Clostridium difficile in the Food Supply

Clostridium difficile in the Food Supply.jpeg

Clostridium difficile is one of our most urgent bacterial threats, sickening a quarter million Americans every year, and killing thousands at the cost of a billion dollars a year. And it's on the rise.

As shown in C. difficile Superbugs in Meat, uncomplicated cases have been traditionally managed with powerful antibiotics, but recent reports suggest that hypervirulent strains are increasingly resistant to medical management. There's been a rise in the percentage of cases that end up under the knife, which could be a marker of the emergence of these hypervirulent strains. Surgeons may need to remove our colon entirely to save our lives, although the surgery is so risky that the operation alone may kill us half the time.

Historically, most cases appeared in hospitals, but a landmark study published in the New England Journal of Medicine found that only about a third of cases could be linked to contact with an infected patient.

Another potential source is our food supply.

In the US, the frequency of contamination of retail chicken with these superbugs has been documented to be up to one in six packages off of store shelves. Pig-derived C. diff, however, have garnered the greatest attention from public health personnel, because the same human strain that's increasingly emerging in the community outside of hospitals is the major strain among pigs.

Since the turn of the century, C. diff is increasingly being reported as a major cause of intestinal infections in piglets. C. diff is now one of the most common causes of intestinal infections in baby piglets in the US. Particular attention has been paid to pigs because of high rates of C. diff shedding into their waste, which can lead to the contamination of retail pork. The U.S. has the highest levels of C. diff meat contamination tested so far anywhere in the world.

Carcass contamination by gut contents at slaughter probably contributes most to the presence of C. diff in meat and meat products. But why is the situation so much worst in the US? Slaughter techniques differ from country-to-country, with those in the United States evidently being more of the "quick and dirty" variety.

Colonization or contamination of pigs by superbugs such as C. difficile and MRSA at the farm production level may be more important than at the slaughterhouse level, though. One of the reasons sows and their piglets may have such high rates of C. diff is because of cross-contamination of feces in the farrowing crate, which are narrow metal cages that mother pigs are kept in while their piglets are nursing.

Can't you just follow food safety guidelines and cook the meat through? Unfortunately, current food safety guidelines are ineffective against C. difficile. To date, most food safety guidelines recommend cooking to an internal temperature as low as 63o C-the official USDA recommendation for pork-but recent studies show that C. diff spores can survive extended heating at 71o. Therefore, the guidelines should be raised to take this potentially killer infection into account.

One of the problems is that sources of C. diff food contamination might include not only fecal contamination on the surface of the meat, but transfer of spores from the gut into the actual muscles of the animal, inside the meat. Clostridia bacteria like C. diff comprise one of the main groups of bacteria involved in natural carcass degradation, and so by colonizing muscle tissue before death, C. diff can not only transmit to new hosts that eat the muscles, like us, but give them a head start on carcass break-down.

Never heard of C. diff? That's the Toxic Megacolon Superbug I've talked about before.

Another foodborne illness tied to pork industry practices is yersiniosis. See Yersinia in Pork.

MRSA (Methicillin-resistant Staph aureus) is another so-called superbug in the meat supply:

More on the scourge of antibiotic resistance and what can be done about it:

How is it even legal to sell foods with such pathogens? See Salmonella in Chicken & Turkey: Deadly But Not Illegal and Chicken Salmonella Thanks to Meat Industry Lawsuit.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: USDA / Flickr. This image has been modified.

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Clostridium difficile in the Food Supply

Clostridium difficile in the Food Supply.jpeg

Clostridium difficile is one of our most urgent bacterial threats, sickening a quarter million Americans every year, and killing thousands at the cost of a billion dollars a year. And it's on the rise.

As shown in C. difficile Superbugs in Meat, uncomplicated cases have been traditionally managed with powerful antibiotics, but recent reports suggest that hypervirulent strains are increasingly resistant to medical management. There's been a rise in the percentage of cases that end up under the knife, which could be a marker of the emergence of these hypervirulent strains. Surgeons may need to remove our colon entirely to save our lives, although the surgery is so risky that the operation alone may kill us half the time.

