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Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

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December 30, 2008

Aflatoxins, or Another Reason to Shun Peanuts

By Worker Bee
115 Comments

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”

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115 Comments on "Aflatoxins, or Another Reason to Shun Peanuts"

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Earth Beauty
7 years 8 months ago

Just when I am beginning to like peanuts…sigh…

Rick Rayfield
3 years 11 months ago

Aspergillus mold grows on almost ANY food staple, including peanuts, if IMPROPERLY stored. Eat GOOD peanuts and GOOD peanut butter. You do not eat moldy bread do you?
Peanuts get a bum rap- like the one above- because kids eat so much peanut butter and kids’ livers are more susceptible to alfatoxin poisoning than adults.
As an active 60-year old adult, and a PhD biologist, without a serious weight problem, I eat peanut butter almost every day.

Valoner
Valoner
3 years 7 months ago

Dear ray. Sadly,my super healthy skinny father was diagnosed and subsequently died due to liver cancer. He didn’t drink nor did he have hepatitis, but he always had a can or jar of peanuts to munch on.. I am convinced his demise was due to prolonged exposure to aflatoxin infiltrated peanuts. Everyone beware. We had a namebrand in our house. Our family has great genetics with no incidence of cancer. Be careful! Sandy

Fitness Mantra
7 years 8 months ago

Hi,
Does this apply to peanut butter as well? As a vegetarian, I am slowly losing my sources for good protein (after reading your soy post and now this!)
-FM.

Mark Sisson
7 years 8 months ago

Unfortunately, yes. That goes for peanut butter as well. Being a vegetarian and primal is a tough task indeed.

Jane
Jane
7 years 8 months ago

Almond butter is delish tho! And it doesn’t have the same issues as does peanut butter. Yay for real nuts!

Rudy
Rudy
7 years 8 months ago

I second Jane’s opinion, Almond butter is healthier and it tastes better. On peanuts, it seems the amount of aflatoxins a person inhales/eats effects their cancer risk, but if we eat fresh, clean peanuts, is it safe to assume the aflatoxin levels are minimal? After all, the cancer rates in China were based on people who were working at a peanut mill, inhaling the aflatoxins.

goodfriendsam
7 years 8 months ago

Mark – I’m a big fan, but I think there are some problems here.

Let’s not forget that walnuts, almonds, and other nuts also can and do have aflatoxins. While we can’t do anything to reverse this problem with premade nut butters (peanut, almond, or whatever), aflatoxins can be neutralized with the Price-Pottenger recommended method of soaking the nuts for around 8 hours in salt and then roasting them at very low heat (such as in a food dehydrator) until completely dry. We should be soaking our nuts anyway to keep the enzymes in tact.

robert
4 years 3 months ago

Yes but that does not get rid of the lectins. It also means buying and soaking raw nuts. Not many people will do this.

Son of Grok
7 years 8 months ago

I have always know that aflatoxins = bad… but more because I have been told. I never really bothered to research it or understand why they are bad. Thanks for the info Mark!

The SoG

JE Gonzalez
7 years 8 months ago

Well, now you gave given the best reason ro srear clear of peanuts but also of CORN! I don’t mind, but that will not make my folks proud. The only carb they really eat are corn tortillas. Coincidentally I was telling my mum about Gary Taubes’ Good Calories Bad Calories, and I told her to give up the tortillas for 30 days. Good timing, I hope.

bethinNC
bethinNC
7 years 8 months ago

We stick w/ Valencia peanut butter (organic). Trader Joes carries this for a good price. It isn’t ideal, but I’ve always heard Valencia peanuts were naturally resistant to aflatoxin, at least to a degree.

Lauren B
7 years 8 months ago

You will have to pry my peanut butter out of my cold dead hands! After giving up sugar and gluten, it is my one omega-6 filled “junk” food. 😀

Almond butter is way too expensive for my student budget, but it’s nice to know there’s a healthier alternative.

Son of Grok
7 years 8 months ago

Lauren… make your own almond butter. It is a fraction of the price.

