which exceeds the production of it from natural methods alone (Earthrise Homepage). Once it is ready, the algae is pumped into a harvesting building, where it is then dried.
Health and nutrition companies have tried to minimize the nutrients lost during drying while maximizing the pure microalgae biomass recovered, while still keeping costs low. Most microalgae taken directly from the ponds is almost useless to the human body because of the cell wall. This cell wall holds in all of the nutrients, and our bodies do not have the capabilities to digest this. Spirulina seems to be special in that it is relatively easily digestible in its fresh form (Richmond 97). However, for the rest of the algal production, companies have had to overcome this problem through different drying techniques, to essentially explode the cell wall. These include sun drying, drum drying, freeze drying, spray drying and cooking. There have been studies on the different methods to determine which destroys the cell wall the most efficiently. In the book Microalgae: Biotechnology and Microbiology, it states that for all microalgae, drum drying destroyed the cell wall the best, but since Spirulina has such a thin, fragile cell wall to begin with, sun drying is sufficient to sterilized the algae and make it usable by our bodies (202).
All this effort is made to ensure the least amount of nutrients are lost. Now I will look at the nutrition contained within the cell wall to see if these methods help to make it better than our conventional nutrition sources. To begin with, Spirulina has an almost entirely balanced amino acid content. It even contains methionine, which is one amino acid that most other microalgae lack (Becker 216). It only contains marginal amounts of sulfur-containing compounds and tryptophan (which are needed by our bodies), but has extremely high lysine concentrations (Becker 216).
Fifty to seventy percent of the algae's dry weight comes from protein, which is significantly higher than for land plants. Spirulina also has a high lipid content that has been quoted as high as 16.6% (Richmond 94). This algae has a very low percentage of nucleicacids compared to other bacteria, and an extremely high concentration of vitamin B12, both of which are optimal conditions (Richmond 99). It is also high in many other vitamins, including B-carotene, which is a particular one of interest, since it is a source of Vitamin A, and has been shown that high concentrations in laboratory tests decrease cancer risks (Richmond 100). Another important nutrient is gamma-linolenic acid (GLA). This has been shown to help arthritis, heart disease, obesity, and zinc deficiency. A deficiency in this acid has even been associated with alcoholism, manic depression, some symptoms of aging, and schizophrenia (Richmond 100). A final nutrient is phycocyanin, which is thought to stimulate the immune system, thus giving us greater protection against infection and disease (Richmond 100). This vitamin content can fluctuate, however, depending on environmental and cultivation fluctuations, especially for vitamins B1, B2, C (Becker 188).
All of this nutritional has great potential in theory, but to further understand its importance, I found a few studies done to show how the body reacts to this unconventional food source. In the book Microalgae: Biotechnology and Microbiology, there were a few caveats. Microalgae should not be use as the sole source of protein, only as a supplement. This probably because although it is very high in many nutrients, it is also lacking a few key compounds necessary for our health (211). It should also not be taken in quantities exceeding 100g, to avoid a negative shift in health (246).
The first study I will look at also come from this book. Mildly and significantly malnourished children were fed algal supplements. Throughout the course of the study both sets of children increased increase in weight, and problems associated with malnutrition, like diarrhea, were cured (Becker 246). No undesirable side effects were noticed.
In the second study, a depletion-repletion cycle was used where lab rats are first denied proteins, and then supplemented with different feeds. The highest enzyme activity was noticed using casein, with Spirulina-fed subjects having only slightly less activity (Richmond 97).
I conducted a small-scale study of my own at home. My roommate always complains of being tired and can't study for more than a couple of hours before falling asleep. I received a raspberry flavored algae sample in the mail and asked her to eat it and see if she noticed a difference. We went to the library at around 8 p.m. and she was still going strong when I leaned over to her at 1 a.m. to ask if she was ready to go, because I couldn't stay awake any longer. The next day, however, she was right back to normal. This shows me that to have positive effects, the supplements probably should be taken on a regular basis.
There have been reports of people living on algae for extended periods of time. While some experienced no bad side effects, others complained of discomfort, nausea, vomiting, and poor digestibility (Becker 244). My advice to the newcomer would be to try it, and if any of the negative effects are experienced, quit using it and try a different, more conventional supplement.
