If you’ve set foot in a supermarket this year, you have very likely seen products touting the inclusion of probiotics, which consumer analytics researchers at SPINS have dubbed “the number one ingredient by sales in both natural and conventional retail channels.”
Just last month, for example, PepsiCo announced probiotic-infused Tropicana juices are on their way – a last-ditch effort at reviving moribund sales.
Why, exactly, are probiotics such a big deal? Should you start buying foods with added probiotics? Should a probiotic supplement become part of your daily routine?
Here is your “gotta-know” guide to probiotics and gut health:
1. The human gut is the epicenter of health.
Probiotics are microorganisms – mainly bacteria – that benefit the body, especially the digestive tract (which houses approximately 100 trillion microbial cells, representing roughly 1,000 different species). Our bodies contain approximately 37 trillion human cells, which means microbial cells outnumber us three-to-one! Our gut microbiome is so well-populated that it weighs almost six pounds.
These microorganisms don’t just sit there and take up space. They affect our metabolism, physical and psychological health, and immune function (yes, psychological health; the human gut is commonly referred to as “the second brain”). Without a doubt, research – some of which is still in very early stages – shows a clear link between what lives in our digestive tract and our overall health.
Healthy bacterial populations (AKA: “good bacteria”) in our digestive tract can produce beneficial compounds that can actively help to suppress disease. For example, when gut bacteria ferment fiber in our colon, they produce various short-chain fatty acids, including butyrate, which appears to have a protective effect against colon cancer.
2. The key to gut health: eat more plants!
A lot of mainstream advice on gut health mentions probiotic supplements (we’ll get to those in a minute) as well as including fermented and cultured foods (i.e.: dairy/non-dairy yogurt, kimchi, kombucha, natto, sauerkraut). Another important factor, however, is often left out: what we eat on a daily basis.
The microbes in our gut need healthy food to thrive, and nothing beats prebiotics. Prebiotic foods include: apples, asparagus, bananas, beans, beets, chia seeds, garlic, lentils, onions, spinach, sweet potatoes, and turnips. The common thread: plant-based foods.
Recent studies give credence to the idea that the gut bacteria of people who eat plant-based diets is unique in three characteristics: it contains fewer pathogens, more protective species, and also leads to reduced levels of inflammation.
This “plant-based gut flora” follows a continuum; that is to say, the more plant-based the diet, the more pronounced the difference. It has been theorized that this change in the composition of the gut microbiome may help explain why plant-based, or highly plant-based, diets are linked to lower rates of chronic disease.
One strand in particular – faecalibacterium pausnitzii – is most abundant in individuals who eat fiber-rich, plant-based diets. Low levels of this bacteria are associated with higher rates of intestinal disorders (i.e.: IBS) and type 2 diabetes. Remember, the average American eats 14 grams of fiber a day, well below the recommended 30 grams. Where do you find fiber? Exclusively in plant-based foods.
3. Proton-Pump Inhibitors Are Bad News
It has been well established that antibiotics are detrimental to gut health, since they expel both the harmful and beneficial bacteria (of course, there are certain medical conditions that require antibiotic treatment).
What isn’t discussed as often are the negative effects proton-pump inhibitors (PPIs) have on gut health. You may know PPIs through their brand names: Prilosec, Prevacid, or Zegerid being the most common.
Recent research has shown that the gut flora composition of PPI users differs from that of non-PPI users. Specifically, PPI use leads to a less diverse gut flora and an increase in harmful bacterial species (i.e.: Enterococcus, Staphylococcus, and Streptococcus). This less-than-optimal environment predisposes individuals to enteric bacterial infections.
If frequent heartburn is a concern, consider nutrition therapy instead of PPIs.
4. The Jury Is Still Out on Probiotic Supplements and Probiotic-Fortified Foods
So, what’s the deal with probiotic supplements? And what about juices, cereals, and other snacks with added probiotics? Do they make a difference? And, if they do, are certain brands better than others?
Here is where things get a little nebulous. First, keep in mind that supplements are not regulated, which means there is no third party verifying that what you buy matches what the label on the supplement bottle claims.
Even if you are buying foods or beverages with added probiotics (in which case there is regulation), the current scientific literature concludes that “the evidence does not demonstrate that probiotics have any effect on gut bacteria in healthy people.” There is an important caveat: “that is not to say that all probiotics definitely have no effect; further high-quality research is needed.”
In a way, probiotic supplements (for healthy people) miss the point. Remember, our current understanding of gut health is that diversity is key. However, we only know that a handful of bacteria (i.e.: lactobacillus acidophilus), when taken in supplement form, survive the long transit through our digestive tract. Gut health appears to be one area of nutrition research that will grow tremendously over the next decade or two, so we can look forward to lots of new information.
Until we have more answers, as with most things in nutrition, a “food first, then supplements” approach appears most appropriate. Add “gut health” to the list of why eating more plant-based foods is a good idea.
Andy Bellatti, MS, RD is a Las Vegas-based nutritionist with a plant-centric and whole-food focus who takes an interest in food politics, deceptive food marketing, sustainability, and social justice. His work has been published in Grist, The Huffington Post, Today’s Dietitian, Food Safety News, and Civil Eats, among others. He is also the Strategic Director of Dietitians for Professional Integrity, a group that advocates for ethical and socially responsible partnerships within the Academy of Nutrition and Dietetics. You can read more of his work on his Small Bites blog and can also follow him on Twitter and Facebook.