Boosting Immunity with Mushrooms
Do you suffer from seasonal allergies? Runny nose, itchy eyes, sneezing? While your allergies may make you feel lousy because your immune system is busily attacking things left and right, that same heightened state of alertness may have benefits for your overall health.
Individuals suffering from allergies appear to have a decreased risk for certain cancers.70 Yes, your immune system might be in overdrive striking out at harmless things like pollen or dust, but that same overvigilance may also take down budding tumors in the body. It would be nice if there were a way to boost the part of the immune system that fights infections while down-regulating the part that results in chronic inflammation (and all those annoying symptoms).
Mushrooms may just do the trick.
Just as algae can be thought of as single-celled plants, yeast can be thought of as single-celled mushrooms. Thousands of edible mushrooms grow naturally, with worldwide annual commercial production in the millions of tons.71 But check the nutrition label on a carton of mushrooms and you won’t see much beyond some B vitamins and minerals. Is that all mushrooms have? No. What you don’t see listed is the array of unique myconutrients that may boost our immune function.72
Researchers in Australia split people into two groups. One group ate its regular diet, while the other ate its regular diet plus a cup of cooked white button mushrooms every day. After just a week, the mushroom eaters showed a 50 percent boost in the IgA levels in their saliva. These antibody levels remained elevated for about a week before dropping.73 So, for sustained benefits, try to make mushrooms a steady part of your diet.
But wait. If mushrooms trigger such a dramatic rise in antibody production, shouldn’t we be concerned they may worsen the symptoms of allergic or autoimmune diseases? On the contrary, it seems mushrooms may have an anti-inflammatory effect. In vitro studies have shown that a variety of mushrooms, including plain white button mushrooms, appear to blunt the inflammatory response, potentially offering a boost in immune and anticancer function without aggravating diseases of inflammation.74 The first randomized, double-blind, placebo-controlled clinical study of its kind, published in 2014, confirmed an apparent antiallergy effect in children with a history of recurrent upper-respiratory-tract infections.75
Food Poisoning
Pathogens (from the Greek pathos, for “suffering,” and genes, meaning “producer of”) can also be found in what you eat. Foodborne illness, or food poisoning, is an infection caused by eating contaminated food. According to the CDC, about one in six Americans develops food poisoning every year. Roughly forty-eight million people are sickened annually—larger than the combined populations of California and Massachusetts. More than one hundred thousand of them are hospitalized, and thousands die, just because of something they ate.76
In terms of healthy years of life lost, the top five most devastating pathogen food combinations are Campylobacter and Salmonella bacteria in poultry, Toxoplasma parasites in pork, and Listeria bacteria in deli meats and dairy products.77 One of the reasons animal foods are the leading culprits is that most foodborne pathogens are fecal pathogens. Because plants don’t poop, the E. coli you may get from spinach didn’t actually originate in the spinach; E. coli is an intestinal pathogen, and spinach doesn’t have intestines. The application of manure to crops has been found to increase the odds of E. coli contamination by more than fiftyfold.78
Eggs and Salmonella
The single greatest public health burden in the United States in terms of food poisoning is Salmonella. It’s the leading cause of food poisoning-related hospitalizations, as well as the number-one cause of food poisoning-related death.79 And it’s on the rise. Over the past decade, the number of cases has increased by 44 percent, particularly among children and the elderly.80 Within twelve to seventy-two hours after infection, the most common symptoms appear—fever, diarrhea, and severe abdominal cramps.81 The illness typically lasts between four and seven days, but among children and the elderly, the disease can be severe enough to require hospitalization—or funeral arrangements.
Many people associate Salmonella with eggs—and for good reason. In 2010, for instance, more than half a billion eggs were recalled due to Salmonella outbreaks.82 However, the egg industry mantra remained: Stop whining; eggs are safe. Responding to cries for a recall in an op-ed published in USA Today, the chairman of the industry trade group United Egg Producers insisted that “completely cooked eggs are completely safe eggs.”83 But what exactly does “completely cooked” mean?
