Peanut Butter: Yay or Nay? {Carcinogens & Storage Tip}

So, I read a tweet the other day from blog buddy Susan of the Great Balancing Act that surprised me:

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Peanut butter? A carcinogen-containing food? Who knew. Perhaps this is common knowledge for most of you, but this was the first time I’d heard about this.

So, what is a carcinogen exactly? According to, the definition of a carcinogen is “a substance or agent causing cancer.”

Whoa…heavy stuff. I wanted to learn more about this to see if I should be concerned, so I looked for articles about the topic online. I learned that peanut butter itself isn’t a carcinogen, but there is a mold that can grow on peanuts that produces aflatoxin, which is a carcinogen. I also learned that there are ways to supposedly kill the toxin and that aflatoxin-free peanut butters exist. Read on for more…

This article (click) by Dr. Weil was pretty informative, though overall it seemed like Dr. Weil didn’t think the carcinogen levels of peanut butter were too threatening when eaten in moderation. I was thrown off a bit by this line since I usually think of health food store options as being…well…healthier:

“A few years ago, Consumers Union looked into the question of aflatoxins in peanut butter and found that the amounts detectable varied from brand to brand. The lowest amounts were found in the big supermarket brands such as Peter Pan, Jif and Skippy. The highest levels were found in peanut butter ground fresh in health food stores.”

And I actually found this statement from the Dr. Weil article most interesting (since I’m an almond butter lover):

“I still prefer almond butter and cashew butter, because they have a better fatty acid profile.”


But back to the peanut butter discussion, according to this article (click) on, you can actually enjoy peanut butter sans toxins if you just refrigerate it.

Here’s a good snippet from the article in relation to the snippet above from Dr. Weil:

“…don’t think that switching to the overly processed, non-organic version of peanut butter will save you because those peanuts are treated with a host of pesticides that seep right through that thin skin.”

This article (click) from provides the advice I’ll probably end up taking:

“The bottom line when it comes to peanut butter and your health: Buy organic to prevent pesticide contamination. Refrigerate your jar to prevent fungal growth. And if you’re particularly concerned about aflatoxins, buy from top-notch natural brands like Arrowhead Mills, which claim to be completely aflatoxin-free.”

Anywho, these are just three articles from what could be a very large number. Have you heard anything about peanut butter and carcinogens that I’ve missed? Please share your info, links, etc. in a comment.


Either way, I think I’ll stick with almond butter most of the time (I do like peanut butter and other nut butters every once in awhile) . I know almond butter is really trendy now, but I actually just prefer the taste of almond butter over other nut butters. But, if you’ve never tried almond butter before (or if you tried it once and hated it), it’s worth me mentioning that not all almond butters are made the same. I’ve tasted some that were flavorless, bland, and basically horrible, so don’t give up after trying just one.

My personal favorite almond butter is Barney Butter. It’s expensive, but worth it to me for the deep-roasted flavor that just tastes so much better than others I’ve tried. I recently picked up some Justin’s Maple Almond Butter that I’m really enjoying (it’s great for the Not-So-Sweet fans out there). I usually try to purchase both on sale, and I’ve seen the Justin’s brand at Target!


Or course, I also really like making my own almond butter. πŸ˜‰ Click here for my Honey-Roasted Cinnamon Wink Almond Butter recipe.


Reader Question: What do you think? Peanut butter: yay or nay? Does the carcinogen issue scare you away from peanut butter? Do you think you’ll change how you store your peanut butter? Do tell!

34 thoughts on “Peanut Butter: Yay or Nay? {Carcinogens & Storage Tip}”

  1. I love Barney Butter and get so excited when it’s on sale at the store. This was very interesting to read and so glad that you brought it up. I think I will continue to consume peanut butter in moderation and keep it in the fridge to be on the safe side.

    On a completely different topic: I recently got into zumba and absolutely love it. The only problem I’m having is getting all the moves right and it doesn’t help that my hand-eye coordination is horrible, but I am trying.
    have a good weekend!! =)

    • So excited to hear you’re into Zumba now!! I’m so glad to hear you’re enjoying it. It’s a great workout and so fun. Don’t be too hard on yourself with getting the moves right. Zumba is more about letting the music move you and enjoying the party. So let loose and dance like no one’s watching! πŸ˜‰

  2. I like peanut butter, but I definitely prefer almond, sunflower and cashew butter! Plus peanuts are meant to be highly inflammatory. I occasionally use it though, I love peanut butter sauce over tofu – thai style! I should store it in the fridge though!

  3. Nah, I’ll still buy/eat my natural peanut butter and store it in the cabinet, lol. If getting salmonella from peanuts back in ’08 didn’t turn me off them, this won’t either.

  4. I had not heard about the carcinogen’s in peanut butter, though I have known about the pesticides (always buy organic PB! that is so important). I’ll have to look into it more but I don’t eat all that much of it, so I guess I’m not too worried (maybe 3-4 tablespoons a week?). I like almond butter but it’s just not the same for me πŸ™‚

  5. Great post Diana!! Honestly, if I didn’t already have cancer, the carcinogenic aspect of peanut butter wouldn’t freak me out as much. But Hodgkin’s disease actually never fully goes away, I will always have a little piece of cancer around my heart. So I am taking NO chances and not giving it any excuse to decide to start growing again when the chemo is through. It’s really a matter of evaluating your personal heath and knowing where you want to step up your game or let things slide.