Historically, most cases appeared in hospitals, but a landmark study published in the New England Journal of Medicine found that only about a third of cases could be linked to contact with an infected patient.

Another potential source is our food supply.

In the US, the frequency of contamination of retail chicken with these superbugs has been documented to be up to one in six packages off of store shelves. Pig-derived C. diff, however, have garnered the greatest attention from public health personnel, because the same human strain that's increasingly emerging in the community outside of hospitals is the major strain among pigs.

Since the turn of the century, C. diff is increasingly being reported as a major cause of intestinal infections in piglets. C. diff is now one of the most common causes of intestinal infections in baby piglets in the US. Particular attention has been paid to pigs because of high rates of C. diff shedding into their waste, which can lead to the contamination of retail pork. The U.S. has the highest levels of C. diff meat contamination tested so far anywhere in the world.

Carcass contamination by gut contents at slaughter probably contributes most to the presence of C. diff in meat and meat products. But why is the situation so much worst in the US? Slaughter techniques differ from country-to-country, with those in the United States evidently being more of the "quick and dirty" variety.

Colonization or contamination of pigs by superbugs such as C. difficile and MRSA at the farm production level may be more important than at the slaughterhouse level, though. One of the reasons sows and their piglets may have such high rates of C. diff is because of cross-contamination of feces in the farrowing crate, which are narrow metal cages that mother pigs are kept in while their piglets are nursing.

Can't you just follow food safety guidelines and cook the meat through? Unfortunately, current food safety guidelines are ineffective against C. difficile. To date, most food safety guidelines recommend cooking to an internal temperature as low as 63o C-the official USDA recommendation for pork-but recent studies show that C. diff spores can survive extended heating at 71o. Therefore, the guidelines should be raised to take this potentially killer infection into account.

One of the problems is that sources of C. diff food contamination might include not only fecal contamination on the surface of the meat, but transfer of spores from the gut into the actual muscles of the animal, inside the meat. Clostridia bacteria like C. diff comprise one of the main groups of bacteria involved in natural carcass degradation, and so by colonizing muscle tissue before death, C. diff can not only transmit to new hosts that eat the muscles, like us, but give them a head start on carcass break-down.

Never heard of C. diff? That's the Toxic Megacolon Superbug I've talked about before.

Another foodborne illness tied to pork industry practices is yersiniosis. See Yersinia in Pork.

MRSA (Methicillin-resistant Staph aureus) is another so-called superbug in the meat supply:

More on the scourge of antibiotic resistance and what can be done about it:

How is it even legal to sell foods with such pathogens? See Salmonella in Chicken & Turkey: Deadly But Not Illegal and Chicken Salmonella Thanks to Meat Industry Lawsuit.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: USDA / Flickr. This image has been modified.

Original Link

Virus in Chicken Could Be Linked to Obesity

NF-May31 Infectobesity Adenovirus 36 and Childhood Obesity.jpeg

Recently, there has been research examining the connection between poultry consumption and weight gain. One study out of the Netherlands examining about 4,000 people, correlated chicken consumption with weight gain. Another study followed 89,000 people in four other countries and found that animal protein intake was associated with long-term weight gain, and poultry was the worst, with 40 percent more weight gain than red meat or processed meat.

What makes poultry so bad? Yes, chickens are fatty these days because of the way we've genetically manipulated them--up to ten times more fat and calories than they used to have--but one bizarre theory postulated that it might be due to an obesity-causing chicken virus. In one study, one in five obese humans tested positive to the chicken virus SMAM-1, with those exposed to the chicken virus averaging 33 pounds heavier than those testing negative.

SMAM-1 was the first chicken virus to be associated with human obesity, but not the last. The original obesity-causing chicken virus SMAM-1 was able to effectively transmit obesity from one chicken to another when caged together, similar to a human adenovirus Ad-36, a human obesity-associated virus first associated with obesity in chickens and mice. Ad-36 spreads quickly from one chicken to another via nasal, oral or fecal excretion and contamination, causing obesity in each chicken. This of course raises serious concerns about Ad-36-induced adiposity in humans.