The egg industry itself funded research on Salmonella and the various ways to cook eggs. What did they find? Salmonella in eggs can survive scrambled, over-easy, and sunny-side-up cooking methods. Sunny side up was found to be the riskiest. The industry-funded researchers bluntly concluded: “The sunny-side-up method should be considered unsafe.”84 In other words, even the egg industry itself knows that its product, prepared in a manner that millions of Americans eat on any given day all across the country, is unsafe. Actually, we’ve known this for some time. Twenty years ago, Purdue University researchers determined that Salmonella can survive in cooked omelets and french toast.85 Salmonella may even survive in eggs boiled up to eight minutes.86
Given all of this, it should come as no surprise that, according to the Food and Drug Administration (FDA), an estimated 142,000 Americans are sickened each year by Salmonella-tainted eggs.87 That’s an egg-borne epidemic each year in the United States. But eggs are “only” number ten on the worst pathogen-food combination list.
Poultry and Salmonella
Eating chickens, not their eggs, is actually the most common source of Salmonella poisoning.88 A nationwide outbreak of a particularly virulent strain of the bacteria was linked to our sixth-largest poultry producer, Foster Farms. It lasted from March 2013 until July 2014.89 Why did the outbreak last so long? It was largely because the company continued to churn out contaminated chicken despite repeated warnings from the CDC.90 Though the official tally of cases numbered only in the hundreds, the CDC estimates that for every confirmed case of Salmonella, another thirty-eight slip through the cracks.91 This means Foster Farms’ chicken may have sickened more than ten thousand people. When U.S. Department of Agriculture officials went in to investigate, they found that 25 percent of the chickens they sampled were contaminated with the same strain of Salmonella, likely the result of fecal matter found on the chicken carcasses.92
Mexico banned the importation of Foster Farms’ chicken, but in the United States, it remained available throughout the country.93 When a car manufacturer’s brakes malfunction, it announces a recall due to safety concerns. Why hasn’t Salmonella-tainted chicken been recalled? The U.S. Department of Agriculture once tried to shut down a company found to be repeatedly violating Salmonella standards. The company sued and won. “Because normal cooking practices for meat and poultry destroy the Salmonella organism,” the judges in the case concluded, “the presence of Salmonella in meat products does not render them ‘injurious to health.’ ”94
If proper cooking kills the bug, then why do hundreds of thousands of Americans continue to be sickened by Salmonella contaminated poultry every year? It’s not like E. coli and medium-rare hamburgers—who undercooks chicken? The problem here is cross-contamination. Between the time the fresh or frozen bird is picked up from the store and when it’s slid into the oven, the germs on the chicken can contaminate hands, utensils, and kitchen surfaces. Studies have shown that up to 80 percent of the time, placing fresh chicken on a cutting board for a few minutes can transfer disease-causing bacteria.95 Then, if you put cooked chicken back on the same cutting board, there’s about a 30 percent chance that the meat will become recontaminated.96
Foster Farms’ tone-deaf response to the outbreak may actually prove the most foresighted: “It is not unusual for raw poultry from any producer to have Salmonella bacteria,” they quoted in a press release. “Consumers must use proper preparation, handling and cooking practices.”97 In
other words, it should be considered normal for chicken to be contaminated with Salmonella. Eat at your own risk.
