Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
30 Dec

Aflatoxins, or Another Reason to Shun Peanuts

We already tend to steer clear of peanuts for some obvious (to our readers) reasons: the fact that they’re legumes, rather than actual nuts; the potentially dangerous, “anti-nutrient” lectins found in them; and their prominent spot in the upper echelons of the “Most Common Food Allergens” list. But there’s another reason to steer clear of peanuts, something we’ve touched on briefly in the past but never expounded upon. Peanuts, along with a couple other crops we tend to avoid, like corn and cereals, are especially susceptible to a mold that produces a mycotoxin called aflatoxin.

Aflatoxin is a carcinogen that has been shown to cause liver cancer in rats (and, presumably, in humans). The amounts given to the rats in the study were highly concentrated, of course, with the express intent to study the effects of acute aflatoxicosis. You won’t be getting a couple grams of aflatoxin with every bag of peanuts or anything, so acute aflatoxicosis isn’t a big issue for people – at least in the US.

That’s not to suggest that correlations between aflatoxin ingestion and cancer rates in humans haven’t been found. In China, for example, a study of five groups of people from different villages found definite positive correlations between the amount of aflatoxin ingested and liver cancer mortality rates. Those villagers who ingested less aflatoxin were less likely to develop liver cancer; those who ingested more were more likely. Unsurprisingly, the three major sources of aflatoxins in this study were peanuts, peanut oil, and corn. Similar reports of aflatoxicosis have been made in India and Kenya.

India, China, Kenya – all developing countries with huge populations to feed. As the recent Chinese pet food contamination debacle attests, health and food standards in developing nations are often lacking. Aflatoxins develop because of these substandard conditions, whether it’s drought afflicted crops weakened and vulnerable to the mold that produces aflatoxin, or insufficient storage facilities letting in the moisture and humidity that creates the mold. Hot, humid climes and improper storage – the real culprits.

The FDA is aware of aflatoxin, and all susceptible foods are tested to ensure they pass muster. Of course, “muster” to the FDA could mean “not so much that acute aflatoxicosis becomes imminent.” What about chronic (a descriptor our nation’s health “experts” seem loathe to address) ingestion of aflatoxins? You know… long term effects? Eating toxic aflatoxin, even in relatively small amounts, over a long period of time (say, slathered on to your morning toast every morning) just doesn’t seem like the best idea.

Well, a link between aflatoxin exposure and stunted growth in West African children has been shown (bolstered by similar laboratory findings in animals), but no specific mechanism has been proposed to explain the relationship. Still, though, the very fact that much of the evidence seems to be pointing towards aflatoxin as a dangerous, development-stunting carcinogen, with a greater propensity to reside in peanuts and cereal grains, only bolsters my resolve to stay off impostor nuts and cereal grains (in or out of the closet alike). If there’s one thing everyone can agree on, it’s that increased liver cancer and stubby limbs are unequivocally devolutions.

I don’t know about you, but the evidence against eating corn and peanuts and cereal grains just seems to be stacking up incredibly high. So high, in fact, that were it not for the remarkably solid foundation of facts, scientific evidence, and personal experience, I would worry it might topple over.

Carol Esther Flickr Photo (CC)

Further Reading:

The Definitive Guide to Grains

Dear Mark: Nuts

10 Ways to “Go Nuts”

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. I have been eating organic valencia peanut butter for a long time with no ill effects….from time to time, i do cleanses, including liver cleanses, just to stay overall detoxed…

    Selene wrote on March 19th, 2012
  2. What are the chances that Grok would have eaten peanuts?

    dulst wrote on March 31st, 2012
  3. Why, when one buys in-the-shell peanuts by the bag, is there no certification on the bag that the contents were inspected? Even p-butter should show whether it is inspected, yes?.
    Also, what can a whole-peanut consumer watch for when opening peanuts? Some shells are a dark color inside — does that matter? If a kernel tastes weird, should it be carefully and completely expelled? Does or does not roasting, or re-roasting increase safety? Questions, questions…

    Pete wrote on April 29th, 2012
  4. Paranoid crap

    Really ? wrote on August 2nd, 2012
  5. Hey, after a bit of research, I found a very informative article regarding U.S. standards regarding aflotoxins:

    It cites an FDA maximum limit of 20 parts per billion for this toxin in human food. I’ve seen from the UN FAO that those European countries that have legal limits have set them at 5 to 10 to 15 parts per billion for coffees:

    Last, I saw a pie chart from the UN FAO showing the breakdown of foods that are responsible for aflotoxin exposure:

    I did not see a category for oil nuts (like peanuts) except “Other”.

