Aflatoxins in Nuts: Danger or Hype?
Some of the scary things you may have heard about nuts and aflatoxins are probably exaggerated or taken out of context. Nonetheless, these are not imaginary concerns. Nutrition Diva explains.
Monica Reinagel, MS, LD/N, CNS
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Aflatoxins in Nuts: Danger or Hype?
Nuts are generally thought of as healthy food choices. They are somewhat high in calories, due to their relatively high fat content. But these aren’t just empty calories. Along with those healthy unsaturated fats, you’re also getting fiber and protein, which help keep you from getting hungry. Perhaps that’s why dieters who include nuts in their meal plans lose more weight and report feeling less hungry. And in general, people who eat nuts on a regular basis are more likely to maintain a healthy weight.
Nuts are also rich in vitamin E, which is good for your skin, heart, and brain. They also contain phytosterols, natural plant compounds that help to regulate your cholesterol levels. Regular nut consumption is linked with reduced risk of heart disease and other diseases.
So far the news is all good. But, several Nutrition Diva listeners have written to ask me about aspergillus or aflatoxin in nuts—and whether this is something that we need to worry about. I can tell you that some of the scariest things you may have encountered online are probably exaggerated or taken out of context. Nonetheless, these are not imaginary concerns.
What Are Apergillus and Aflatoxins?
Aspergillus is type of fungus that’s found in the soil and can cause disease in certain food crops, especially legumes, grains, and tree nuts. An aspergillus infection can weaken the plants enough to reduce crop yield, which is a concern for the farmers. But even if crop yields are affected only minimally, the aspergillus fungus continues to be a problem after the crops are harvested. It can cause grains or nuts to rot in storage—leading to more losses for farmers or distributors.
But the main concern in terms of human health is that aspergillus produces potentially harmful compounds called mycotoxins—in particular, a group of mycotoxins called aflatoxins. These are known to be carcinogenic.
Chronic aflatoxin exposure can lead to liver damage or liver cancer, especially in individuals with pre-existing conditions such as a Hepatitis B infection. Breathing in the spores of the aspergillus fungus can also cause lung irritation or damage, again, especially in individuals with pre-existing lung disease, such as tuberculosis or COPD.
Aspergillus produces potentially harmful compounds called mycotoxins—in particular, a group of mycotoxins called aflatoxins. These are known to be carcinogenic.
And that’s why most developed nations have very stringent monitoring for aspergillus and aflatoxin in foods. Products that are most likely to be infected, such as peanuts or tree nuts are routinely screened and if aspergillus or aflatoxin levels are above a certain threshold, the foods cannot be distributed.
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All of this has obviously motivated growers and distributors to develop practices that will reduce the presence of aspergillus and aflatoxin in food and feed crops. And these efforts have been very successful. According to the World Health Organization, “control strategies have mostly eliminated harmful exposures in developed countries.”
Unfortunately, those living in developing nations may still be exposed to harmful levels of contamination—especially in tropical regions where these crops may serve as a dietary staple. The WHO says that “Food insufficiency and lack of diversity substantially contribute to the susceptibility of individuals and communities to aflatoxins.” When you consider that Hepatitis B and tuberculosis are also much more common in developing countries, you can see that aflatoxins present a real public health concern in these developing nations.
The World Health Organization and the Centers for Disease Control are working hard on a number of initiatives to combat the problem, everything from public information campaigns, to developing aspergillus resistant strains of these crops, to enhanced screening protocols. But the problem is not yet solved.
How Can You Protect Yourself?
If you live in a developing nation, you can reduce your potential exposure by limiting your consumption of peanuts and other groundnuts, corn, and cottonseed oil, commodities that are most likely to be infected.
If you live in a developed nation, aflatoxin exposure is probably not something you need to be too concerned about, not only because of better screening and detection, but because these foods are less likely to be your primary source of calories. Perhaps that’s just one more argument for a reasonably varied diet.
The Advantages of Variety
Not only does variety ensure that you are getting a broader array of nutrients, it also reduces the chances that you’ll be over-exposed to a potentially harmful substance.
Tuna, for example, is a terrific source of protein. But eating tuna every single day could expose you to excessive amounts of mercury. Broccoli is a super nutritious vegetable but if it were the only vegetable in your diet, you’d be missing a lot of key nutrients. Remember it’s also possible to overdo a good thing. Brazil nuts are very high in the antioxidant selenium. So high in fact, that eating too many Brazil nuts can actually cause selenium overload.
See also: Can you Get Too Many Vitamins?
Try to get your protein from a variety of sources. Mix up those vegetable choices. Alternate between different nuts or grains. You get the idea. But if you don’t, there’s more in my episode: How Important Is a Varied Diet?
On the other hand, when it comes to less nutritious foods like snacks and treats, having too much variety can lead you to overeat. You can play this variety card to your advantage. If you have lots of kinds of vegetables on hand, you’re likely to eat more vegetables. But if you only keep one kind of chip or cookie in the house at a time, it may help you eat less of that stuff.
See also: Is a Varied Diet Overrated?
Have a Nutrition Question? Give Me a Call
If you have a nutrition worry or question that you’d like me to talk about in a future episode, call the Nutrition Diva listener line at 443-961-6206 and leave me a message.
Mixed nuts image courtesy of Shutterstock.
About the Author
Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes’ most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation’s leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.