The easiest way to test this hypothesis is to experimentally infect humans with the virus. However, ethical reasons preclude experimental infection of humans, and so the evidence will have to remain indirect. In the absence of direct experimental data, we must rely on population studies, similar to how researchers nailed smoking and lung cancer. About 15 percent of Americans are already infected with Ad-36, so we can follow them and see what happens. That's exactly what a research team out of Taiwan did (highlighted in my video Infectobesity: Adenovirus 36 and Childhood Obesity). They followed 1,400 Hispanic men and women for a decade and found that not only were those exposed to the virus fatter than those who were not, but also over the ten years, those with a history of infection had a greater percentage of body fat over time.

Most studies done to date on adults have found a connection between exposure to Ad-36 and obesity, and all studies done so far on childhood obesity show an increase in prevalence of infection in obese children compared to non-obese children. We're now up to more than a thousand children studied with similar findings. Obese children who tested positive for the virus weighed 35 pounds more than children who tested negative.

The virus appears to both increase the number of fat cells by mobilizing precursor stem cells and increase the accumulation of fat within the cells. If we take liposuction samples of fat from people, the fat cell precursors turn into fat cells at about five times the rate in people who came to the liposuction clinic already infected. Fat taken from non-infected people that was then exposed to the virus start sucking up fat at a faster rate, potentially inducing obesity without increasing food intake.

Just as Ad-36 can be transmitted horizontally from one infected chicken to another in the same cage, subsequently causing obesity in each chicken, this same virus is also easily transmitted among humans, raising the question as to whether at least some cases of childhood obesity can be considered an infectious disease. Researchers publishing in the International Journal of Pediatric Obesity speculate that this animal adenovirus may have mutated to become a human adenovirus capable of infecting humans and causing obesity.

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Glasseyes view / Flickr

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How a Gluten-Free Diet Can Be Harmful

NF-Feb23 Gluten-Free Diets - Separating the Wheat from the Chat .jpeg

Until only a few years ago, almost the whole of the scientific world maintained that the wheat protein gluten would provoke negative effects only in people with rare conditions such as celiac disease or wheat allergies. But by the early part of 2013, it was largely becoming accepted that some non-celiac patients could suffer from gluten or wheat sensitivity. Indeed, a consensus panel of experts now officially recognizes three gluten-related conditions, wheat allergy, celiac disease and gluten sensitivity.

What percentage of the population should avoid wheat? About 1 in a 1,000 may have a wheat allergy, and nearly 1 in a 100 may have celiac disease. Celiac disease appears to be on the rise, though there's still less than about a 1 in 10,000 chance an American will be diagnosed with celiac in a given year. Our best estimate for wheat sensitivity is in the same general range as celiac, slightly higher than 1 percent. That's still potentially millions of people who may have been suffering for years who could have been cured by simple dietary means, yet who were unrecognized and unaided by the medical profession.

Although gluten sensitivity continues to gain medical credibility, we still don't know how it works. We don't know how much gluten can be tolerated, if it's reversible or not, or what the long-term complications might be of not sticking to a gluten-free diet. Considering the lack of knowledge, people with gluten sensitivity should consider reintroducing gluten back into their diet every year to see if it's still causing problems.

The reason health professionals don't want to see people on gluten-free diets unless absolutely necessary is that, for the 98 percent of people that don't have gluten issues, whole grains--including the gluten grains wheat, barley and rye--are health promoting, linked to reduced risk of coronary heart disease, cancer, diabetes, obesity and other chronic diseases.

Because some people have a peanut allergy doesn't mean everyone should avoid peanuts. There is no evidence to suggest that following a gluten-free diet has any significant benefits in the general population. Indeed, there is some evidence to suggest that a gluten-free diet may adversely affect gut health in those without celiac disease, gluten sensitivity, or wheat allergy. A study out of Spain, highlighted in my video, Gluten-Free Diets: Separating the Wheat from the Chat, found that a month on a gluten-free diet may hurt our gut flora and immune function, potentially setting those on gluten-free diets up for an overgrowth of harmful bacteria in their intestines. Why? Because the very components wheat sensitive people have problems with, like FODMAP and fructans, may act as prebiotics and feed our good bacteria.