    Tom wrote on September 5th, 2012
  6. I thought I would chime in since my mom worked for the USDA in the lab that examined almonds. I am pregnant and was mentioning my plans to add almond flour and almond butter to recipes when she warned me not to use store-bought varieties because of the aflatoxin.

    Her explanation was that these products are made from the broken pieces of nuts that remain after all the higher grade nuts have been sorted out. They have the highest allowance for “serious damage” meaning nuts unfit for human consumption (3% for Grades U.S. No. 1 Whole and Broken and US No. 1 Pieces). Additionally, some portion of samples from each manufacturer is allowed to be above the USDA maximum. When her colleague assessed various almond products for aflatoxin those made purely from the lowest grade nuts had the highest concentrations. Organic can actually be worse because the pesticides prevent much of the mold responsible for aflatoxin.

    Her recommendation was to buy whole almonds (or whole peanuts, she didn’t comment on Valencia) and grind them into your own butter or flour. The US #1 whole almonds have allowances of 1 1/2% or lower, and you can remove shriveled or damaged nuts as you find them.

    She did comment that peanut butter is even worse, so the same recommendations would apply. Overall, she said it’s fine to have processed nut products once in a while since everything has risks, but if you eat them often or are pregnant or feeding little ones, make your own from higher grade nuts.

    Christine wrote on December 7th, 2012
  7. Who cares if peanuts are a “real nut” or not? What matters is its nutritional profile. In many ways this is more similar to nuts than to legumes and what’s so bad about legumes anyway?

    Sean wrote on February 10th, 2013
  8. High dosed vitamin C neutralizes aflatoxins just like it neutralizes innumerable other poisons. Everyone should be taking at least 10grams/day.

    snfkd wrote on May 10th, 2013
  9. Read this whole post and all the comments while eating a bag of salted peanuts- shells included. I have no regrets.

    blindoctor wrote on September 6th, 2013
  10. I live in Thailand. I’ve been eating about 2 lbs per week of pistachios – air cooked, in a recloseable bag, for the last couple months. I don’t have ANY faith in the Thai food standards, and I’ll be stopping all peanut consumption over here. One of the problems of living in a 4th rate country.

    Vern L wrote on September 10th, 2013
  11. You say that Aflatoxin affects the livers of rats and you prove that with a very extensive scientific study by Janet L. Clifford and K.R Rees, but you presume that they also affect humans. The link of the study that you are referring to is not available. What study were you referring to? Exactly how much would a human have to eat in order for it to affect their liver? And how long were the subjects eating aflatoxin? their whole lives? a short period of time? Are their other factors in this (developing) country that could potentially affect the liver?

    meghanpoopinallen wrote on November 8th, 2013
  12. I have had mouldy tasting organic cashew butter – the kind that comes in individual pouches. Had to spit it out. Waited a few months, bought another one, same reaction. Now I will not touch the stuff. Never had that reaction over peanut butter,
    and don’t have/haven’t had trouble with cashews in general. but. wow, that particular taste is baaaaad.

    Janet wrote on March 30th, 2014
  13. I just wanted to mention something here, in case anyone is still reading this thread (which I’m sure they are). I recently went to my local farmer’s market in Los Angeles. There was a guy there selling peanut butter and peanuts from (i think?) near Fresno. I asked him what his thoughts were about molds and safety of peanuts. He said that the problem occurs when peanuts are left to sit in a moist field in humid or rainy climates. He said that his peanuts were completely dry all the time because of the weather in that region. I thought that was an interesting point, and since I’m not planning to give up peanuts entirely, looking into where specific peanuts come from, and what the weather is like there, may be a helpful strategy.

    Robin H wrote on November 14th, 2014
  14. Oh, and I should add… He believed that if you buy from very small farmers, the peanuts were much less likely to be contaminated, because it is very difficult to properly take care of all your peanuts when you have too many. I mentioned the study that found the larger peanut butter companies had less mold in them, but he reminded me that small brands did not equal small farms. The off-brands were more likely to buy peanuts from random sources, which may have changed hands a couple of times and were probably not that fresh. I guess his point was that if you buy from small, local farmers (especially in a dry climate), that is where your contamination rate is likely lowest. Who knows if this is true or not, but it sounds good to me.

    Robin H wrote on November 14th, 2014
  15. “were it not for the remarkably solid foundation of facts, scientific evidence…”

    Such as?

    Chris wrote on January 19th, 2015
  16. So are there any ways of getting rid of the aflatoxins in peanuts, or at least reducing the aflatoxins?

    I don’t think anything could survive five minutes in my pressure cooker on high. That’s the only idea I have for reducing the aflatoxins. I like peanut butter and I generally blend my own to cut grocery costs.

    Mike wrote on April 4th, 2015

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