The thing I love most about science is that just when you think you’ve figured something out, you realize you still have a whole lot of learning to do. And every once in a while, there is a major paradigm shift that fundamentally alters your understanding of human health.
Such is the case with our understanding of the bacteria that live deep inside our bodies (particularly in our guts). This intricate system of living, thriving organisms is so vast and amazing that scientists have even given it its own name: the microbiome.
Bacteria have long had a reputation as “bad guys” that do nothing but cause illness and disease. After all, some of the most miserable or life-threatening conditions can be blamed on bacteria—pneumonia, meningitis, strep throat, food poisoning, gonorrhea, syphilis, ulcers, tetanus, and dysentery, to name just a few.
But in reality, disease-causing bacteria represent only a small proportion of the actual bacteria in and on our bodies. The majority of our bacteria, our microbes, are actually protective and health promoting. Their strong, robust presence is what keeps harmful bacteria at bay, what helps convert ingredients in our diet into life-producing nutrients, and consequently, what helps us stay healthy most of the time. It’s only when bad bacteria gain a stronghold, start to outnumber the friendly bacteria, and overtake the capacity of our immune systems to keep them in check that infections crop up.
For more than a century, we’ve known about the existence of friendly bacteria. It’s only been in the past several years, though, that we’ve discovered just how diverse and wide ranging the benefits of probiotics truly are.
Protection Beyond the Gut
As I already mentioned, probiotics are our first line of defense against pathogenic microbes. In fact, it is estimated that up to 80% of our immune strength comes courtesy of the beneficial bacteria in and around our guts. They also line our skin and airways, poised to attack foreign invaders that enter and attempt to wreak havoc.
It’s probably common knowledge that, since a vast majority of friendly bacteria reside in the gastrointestinal tract, probiotics play a significant role in proper digestion and absorption of vitamin and nutrients. They also protect against many GI problems, including diarrhea, constipation, irritable bowel syndrome, chronic bowel diseases, and even colon cancer.1-3
And a growing body of research confirms that the value of probiotics may extend far beyond immune and digestive support. Here’s just part of an ever-growing list:
Allergies: In a recent meta-analysis of 23 clinical trials (which included 1,919 patients), 17 of those studies showed that the use of probiotics for hay fever provided significant relief.4
Skin concerns: Several studies indicate that probiotic supplementation may prevent and treat eczema, especially in infants and young children. A meta-analysis of 17 trials concluded that, “probiotic supplementation prevents infantile eczema, thus suggesting a new potential indication for probiotic use in pregnancy and infancy.”5-6
Depression and mood: Bacteria have even been shown to affect brain function and mental/emotional health. In fact, there’s evidence that the gut and brain actually communicate, and gut microbes play a critical role in this communication feedback loop. This has implications for a variety of mental health issues, including anxiety, autism, and depression. In one recent study of 40 patients with depression, probiotic supplementation resulted in a substantial decrease in negative or aggressive thoughts, and participants dwelled far less on their sad mood than those who took placebo.7-8
Obesity: Fascinating research shows that the gut bacteria of obese people differ drastically from those of lean people. Moreover, transplanting the bacteria of lean people into obese people (or vice versa) can influence the body weight of the recipient! This suggests, according to some scientists, that “the gut ecosystem is a relevant target for weight management.” Additional research points out that alterations in the microbiome can promote fat deposition and trigger inflammation.9-10
Diabetes: Similarly, a decade’s worth of data highlights that changes in gut bacterial composition are common in patients with type 2 diabetes, and can contribute to the development of the disease as well. As the researchers of one study put it, “dietary interventions in conjunction with probiotics—a novel multifactorial strategy to abrogate progression and development of diabetes—hold considerable promise through improving the altered gut microbial composition and by targeting all the possible risk factors.”11-13
Urinary and vaginal health: The genital and urinary tracts are highly susceptible to infection, but probiotics can help prevent and treat bacterial vaginosis and yeast and urinary tract infections.14-16
Preliminary research also reveals that probiotics show promise in preventing oral health concerns (bad breath, gum disease, and cavities), bone loss, autoimmune diseases, and even pre-term birth.17-19 Truly remarkable.
Boost Your Beneficial Bugs
This science is still relatively early and complicated, but researchers from all over the world (including those funded by the National Institutes of Health) are focused on the incredible promise of probiotics. The most exciting news of all is that you may be able to gain many of these health benefits (and likely more that we don’t yet even know about) by taking a high-quality probiotic supplement every day.
Currently, there are plenty of options on the market, and choosing a good supplement can be tricky. First, look for products that encapsulate the bacteria so that they can reach the digestive tract without being destroyed along the way by the acidic environment. Also look for a product that contains a blend of different types of organisms, with 1 to 10 billion colony forming units (CFUs) per dose.
One family of bacteria typically included in good supplements is Lactobacillus (which includes acidophilus, rhamnosus, casei, and many others). These lactic acid-producing bugs normally live in the digestive, urinary, and genital systems. Another family, Bifidobacterium (which includes bifidum and longum), is found mainly in the gastrointestinal tract and mouth.
Fermented foods (yogurt, kefir, sauerkraut, buttermilk, kimchi, cheese, miso, and tempeh) also are naturally high in probiotics. The fermentation process releases health-promoting lactic acid-producing bacteria. I’ll discuss fermented foods in greater detail in a future letter.