Thursday, October 28, 2010

Peanuts and Lectins and Aflatoxins, Oh My!

When I started this blog one of the first things I did was to replace my vegetable oil (read-soybean oil) with peanut oil. Peanut oil has been around a long time, plus peanuts are an oily food, it only makes sense that one could easily make oil. Easy to make equals less processing.

Then I noticed that Sally Fallon recommends eating peanut oil only occasionally. Okay, that was fine, I moved on to beef tallow and coconut oil and ate fewer thing requiring vegetable oils in general. But I continued to eat peanuts which, as you probably already know, are not nuts at all but legumes or beans. I never gave this truth much thought. I eat beans and consider them good for me. So who the heck cares that peanuts are legumes? Then I met the paleo people. They of course don't eat beans and legumes because of their high lectin content. Lectins are 'antinutrients' that inhibit your ability to absorb the protein stores that are found in beans and legumes. They are called antinutrients because they limit your ability to digest the actual nutrients that are available in your foods, so I get it. I mean if you are unable to digest, absorb and utilise a food, who gives a flying fork if it is high in protein?? Traditional bean preparation has been to soak dried beans, change the water out every couple of hours and then discard the soaking liquid. I have done this for years because I wanted to reduce the cooking time of my dried beans. But it turns out that soaking also reduces the lectin content of the beans. Don't you just love that much of proper food preparation is instinctual? Fermentation also is a good way to pre-digest some of those lectin beasties. So always soak your dried beans for a minimum of 24 hours and better if you soak for 2-3 days until they start to sprout. Always throw out the soaking liquid. And if you use canned beans, always throw out the liquid they are canned in and wash them thoroughly before adding them to your dish. This doesn't get rid of ALL the lectins, but it's good enough for me. The paleo people feel strongly that beans and legumes would not have been part of paleolithic man's diet because one needs to cook them. Therefore beans and legumes are not paleo. And lastly, soaking beans much longer or until they sprout allows the bean to "come life" and much of the starch converts to proteins as the bean prepares to grow into a plant. Remember that sprout craze 20 years ago? There you go, that's the science behind it. You can sprout any beans or seeds or non-irradiated nuts, including wheat. I have started only buying sprouted breads and all the boys (both the little ones and the big one) love it. They don't even realize that I changed it up on them.

But back to peanuts. Now you can start to see why it is significant to identify peanuts as legumes rather than a nut. Biologically they are vastly different than nuts. They aren't even brothers or cousins.

Then a couple weeks ago I was discussing all this with a like minded colleague. I respect this friend's opinion because she is dairy, gluten and refined sugar free. (My hero!) She said that she no longer eats peanuts because of the carcinogens. Wha-wha-what???? Carcinogens? Seriously? She sent me some sources and information and what I read really shocked me!

It turns out that there is this nasty little mold, called Aspergillus flavus, that gets into peanuts and other stored seed kernels (like corn or wheat) and creates these toxins which are carcinogens, which is called aflatoxins. (And yes, I am well aware that that last website was for a veterinarian, like animals, but the info is still pretty good.) Not all peanuts have them but those that have been stored have a higher likelihood of being infested. It is apparently pretty common. One website I found said that in a recent study all major brands of peanut butter contained some level of aflatoxins above the believed safe level. The health food store peanut butter which is 'grind your own' contained the highest levels of aflatoxins, undoubtedly because they were stored longer in open containers that allowed air flow. Yikes! Many folks feel like roasting kills the mold, but others are not as sure. If a commercial peanut butter still contains some traces, likely a commercial high heat roasting and refining process is not killing the mold in entirety.

Fortunately Dr Weil at his website tells us not to lose our heads. Aflatoxins create the risk for liver cancer. And since adolescents generally consume high amounts of peanut butter you'd think that there would be a ton of kids out there with liver cancer. But there haven't been any liver cancer epidemics reported in the under 12 set. Nevertheless, perhaps we don't know all there is to know about peanuts and their oil. Not to mention that many schools and public places have forbidden the use of peanut products due to severe allergy concerns. So, I think we will probably just steer clear. My Things like almond butter (I prefer it) so why don't I just use that? Almonds are not at risk for aflatoxin contamination. I have also heard that sunflower seed butter is approved because it is not a peanut nor a tree nut, another common allergy. I have never eaten 'sun butter'.

Peanuts likely do not present a grave health problem for you. But they are not as safe as some other foods. I liken it to mercury levels in tuna. You know you shouldn't be eating 3 pounds of tuna every week, so use the same caution with peanuts. But the paleo people get a plus one for using their instincts about food to guide them to healthy diet.


  1. Why don't you use Canola oil? That's what I have been using. Is that not good? Also, I read on the Rancho Gordo site that you are not supposed to throw out the bean water. They said to cook in the soaking water. I wonder why:

  2. OK, now I'm officially afraid to eat anything. Anything at all. I'm craving bean soup for lunch. I guess I must be suicidal.

  3. Thanks for this post. I have a 5 year old that loves peanut butter and eats it often, so after finding out about residual aflatoxins, I am looking for alternatives. I'll try the sunflower and almond butters. I also read on Wikipedia (Aflatoxin) that medical research indicates that a regular diet including apiaceous vegetables such as carrots, parsnips, celery and parsley, reduces the carcinogenic effects of aflatoxin. I like the info on beans. I still think they are a good food, if optimally prepared. All things in moderation.