In recent years, we've learned a lot more about how the immune system works -- or doesn't work. It turns out that pathogenic microorganisms are invading our bodies every day. They're in the air we breathe and the food we eat. They're on the surface of just about everything we touch.
Not getting sick is more about fighting germs than avoiding them. Our immune systems are engaged in a constant battle, and usually destroy these bugs before they can cause our bodies to generate noticeable symptoms.
The most interesting update to the germ theory is that, yes, microorganisms can make us sick -- but when we don't get sick it's usually because other microorganisms protected us.
Some 200 trillion tiny creatures -- bacteria, fungi and viruses -- live in our bodies and on the surface of our skin and hair. For every human cell in our body, there are 20 non-human cells. The vast majority of these critters live in our digestive systems -- probably far more than 1,000 species of different microorganism inhabit our guts.
The scientific understanding of gut microbes is still in its infancy -- we haven't even identified most of these species, and we don't fully understand how they all work. However, it has become clear that gut microbes play a vital role in protecting our bodies from invading pathogens.
Using mice as test subjects, researchers have discovered that the right mix of gut bacteria can mean the difference between getting sick from an invading pathogen, and not getting sick. Scientists were able even to control the degree to which mice got sick by fiddling with various combinations of gut bacteria.
Gut microbes achieve this protection in at least four ways. First, they lower the pH level inside the intestine, which favors good microbes and harms bad ones. Second, they coat the lining of the intestines, which creates an actual wall of defense that's both physical and chemical -- pathogenic bacteria has a harder time escaping the gut and entering the blood stream. And third, they starve the invaders by eating their food supply. And fourth, they exhibit a poorly understood role in controlling, training and generally directing the entire body's immune system.
A very recent study, for example, found that protection from airborne flu virus in the lungs is actually directed or signaled by gut microbes. Researchers discovered that a compromised gut ecosystem increases the likelihood of getting the flu because a healthy gut is required in order for the lungs to defend against pathogens.
This whole emerging science around the gut microbiome is new. But we already know enough to take action based on what has been discovered so far. The bottom line is that with a healthy gut ecosystem, you'll get sick a lot less and enjoy much better health than if you have a damaged or compromised gut ecosystem.
The most efficient way to damage gut microbes is to take antibiotics, which can wreck your gut for months and even years. But other factors cause harm, too.
The gut environment changes dramatically hour by hour, day by day. And it's likely that a wide range of environmental factors damage the ecosystem. Chlorinated water, toxic food, pollution, household chemicals -- all these probably take their toll.
You can also starve your gut bacteria by eating sterile processed industrial foods instead of whole, fresh foods. Certain types of foods function as prebiotics (not to be confused with probiotics). Prebiotics are foods you cannot digest, but which gut bacteria transform into food for themselves through fermentation in the colon. Prebiotic foods include whole grains, root vegetables, raw goat milk, garlic, onions and some green vegetables.
If you care about your health, you're probably already eating a pretty healthy diet. So why are you still getting sick as often as you do? We've found that many people who eat well and exercise, still get sick because of stress.
Recent science has shown that stress is one of most high-impact ways to negatively change the gut ecosystem. Research at Ohio State University found that stress changes all aspects of gut microbes, including the number of cells, the balance of various species and the number of species. The lowering of intestinal microbe diversity was found to be directly associated with the ability to resist disease. The lead researcher in the project said it plainly: "Stress dysregulates the immune response."
Also note that stress is not only caused by emotional distress. You can also stress your body through sudden, extreme exercise that you're not fully conditioned for or any other physical shock to the body.
Of all the factors that allow otherwise healthy people to get sick, stress is probably the most common trigger. One reason is that it can happen suddenly. You're eating well and feeling great, but then have an upsetting encounter with your spouse, child or boss. The next day, you're sick! Just like that. What's happening is that your immune system, guided by your gut microbes, had been keeping invading pathogens at bay and under control. Then the emotional distress wipes out a critical mass of gut microbes, which causes a general lowering of the defensive barrier, and in come the pathogens.
But even if you don't kill your gut microbes, they can slowly die of natural causes -- which is why you need to replenish your supply. (In the mouse study referenced above, scientists planted good gut bacteria into mice, which lived in the rodents' digestive tracts for only a month or so.)
You re-stock your gut by eating a diet rich in probiotics, which are foods teaming with healthy microbes -- raw, organic fruits and vegetables, raw fermented foods (like sauerkraut, olives, kimchi, pickles, etc.), raw goat milk, and raw goat or sheep milk cheese. Note that because heat kills all or most good bacteria, fermented foods that come in a jar or can won't work, nor will pasteurized milk, as these products have been sterilized in the factory. (Note that some health food stores carry good fermented foods in jars, but they'll make a big deal on the label of saying they're "cultured" and "raw" -- that's how you know.)
There's no need to buy specially marketed probiotic products – a healthy diet will keep your gut microbes healthy and strong.
How to avoid getting sick
So if you want to stay well, and feel great -- even while everyone around you gets sick as a dog -- you need to take a multifaceted approach:
1. Listen to your mother: Wash your hands and avoid sick people.
2. Avoid antibiotics in consultation with your doctor. If you can muddle through without them, and your doctor approves, choose to not take antibiotics.
3. Avoid pollution, conventional household cleaning chemicals (use natural products from the health food store), fire smoke, heavy alcohol and other toxins.
4. Eat probiotic foods -- raw, organic fruits and vegetables, raw fermented foods, raw goat milk, and raw goat or sheep milk cheese.
5. Feed your gut microbes the prebiotic foods they need: whole grains, root vegetables, raw goat milk, garlic, onions and green vegetables.
6. Avoid stress -- change your stress-driven view of life, meditate, do yoga, take a vacation, get plenty of sleep, laugh, don't allow yourself to get worked up -- stay chill.
Of course, if you do damage to your gut microbes -- by taking necessary antibiotics, getting stressed out or some other way -- double up your efforts to rebuild your gut with the right foods and a relaxed frame of mind.
We can't guarantee that you'll never, ever get sick. But by making these six lifestyle changes, you'll have your best chance of getting sick less often, and less severely if you do catch something.