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  • Children living in households that hand-wash their dishes are less likely to develop allergies than those living in households where dishwashers are used
  • The hygiene hypothesis suggests that exposure to microbes early in life is beneficial, as it stimulates your immune system and reduces your risk of allergies
  • Hand-washing leaves more bacteria behind on dishes than dishwashers do, which may actually be beneficial
  • Eating small amounts of foods such as peanuts, which is a common food allergen, early on in life may also “train” your child’s immune system to avoid allergy in the first place
 

Got Allergies? Here’s How Dishwashers Can Hurt You and Peanuts Can Help You

March 11, 2015 | 292,315 views
| Available in EspañolDisponible en Español

By Dr. Mercola

Your body is a complex ecosystem made up of more than 100 trillion microbes that must be properly balanced and cared for you to achieve optimal health.

This system of bacteria, fungi, viruses, and protozoa living on your skin and in your mouth, nose, throat, lungs, gut, and urogenital tract is referred to as the “human microbiome.”

It varies from person to person based on factors such as diet, health history, geographic location, and even ancestry. When your microbiome falls out of balance, you can become ill.

Those organisms perform a multitude of functions in key biological systems, from supplying critical vitamins to fighting pathogens, modulating weight, and metabolism.

This army of organisms also makes up 70 percent of your immune system, “talking” directly to your body’s natural killer T-cells so that they can tell apart “friendly” microbes from dangerous invaders.

Meanwhile, it’s becoming common knowledge that growing up in an overly clean environment – complete with antibacterial soap and hand sanitizers – might backfire because it keeps you from getting normal and healthy microbe exposure.

The hygiene hypothesis suggests that exposure to bacteria and other microbes early in life is beneficial, as it stimulates your immune system, which then develops tolerance and reduces your risk of allergies.

The same can be said about food allergies, researchers claim, noting that eating small amounts of foods such as peanuts, which is a common food allergen, early on in life may “train” your child’s immune system to avoid allergy in the first place.

Dishwasher Use Linked to Allergies

Researchers from Sweden's University of Gothenburg recently added another piece of research in favor of the hygiene hypothesis, concerning a device that’s found in about 75 percent of US homes:1 the dishwasher.

If you have a dishwasher in your home, you probably consider yourself lucky. But there may be reason to wash your dishes by hand instead. Because they use very hot water (water typically too hot for human touch), dishwashers kill far more germs, and leave your dishes cleaner, than ordinary hand washing.2

But this purported benefit might also be their downfall. In a study of more than 1,000 Swedish children, those with increased microbial exposure were less likely to develop allergies… and this included potential exposure through hand-washed dishes.3

In households where dishes were always washed by hand, rates of allergies in the children were half those from households that used dishwashers. The children using hand-washed dishes were less likely to develop eczema, asthma, and hay fever.

According to the researchers:

“We speculate that a less-efficient dishwashing method may induce tolerance via increased microbial exposure.”

Fermented and Farm-Fresh Foods Also Reduced Allergy Risk

This portion of the study hasn’t been as widely publicized by the media as the dishwasher finding, but the study also showed lower rates of allergies in children who ate more fermented foods and foods that came fresh from the farm, including eggs, meat, and unpasteurized (raw) milk.

Both of these were included as examples of lifestyle factors that may increase microbial exposure. Research shows, for instance, that women who take probiotics—i.e. healthy bacteria—during pregnancy reduce their child's risk of developing allergies.4

Daily supplements of probiotics have also been shown to reduce a child's risk of eczema by 58 percent.5 Well, some fermented foods can contain about 100 times more beneficial bacteria than a probiotic supplement, making them one of the best ways to nourish your body’s microflora.

As for the farm-fresh foods, kids who grow up in extremely clean homes are more likely to develop asthma and hay fever than kids who grow up on farms or in houses with a little bit of dirt.6

Foods from the farm, such as raw milk, will also have more beneficial bacteria than processed or pasteurized food, as the heating kills off many microbes.