Since Spirulina shouldn't be used as the sole source of nutrients, studies were done to find the most effective mix of algae with conventional food sources. It has been found that "when combined with other cereals, it would improve the nutritional quality of staple foods, and also prevent acceptability and tolerance barriers of algal proteins, making a sound base for industrial production of algal based foods" (Becker 216). One example of this was adding Spirulina to rural diets of wheat and rice. This increased the nutritional status of the tested population, because of the increase in lysine and threonine in the diet (Becker 211).
These examples clearly indicate its successfulness as a dietary supplement for improvingnutrition. But this algae hasn't been become increasingly common on the dinner tablesacross America for a few good reasons. Most people won't accept the powder as supplementary form. Trying to incorporated this into recipes hasn't worked very well either, because the algae has a distinct odor and color, which aren't very appealing to consumers.
The taste is also very strong and disagreeable and is something that most wouldn't want to take the time to acquire. As a child, I remember going to my cousins house, when my uncle had recently heard about the wonders of Spirulina. He prepared it in the form of a dark green slimy shake, with no added flavors. Since he couldn't get to children to voluntarily employ this recent discovery of his into their diets, it was incorporated by way of punishment. From the Worldwide Web, I found recipes for making everything from pasta to shakes to salsa with powder from microalgae, so it seems that some have been able to partially overcome, or mask this foul taste by adding it to common foods. Another reason it isn't more popular is that many report that they notice no effects, good or bad from taking algal supplements. Spirulina costs about $0.09/gram, as compared to an equivalent protein amount of $0.0225/gram, and can be an expensive supplement, especially if its not giving the desired results (Tyler 300).
The nutritional value of Spirulina is said to be a recent discovery to the modern world, but in reality it is a rediscovery of a food source, since people of Africa and Mexico have been eating it for centuries (Tyler 299). In Mexico the Indians call it tecuitlatl, and collect it from around the lake there when its density is high. They lay this collection on the sand and let it dry into a cake about 2-3 cm thick. The Indians find it very palatable "trading it by all the merchants of the land, as cheese is among us" (Richmond 98).
The people along the shores of Lake Chad in central Africa were found in 1963 to have a similar cake-like food made of algae called dihe. It was also discovered to be eaten by a tribe found in the Sahara desert 10 years later. The dihe biscuits are usually only eaten for superstitious reasons by pregnant women, but algae can be found in several of their sauces, and is a staple that goes along with their standard meal of millet (Richmond 98).
In this synthesis, I have tried to show the good and bad and indifferent effects of eating Spirulina. I have showed that while it is generally accepted as a good source of nutrition, it can not be the only source for any extended period of time, and also that a limited amount is recommended per day, but there aren't any fatal or serious side effects. Further acceptance of its safeness can come from the utilization for centuries by the examples given from Africa and Mexico. Earthrise claims it to use 1/3 of the water as soy, 1/5 as much as corn, and only 2% of the water requirements of beef. It is also said to require 20 times less land area than soybeans for cultivation, and 200 times less than beef. It is also cultivated best in non-fertile, desert environments (Planet News). These statistics can be compared to the cost difference per gram between beef and Spirulina to determine which is the cheapest and most environmentally advantageous method in reality. People always need hope for the future, when the statistics of birth to death rates continue to increase. It is only natural to wonder where the food of tomorrow will come from. Until some other wonder plant comes along, Spirulina will continue to be tossed around as a solution to these problems.
Works Cited
Borowitzka, Michael and Lesley, eds. 1988. Micro-Algal Biotechnology.
Cambridge University Press, Cambridge.
Earthrise Homepage: http://www.earthrise.com/spirulina/
"Indian Journal of Microbiology" Bhagyalakshmi, et. al. Vol. 35 (1), 1995.
Pps 2-4.
"Planet News" vol. 1 (20), April 1995. pps 1-2
Becker, E.W. 1994. Microalgae: Biotechnology and Microbiology. Cambridge
University Press, Cambridge.