Many plants naturally contain substances that can have a toxic (poisonous) effect on humans and animals. To the plant, these toxins (poisons) serve different functions. They can prevent feeding or assist in the defense against microorganisms. For the human organism, these substances can have a more or less harmful effect on health. However, if the potentially hazardous substances are known and possible sources are avoided, any health risk is very low.
Hemagglutinins in legumes.
Hemagglutinins are proteins that cause red blood cells to clump together in the body. This can cause severe intestinal inflammation and bleeding. It is assumed that even the consumption of five to six raw green beans can cause these effects. Mild symptoms of poisoning are often experienced as stomach upset. Hemagglutinins occur naturally in legumes. Legumes include beans, peas, and lentils. Common bean (also called phasin here) and fire bean have particularly high concentrations. Boiling for about 15 minutes breaks down these substances. Legumes should therefore not be eaten raw. During the germination process of legumes, the toxic substances are already partially degraded. Legume sprouts, such as soybean and lentil sprouts, therefore only need to be blanched briefly before consumption. Blanching means cooking for a short time in bubbling boiling water.
Solanine in potatoes and tomatoes
There is always uncertainty about whether or not you can eat potatoes and tomatoes that have turned green. Potatoes and tomatoes belong to the nightshade genus. Elevated concentrations of the glycoalkaloid solanine are contained in greened areas, in the sprouts, around the eyes and in the skin of these plants. Excessive intake of solanine can cause nausea, vomiting, headache, stomach pain, and even respiratory distress, convulsions, and unconsciousness. Solanine content is affected by several factors, including variety, growing conditions, ripeness and storage. If you follow these tips, there is not likely to be a health hazard:
- Solanine content decreases as tomatoes ripen and turn red. Therefore, unripe green tomatoes should not be consumed.
- For potatoes, care should be taken to ensure good storage conditions. The ideal storage temperature for potatoes is 10 ° C. Too high and too low temperatures can lead to an increase in alkaloid content, as well as too much light exposure and too long storage.
- Injured tubers contain significantly more glycoalkaloids than comparable, non-injured potatoes. Injured and green spots therefore best removed.
- Since the solanine is water-soluble, it passes into the cooking water during cooking. This should not be used further.
Prussic acid in bitter almonds
The prussic acid contained in some foods can lead to acute poisoning, because prussic acid blocks the respiration of the cells. The cells then no longer receive oxygen. If foods with a high prussic acid content are consumed chronically, failure symptoms of the nervous system can occur. Prussic acid is contained in various foods that are particularly important in the tropics, e.g. yam, sweet potato, sweet sorghum and bamboo. In addition, the seeds of many fruits contain prussic acid, including the seeds of lemons, peaches, apricots, cherries, apples, pears and plums. In our latitudes, bitter almonds are of particular importance. The bitter almond oil produced from them can have an acute toxic effect in larger quantities. It is described that in children already 10 drops can be fatal. Bitter almond oil should therefore not be made yourself, but resort to bitter almond flavoring.
Oxalic acid, myristicin and elimicin.
Oxalic acid is found in numerous plants. There is no fear of acute poisoning due to this substance. Oxalic acid has the undesirable effect of binding calcium from food in the intestine. Insoluble salts are then formed, which are excreted in the stool. The calcium is thus no longer available to the body. In some people, an increased concentration of oxalic acid can also promote the formation of kidney stones (so-called oxalate stones).People who have a corresponding predisposition and those with chronic intestinal diseases are particularly affected. Spinach, beet, chard and rhubarb are particularly rich in oxalic acid. Oxalic acid levels can be lowered by cooking the vegetables and pouring away the cooking water. Myristicin is an essential component in the essential oil of nutmeg. In addition, the substance is also present in smaller amounts in other spices. These include dill, parsley, anise oil and lemon oil. Nutmeg also contains another substance, elimicin. In the body, these substances act like the drug mescaline, hallicinations and disturbances of consciousness may occur. Severe poisoning can occur even with the ingestion of about 15 g. Ingestion of large quantities of powdered nutmeg is particularly dangerous for children.
Glycyrrhicin in licorice.
Who doesn’t like licorice? They tempt in the form of snails, kittens and chewy candies. Licorice is obtained from the roots of the licorice plant. A natural substance of this plant root is glycyrrhicin. Studies have found that regular consumption of more than 100 milligrams of glycyrrhicin per day can lead to an increase in blood pressure. Therefore, it is advised to all people suffering from cardiovascular diseases and diabetes, as well as pregnant women, not to eat too much licorice.
Natural flavorings in spices and herbs.
Natural flavoring agents are found in numerous spices and herbs. These include estragole and methyl eugenol. They occur in anise, fennel, tarragon, basil, nutmeg, allspice and lemongrass, among others. In animal studies, both substances have been shown to cause cancer and damage the genetic material. However, it is still unclear whether these results can be transferred to humans. As a precaution, however, the Federal Institute for Risk Assessment (BfR) recommends that the spices and herbal tea drugs mentioned should not be used permanently and regularly in higher quantities. Another note of reassurance: Only a small proportion of the aromatic substances gets into the tea infusion of fennel tea. This has been proven in studies.
Coumarin in woodruff
Coumarin is a fragrance substance of woodruff. In light doses, coumarin has a mildly exhilarating effect and can help relieve headaches. But in higher dosages, coumarin causes headaches and dizziness. This substance also has an inhibitory effect on blood clotting. If it is regularly supplied in higher doses, it can cause damage to the liver. Because of the harmful effects of larger quantities, coumarin may not be used as a flavoring agent in Germany. Friends of May punch prepared with woodruff should not use more than three grams of the herb per liter of punch.
