“All diseases begin in the gut” -Hippocrates, 460-370 BC
The human body is similar to the planet Earth in that it is inhabited by extremely large numbers of various organisms. There is a symbiotic relationship between the Earth and its micro-organisms (plants, insects, animals, and people) and the same goes for humans and our little micro-ecosystem composed not only of organs, cells and various biochemical compounds, but colonies of bacteria, yeasts and viruses as well. Today I want to focus on bacteria: beneficial bacteria strains, specifically.
The largest colonies of microbes live in our digestive tract. A healthy adult, on average, carries 4-5 lbs. of bacteria in their gut! This equates to around one hundred trillion microorganisms from a thousand different species, just within the gut alone! (1) These species collectively have one hundred times more genes than the human genome does. (2) In fact, when the Human Genome Project mapped the human genome in 2003, they made the discovery that humans actually share 99.9% of their DNA, meaning my DNA and your DNA for example, differ very slightly. (3) So although our DNA has been shown to have many similarities, our microbiome, however, differs substantially: we actually only share about 10% of our microbiome with one another, our quantities and bacterial strain diversity differs that much! Also, there are ten times more microbes in the human body than there are human cells (4), so it is safe to say that technically, at the cellular level we are more microbe than we are human! Now you may be asking yourself, “how can bacteria play an important role in human health?” Here are just a handful of benefits these bacteria have been claimed to have a role in:
- Protecting us from various infections
- Manufacture important B vitamins such as vitamin B12
- Promotes normal gastrointestinal function
- Helps regulate metabolism
- Protects our intestinal mucosa
- Contributes to healthy bowel elimination and prevents diarrhea and constipation
- Manufactures vitamin K2 (which delivers calcium to our bones)
- Creates short-chained fatty acids such as butyrate which can protect the colon from cancer.
- Can help alleviate allergy symptoms
- Can improve mood and cognition
- Alters gene expression (it appears through short-chain fatty acid production)
- May help with glucose tolerance and obesity
- Seems to aid in various autoimmune conditions
- And potentially much, much more…
Wow, that’s quite the list of possible benefits! Below I reveal what some of the research has shown regarding some of these claims. It is important to remember however that even with the mounting number of studies and research accumulating in this field, it seems we are still in the infantile stages of understanding all the ‘ins and outs’ of these little buggers, especially when it comes to how to best apply them in a clinical setting. It is still far from the end all-be all regarding health at the moment, but the future looks promising!
So what are probiotics? Probiotics are all the rage these days, but is there any scientific, peer-reviewed evidence to support the health claims that follow them? First, let’s start with the term: “probiotic”. Probiotic was derived from the Greek, meaning “for life”. These are products of fermentation (strains of bacteria and yeasts) that are dubbed “beneficial” due to semi-recent discoveries of the roles they play in maintaining health and managing various diseases. When you read an article online or in a health magazine referring to “probiotics”, they are referring to supplemental forms of these beneficial micro-organisms, or fermented foods such as kimchi, kefir, yogurt, kombucha, natto, etc. But are these bacteria strains really that beneficial? Or is this the latest fad in health and wellness generated by supplement companies to get you to spend more money on products and miracle ‘cures’? Well, for starters, the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) have stated that there is adequate scientific evidence to indicate that there is potential for probiotic foods to provide health benefits and that specific strains are safe for human use. (5) So probiotics do have some credibility it seems, but do their specific health claims hold water? Lactic acid bacteria (found in fermented foods such as kimchi, kombucha, sauerkraut, etc.) have been shown to possess a variety of benefits, although pending on how well they survive transport through stomach acid and the small intestine to colonize in the large intestine. (6) That is why I recommend when taking a probiotic supplement or consuming fermented foods, to consume them with meals. This is because when you eat food the stomach breaks it down into chyme which temporarily lowers the acidity of your stomach (thus helping the beneficial bacteria strains survive the stomach acid). But any who, back to the discussion at hand, here is a list of the benefits of these probiotics observed through scientific research thus far:
Boosts immunity: There are a handful of studies showing that probiotic supplementation enhances immune function, (7) , (8), (9) In this study, a randomized, double-blind, placebo-controlled intervention was performed on 479 healthy adults (aged 18-67) over three months during winter/spring periods. The participants were split into two groups; the control group, which supplemented with vitamins and minerals, but no probiotics, and the probiotic-treatment group which also supplemented with vitamins and minerals, but included probiotics (lactobacillus gasseri, bifidobacterium longum and bifidobacterium bifidum strains). Cellular immune parameters were evaluated as well as symptoms and stool samples after 14 days (to quantify fecal lactobacilli and bifidobacteria strains). The results? The total symptom score, the duration of common cold episodes and days with fever during a cold episode were lower in the probiotic-treated group than in the control group! (10) Probiotics may also offer some anti-aging benefits as well, especially regarding age-related decline in cytokine production. (11) Interestingly enough, probiotics effects on the immune system seem to vary based on the individual’s health status. For instance, in healthy subjects probiotics seem to have an immunostimulatory effect where-as they down-regulate immunoinflammatory responses (basically suppressing the immune system) in hypersensitive individuals with over-active immune systems, such as what is seen in allergies. (12)
Can protect against cancer: There is some evidence suggesting that certain microbes in the intestine can influence the onset of cancer by producing enzymes such as glycosidase, azoreductase, nitroreductase and B-glucoronidase, which transform pre-carcinogens into active carcinogens. (13) Preliminary data suggest that certain probiotics may protect against this carcinogenic activity (14) , (15). In a double-blind trial conducted on 138 patients with superficial transitional cell carcinoma of the bladder, patients receiving oral lactobacillus casei (probiotic strain) had more success preventing primary multiple tumors as well as single tumors with the probiotic intervention vs. the placebo group. (16). I cannot wait for more placebo-controlled research to immerge in this area, especially since cancer affects around 12 million people in the U.S., with estimated health care costs around $93 billion!
