Aflatoxins: Poisons Hiding in Plain Sight

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There’s a good chance these toxins are lurking in your child’s lunchbox—and they are some of the most poisonous natural compounds known to humankind. Find out how to eliminate them from your home and from your body.

Many of us who have studied whole-food and holistic nutrition have heard of aflatoxins in peanut butter. They’re one of the prime reasons many of us have kicked peanut butter to the curb and starting started using almond butter instead (or, peanut butters from climates where aflatoxins are not present.) All this said, the conversation over aflatoxins is far too often cut short – and the hazards of these toxins are grossly underestimated.

Think about it -- If you noticed mold growing on your bread, you would toss it out, right? What if the mold on that bread was invisible? Further, what if that invisible mold was one of the most carcinogenic, toxic naturally occurring substances known to humankind? This scenario is not far from the truth. The deadly mycotoxin called aflatoxin is disturbingly common in our foods today.

As alarming as it sounds, even apparently healthy foods can kill you. Aflatoxins are among the most poisonous natural compounds on the planet, and aflatoxicosis is what happens if you ingest enough. Aflatoxin B1 (the most common aflatoxin) is the most potent naturally occurring liver carcinogen known to humankind.[1][2][3]

That’s right – multiple sources now refer to Aflatoxins as the MOST deadly naturally occurring toxin.

It’s estimated that about 4.5 billion people are exposed to aflatoxins each year in developing countries, although the numbers are largely unmonitored and on the rise.[4] People consuming normal-appearing corn, peanuts, or grain have become critically ill and even died from acute aflatoxin poisoning, which can cause life-threatening hemorrhage, liver damage, pulmonary edema, convulsions and brain damage.

The strength of the aflatoxin blow depends on factors such usage, level and duration of exposure, immune status and overall health.

Acute aflatoxicosis in humans is relatively rare, but the more chronic, lower-level exposure is probably more prevalent than reports would suggest because the symptoms are difficult to recognize. Chronic exposure is a significant concern due to its insidious nature and potential long-term effects, which include immunosuppression, cirrhosis, and liver cancer. There are at least 13 different species of mold that produce 20 different aflatoxins, with aflatoxin B1 considered the most toxic. Aflatoxins affect nearly every system of the body, as the following list shows:[5]

  • Respiratory: Pulmonary edema, cancer
  • Cardiovascular: Heart inflammation
  • Neurological: Reduced oxygen flow, headache, neuron death, encephalopathy, impaired memory, insomnia, disorientation, loss of coordination; tumors in both central and peripheral nervous system
  • Gastrointestinal: Liver damage, liver cancer, vital hepatitis, parasite infestation
  • Urinary: Kidney damage and tumors
  • Reproductive and Developmental: infertility, teratogenic, abnormal growth and development in children
  • Endocrine: Tumors and cancer
  • Blood: Blood and bone cancers
  • Immune: Immunosuppression, autoimmune reactions and allergies
  • Other: Mitochondrial malfunction, interference with protein and RNA synthesis, apoptosis (cell death)

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Aflatoxins Are Everywhere

Aflatoxins are poisonous compounds produced by certain strains of the fungi Aspergillus flavus and A. parasiticus, which grow when temperature and humidity conditions are favorable. The highest levels are typically found in foods from warmer regions with greater climatic variation. However, aflatoxin-producing molds show an affinity for multiple types of crops and can grow under a broad-range of moisture and temperature conditions.

Although aflatoxicosis is a greater problem in developing nations, it nevertheless remains a significant concern in North America.[6][7] According to the Food and Agriculture Organization (FAO), about 25 percent of the world's crops are affected by mycotoxins — including aflatoxins — and scientists warn that extreme weather and drought cycles are increasing their prevalence.[8] Fortunately, scientists are developing innovative ways to reduce aflatoxins, such as UC Davis researchers who are using benign fungi to displace Aspergillus from pistachio trees.[9]

Aflatoxins can be found in variety of foods you may already have in your pantry. According to the US Food and Drug Administration’s 2012 Bad Bug Book:[6]

"In the United States, aflatoxins have been identified in corn and corn products, peanuts and peanut products, cottonseed, milk, and tree nuts such as Brazil nuts, pecans, pistachio nuts, and walnuts. Other grains and nuts are susceptible but less prone to contamination."

Contamination is most common in the southeastern US in peanuts and corn products, but it shows up in other grains and legumes as well, including quinoa,coffee beans, cocoa beans, soybeans, spices, dairy, dried fruit and wine. Aspergillus typically gains a foothold during harvest and increases in storage. Improper food drying is a major factor in its growth.