The SoG

Bokonon
Bokonon
2 years 15 days ago
Or grow your own peanuts like we do. It is the easiest crop to grow and can be grown in pots or barrels or in the ground. In fact, they will grow in spite of you. My wife and I live on a very small lot, but grow most of our own fruits and vegetables (vertically). We harvest about 10 pounds of peanuts twice a year (we live in Southern California). That is plenty for just the two of us old empty-nesters. Shell them right away after harvest, set aside the 20 or so you want to replant, then dry… Read more »
Andrew R - Go Healthy Go Fit
7 years 8 months ago

All this talk about bad peanuts and sweeeeet almonds… makes me want an almond! But seriously, great idea to extrapolate on why peanuts aren’t the best kind of nut for anyone.

All the Best,

Andrew R

Nikki
5 years 4 months ago

That?s really srewhd! Good to see the logic set out so well.

Ellen
Ellen
7 years 8 months ago

Yes, supposedly Valencia peanuts are grown in more arid conditions making them less resistant to mold? Do you know anything about that Mark?

Sonagi
Sonagi
7 years 8 months ago

@bethinNC and Ellen:

I like peanut butter too much to give it up and buy a brand made from Valencia peanuts for the reason explained by Ellen. Peanut butter is an occasional treat, not a daily staple, so I’m not terribly concerned about an overload of aflatoxins.

Przepisy
7 years 8 months ago

hahahaha amazing picture 🙂

Bruce W
Bruce W
7 years 8 months ago
I’m going to throw in a comment here related to this site’s great information. Life is not risk free, and you cannot spend all your time trying to eliminate every infinitesmal risk. I’d like to see more risk assessment data here accompanying the posts. For example, every time you step into a car, which many people do every day, this behavior poses a risk that in all probability greatly exceeds that of consuming peanut butter. I just saw a very fit 84-year old, he still travels the world and does zip lines; and he told me he finishes each day… Read more »
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[…] his Trader Joe’s whoring (he got me hooked on their turkey chili), reason to question peanuts and green tea (not that I’m ready to decrease my own consumption), a Willy Wonka to feed the […]

JimE
JimE
7 years 8 months ago

I’ve given up so much in my quest to be healthy. I’m with Loren B., you’ll have to pry the peanut butter out of our “cold dead hands”! However I am going to look into making my own almond butter.

Ursula
Ursula
7 years 8 months ago

I also love peanut butter. Living in SA I have not seen Almond Butter on sale yet. Can anybody give me the recipe please?
Thanks so much. Hard work to get healthy, but ultimately worth it.

Mike
Mike
7 years 8 months ago

The corn issue is frustrating for me. I love eating Mexican food and have given up the flour tortillas. Now I hear the corn are not good either. Without either one, it makes dinner difficult if we are having beef or fish fajitas. It is so fun to pile the meat, avocado, lettuce, cheese and fresh salsa on a tortilla and munch away!

Suggestions?

Sonagi
Sonagi
7 years 8 months ago

@Mike:

Koreans and Japanese wrap grilled meat and toppings in lettuce leaves and other raw greens. I find it easier and less messy to eat burrito or fajita fixings in a bowl.

Mike
Mike
7 years 8 months ago

Sonagi – thanks for the lettuce tip. I had started doing that as a substitute for pita bread when eating middle eastern beef shawarma. When eating fajitas, I just need to think of the lettuce as something that wraps the food instead of going on top!

I was lucky enough to have the lettuce wrap grilled meat while in Korea once and though I looked ridiculous trying to roll the lettuce with my chopsticks, I enjoyed the food very much.

tt
tt
7 years 7 months ago
Almond cream good for you? I guess you still trust in the FDA. It is full of cyanide I wonder why they are not banning marzipan. Peanuts are too healthy for you that is why the FDA wants to ban it because it is controlled buy the pharmaceutical companies. Is it not strange that its always this salmonella scare? They just want to increase “food safety”. In other words irradiate food so there would be no health benefits left in them at all. Oh my gush, 120 people had to go to the toilet 2 times more than before. What… Read more »
Mike
Mike
7 years 7 months ago

I tried the lettuce wraps for my Mexican food per Sonagi’s suggestion. It was OK, but, lettuce really cannot hold much food. I am looking for another type of edible substrate for my mexican food nights in place of the tostada or flour tortilla. I am starting to think about some kind of fried plantain or squash or ???? Anyone got some new ideas on this one?