Why are American consumers placed at such high risk? Some European countries have got Salmonella contamination in poultry down as low as 2 percent. How? Because it’s illegal to sell chicken tainted with Salmonella. What a concept! They don’t allow the sale of fowl fouled with a pathogen that sickens more than a million Americans a year.98 In a meat industry trade publication, an Alabama poultry science professor explained why we don’t have such a “heavy-handed” policy: “The American consumer is not going to pay that much. It’s as simple as that.” If the industry had to pay to make it safer, the price would go up. “The fact,” he said, “is that it’s too expensive not to sell salmonella-positive chicken.”99
Fecal Bacteria on Meat
The contamination problem extends far beyond a single poultry producer. In a 2014 issue of Consumer Reports, researchers published a study on the true cost of cheap chicken. They discovered that 97 percent of chicken breasts found in retail stores were contaminated with bacteria that could make people sick.100 Thirty-eight percent of the Salmonella they found was resistant to multiple antibiotics; the CDC considers such pathogens to be a serious public health threat.101
As the Mayo Clinic rather indelicately put it, “Most people are infected with Salmonella by eating foods that have been contaminated by feces.”102 How does it get there? In slaughter plants, birds are typically gutted by a metal hook, which too often punctures their intestines and can expel feces onto the flesh itself. According to the latest national FDA retail-meat survey, about 90 percent of retail chicken showed evidence of contamination with fecal matter.103
Using the presence of bugs like E. faecalis and E. faecium as markers of fecal contamination, 90 percent of chicken parts, 91 percent of minced turkey, 88 percent of minced beef, and 80 percent of pork chops are tainted on the retail level nationally.104
While outbreaks of Salmonella infection have increased, E. coli infection from fecal matter in beef has decreased.105 Why is beef getting safer but chicken getting riskier?106 One likely factor is that the government was able to enact a ban on the sale of beef contaminated with a particularly dangerous strain of E. coli. But why is it illegal to sell beef known to be contaminated with a potentially deadly pathogen but perfectly legal to sell contaminated chicken? After all, Salmonella in chicken kills far more people than E. coli in beef.107
The problem dates back to a famous case in 1974 when the American Public Health Association sued the U.S. Department of Agriculture for putting its stamp of approval on meat contaminated with Salmonella. Defending the meat industry, the USDA pointed out that because “there are numerous sources of contamination which might contribute to the overall problem,” it would be “unjustified to single out the meat industry and ask that the [USDA] require it to identify its raw products as being hazardous to health.”108 In other words, because Salmonella has also been linked to dairy and eggs, it wouldn’t be fair to force only the meat industry to make their products safer. That’s like the tuna industry arguing there’s no need to label cans of tuna with mercury warnings because you could also get exposed by eating a thermometer.
The Washington, D.C., Circuit Court of Appeals upheld the meat industry’s position, asserting that the USDA can allow potentially deadly Salmonella in meat because “American housewives and cooks normally are not ignorant or stupid and their methods of preparing and cooking of food do not ordinarily result in salmonellosis.”109 That’s like saying minivans don’t need airbags or seat belts, and kids don’t need car seats, because soccer moms don’t ordinarily crash into things.
Avoiding Chicken to Avoid Urinary Tract Infections
Where do bladder infections come from? Back in the 1970s, studies of women over time found that movement of bacteria from the rectum into the vaginal area preceded the appearance of bladder infections.110 It took another twenty-five years, though, before DNA fingerprinting techniques proved that E. coli strains residing in the gut serve as the reservoir for urinary tract infections (UTIs).111
Another fifteen years passed before scientists tracked down the ultimate culprit, the original source of some of the UTI-associated bacteria in the rectum: chicken. McGill University researchers were able to capture UTI-causing E. coli at the slaughter plants, tracing them to the meat supply and, eventually, to urinary specimens obtained from infected women.112 As a result, we now have direct proof that bladder infections can be a zoonosis—an animal-to-human disease.113 This is a critical discovery, since UTIs affect more than ten million women each year in the United States at the cost of more than $1 billion.114 Even worse, it turns out that many of the strains of E. coli in chicken that cause UTIs are now resistant to some of our most powerful antibiotics.115
