And people worry about cancer from pesticides on their food…

ResearchBlogging.org
A recent study published in Environmental Health Perspectives looked at the relationship between aflatoxin, produced by certain mold growing on food, and liver cancer. The results are a bit of an eye opener – they suggest that, at the upper end of their estimate, aflatoxin may cause almost 30% of all cases of liver cancer worldwide.

First, a bit of background. Aflatoxins are a group of toxic compounds produced by fungi from the genus Aspergillus. One of these, Aflatoxin B1, is a very potent liver carcinogen, classified as a confirmed human carcinogen by the International Agency for Research on Cancer. The risk of developing cancer is much higher in people infected with hepatitis B; it also appears to act synergistically with hepatitis C.

The type of Aspergillus that produces Aflatoxin B1 is found mainly on corn, peanuts, cottonseed and tree nuts, although it can be found on other crops after improper storage. It grows primarily in warmer climates, and generally isn’t found in Canadian-grown crops; however, with global transport of crops it can be found worldwide.

The authors of the Environmental Health Perspectives study, Yan Liu and Felicia Wu, looked at how much aflatoxin people are exposed to worldwide, based on concentrations measured in food and food consumption data. They also looked at the relationship between exposure to aflatoxins and the development of liver cancer, for people with and without chronic hepatitis B, and the prevalence of hepatitis B in different parts of the world. From these data, they estimated the annual incidence of hepatocellular carcinoma (liver cancer) in different parts of the world for people with and without hepatitis B. There are obviously some limitations in the underlying data, resulting in uncertainty in the estimates, but overall they found that aflatoxin likely has a causative role in at least 4.6% of all cases of hepatocellular carcinoma, and as high as 28.2%.

Even given the uncertainty in the estimate, these numbers indicate that aflatoxin is a fairly major public health issue. The majority of aflatoxin-caused cancers occur in developing countries, due to the increased occurrence of Aspergillus in tropical climates, poor food handling and storage, and generally higher incidence of chronic hepatitis B, though there is still exposure to aflatoxin in Canada and other developed countries.

So what can be done to reduce the effects of aflatoxin? Obvious measures that come to mind are reducing Aspergillus growth on crops, including proper crop storage, and where necessary use of (approved and safe) fungicides. The effects of aflatoxin could also be substantially reduced by increasing hepatitis B vaccinations in countries with either high rates of hepatitis B or high aflatoxin exposures.

Liu, Y., & Wu, F. (2010). Global Burden of Aflatoxin-Induced Hepatocellular Carcinoma: A Risk Assessment Environmental Health Perspectives, 118 (6), 818-824 DOI: 10.1289/ehp.0901388

3 Responses to And people worry about cancer from pesticides on their food…

  1. Everett Williams says:

    The story of aflatoxin is far from a new one. It is found at greater or lesser levels in every bit of corn and peanut food that we eat. The peanut industry has gone out of it’s way to thwart proper testing for it for a very long time. We had a peanut product factory somewhere in the panhandle of Texas that had significant problems with aflatoxin, but was not tested even once in the entire time until it was shut down, which was over five years. The test is not that hard. Considering the conditions you named, can you imagine that a single peanut raised and stored in Georgia entirely escapes this bit of nastiness. No, the problem here is not knowledge, but regulation.

  2. ashartus says:

    Definitely not a new problem (just a new study). Like most other food safety problems, it comes down to cost vs. safety improvement; I think we’re still a ways away from getting the optimum balance between the two – though perhaps it’s easy for me to say since a modest increase in food prices wouldn’t affect me too much, unlike in developing countries (where this is a huge problem).

  3. carcinoma cancer

    And people worry about cancer from pesticides on their food… | exposure/effect

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