Naturally occurring toxins in food

"Everything natural is harmless" is one of the most enduring myths of our times, and it’s time to take a closer look at this topic especially when it comes to the food we eat. If we think that anything fresh, green and naturally derived is always safe and healthy, we are wrong, with odd reports of deaths due to accidental overdoses of something as seemingly harmless as vegetable juices!

Experts are increasingly being flooded with questions about what is safe and healthy when it comes to green foods. So, let’s come face to face with the fact that some of the world’s deadliest poisons are natural and green.

Top naturally toxic fruits and vegetables:

Apples: Apple seeds are known to contain naturally occurring toxins – cyanide - and can become poisonous if taken in large doses. So while one apple with seeds won’t kill you, it is a bit eerie to think that we come into close contact with potentially deadly poison while biting into one of the most delightful fruits of all times. We do chew apple seeds accidentally, don’t we?

Almonds: Almond, a seed (and not a nut contrary to popular belief) and one of the most celebrated health foods in all times due to its highly nutritious content is also a food item that needs a closer look. They are mainly of two varieties, the sweet and bitter. It is the bitter type of almonds that carry the toxic prussic acid, which can be further refined into the poison cyanide. It is therefore dangerous to consume a handful of raw, unprocessed almonds, without leaching out the harmful acid first (the poison is destroyed by heating).

All almonds presently sold in the USA are heat-treated to remove traces of poison and bacteria, and countries like New Zealand have actually banned the sale of raw almonds. Some of the most flavorsome almonds are bitter almonds with the strongest smell and are used commercially in making almond oil, perfume and cosmetics.

Tomatoes: A berry, a fruit or a vegetable? The debate centered around what a tomato really is, has perhaps taken the sting away from a lesser known fact that a tomato plant is a potentially poisonous thing for humans. A tomato plant’s leaves and stems contain a chemical called “Glycoalkaloid” which when eaten causes extreme nervousness and stomach upsets.

Cherries: Another one of the most delicious fruits, cherries make it to the list of top fruits that have naturally occurring poison in their seeds. Seeds of cherries produce prussic acid when either crushed, chewed or injured even mildly, so avoid sucking on cherry seeds the next time you are enjoying this perfectly delectable fruit. Don’t chew it either, if you do so for any strange reason.

Potato: The uncrowned king of the vegetable family, with unassuming demeanor, the humble potato has a secret that it hides, despite its raving global popularity. Just like tomatoes, the potato plants leaves and stem are poisonous and this poison sometimes spreads to the potato itself, when it turns green in patches or grows small green sprouts. The green coloring happens due to the presence of high amount of glycoalkaloid poison. A green potato is a sick potato, and you must avoid it at any cost. Although a rare occurrence- potato poisoning, when it does occur, leads to weakness and confusion, followed by coma. Death by potato makes really bad press for an otherwise outrageously popular vegetable across the world.

What makes fresh fruits and vegetables turn toxic?

Vegetables such as cucumber, gourds and some from the fenugreek family are known to be bitter, due to the presence of complex compounds in small quantities. In ‘lauki’ a most popular Indian bottle gourd, this toxin is called Tetracyclic triterpenoid cucurbitacin that creates havoc on the human body in large doses. As these compounds are normally present in small doses they are not considered life threatening or poisonous. However, if you bite into any particular one of these that is excessively bitter, it’s best not to eat it any further. Throw away any highly bitter or weird tasting cucumber or gourd that may have come into your vegetable basket – its safer that way.

Experts also advise against mixing juices of naturally bitter vegetables (like the Indian Karela or bitter gourd) with other juices like bottle gourd or Lauki, as the bitter taste may mask the accidental toxicity in the other juice that is not meant to be consumed, if bitter.

What precautions make fresh fruits and vegetables safe?

First of all, take hygiene steps to avoid microbial contamination. Washing vegetables and fruits with clean potable water is most desirable, or alternatively, with potassium permanganate or a chlorine solution, if you plan to eat them raw. Peeling the outer layer is another safe practice if for some reason the washing is not thorough. Although you lose the vitamin, mineral and fiber content to a certain degree, it is still better.

Cooking is another method of safe consumption, as heat largely destroys whatever toxins that might be present. So, to be on the safer side, if you are offered raw salads and fresh juice, avoid them completely unless you are sure about the sources. Choose safely grown organic vegetables and fruits, so that you also reduce your intake of harmful chemical pesticides that lurk on the surface. When in doubt, either while debating whether to use that overripe pear or bruised papaya, follow the old dictum: “better outside than in.” Think safe, be cautious, and stay healthy.