Gluten, itself, may also boost immune function. After less than a week on added gluten protein, subjects experienced significantly increased natural killer cell activity, which could be expected to improve our body's ability to fight cancer and viral infections. Another study found that high gluten bread improved triglyceride levels better than regular gluten bread.

Ironically, one of the greatest threats gluten-free diets pose may be the gluten itself. Self-prescription of gluten withdrawal may undermine our ability to pick up celiac disease, the much more serious form of gluten intolerance. The way we diagnose celiac is by looking for the inflammation caused by gluten in celiac sufferers, but if they haven't been eating a lot of gluten, we might miss the disease. Hence, rather than being on a gluten-free diet, we want celiac suspects to be on a gluten-loaded diet. We're talking 4-6 slices of gluten packed bread every day for at least a month so we can definitively diagnose the disease.

Why does it matter to get a formal diagnosis if you're already on a gluten-free diet? Well, it's a genetic disease, so you'll know to test the family. But most importantly, many people on gluten-free diets are not actually on gluten-free diets. Even 20 parts per million can be toxic to someone with celiac. Many on "gluten-free diets" inadvertently eat gluten. Sometimes gluten-free products are contaminated, so even foods labeled "gluten-free" may still not be safe for celiac sufferers.

As editorialized in the Lancet, the irony of many celiac patients not knowing their diagnosis, while millions of non-sufferers banish gluten from their lives, can be considered a public health farce.


Though the medical profession now recognizes wheat sensitivity as a discrete entity, it's still not clear if it's actually the gluten to which people are reacting. For a review of the controversy, see Is Gluten Sensitivity Real?

In How to Diagnose Gluten Intolerance, I go step by step how someone may want to proceed who suspects they might be sensitive to gluten-containing grains.

More on the benefits of whole grains in general in Whole Grains May Work As Well As Drugs and Alzheimer's Disease: Grain Brain or Meathead?

More on keeping our gut flora happy in videos such as Prebiotics: Tending Our Inner Garden and How to Change Your Enterotype.

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Whatsername? / Flickr

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Viral Food Poisoning from Pesticides?

NF-Mar3 Did Pesticides Cause Your Food Poisoning?.jpg

Although the most serious causes of food poisoning like Salmonella come largely from animal products (for example, most foodborne-related deaths have been attributed to poultry), millions of Americans are sickened by produce every year, thanks to noroviruses. Noroviruses can spread person-to-person via the fecal-oral route or by the ingestion of aerosolized vomit, which together may explain most norovirus food outbreaks. But a substantial proportion remained unexplained. How else can fecal viruses get on our fruits and veggies?

The pesticide industry may be spraying them on (See Norovirus Food Poisoning from Pesticides).

The water that's used to spray pesticides on crops may be dredged up from ponds contaminated with fecal pathogens. When you hear of people getting infected with a stomach bug like E. coli from something like spinach, it's important to realize that the pathogen didn't originate from the spinach. Intestinal bugs come from intestines. Greens don't have guts; plants don't poop.

"The application of pesticides may therefore not only be a chemical hazard, but also a microbiological hazard for public health." What is the industry's solution? To add more chemicals! "The inclusion of antiviral substances in reconstituted pesticides," researchers assert, "may be appropriate to reduce the virological health risk posed by the application of pesticides." Or we could just choose organic.

Likewise the Salmonella in alfalfa sprout seeds (See Don't Eat Raw Alfalfa Sprouts) likely came from manure run-off or contaminated irrigation water. But this pesticide angle adds a whole new route for fecal pathogens to pollute produce. Broccoli Sprouts are safer, and organic sprouts may therefore be safer still (See Broccoli Sprouts).

Organic foods may also be healthier (see Cancer Fighting Berries) and don't carry the potential chemical hazards associated with pesticides. See my videos:

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: jetsandzeppelins / Flickr

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