Can Beans be Toxic?

YES!!

I had a panic attack while I was researching for our next focus, beans.

RED KIDNEY BEANS ARE TOXIC!!

Red Kidney Beans, are they a possible source for food poisoning?

Don't freak out and get rid of all your kidney beans, I almost did, but I started to research more and what I found blows my mind as too why this isn't common knowledge! So lets make it!!

First off, when cook PROPERLY red kidneys beans are HARMLESS.

But how are you supposed to PROPERLY cook red kidney beans? Can't I just cook them like I cook all my other beans?

According the the FDA and the Public Health Laboratory Services of the UK, the proper and safe cooking method for RED KIDNEY BEANS is:

Soak in water for AT LEAST 5 HOURS. Then Rinse, and with fresh water briskly boil for 10 MINUTES, stirring occasionally. After this process you can continue to cook how ever you desire, on the stove or in you slow cooker, or you can eat them. (Source)

OK, so now that we know how to cook our red kidney beans, what is this toxic? What does it do? Is it in all beans? Can they kill me?

The toxin in red kidney beans is a lectin. Lectins are

Protein or glycoprotein substances, usually of plant origin, that bind to sugar moieties in cell walls or membranes and thereby change the physiology of the membrane to cause agglutination, mitosis, or other biochemical changes in the cell (Source)

To me, who is not a biologist, that means, that lectins change the chemicals of the cells of my body... (but so does the Common Cold, please don't freak out people!)

But the toxin in red kidney beans is a more specific lectin, a hemagglutinin:

Agents that cause agglutination of red blood cells. They include antibodies, blood group antigens, lectins, autoimmune factors, bacterial, viral, or parasitic blood agglutinins, etc (Source)

This means, something that effect the blood, good or bad.

But to be the most specific, the toxin is, Phytohemagglutinin:

Mucoproteins isolated from the kidney bean (Phaseolus vulgaris); some of them are mitogenic to lymphocytes, others agglutinate all or certain types of erythrocytes or lymphocytes. They are used mainly in the study of immune mechanisms and in cell culture (Source)

After all the science mumbo jumbo, the toxin in red Kidney beans is a food borne Pathogen, a Natural Toxin. Honestly, I am not to worried about it, because 1) I have never gotten food poisoning, and 2) I am going to start cooking my beans properly!

So what does the Phytohemagglutinin do to us? It is a natural toxin, so be prepared for vomit! 

The onset time from consumption of raw or undercooked kidney beans to symptoms varies from between 1 to 3 hours. Onset is usually marked by extreme nausea, followed by vomiting, which may be very severe. Diarrhea develops somewhat later (from one to a few hours), and some persons report abdominal pain. Some persons have been hospitalized, but recovery is usually rapid (3 - 4 h after onset of symptoms) and spontaneous. (Source)

That does sound like a horrible case of food poisoning! And No! Beans will not kill you, unless you do not replenish liquids lost from vomiting or diarrhea. PLEASE, GO TO A DOCTOR IF YOU THINK YOU HAVE SERVE FOOD POISONING!!

Is this toxin in other beans? Yes it is! But not in nearly the same toxic quantities!

White kidney beans, another variety of Phaseolus vulgaris, contain about one-third the amount of toxin as the red variety; broad beans (Vicia faba) contain 5 to 10% the amount that red kidney beans contain. (Source)

Beans are safe to eat, but just like undercooked or improperly cooked meat, they can cause food poisoning!

Next week well will talk about the antioxidant properties of beans!






Sources:
FDA Bad Bug Book, 2011, accessed 6 June 2012; http://www.fda.gov/Food/FoodSafety/FoodborneIllness/FoodborneIllnessFoodbornePathogensNaturalToxins/BadBugBook/ucm071092.htm?utm_campaign=Google2&utm_source=fdaSearch&utm_medium=website&utm_term=red%20kidney%20beans,%20phytohaemagglutinin&utm_content=2