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Tag: mycotoxins

  • Is Aflatoxin a Concern? | NutritionFacts.org

    Is “toxic mold syndrome” a real thing? What do we do about toxic mold contamination of food?

    In recent years, mold has been blamed for all sorts of “vague and subjective” symptoms, but we have little scientific evidence that mold should be implicated. However, this “concept of toxic mold syndrome has permeated the public consciousness,” perpetuated by disreputable predatory practices of those making money testing homes for mold spores or testing people’s urine or blood. But all these tests are said to “further propagate misinformation and inflict unnecessary and often exorbitant costs on patients desperate for a clinical diagnosis, right or wrong, for their constellation of maladies…The continued belief in this myth is perpetuated by those charlatans who believe that measles vaccines cause autism, that homeopathy works, that fluoride in the water should be removed….”

    Mold toxin contamination of food, however, has emerged as a legitimate issue of serious concern, and mycotoxins are perhaps even more important than other contaminants that might make their way into the food supply. Hundreds of different types have been identified, but only one has been classified as a known human carcinogen, and that’s aflatoxin. The ochratoxin I’ve previously discussed is a possible human carcinogen, but we know aflatoxin causes cancer in human beings. In fact, aflatoxins are amongst the most powerful known carcinogens.

    It has been estimated that about a fifth of all liver cancer cases may be attributable to aflatoxins. “Since liver cancer is the third-leading cause of cancer deaths worldwide, and mortality rapidly follows diagnosis, the contribution of aflatoxins to this deadly cancer is significant.” And once aflatoxin makes it into the food, there is almost nothing we can do to remove it. Cooking, for example, doesn’t help. Indeed, as shown below and at 1:50 in my video Should We Be Concerned About Aflatoxin?, once it makes it into crops or into the meat, dairy, and eggs from animals consuming those crops, it’s too late. So, we have to prevent contamination in the first place, which is what we’ve been doing for decades in the United States. Because of government regulations, “companies in developed countries…are ‘always sampling’ for aflatoxin,” resulting in nearly $1 billion in losses every year. That may get even worse if climate change exacerbates aflatoxin contamination in the Midwest Corn Belt.

    So, on a consumer level, it is more of a public health problem in the less industrialized world, such as in African countries, where conditions are ripe and farmers can’t afford to throw away $1 billion in contaminated crops. Aflatoxin remains a public health threat in Africa, Southeast Asia, and rural China, affecting more than half of humanity. This explains why the prevalence of liver cancer in those areas may be 30 times higher, yet it is not a major problem in the United States or Europe.

    Only about 1% of Americans have detectable levels of aflatoxins in their bloodstream. Why not 0%? The U.S. Food and Drug Administration works to ensure that levels of exposure to these toxins are kept as low as practical, not as low as possible. In California, for instance, there has been an increase in “unacceptable aflatoxin levels” in pistachios, almonds, and figs. Unacceptable in Europe, that is, so it affects our ability to export, but not necessarily unacceptable for U.S. consumers, as we allow twice as much aflatoxin contamination.

    Figs are unique since they’re “allowed to fully ripen and semidry on the tree.” This makes them “particularly susceptible to aflatoxin production.” It would be interesting to know about the fig-consuming habits of the 1% of Americans who were positive for the toxin. If figs were to blame, I’d encourage people to diversify their dried fruit consumption, but nuts are so good for us that we really want to keep them in our diets. The cardiovascular health benefits we get from nuts outweigh their carcinogenic effects; nut consumption prevents thousands of strokes and heart attacks for every one case of liver cancer. “Thus, the population health benefits provided by increased nut consumption clearly outweigh the risks associated with increased aflatoxin B1 exposure.”

    So, we’re left with aflatoxin being mostly a problem in the developing world, and, because of that, it “remains a largely and rather shamefully ignored global health issue….” Where attention has been paid, it has been largely driven by the need to meet stringent import regulations on mycotoxin contamination in the richer nations of the world, rather than to protect the billions of people exposed on a daily basis.

    Doctor’s Note

    This is the last video in a four-part series on mold toxins. If you missed the others, check the related posts below. 

    Michael Greger M.D. FACLM

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  • Are the Effects of Ochratoxin Concerning? | NutritionFacts.org

    The overall cost-benefit ratio for mycotoxins depends on which food is contaminated.

    Ochratoxin has been described as toxic to the immune system, developing fetus, kidneys, and nervous system, as well as being carcinogenic, but that is in animal studies. Ochratoxin “causes kidney toxicity in certain animal species, but there is little documented evidence of adverse effects in humans.” That’s why it’s only considered a possible human carcinogen.

    Big Ag assures that current ochratoxin levels are safe, even among those who eat a lot of contaminated foods. The worst-case scenario may be young children eating a lot of oat-based cereals, but, even then, “their lifetime cancer risk is negligible.” Individuals arguing against regulatory standards suggest we can eat more than 42 cups of oatmeal a day and not worry about it. Where do they get these kinds of estimates?