School-aged children who drank raw milk were 41 percent less likely to develop asthma and about 50 percent less likely to develop hay fever than children who drank store-bought (pasteurized) milk, according to one study that used data from more than 8,000 children.7

Other ‘Dirty’ Things That Might Be Good for You

There's a tendency in our modern culture to be obsessive about cleanliness, especially in children. But the evidence is growing that a little dirt is good for you and probably even essential to keeping your body in sound working order.

A biochemist from the University of Saskatchewan has theorized, for instance, that nasal mucus, or as it’s more commonly known, boogers, has a sugary taste that’s meant to entice you to want to eat it.

Doing this, he believes, may help introduce pathogens from your environment to your immune system, resulting in the building up of natural defenses.

Other “dirty” factors associated with a lower risk of allergic disease include having a dog or other pet in the home, attendance at day care during the first year of life,8 and even receiving oral dust-mite drops twice a day from the age of 6 months to 18 months.

Dust mites are one of the most common allergens in the US and the UK, and are a common trigger for asthma symptoms as well. Remarkably, dust-mite exposure reduced the incidence of allergy by 63 percent, and this was among infants at high risk of allergy (they had a history of allergy in both parents).

Among the infants exposed to dust mites, only 9.4 percent developed allergy to dust mites or other allergens compared to more than 25 percent in the placebo group.9

In a separate study, researchers found that urban babies exposed to cockroach, mouse, and cat allergens (via house dust), as well as to certain types of bacteria, during their first year of life were less likely to suffer from wheezing and allergies at the age of 3.10

In fact, wheezing was three times more common among children who grew up in homes without allergen exposure. Dr. Todd Mahr, an allergist-immunologist and chair of the American Academy of Pediatrics' Section on Allergy & Immunology, told WebMD:11

"The environment appears to play a role, and if you have too clean of an environment the child's immune system is not going to be stimulated."

You Need Dirt to ‘Exercise’ Your Immune System

Your immune system is composed of two main groups that work together to protect you. One part of your immune system deploys specialized white blood cells called Th1 lymphocytes, which direct an assault on infected cells throughout your body.

The other major part of your immune system attacks intruders even earlier. It produces antibodies that try to block dangerous microbes from invading your body's cells in the first place. This latter strategy uses a different variety of white blood cells, called Th2 lymphocytes.

The Th2 system also happens to drive allergic responses to foreign organisms. At birth, an infant's immune system appears to rely primarily on the Th2 system, while waiting for the Th1 system to grow stronger.

But the hygiene hypothesis suggests that the Th1 system can grow stronger only if it gets "exercise," either through fighting infections or through encounters with certain harmless microbes.

Without such stimulation, the Th2 system flourishes and the immune system tends to react with allergic responses more easily. In addition to allergies and asthma, eczema, autoimmune diseases, and even heart disease have been associated with the hygiene hypothesis

One study found early exposure to viral infections during childhood could reduce the risk of heart disease later in life by up to 90 percent.12 Even depression has been connected to early exposure to pathogens, via an inflammatory connection.13 Neuroscientist Charles Raison, MD, who led that study, said:14

"Since ancient times benign microorganisms, sometimes referred to as 'old friends,' have taught your immune system how to tolerate other harmless microorganisms, and in the process, reduce inflammatory responses that have been linked to the development of most modern illnesses, from cancer to depression."

Exposure to Peanuts During Infancy May Prevent Peanut Allergy, Researchers Say

An estimated one to three percent of children in Western Europe, Australia, and the US are allergic to peanuts, and parents are typically warned not to give peanut-containing foods to their young children. Peanut allergies are also starting to become more prevalent in Asia and Africa. Allergic reactions can vary in severity, from difficulty breathing, swelling of the tongue, eyes or face, stomach ache, nausea, skin rashes, and in severe cases, anaphylactic shock that can lead to death.

However, according to one recent study15,16,17 early avoidance of peanuts may in fact be part of the reason why peanut allergy is so common. The randomized controlled trial enrolled 640 children between the ages of four and 11 months, all of whom were at high risk of developing an allergy against peanuts as they’d already been diagnosed with eczema or egg allergy, or both. Severity of preexisting sensitivity to peanuts was determined with the use of a skin-prick test, The children were then divided into two groups based on having a positive or negative test result, and each of those groups were again divided into two; half were given peanuts on a regular basis while the others were told to avoid peanuts until the age of five.