Unfortunately, aflatoxins are very stable and can survive relatively high temperatures without degradation — which means they can’t always be destroyed by cooking or processing. For example, one study found that roasting green coffee at 180 degrees Celsius for 10 minutes reduced aflatoxin levels only by 50 %.[10] The one exception may be that corn processed using traditional methods (such as corn tortillas) may significantly reduce aflatoxin levels due to the alkaline conditions.[11]

Therefore, these toxic agents not only present a problem in raw foods but in processed foods as well — the most notable example being peanut butter – but you can also ingest aflatoxins by consuming the meat or dairy of animals who consumed aflatoxin-contaminated feed.

The aflatoxin levels in many of these foods is extremely small. However, it’s important to realize that ALL toxins add to your overall detox load. International Food Policy Research Institute cautions that consuming even tiny amounts of aflatoxin may have a cumulative effect.

Sadly, even our house pets are at risk for aflatoxin poisoning. Contamination is more common in processed dog food than cat food because commercial dog foods contain more corn products. A recent survey of premium pet food in Brazil found 22 percent to contain aflatoxin B1, and a full 93 percent contained other dangerous mycotoxins.[12] In dogs and cats, acute aflatoxicosis is a medical emergency with clinical signs such as severe vomiting with bloody diarrhea, anorexia, fever, sluggishness, discolored urine, and jaundice.

Regulators Do NOT Require Foods to Be Aflatoxin-Free

While there is some governmental inspection, the food industry is largely responsible for doing its own monitoring for aflatoxin contamination. Government regulators acknowledge aflatoxin exposure is a public health concern, but they do allow it to be present at low levels. FDA allows aflatoxin up to 20 parts per billion, whereas only 15 parts per billion is tolerated by Canada and Australia. However, FDA’s restrictions do not apply to foods produced and sold in the same state, only to those crossing state lines.

FDA allows much higher levels of aflatoxin in animal feed — up to 300 parts per billion. And with the lack of any federal inspection requirement, actual levels in animal feed may be much higher, which increases the chances some of these toxins will pass through to your meat and dairy products.

From Mold’s Point of View, Peanut Butter is the BEST FOOD EVER

We started out this conversation focusing on peanut butter. Aflatoxin-producing molds are extremely common in the soils where peanuts are grown. When it comes to aflatoxin contamination, peanut butter is notoriously the worst — or from the mold’s perspective, the best food ever.[13]

In the US, more than 99 percent of peanut farms use conventional farming practices, which includes the use of fungicides. Be careful: Organic peanut butters may contain even more aflatoxin than inorganic brands because fungicide is not used in their production. I am not trying to dissuade you from buying organic peanut butter, because pesticide levels in conventionally raised peanuts can be very high due to their soft, permeable shells — and you certainly don’t want that. Just be aware that in this case, the organic label does not protect you.

The most problematic source of peanut butter contamination appears to be the “grind-your-own” variety offered in various nutrition stores. Unless the peanut grinding machines are thoroughly cleaned every day, they can become Aspergillus breeding grounds. Once the machines are contaminated, molds and mycotoxins pass right into your peanut butter, and their levels only increase during storage.

You may want to do a little research before buying your next jar of peanut butter. I’ve included some pointers in next section. For more information about peanuts and peanut butter, refer to my own Peanut FAQ page.

Twelve Tips for Reducing Your Aflatoxin Exposure

What can you do to reduce the aflatoxins in your child’s PB&J? The type of peanuts and where they are grown make a difference. Proper storage is also important. That said, it is nearly impossible to avoid all aflatoxin exposure in today’s world, so it’s important to make detoxification part of your ongoing health routine. I have included some tips about aflatoxin below.  

  1. Valencia peanuts are grown mostly in New Mexico where mold levels are lower due to the drier climate, so look for organic peanut butters made from Valencia peanuts exclusively (not, “Valencia and ‘other’ peanuts).
  2. A representative with Justin’s reported that they test all of their own nut butters to ensure aflatoxin levels are below 10 parts per billion (according to KerryAnn Foster of Intentionally Domestic). Justin’s nut butters do not appear to be certified organic but the website reports they are GMO-free.
  3. Whole Foods advertises its 365 Organic Everyday Value Peanut Butter’s aflatoxin levels to be between zero and 10 parts per billion, verified by testing.
  4. Consider giving “jungle peanuts” a try, an heirloom variety from the Amazon rainforest. Jungle peanuts are sold as raw nuts and raw nut butters. They are reportedly higher in nutrition and typically touted as aflatoxin-free. However – they aren’t cheap! (You get what you pay for.)
  5. Regardless of what peanut butter you choose, always store it in the refrigerator.
  6. If you grind your own, wash your grinder thoroughly.
  7. In general, whole nuts tend to be less contaminated than nut pieces or butters. If your nuts taste sour, bitter or otherwise funky, toss them out.
  8. Some studies show that soaking and fermenting your nuts and grains can significantly lower their aflatoxin levels, as well as mitigating the toxic effects. Lactic acid during fermentation seems to bind to aflatoxins and cuts off mold’s energy supply.[14]
  9. Studies show chlorophyll may effectively block absorption of aflatoxin, so have your peanut butter with a side of greens.[15]
  10. Optimize your glutathione levels, as glutathione helps the body with aflatoxin detoxification, among other things.
  11. Activated charcoal will absorb some mycotoxins, but for aflatoxins, animal studies show bentonite or montmorillonite clay are superior to activated charcoal.[16]
  12. Other plant agents that may be useful for detoxification include milk thistle,[17] marshmallow rootdandelion root, and extract of the leaves of Adhatodavasica Nees, an Ayurvedic medicinal plant.[18]