Jolly Hibits
3 years 5 months ago

Try brown rice tortillas, they are good, tho wish they were organic.

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[…] Lose the peanuts, the candy-coated almonds, the caramel-fudge-encrusted macadamia nuts, those clusters of candy and nuts masquerading as healthy snacks (they may have exotic spices like anise and cayenne, but they’re still covered in a fine sheen of syrup). Eat real nuts and seeds instead: almonds, walnuts, pecans, pumpkin, sunflower, hemp. And please – do not eat those dried crispy soybeans. […]

Kevin
Kevin
7 years 7 months ago

I don’t get this one-

Grok & Erg are out foraging, Erg finds a heaving peanut (vine, tree, bush, dispenser…?) and starts to eat, when Grok says,”whoa, Erg, no eat yummy energy dense peanut, it a legume, not actually a nut.”

Our ancestors would not have known/cared about the classification, and raw peanuts are non-toxic, right? How is the peanut not primal food?

Carla Golden
7 years 2 months ago
I’m currently reading The China Study and wanted to know what one of my favorite meat eaters thought about it so I searched your site and got this article as one result. The research in The China Study shows that there is a direct correlation of aflatoxin exposure expressed as liver cancer to dietary animal protein. The higher the animal protein intake (20% of diet) the more likelihood of liver cancer. The lower animal protein (5%) intake did not promote liver cancer. Plant protein of any percentage did not lead aflatoxin exposure to liver cancer and could in fact reverse… Read more »
gcb
7 years 2 months ago

Is that the same study that showed the highest intake of fruits and vegetables was among the fattest people?

http://www.proteinpower.com/drmike/obesity/another-china-study/

gcb
7 years 2 months ago

Or did you mean the China Study book by T. Colin Campbell, which is well-dissected by Anthony Colpo? http://www.anthonycolpo.com/the_china_study.html

Michael F
Michael F
4 years 8 months ago

Yes! The China Study. PROVES that Aflotoxin exposure WILL trigger some type of cancer/mutation in a lifetime if one has an acidic diet.

Carla Golden
7 years 2 months ago

The China Study book. I’ll go read the dissection. Thanks for the link!

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[…] inflammation at bay. It’s also important to eat a clean diet, which will minimize environmental toxins that can stimulate the body’s inflammatory response. Of course, I would especially suggest a […]

Scooter
Scooter
6 years 8 months ago

I will await further data on this. Peanut butter is one of the most satisfying snacks from a taste perspective, and I continue to enjoy it most days. To me, Almond butter is a sad, sad substitute with respect to flavor even though it is apparently healthier.

Cari
Cari
6 years 8 months ago

Wow! I didn’t know! Thank you!
Costco has a huge and cheap Almond Butter. Also we just tried several other nut butters from Whole Foods (not as cheap at all but good). Sunflower Butter and Cashew Butter.

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[…] to humans. In addition to being a lethally toxic allergen to many people, peanuts also contain aflatoxins which have proven to be […]

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[…] to humans. In addition to being a lethally toxic allergen to many people, peanuts also contain aflatoxins which have proven to be […]

Carlos
Carlos
6 years 1 month ago

Beware aflatoxins in coconut products made from copra.

Jeanie
Jeanie
5 years 11 months ago
I have had bad reactions to nuts for several years, and now I believe that Aflatoxins were the culprit. Once, after ingesting a handful of walnuts (two or three tasted “bad”), the pain in my liver area was so bad that my doctor told me that I would be breaking out in the rash for Shingles by the following week. When I didn’t, he was stunned. Five years ago, 15 minutes after ingesting a peanut butter sandwich, I was nauseous, achy, and the liver once again ached. This went on for three days. I was scheduled for surgery the following… Read more »
Mary
Mary
3 years 7 months ago

IF U BELIEVE EVERYTHING ABOUT FOODS YOU WOULD STARVE.

