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Natural toxins in food

Food that we eat contains more toxins than we can imagine. Naturally occurring toxins are produced by various plants species as a response to stressful environmental conditions, such as drought, low or high temperature, insects… These toxins belong to different chemical classes (amines, glycoalkaloids, glycosides…), but their final effect on human health is always more or less harmful.

Here are few more examples of naturally occurring toxins in plants:

Seeds from apples and pears and kernels from apricot and peach contain substance called amygdalin. This substance can release hydrogen cyanide and induce illness or even death if ingested in higher dose. Concentration of amygdaline may vary from kernel to kernel, and although kernels from apricot can be purchased normally in most healthy food stores, maximal dose should be 4 kernels per day. Apple and pear seeds will not induce damage if ingested accidentally, but you should avoid eating them whenever possible.

Kumara is a member of sweet potato family. This vegetable produces toxin, known as ipomeamarone when plant is injured, attacked by insects or when exposed to stressful environmental conditions. Cattle poisoning associated with poisonous kumara have been recorded and experts advice to remove all injured and potentially dangerous parts of kumara when preparing the vegetable for cooking. If kumara taste bitter - it probably contains ipomeamarone and you should not eat it.

Parnish release toxins known as furocoumarins when exposed to harsh weather conditions. Since highest concentration of toxins is found in peel and surface layer, plant should be peeled and all damaged parts should be removed before cooking. Side effects associated with furocoumarins poisoning are stomach ache and painful skin reaction if person is exposed to increased amount of UV light during consumption of the poisonous plant. Level of toxins will drop during cooking, boiling or preparing the plant in the microwave. Cooking water should be thrown away.

Potatoes produce glycoalkaloids as a defense mechanism against microorganisms, UV light and injury. These chemicals give potato a bitter taste, which is the easiest way to identify uneatable potato. Depending on the geographic area and part of the plant you are eating, amount of glycoalkaloids may cause more or less damage. Stomach ache will be immediate reaction to glycoalkaloids in food. In the case that large amount of poisonous potatoes is ingested, death may occur. Since glycoalkaloids do not get destroyed during cooking, potatoes should be carefully cleaned and peeled, including removal of all sprout, damaged and green parts of the plant.

Many beans contain lectins. Red kidney beans contain especially high concentration of these toxins. When ingested raw, kidney beans can induce vomiting, diarrhea and stomach ache. They need to be prepared and cooked properly in order to destroy toxin. First, beans should be soaked in water for 5 hours and then it should be cooked at least 10 minutes at high temperature. Low cooking temperature can't destroy toxin and it can induce even bigger damage than toxin in the raw form.

Rhubarb contains oxalic acid. Highest levels of oxalic acid are located in the plant’s leaves and they should not be eaten. Concentration of oxalic acid depends on the soil, geographic area and maturity of plant. In case you eat plant with too much oxalic acid, you may experience muscle twitching and cramping, respiratory difficulties, bradicardia, pain, vomiting, convulsion and even coma.

Zucchini may contain toxins known as cucurbitacins. These toxins are often seen in wild plants and rarely in commercially available vegetable. Since toxins give zucchini a bitter taste, you can detect uneatable vegetable by taste and strong odor. Cucurbitacins can induce vomiting, stomach cramps and diarrhea.
Cassava and bamboo sticks are inevitable part of Asian cuisine. Both species contains well known poison - hydrogen cyanide. Toxin can be removed if plants are properly treated before eating: cassava should be peeled and sliced and bamboo should be peeled, and leaves and fibrous tissue (located at the base of the stick) should be removed before boiling, baking or roasting the plants.

Honey made of bees that collect nectar from the tutu plants can be poisonous. This plant is native to the New Zealand. Cases of honey intoxication are rare, but they have been recorded in the past.

When you look at the list, it seems that everything we eat is poisonous and dangerous for our health. Reality is actually quite different. Regular fruits and vegetable meals are essential for our well being and most toxins can be avoided if plants are treated and prepared properly before consumption.