Can’t we solve this crisis by simply distributing meat thermometers and making sure people cook chicken thoroughly? No—because of the cross-contamination issue. Studies have shown that handling raw chicken can lead to intestinal colonization even if you don’t eat any of it.116 In that case, it doesn’t matter how well you cook your chicken. You could incinerate it to ash and still walk away infected. After infection, the drug-resistant chicken bacteria was then found to multiply to the point of becoming a major part of the research subject’s gut flora.117
The reason most people have more fecal bacteria in their kitchen sinks than their toilet seats118 is likely because they prepare their chickens in the kitchen, not the bathroom. But what if you’re really careful? A landmark study, published as “The Effectiveness of Hygiene Procedures for Prevention of Cross-Contamination from Chicken Carcasses in the Domestic Kitchen,” put this question to the test. Researchers visited five dozen homes, gave each family a raw chicken, and asked them to cook it. After the bird was cooked, researchers returned to find bacteria from chicken feces—Salmonella and Campylobacter, both serious human pathogens—all over the families’ kitchens: on the cutting board, utensils, cupboard, the refrigerator handle, the oven handle, the doorknob, and so on.119
Obviously, people didn’t know what they were doing, so the researchers then repeated the experiment, but this time gave the families specific instructions. After they cooked the chicken, the subjects were told to wash these surfaces with hot water and detergent, specifically the cutting board, utensils, cupboard, handles, and knobs. Yet the researchers still found pathogenic fecal bacteria all over.120
Reading the study, you could tell the researchers were getting a bit exasperated. Finally, they insisted the subjects use bleach. The dishcloth used to clean up was to first be immersed in bleach disinfectant, and then the subjects were to spray a bleach solution on all surfaces and let it sit for five minutes. However, the researchers returned to still find Salmonella and Campylobacter on some utensils, a dishcloth, the counter around the sink, and the cupboards.121 The extent of the kitchen contamination was much less, but still, it appears that unless you treat your kitchen like a biohazard laboratory, the only way to guarantee you’re not going to leave fecal pathogens around the kitchen is to not bring them into your house in the first place.
There is some good news: It’s not as if you eat chicken once and your gut is colonized for life. In the study in which volunteers became infected after just handling the meat, the chicken bacteria that tried to take over their gut only seemed to last about ten days.122 The good bacteria in their guts seemed able to muscle the bad guys out of the way. The problem, unfortunately, is that people tend to eat chicken more than once every ten days, so they may be constantly reintroducing these chicken bugs into their systems.
Yersinia in Pork
Nearly one hundred thousand Americans are sickened each year by Yersinia bacteria.123 In every outbreak for which a source has been found, the culprit was contaminated pork.124
In most cases, Yersinia food poisoning leads to little more than acute gastroenteritis, but the symptoms can become severe and mirror appendicitis, resulting in unnecessary emergency surgeries.
125 Long-term consequences of Yersinia infection include chronic inflammation of the eyes, kidneys, heart, and joints.126 Studies have found that within a year of contracting Yersinia food poisoning, victims appear forty-seven times more likely to come down with autoimmune arthritis,127 and the bacteria may also play a role in triggering an autoimmune thyroid condition known as Graves’ disease.128
How contaminated are U.S. pork products? Consumer Reports magazine tested nearly two hundred samples from cities across the country and found that more than two-thirds of the pork was contaminated with Yersinia.129 This may be because of the intensification and overcrowding that characterizes most of today’s industrial pig operations.130 As noted in an article in National Hog Farmer entitled “Crowding Pigs Pays,” pork producers can maximize their profits by confining each pig to a six-square-foot space. This basically means cramming a two-hundred-pound animal into an area equivalent to about two feet by three feet. The authors acknowledged that overcrowding presents problems, including inadequate ventilation and increased health risks, but they concluded that sometimes, “crowding pigs a little tighter will make you more money.”131
Unfortunately, this situation is not expected to change anytime soon. Why? Yersinia bacteria do not cause clinical disease in pigs.132 In other words, it’s a public health problem, not an animal production problem. It doesn’t affect the industry’s bottom line. So instead of giving these animals a little more breathing room, the pork industry just largely passes along to society the estimated $250 million (£160 million) cost of sickening tens of thousands of Americans every year.133
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