Children in the treatment group who had a positive skin-prick test were given tiny doses to start, gradually increasing the amount as tolerance grew, while those with a negative test results were given higher doses. Please do note that whole peanuts should be avoided due to choking hazard. Organic peanut butter would likely be ideal. On the whole, those who received small amounts of peanuts three or more times a week ended up having an 80 percent reduction in the prevalence of peanut allergies, compared to those who avoided peanuts up until the age of five. More specifically:

  • Among those who initially had a negative result on their skin-prick test, suggesting their risk of allergy was low, the prevalence of peanut allergy at 60 months of age was just under 14 percent in the avoidance group, and less than two percent among those who regularly ate peanuts
  • Among those with a positive skin-prick test, indicating heightened allergy potential, the prevalence of peanut allergy was just over 35 percent in the avoidance group, and less than 11 percent among those who ate peanuts.

According to lead author Gideon Lack at King's College London:18,19

"This is an important clinical development and contravenes previous guidelines. New guidelines may be needed to reduce the rate of peanut allergy in our children... In primary prevention we can halt the process before the disease starts. In secondary prevention, in the babies who already were positive for peanut allergy, the ball is already rolling downhill, but we can still prevent it, and push it back up the hill. We showed both primary prevention and secondary prevention were effective.”

It’s worth noting that caution is still warranted though. I’d be hard-pressed to recommend feeding your child peanut butter at a young age without taking basic precautions, especially since peanuts are not particularly healthy based on their fatty acid composition. Ideally, work with your pediatrician and get an allergy test to ascertain susceptibility to peanut allergy first, and then start out with minute amounts if the risk of allergy is low. Some women are still advised to avoid peanuts during pregnancy as well, and here I believe there’s far less potential risks involved, and eating peanuts during pregnancy (provided you’re not allergic), may be a safer way to go.

Wash Your Dishes By Hand… and Other Tips for Allergy Reduction

If the hygiene hypothesis is true, and there’s mounting research that it is, there may be good reason to wash your dishes by hand more often. Just recognize that most dishwashers need to be used at least once or twice a month to prevent parts from drying out and damaging the machine. You can also avoid being “too clean,” and in turn help bolster your body’s natural immune responses, by:

  • Letting your child get dirty. Allow your kids to play outside and get dirty (and realize that if your kid eats boogers, it isn’t the end of the world).
  • Not using antibacterial soaps and other antibacterial household products, which wipe out the microorganisms that your body needs to be exposed to for developing and maintaining proper immune function. Simple soap and water are all you need when washing your hands. The antibacterial chemicals (typically triclosan) are quite toxic and have even been found to promote the growth of resistant bacteria.
  • Avoiding unnecessary antibiotics. Remember that viral infections are impervious to antibiotics, as antibiotics only work on bacterial infections.
  • Serving locally grown or organic meats that do not contain antibiotics.
  • Educating yourself on the differences between natural and artificial immunity, and making informed decisions about the use of vaccinations.

Finally, if you’re one of the tens of millions of allergy sufferers in the US, please know there is plenty you can do besides lining the pockets of the pharmaceutical industry. Eating a wholesome diet based on unprocessed, ideally organic and/or locally grown foods, including fermented foods, along with optimizing your vitamin D levels and correcting your omega-3 to omega-6 ratio, will form the foundation upon which your immune system can function in an optimal manner.

For short-term relief of symptoms, you could give acupuncture a try, and irrigate your sinuses with a neti pot. There are also a number of foods and herbs you can try to alleviate symptoms, which are listed here. For more long-term relief, you may want to consider provocation neutralization treatment, or sublingual allergy drops, which work just as well as inhalers. Last but not least, you may want to discuss the peanut issue with your pediatrician. As with bacteria avoidance, strictly avoiding common food allergens could potentially backfire, raising your child’s risk of a food allergy rather than lowering it.

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