    • Thanks Susan! You’re so level-headed. I think I would take the same approach, too. And I love this line especially -> “It’s really a matter of evaluating your personal heath and knowing where you want to step up your game or let things slide.” So true! πŸ™‚

  6. interesting…i prefer pb to any other kind of nut butter, but i usually keep it in the fridge since i buy the natural kind. and not to be disrespectful to those w/ cancer/people’s loved ones w/ cancer…(i’ve had it in my family too), but it seems like everything causes cancer and there are so many conflicting studies that it’s hard to balance everything. so you just gotta pick your battles, i guess!

  7. I’ve never heard that peanut butter is a carcinogen, but I already always refrigerate it when it is open. I love almond butter more, but it is too expensive, so I only buy it occasionally as a treat!

  8. This study doesn’t phase me in the least bit. I grew up on PB sandwiches and my liver has no problems whatsoever. This risk is likely important to people who already have compromised systems and therefore their bodies would not be well equipped to deal with taking in the micro amounts of aflatoxin. The other thing is most people do not understand what 20 ppb means. If you want a density conversion, it’s 20 ng/mL. So in 1 mL of PB you might have 20 nanograms of the toxin (if it’s at the high limit they allow). That’s not a large amount at all, and since anything over that is banned chances are your exposure is even tinier. I’m not altering anything with my intake of PB. I think there are far worse things to be concerned with than this.

    • The problem is that the studies show that low-level exposure, even in the ppb range, over long periods of time still causes liver problems and cancer. And peanuts aren’t the only foods that can expose you to aflatoxin, either. Corn, dairy and multiple other foods can be a route of constant, low-level exposure, as well. It all adds up.

  9. I replied to Susan’s tweet with something along the lines of the fact that I consume a sunflower seed butter and banana sandwich just about every day, so that solves that problem. I love my sunflower seed butter πŸ˜‰

    Anyway, I eat the SSB because of a peanut intolerance, but even if I could eat PB, I’m not sure this news would freak me out that much. Like anything else that they overanalyze, I think it’s an issue of being a conscious consumer–in all sense of the word. Choose wisely and take precautions, but also know that they find something wrong with just about every freaking food out there. Moderation and education.

  10. If you’ve ever read The China Study (and if you have’t you should!) then they have a HUGE section on aflatoxins. I still think that peanut butter tastes the best, but I switch it up with almond butter and sunflower seed butter now to cut down on the aflatoxins and to get a greater range of minerals.

  11. Wow, I had not heard about carcinogens in peanut butter! I eat Trader Joe’s Valencia with flax seeds, so I’m hoping it’s ok. I also just tried Sunflower Butter this morning…did not like it! Haven’t tried almond butter, but I think I might have to!

    • I’m not a fan of sunflower seed butter either. It’s just ok. I prefer almond or peanut butter. And I’ve had that TJ’s PB and I really like it!

      Let me know what you think of almond butter if you try it. Barney Butter and Justin’s are the best IMO. πŸ™‚

  12. definitely have known about the aflatoxin thing for years, but it doesn’t concern me too much b/c I almost never eat PB (I know, I’m weird :P). Great topic though! and Koah loves the stuff, so perhaps I should be concerned for my fur baby πŸ™‚ Have a great weekend!

  13. Interesting! I hadn’t heard that about peanut butter. In the last year or so, I’ve grown sick of almond butter and have switched to peanut butter. I already store my peanut butter in the fridge since it’s always the natural kind, and I never eat more than about a tablespoon of it, so I’m not too worried or likely to change any habits.

    There are way more things that make me worry about carcinogens than peanut butter. Still… interesting to read that about PB.

  14. I’d never heard this about peanut butter either, but I agree with Laura above, “There are way more things that make me worry about carcinogens than peanut butter.” It seems like lately everything causes cancer and I’m trying not to live my life in constant fear. I’m going to keep eating peanut butter in moderation.

    Thanks for the information though…really interesting!

  15. I keep my Peanut Butter in the fridge because my mom did. So that’s a good thing.

    I do switch it up with sunflower seed butter occasionally depending on the circumstances and cashew butter when budget and taste buds allow.

    I’m allergic to almonds so that’s more important than the carcinogenic effects of PB. And like Susan said she is focusing on it because she already has Hodgkins. There are so many things in life we would have to avoid because they “could” cause problems but the chance is minimal often.

  16. I want to highlight the first part of Dr. Weil’s answer: “The carcinogen you’re referring to is aflatoxin, a natural toxin produced by certain strains of the mold Aspergillus flavus and A. parasiticus that grow on peanuts stored in warm, humid silos.” I think it’s important to point out that it’s not peanut butter itself that is carcinogenic; it is the toxin produced by two types of mold that is carcinogenic. Peanut butter is getting a bad rep when it doesn’t deserve it. This difference in wording may not change your decision to continue eating it or not, but it is important to promote scientific accuracy, regardless of your agenda.

    • Hey Rachael, thanks so much for your comment. I definitely didn’t mean to mislead anyone with this post, so I went back and made a couple changes to try to make things more clear.

      I edited this part – “Peanut butter? A carcinogen-containing food?”

      And I added this line to the post – “I learned that peanut butter itself isn’t a carcinogen, but there is a mold that can grow on peanuts that produces aflatoxin, which is a carcinogen. I also learned that there are ways to supposedly kill the toxin and that aflatoxin-free peanut butters exist. Read on for more…”

      Hopefully that helps clarify things.

      Thanks again!

        • You’re so welcome. I’m glad you brought it to my attention. I re-read the post and saw that it was a bit misleading as originally worded. So, I thought an edit would be a good idea. Thanks for keeping me honest! πŸ™‚

  17. Interesting, and something I hadn’t heard about, either! I probably will still buy the fresh-ground peanut butter from Whole Foods (their honey roasted is just too addicting to stop!), but will give Almond Butter a try.


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