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[…] to humans. In addition to being a lethally toxic allergen to many people, peanuts also contain aflatoxins which have proven to be […]

Kate
Kate
5 years 10 months ago

Just wanted to give an FYI that corn tortillas are not a worry. The process of ‘nixtamalization’ gets rid of most of the aflatoxins, should they be present (they aren’t always). The traditional method of soaking the corn works best, but the commercial way isn’t that much worse. Unfortunately, we mostly eat corn incorrectly. The Mexican method of treating the corn is best as it gets rid of most to all of the toxins and it creates a protein out of a starch. So eat corn tortillas. Preferably in Oaxaca, where they are made on a wood-fired clay comal!

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[…] Job on Monday’s WOD! Check out this article that talks about why Peanuts are not the NUT of choice, Almonds are much better for you!!! WARM […]

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[…] Aflatoxins: or another reason to Shun Peanuts – Mark’s Daily Apple […]

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[…] Bench – 5 Rep Max WOD 100 x Lunges CF Football Here CF Endurance Here Weightlifting Shoes! Aflatoxins, or Another Reason to Shun Peanuts Creatine Supplementing for Women: The Good, The Bad and The Bloated How Much Vitamin D? How to: Do […]

kathleen
kathleen
5 years 8 months ago

I have talked to folks at framers markets. I buy raw sprouted peanuts from an organic sprout vendor. They assured me that organic peanuts should be free of aflatoxins because they are organic and not stored like other peanuts and reamain fresher it would be very uncommon to contain any aflotoxins.

Lee
Lee
5 years 7 months ago

Ah it doesn’t measure up to slam peanuts. Peanuts are low in carbs like nuts are low. So all this flack against peanuts is ridiculous. Toxic? Come on! Everyone enjoys peanut butter. I’m sure Grok would have eaten it if he dug em up. BTW Almond butter? It really sucks. Horrible taste.

Kim
Kim
5 years 7 months ago
For years I had a huge craving for peanut butter. But, the “health care professionals” always insisted it was okay, nothing’s wrong with you. Even when I was over 200 pounds, and was exercising like a fiend and never losing an ounce, and also getting sick all the time. I stopped eating peanut butter, and you know what? I HATE PEANUT BUTTER NOW. I HATE THE SMELL OF IT. The smell makes me SICK TO MY STOMACH. I will never be convinced again that peanut butter is good eats, when obviously it is not.
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[…] Raw Nuts- pecans, walnuts, cashews, almonds, macadamia, what ever really (except peanuts) […]

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trackback
5 years 6 months ago

[…] peanut butter? Try almond butter. Not only does almond butter not contain the carcinogens of peanut butter, but it also has a better omega 3: omega 6 ratio. The American diet contains a much too high ratio […]

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[…] per day for five days, then slaughtered the animal and analyzed its tissues for aflatoxin levels. Aflatoxin was found in all cuts, but it was concentrated mostly in the kidneys and, to a lesser extent, the […]

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[…] been paleo or primal for any length of time, of course you know that, (and know why it’s a bad thing) but this was a major, earth-shattering bombshell for me.  Did I already say how much I love […]

Lia
5 years 1 month ago
Ah see peanut butter is one of those things that I can’t give up. I’m paleo, well except for the peanuts, that is. I buy organic peanuts, soak them, dehydrate and roast without the skins. I mostly make my own peanut butter, though sometimes I buy too, not always. I’ve had almond butter, even made my own. I’ve made pretty much any other nut into nut butter(soaked and dehydrated first). I don’t really care for almonds or almond butter and frankly, even after soaking and dehydrating, it still bothers me. Other nuts seem to be okay with me aside from… Read more »
Justin J
Justin J
4 years 11 months ago
For all those people worried about aflatoxins in corn tortillas: Don’t expect there to be many, mainly due to the process of nixtamalization used in the preparation of said tortillas. The ancient process for the most part kills most of the aflotoxins. So keep on eating corn tortillias and masa by products, as far as freaking over some type of ingredient because its toxic, I would be more worried about things like msg, corn syrup, hydrogented vegetable oils, and weird preservatives causing far more dammage than eating peanuts. Rats are slightly different than people remember. Its also like the example… Read more »
Michael F
Michael F
4 years 8 months ago

+1 pecan butter!

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