Offers relief from gastrointestinal conditions: You are now starting to see more and more recommendations to supplement with probiotics if you are someone who suffers from any gastrointestinal disorders (IBS, constipation, diarrhea, Crohn’s disease, etc.) This is probably the most abundantly researched area regarding probiotic intervention and the evidence just continues to mount. In constipated women, ingestion of bifidobacterium lactis resulted in a significant increase in stool frequency after one week (3.5 vs 2.4 per week) and two weeks (4.1 vs 2.4 per week) and stool consistency also improved. (17) In a randomized, double-blind, placebo controlled study in elderly nursing home residents, defecation frequency improved as did number of days experiencing normal bowel movements using the same strain. (18)
In combination with mesalamine, probiotic treatment with saccharomyces cerevisiae reduced relapse rate compared to mesalamine treatment alone in Crohn’s patients. (6% vs 38%) (19)
Daily ingestion for 6 weeks of the strains lactobacillus acidophilus and bifidobacterium lactis resulted in decreased H. pylori density and gastritis on the antrum, as well as decreased urea breath test values compared to baseline. (20)
Administration of the strain, bifidobacterium infantis to women with IBS resulted in significant reductions in abdominal pain/discomfort, bloating/distension, feeling of incomplete evacuation, sense of straining at stool, passage of gas, and composite IBS symptom scores compared to controls. (21)
Significantly fewer tourists given probiotic strains lactobacillus acidophilus and bifidobacterium lactis developed traveller’s diarrhea than controls (43% vs 71%) (22)
Lactobacillus rhamnosus was found equally effective as mesalazine in maintaining clinical remission of ulcerative colitis as well as significantly more effective than mesalazine in prolonging the relapse-free time. (23)
Other areas of interest:
Obesity: A 2011 study published in the journal of Nutrition Research found that fermented kimchee had a significant impact on weight and body fat of the overweight and obese patients who were being studied. Not only did the patients observe fat loss, they also showed improvements in their blood sugar, blood pressure, total cholesterol, fasting insulin and even their waist-hip ratio. Although the sample size was small on this study (22 obese patients) it still contributes to the accumulating data that fermented foods may be one missing component in defining a “healthy diet”. (24)
Lower blood pressure: A meta-analysis of nine randomized, controlled trials involving 543 adults suggests use of a multiple strain, probiotic supplementation (usually for at least a course of eight weeks) may help lower blood pressure. Although the researchers conclude these correlations are not quite 100% definitive, and more research is to be conducted before doctors can recommend them to patients, they are still very interesting and important findings none the less. The more pieces of the puzzle we have, the better what can understand all that contributes to health and disease. (25)
Anxiety/Depression/Anger: In healthy subjects, administration of lactobacillus helveticus and bifidobacterium longum strains alleviated markers of psychological distress, depression, and anger-hostility as well as resulted in a decrease in anxiety scores and cortisol. (26)
Decreased rates of infections: Over a 6-month period, there was a 46% reduced incidence of gastrointestinal infections, a 26% reduction in respiratory tract infections, and a 30% reduction in the total number of infections in infants. (27)
Percentage of days with infections decreased from 15.4 at baseline to 5.7 during probiotic treatment in elderly hospital inpatients. This was significantly greater than the reduction in the controls (non-intervention group). (28)
In women with recurrent urinary tract infections (UTIs), weekly intra-vaginal application of lactobacillus rhamnosus and lactobacillus reuteri resulted in a 73% decrease in UTI incidence compared to the previous year. (29)
Infantile colic: Significant reduction in daily crying time by day 7 in the lactobacillus reuteri group compared to the simethicone group. Improvement continued until day 28, when median crying time was reduced to 51 minutes/day in the lactobacillus reuteri group vs. 145 minutes/day in control group. (30)
Influence our cravings: This recent study shows gut microbiome may influence human eating behaviors and dietary choices to favor consumption of the particular nutrients they grow best on, rather than simply passively living off whatever nutrients we choose to send their way. The authors believe this may occur due to the microbes release of signaling molecules in the gut that can conduct messages to the nervous and endocrine systems. Research suggests that gut bacteria may influence eating decisions using the vagus nerve, which connects 100 million nerve cells from the digestive tract to the base of the brain. (31) So if you’re experiencing a strong craving for sweets and sugar, you may want to check who you have inhabiting your gut!
So to conclude: are probiotics actually beneficial? The medical literature seems to gravitate towards “yes”. Especially considering the fact that our modern-day living has compromised these ‘good’ bacteria (via overprescribed antibiotics, diets high in refined sugar, diets low in fiber, heavy metals exposure, not consuming fermented foods, etc.) This field is only going to continue connecting the dots between gut health and disease; I really look forward to when they understand all the biological mechanisms involved, especially in how beneficial bacteria can affect how our genes get expressed (or don’t). For more information on this exciting field of research, be sure to check out ‘The Human Food Project’ (humanfoodproject.com) and Dr. Martin Blaser (martinblaser.com). For a great review on probiotic facts and myths, check this out: http://onlinelibrary.wiley.com/doi/10.1111/j.1469-0691.2005.01228.x/full Or you can simply google: “microbes health” and fish through some articles that come up. That should keep you off the streets for a while! I will be blogging more about this in the future, and looking more in depth at individual studies and their designs, but for now I just wanted to go over the basics and emphasize how critical these little bugs can be. I hope you found this informative, please submit any questions or contributions in the comments below. I look forward to hearing from you!
To your health and wellness,
Derek Walton, CNTP