Many plants naturally contain substances that can exert a toxic (toxic) effect in humans and animals. The plants serve these toxins (toxins) in different function. They can prevent the predation or assist in the defense against microorganisms. For the human organism, these substances may have a more or less harmful effect. However, knowledge of potentially hazardous substances and avoidance of possible sources makes health risks very low.
Hemagglutinins in legumes
Hemagglutinins are proteins that cause red blood cells to clump together in the body. This can lead to severe intestinal inflammation and bleeding. It is believed that even eating five to six raw green beans can cause these effects. Lighter symptoms of intoxication are often perceived as stomach upset.
Hemagglutinins occur naturally in legumes. The legumes include beans, peas and lentils. Particularly high concentrations of the kidney bean (also called phasin here) and the runner bean. By boiling for about 15 minutes, these substances are broken down. Legumes should therefore not be consumed raw.
In the germination of legumes, the toxic substances are already partially degraded. Seedlings of legumes such as soy and lentil sprouts must therefore be blanched briefly before consumption. Blanching is the short-term cooking in sparkling boiling water.
Solanin in potatoes and tomatoes
Again and again there is uncertainty, whether you can eat green potatoes or green tomatoes or not. Potatoes and tomatoes belong to the genus Solanaceae. In green areas, in the germs, in the area of the eyes and in the shell of these plants, elevated concentrations of the glycoalkaloid solanine are contained. Excessive intake of solanine may cause nausea, vomiting, headache, stomach ache, shortness of breath, convulsions, and unconsciousness.
The solanine content is influenced by several factors, e.g. By variety, growing conditions, degree of ripeness and storage. If you follow the following tips, there is no health risk:
- The solanine content decreases with increasing maturation and red coloration of tomatoes. Immature green tomatoes should therefore not be eaten.
- When potatoes should be paid to good storage conditions. The ideal storage temperature for potatoes is 10 ° C. Too high and too low temperatures can lead to an increase in Alkaloidgehaltes, as well as high light influence and too long storage.
- Injured tubers contain significantly more glycoalkaloids than comparable, non-injured potatoes. Therefore, best remove injured and green spots.
- Since the solanine is water-soluble, it goes into the boiling water during cooking. This should not be reused.
Hydrocyanic acid in bitter almonds
The hydrocyanic acid contained in some foods can lead to acute poisoning, as hydrogen cyanide blocks the respiration of the cells. The cells will not get any oxygen anymore. If foods containing high levels of hydrogen cyanide are consumed chronically, nervous system deficits can occur.
Hydrocyanic acid is contained in various foods that are particularly important in the tropics, eg. Yam, sweet potato, sugar millet and bamboo. In addition, the nuclei of many fruits contain hydrogen cyanide, u. a. the kernels of lemons, peaches, apricots, cherries, apples, pears and plums.
Of particular importance in our latitudes is the bitter almonds. The bitter almond oil produced therefrom can be acutely toxic in larger quantities. It is described that in children already 10 drops can be fatal. Bitter almond oil should therefore not be made by hand, but be used on bitter almond flavor.
Oxalic acid, myristicin and elimicin
In numerous plants, oxalic acid occurs. Due to this substance no acute poisoning is to be feared. Oxalic acid has the undesirable effect of binding calcium from food in the intestine. It then forms insoluble salts that are excreted in the stool. The calcium is thus no longer available to the body.
In some people, an increased concentration of oxalic acid may also promote the formation of kidney stones (so-called oxalate stones). Particularly affected are people who have a corresponding predisposition and those with chronic bowel disease. Particularly rich in oxalic acid are spinach, beetroot, Swiss chard and rhubarb. The level of oxalic acid can be lowered by boiling the vegetables and pouring the cooking water away.
Myristicin is an essential ingredient in nutmeg essential oil. In addition, the substance is also contained in smaller amounts in other spices. These include u. a. Dill, parsley, aniseed oil and lemon oil. The nutmeg contains another substance called elimicin.
In the body, these substances act like the drug mescaline, it can lead to Hallizunationen and disturbances of consciousness. Heavy poisonings can occur even when taking about 15 g. Particularly dangerous is the intake of large quantities of powdered nutmeg for children.
Glycyrrhicin in licorice
Who does not like licorice? They seduce you in the form of snails, kittens and chewy candies. Licorice is obtained from the roots of licorice plant. A natural substance of this plant root is glycyrrhicin.
Research has found that regular consumption of more than 100 milligrams of glycyrrhicin per day may increase blood pressure. It is therefore advised that all persons suffering from cardiovascular diseases and diabetes and pregnant women, not to eat too much liquorice.
Natural flavors in spices and herbs
Numerous spices and herbs contain natural flavors. These include estragole and methyleugenol. They come u. a. in anise, fennel, tarragon, basil, nutmeg, allspice and lemongrass. In animal experiments, a cancer-causing and genotoxic effect was demonstrated for both substances. However, it is still unclear whether these results are transferable to humans.
As a precautionary measure, however, the Federal Institute for Risk Assessment (BfR) recommends that the above-mentioned spices and herbal tea drugs not be used permanently and regularly in higher quantities. One more note to reassure: In the tea infusion of fennel tea reaches only a small proportion of the flavorings. This could be proven in investigations.
Coumarin in the woodruff
Coumarin is a perfume of the woodruff. Cumarin has a light weighting effect and can help relieve headaches. But at higher doses, coumarin causes headaches and dizziness. This substance also inhibits blood clotting. If it is given regularly in higher doses, it can cause damage to the liver.
Due to the harmful effects of larger quantities of coumarin may not be used as a flavoring in Germany. Friends of the Maibowle, which is prepared with woodruff, should not use more than three grams of the herb per liter of punch.