To learn more about natural, evidence-based interventions for Aflatoxins, use the Research Dashboard:

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[1] Yu J et al. “Aspergillus flavus expressed sequence tags and microarray as tools in understanding aflatoxin biosynthesis” Mycotoxin Res. March 2006;22(1):16-21 PMID: 23605496 DOI: 10.1007/BF02954552

[2] Squire RA. “Ranking animal carcinogens: a proposed regulatory approach.” Science1981 Nov 20;214(4523):877-80PMID: 7302565

[3]Zain ME. “Impact of mycotoxins on humans and animals” J Saudi Chem Soc. April 2011;15(2):129-144

[4]Njagi K. “Extreme Weather Increasing Level of Toxins in Food, Scientists WarnMedscape Nurses June 3, 2016

[5]Godfrey S. Bbosa, David Kitya, A. Lubega, Jasper Ogwal-Okeng, William W. Anokbonggo and David B. Kyegombe (2013). Review of the Biological and Health Effects of Aflatoxins on Body Organs and Body Systems, Aflatoxins - Recent Advances and Future Prospects, Prof. Mehdi Razzaghi-Abyaneh (Ed.), InTech, DOI: 10.5772/51201.

[6] FDA “Foodborne Pathogenic Microorganisms and Natural Toxins Handbook” (Bad Bug Book), 2nd Edition, 2012

[7] Lawley, R. “AflatoxinsFood Safety Watch February 1, 2013

[8] Park DL et al. “Minimizing risks posed by mycotoxins utilizing the HACCP concept” FAO Food and Nutrition Division

[9]Warnert, JE “Pistachio Farmers Enlist a Beneficial Fungus to Battle Aflatoxin” July 12, 2012 ANR News Releases, UC Division of Agriculture and Natural Resources

[10]Micco C et al. “The effect of roasting on the fate of aflatoxin B1 in artificially contaminated green coffee beans” Mycotoxin Res. 1992 Sep;8(2):93-7 PMID: 23606005 DOI: 10.1007/BF03192222doi: 10.1007/BF03192222

[11] Torres P et al. “Revising the role of pH and thermal treatments in aflatoxin content reduction during the tortilla and deep frying processes” J Agric Food Chem. 2001 Jun;49(6):2825-9 PMID: 11409972

[12] “Study: Grain-containing pet food not safe in Brazil” February 4, 2016

[13] Ying-Chun Chen et al. “Survey of aflatoxin contamination in peanut products in Taiwan from 1997 to 2011J Food Drug Analysis September 2013;21(3): 247-252

[14]Ahlberg SH et al. “Potential of lactic acid bacteria in aflatoxin risk mitigation” Int J Food Microbiol.August 17, 2015;207:87-102PMID: 26001523 DOI: 10.1016/j.ijfoodmicro.2015.04.042

[15]Jubert C et al. “Effects of Chlorophyll and Chlorophyllin on Low-Dose Aflatoxin B1 Pharmacokinetics in Human Volunteers” Cancer Prev Res December 2009;2(12):1015-22 PMID: 19952359 DOI: 10.1158/1940-6207.CAPR-09-0099

[16]Thieu NQ et al. “Efficacy of bentonite clay in ameliorating aflatoxicosis in piglets fed aflatoxin contaminated diets” Trop Anim Health Prod. 2008 Dec;40(8):649-56PMID: 18975130 DOI: 10.1007/s11250-008-9144-3

[17]Amiridumari H. et al. “Effects of milk thistle seed against aflatoxin B1 in broiler model” J Res Med Sci. 2013 Sep;18(9):786-90.PMID: 24381623 PMCID: PMC3872588

Original article published: 2016-09-03

Article updated: 2018-12-26

[18]Vijayanandraj S et al. “Detoxification of aflatoxin B1 by an aqueous extract from leaves of AdhatodavasicaNees” Microbiol Res. April 2014;169(4):294-300

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of GreenMedInfo or its staff.

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