    They determine the so-called benchmark dose in animals—the dose of the toxin that gives a 10% increase in pathology—then, because one would want to err on the side of caution, divide that dose by 500 as a kind of safety fudge factor to develop the tolerable daily intake. For cancer risk, you can find the tumor dose—the dose that increases tumor incidence in lab animals by 5%—and extrapolate down to the ”negligible cancer risk intake,” effectively incorporating a 5,000-fold safety factor, as seen below and at 1:28 in my video Should We Be Concerned About the Effects of Ochratoxin?.

    It seems kind of arbitrary, right? But what else are you going to do? You can’t just intentionally feed people the stuff and see what happens—but people eat it regularly. Can we just follow people and their diets over time and see if those who eat more whole grains, like oats, for example, are more likely to have cancer or live shorter lives?

    What is the association between whole grain intake and all-cause, cardiovascular, and cancer mortality? Every additional ounce of whole grains eaten a day is associated with not only a lower risk for cancer mortality but also a lower risk of dying from all causes put together. Below and at 2:05 in my video are findings from all the big cancer studies. Every single one trended towards lower cancer risk.

    The bottom line is that you don’t find adverse effects confirmed in these population studies. This is not to say ochratoxin is necessarily harmless, but “any such risk does not outweigh the known benefits of wholegrain consumption.” In fact, healthy constituents of the whole grains themselves, like their antioxidants, may directly reduce the impacts of mycotoxins by protecting cells from damage. So, eating lots of fruits and vegetables may also help. Either way, “an overall healthy diet can play a significant role in mitigating the risk of contaminants in grain.”

    In summary, healthy foods like whole grains are good, but just not as good as they could be because of ochratoxin, whereas less healthful foods, like wine and pork, are worse because of the mycotoxin, as shown below and at 2:52 in my video. Ochratoxin was detected, for example, in 44% of tested pork.

    Doctor’s Note

    This is the third video in a four-part series on mold toxins. If you missed the first two, see Ochratoxin in Breakfast Cereals and Friday Favorites: Ochratoxin and Breakfast Cereals, Herbs, Spices, and Wine.

    Should We Be Concerned About Aflatoxin? is coming up next.

    Michael Greger M.D. FACLM

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  • Mold Toxins in Cereals, Herbs, Spices, and Wine | NutritionFacts.org

    Most crops are contaminated with fungal mycotoxins, but some foods are worse than others.

    Oats can be thought of as “uniquely nutritious.” One route by which they improve human health is by providing prebiotics that “increase the growth of beneficial gut microbiota.” There are all manner of oats, ranging from steel-cut oats to, even better, intact oat groats (their form before being cut), all the way down to highly processed cereals, like Honey Nut Cheerios.

    “Rolling crushes the grain, which may disrupt cell walls and damage starch granules, making them more available for digestion.” This is bad because we want the starch to make it all the way down to our colon to feed our good gut bacteria. Grinding oats into oat flour to make breakfast cereals is even worse. When you compare blood sugar and insulin responses, you can see significantly lower spikes with the more intact steel-cut oats, as shown below and at 0:54 in my video Ochratoxin in Certain Herbs, Spices, and Wine.

    What about ochratoxin? As seen here and at 1:01 in my video, oats are the leading source of dietary exposure to this mold contaminant, but they aren’t the only source.

    There is a global contamination of food crops with mycotoxins, with some experts estimating as much as 25% of the world’s crops being affected. That statistic is attributed to the Food and Agriculture Organization of the United Nations, but it turns out the stat is bogus. It isn’t 25%. Instead, it may be more like 60% to 80%. “The high occurrence is likely explained by a combination of the improved sensitivity of analytical [testing] methods and the impact of climate change.”

    Spices have been found to have some of the highest concentrations of mycotoxins, but because they are ingested in such small quantities, they aren’t considered to be a significant source. We can certainly do our part to minimize our risk, though. For instance, we should keep spices dry after opening sealed containers or packages.

    What about dried herbs? In “Mycotoxins in Plant-Based Dietary Supplements: Hidden Health Risk for Consumers,” researchers found that milk thistle–based supplements had the highest mycotoxin concentrations. It turns out that humid, wet weather is needed during milk thistle harvest, which is evidently why they get so moldy. “Considering the fact that milk thistle preparations are mainly used by people who suffer from liver disease,” such a high intake of compounds toxic to the liver may present some concern.

    Wine sourced from the United States also appears to have particularly high levels. In fact, the single highest level found to date around the world is in a U.S. wine, but there’s contamination in wine in general. In fact, some suggest that’s why we see such consistent levels in people’s blood—perhaps because a lot of people are regular wine drinkers.

