Brown algae, red algae, green algae, blue-green algae, blue-green algae - many algae in dazzling colors grow around the globe in Neptune's garden. And even though this vegetable patch is below sea level, man also makes a colorful harvest here. If you like sushi or other Asian dishes, you have probably already had an algae leaf on the spoon or, more authentically, between the chopsticks.
Algae as a dietary supplement?
The ingredients of some algae, so-called microalgae, are also offered in tablets or powders as dietary supplements. However, the colorful "sea foliage" should be used wisely: due to its exceptional high iodine content Some algae landing on the plate have one negative influence on the thyroid gland.
Also, the question of what to look for, if you want to supplement your food with tablets or powders of algae, will be answered here in the rest of the article.
Algae - what plants are they?
In the algae mentioned two groups are distinguished: the so-called macroalgae are what you would classically call marine algae, literally underwater plants. These include the brown, red and green algae, which are found in many Asian dishes.
On the other hand, the blue-green algae, which are also called blue-green algae, are not really algae, but a special type of bacterium. These cyanobacteria have the peculiarity that they - like plants - can gain energy with the help of chlorophyll. The chlorophyll gives them their green-blue color.
Algae have seen blue algae before, as they like to form in calm waters that are exposed to light. Owners of aquarium know how to sing a song about the invaders who cling to the glass walls and so dim the view of the native underwater world greenish.
Blue-green algae can be harmful to your health
The cyanobacteria can form toxins that can have a harmful effect on health in high concentration. If the blue-green algae bloom in masses, a health risk can occur in bathing lakes, for example. The following symptoms may occur when in contact with blue-green algae or after ingestion of water mixed with the poisons:
- Skin and mucous membrane irritation
- respiratory diseases
- allergic reaction
Ingestion of larger quantities is especially dangerous for infants.
When Europeans eat like Asians
The Japanese traditionally land large amounts of algae in the kitchen pot, since the absence of large areas of agricultural land and the direct availability of algae on the long coastlines of the Japanese islands have been inviting the use of sea vegetables for centuries.
As healthy as the high-fiber and low-fat Asian cuisine is, the iodine content of some of its algae far exceeds anything the ingredients of European cuisine have to offer. The Brown algae Kombu it has something in it: it can store amazing amounts of iodine. Compound iodine levels are 40,000 times that of normal seawater, and one-twelfth of a gram of dried leaves is enough to cover a person's daily intake of iodine.
Excessive iodine intake as a threat to the thyroid gland
A sudden, excessive intake of the mineral may have undesirable consequences: so-called "functional autonomies" in the thyroid can be activated.
These are nodules (autonomous adenomas), which form especially in the case of prolonged deficient iodine intake. If these iodine-thirsty areas of the thyroid gland are suddenly supplied with an excess of iodine, they begin to produce thyroid hormones out of bounds and ligaments: an acute hyperthyroidism (hyperthyroidism) can be the result.
Japanese are (almost) resistant
Since the Japanese and other Asians consume a lot of iodine throughout their lives because of their high consumption of algae, there are virtually no autonomic nodes in the population for thyroid examinations, and therefore there are no problems with algae consumption.
But even for the tried-and-true Asians, it can sometimes be too much of a good thing: in some areas of the Japanese coast, an astounding number of people are found with a goiter, as they are increasingly found in the iodine-poor Alpine countries.
The goiter, an enlargement of the thyroid gland, is actually an iodine deficiency syndrome, but it can also be triggered by a very high iodine intake. In this case, the system responsible for uptake of the iodine into the thyroid gland is so irritated by the iodine flooding that it stops recording without further ado.
This leads to an iodine deficiency in the thyroid gland despite the Jodüberangebotes in the blood. This, too, as Wolf f-Chaikoff block known effect, may also affect the unborn child of a pregnant woman, so this should (except for a sufficient) pay attention to a not too high intake of the element.
Eat algae: You can pay attention to that
First of all, it has to be stated that only part of the Asian algae is so extremely iodine-rich. Above all, these are the brown algae kombu and wakame. Kombu is usually boiled in water, and the resulting broth is the basis of most Japanese soups. The firm green leaves of the wakame are used as an ingredient in soups and salads. Nori, on the other hand, serves as a "wrap serving" of maki sushi. However, if you do not eat too much wild sushi, you do not have to worry about it, as Nori does not seem to have extreme levels of iodine.
The iodine content of the algae varies not only from variety to variety, but may also be very different depending on the harvesting time and place of growth. In addition, the algae lose in preparation up to 87 percent of the iodine content. However, since the recommended amount of iodine in the dry weight of algae is in some cases 20 to 195 times the limit, the problem must not be trivialized.
Beware of too much iodine
According to the Federal Institute for Risk Assessment (BfR), the iodine content in dried algae varies greatly and is between five and 11,000 micrograms per gram. However, the BfR recommends as Maximum amount only 0.5 milligrams a day.
In a statement issued in 2007, the BfR points out that with high iodine contents already the consumption of ten grams of algae leads to an excessive absorption of iodine. However, products often lack information on the amount of algae contained or the iodine content.
Microalgae: panacea and food source of the future?
When referring to microalgae, it is primarily the species Aphanizomenon flos-aquae (also called "AFA algae"), chlorella and spirulina. They have in common is that many myths about the often referred to as "Uralgen" single-celled tendrils. Because of their wealth of protein and the fact that they do not need arable land for cultivation, and how plants use photosynthesis to produce their own biological building blocks, many consider them a solution to the food problem of a steadily growing world population. Although this idea is not entirely new, previous efforts have brought no success in the large-scale cultivation of algae.
The mentioned microalgae, especially the AFA algae, also serve as the basis of countless tablets and powders sold as dietary supplements. The "Uralgen" is often, more or less explicitly, an effectiveness in numerous diseases, up to cancer and AIDS, assumed. However, such claims have not been proven so far.
Are algae products medicines?
Any product claimed to cure, alleviate, or prevent any disease is considered a medicinal product by law. However, these require a state authorization, which requires proof that the product actually has the desired effect and no harmful effects. Since no algae product is currently authorized as a medicinal product in the Federal Republic of Germany, none of these products can be said to have medicinal properties. It is therefore advisable to consult a doctor instead of trying to cure yourself or others with an algae product.
Toxic substances in algae
The issue is further explosive in that the toxic substance microcystin is contained in many AFA products. Microcystins are found in many cyanobacteria species and are often included in finished products made from blue-green algae available on the market as dietary supplements.
Microcystin has liver damage and is considered a tumor promoter - the substance itself is therefore not carcinogenic, but increases the likelihood of carcinogenic substances. In an American study, all of the AFA products studied contained these microcystins, sometimes exceeding the WHO tolerable maximum levels. For this reason, it is not recommended to give AFA algae products to children, and a dose reduction is recommended for adults.