The word algae has negative connotations in the minds of many Europeans: Algae plague in the Mediterranean Sea, algalization of ponds or eutrophication of water bodies by algae. Slowly but steadily, however, knowledge about algae as a possible – perhaps healthy – food component is increasing.
What are disease-causing algae?
An alga is a plant that, like all its green relatives, performs photosynthesis. The only difference is that its habitat is water, so it floats freely in the water or roots on the bottom in shallow waters. Biologically, there are very many species, some of which are so different that their only commonality is the structure of their cells. All algae have cells with a cell nucleus, which identifies them as the lowest level of higher organisms (=eukaryotes – all life forms possessing a true cell nucleus). In biology, blue-green algae, which are not plants but bacteria, were also wrongly given this name. However, the latter belong to the living beings with cells without a true cell nucleus (prokaryotes).
Occurrence, distribution, and characteristics
Algae are found all over the world in fresh and salt water. They are usually visible to the naked eye: leaves in all shapes and colors floating in the water or a green mass on the water surface, where usually only the microscope shows that they are clusters of cells of algae. In principle, algae have an important role in the ecological cycle. They absorb carbon dioxide dissolved in the water, convert it into oxygen with the help of sunlight and release it back into the water (photosynthesis). However, if the water body is polluted by sewage, which acts like fertilizer on algae growth, algae proliferation occurs and the water body suffocates. The spread of sewage treatment plants has largely eliminated this problem in Europe. It can be very dangerous to human health to swim in heavily algalized waters. As a food component, algae are consumed mainly in Asian countries. As a result of globalization, they have been able to convince more and more people of their properties in our latitudes as well.
Meaning and function
An alga from clean waters can be compared nutritionally with lettuce or leafy vegetables. It contains vitamins and minerals and pleases calorie-conscious eaters with its low energy content. The chlorophyll found in all plants and the carotenoid found in some algae are considered to strengthen the immune system. Thus, algae have some antibiotic and antiviral effects. The question of whether an algae is questionable or beneficial to health also largely depends on when it is harvested and preserved and how fresh it is at the time of consumption. Those who live a health-conscious lifestyle generally avoid seaweed out of an abundance of caution, preferring freshwater seaweed instead. This is usually grown under special conditions (special water composition) to achieve optimal health value.
Diseases and ailments
To understand the problems related to the consumption of algae, a basic knowledge of the cycle of substances in the water body is necessary. All polluting substances, whether in water, air, or soil, eventually return to their point of origin unless they are chemically broken down, decomposed, or altered. However, this is not true for some of these substances (heavy metals such as lead or cadmium, carcinogenic substances, radioactive substances). It is well known that fish and crustaceans from the world’s oceans in particular have long since ceased to be as healthy as assumed, as the content of questionable chemical compounds in their bodies has multiplied in recent years. Consumption means that the substances of concern are also accumulating more and more at the end of the food chain (in humans). An example for clarification: Algae in the sea take up a certain amount of pollutants from the water, animal plankton feeds on these algae and thereby multiplies the intake of pollutants in its organism. Smaller fish and larger fish then complete the food chain with a steady multiplication of pollutants in their bodies. When these animals die in the water, the pollutants are released and a multiple of them becomes accessible to the algae again. Thus, residues of lead, mercury and cadmium could be detected in many algae.It is therefore important to trace the origin of algae consumed or taken in tablet form. The iodine content of individual algae species is also quite high. Iodine has a positive effect on the body only in certain doses, too much iodine (hyperthyroidism, Graves’ disease) as well as too little iodine (goiter due to hypothyroidism) can lead to serious diseases. For all these reasons, it must be said that algae can only be considered beneficial to health if it is certain that they were raised in controlled clean waters.