    Ochratoxin is said to be a kidney toxin with immunosuppressive, birth defect–causing, and carcinogenic properties. So, what about ochratoxin decontamination in wine? That is, removing the toxin? Ideally, we’d try to prevent the contamination in the first place, but since this isn’t always practical, there is increased focus on finding effective methods of detoxification of mycotoxins already present in foods. This is where yeast enters as “a promising and friendly solution,” because the mycotoxins bind to the yeast cell wall. The thought is that we could strain out the yeast. Another approach is to eat something like nutritional yeast to prevent the absorption.

    It works in chickens. Give yeast along with aflatoxin (another mycotoxin), and the severity of the resulting disease is diminished. However, using something like nutritional yeast as a binder “depends on stability of the yeast-mycotoxin complex through the passage of the gastrointestinal tract.” We know yeasts can remove ochratoxin in foods, but we didn’t have a clue if it would work in the gut until 2016. Yeast was found to bind up to 44% of the ochratoxin, but, in actuality, it was probably closer to only about a third, since some of the bindings weren’t stable. So, if you’re trying to stay under the maximum daily intake and you drink a single glass of wine, even if your bar snack is popcorn seasoned with nutritional yeast, you’d still probably exceed the tolerable intake. But what does that mean? How bad is this ochratoxin? We’ll find out next.

    Doctor’s Note

    This is the second video in a four-part series on mold toxins. The first one was Ochratoxin in Breakfast Cereals.

    Stay tuned for Should We Be Concerned About the Effects of Ochratoxin? and Should We Be Concerned About Aflatoxin?. You can also check: Friday Favorites: Should We Be Concerned About Ochratoxin and Aflatoxin?.

    Michael Greger M.D. FACLM

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  • Fungal Toxins for Breakfast? | NutritionFacts.org

    One of the few food contaminants found at higher levels in those eating plant-based diets are mycotoxins, fungal toxins in moldy food ingredients, such as oats.

    In France, exposure to dietary contaminants was compared between vegetarians and meat-eaters, and the results showed that exposures to persistent organic pollutants like PCBs and dioxins were dramatically lower among those eating more plant-based foods. This was due to their avoidance of foods of animal origin, though they did have higher estimated exposure to some mycotoxins, fungal toxins present in moldy food.

    There are many types of mold on the planet, possibly millions, and the vast majority are harmless. However, over the last several years, certain mold toxins, such as aflatoxin and ochratoxin, have been popping up in breakfast cereals. Hundreds of samples were taken off store shelves, and about half were found to be contaminated with ochratoxin, but those store shelves were in Pakistan, which has a sub-tropical climate with monsoons and flash floods, leading to fungal propagation. Similar results have since popped up in Europe, in Serbia, for instance. They’ve also been found in Spain and seen in Portugal. Then, mycotoxins were discovered in breakfast cereals in Canada. What about breakfast cereals sold in the United States?

    Researchers collected 144 samples and, similar to other countries, found that about half contained ochratoxin, but only about 7% exceeded the maximum limit established by the European Commission. What is the significance of finding ochratoxin in U.S. breakfast cereals? In the largest study to date, which included nearly 500 samples of cereal off store shelves across the United States, overall detection rates were about 40%, though only 16 of the samples violated the European standards. All the cereals with ochratoxin were oat-based; however, about 1 in 13 of the oat-based cereal samples tested were contaminated.

    Ochratoxin has become increasingly regulated by many countries to minimize chronic exposure. Shown below and at 2:23 in my video Ochratoxin in Breakfast Cereals are the current regulations for mycotoxins in cereal-based baby foods, for example, worldwide.

    Some countries are very strict, like in the European Union; other countries are less so, and one country in particular has no standards at all. Ochratoxin is not currently regulated at all in the United States.

    What about sticking to organic products? One might expect them to be worse due to the fact that fungicides are not allowed in organic production. However, “mycotoxin concentrations are usually similar or reduced in organic compared with conventional products.” For example, in one of the breakfast cereal studies, researchers found similar contamination, and the same was found for infant foods. It cannot be concluded that organic is better than conventional from a mycotoxin perspective. “Despite no use of fungicides, an organic system appears generally able to maintain mycotoxin contamination at low levels.” But how much is that saying, given how widespread it is? How concerned should we be about the public health effects from “long-term exposure to this potent mycotoxin”?

    If you look at blood samples taken from populations going back decades, sometimes 100% of people turn up positive for ochratoxin circulating in their bloodstream. In some sense, mycotoxins “are unavoidable contaminants of food,” since they are not easy to detect and many of them can remain hidden. And, once foods have become contaminated, mycotoxins aren’t destroyed by cooking. So, are there some foods we should simply try to avoid due to a higher risk of contamination? That’s exactly the question I’m going to address next.

    Doctor’s Note

    This is the first video in a four-part series on mold toxins. Check related posts below for the other three.

    Michael Greger M.D. FACLM

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