A Probiotics Primer
All this recent talk about yogurt reminded me that it was high time I took up the issue of probiotics, an area of tremendous growth in the food industry… and equally tremendous confusion among the rest of us.
What Probiotics Are… and Aren’t
Probiotics are strains of live, “friendly” bacteria that, when eaten, colonize your intestines and provide some sort of health benefit. The difference between a probiotic and any ol’ friendly bacteria is that to be called a probiotic, the particular species and strain of that bacteria has to have proven health benefits in humans. A few species of bacteria have been studied as probiotics most extensively (e.g. Lactobacilli and Bifidobacteria), but since there are so many different strains of these bacteria species, unless a particular strain has been studied and shown to demonstrate a specific benefit, you can’t assume it will have the same benefit as another strain in the same species.
If the idea of eating bacteria to colonize your intestines weirds you out, get over it. Your gut is already home to billions of these bacteria–collectively called your “gut flora” (sounds so pretty, no?). In fact, the majority of your poop is made up of these dead flora, so you encounter them more often than you probably even realized. The makeup of your particular gut flora is unique to you, and is influenced by a variety of factors including how you were delivered at birth, your diet, your environment, use of various medication, and who you’ve been kissing. Both helpful and harmful bacteria live in your gut, but when everything is in balance, the good ones keep the bad ones in check and prevent them from replicating too fast. Trouble happens when enough good guys get killed off (say, by antiobiotics) or you’re exposed to an infectious strain of bacteria that the harmful ones get out of control.
Scientists are only just now starting to discover all of the roles for your gut flora in maintaining good health. We’ve known for years that they play a role in helping digestion (breaking down fiber and some starches), manufacturing some vitamins, helping to prevent yeast infections, and producing substances called Short Chain Fatty Acids (SFCAs) that help you absorb minerals like calcium and iron. But new research is also emerging to suggest that a diverse gut microflora may also play a role in preventing food allergies or obesity (!). Since our Western diets are pretty processed and unvaried and our urban lifestyles are pretty sanitized, it won’t surprise you to learn that people living in industrialized countries have also been obseved to have a lot less variation in the gut flora than, say, people in developing countries.
Where the Probiotics Are
As the definition above suggests, only a live bacteria species and strain that has been demonstrated to have beneficial health effects in people can actually be called a “probiotic.” Of course, this doesn’t necessarily mean that you can’t benefit from the live, active bacteria found in traditional fermented or cultured foods like:
- cultured dairy products such as yogurt or kefir
- fermented drinks like Kombucha tea
- fermented foods like miso, sauerkraut and kimchi
- (gluten-free) fermented Indian breads like Dosas or Iddli
It just means that the people who make those foods didn’t have the time or money to invest in a costly clinical trial to prove the “probiotic” benefits of the bacteria strains present in their particular products. In fact, Dannon was sued for false advertising as a result of marketing that implied its Activia yogurt somehow conferred a health benefit over and above that of any plain ol’ yogurt brand. (The company has since changed its marketing and settled the lawsuit in 2008 without admitting wrongdoing.) In other words, all yogurts that contain live Lactobacillus species or Bifidobacteria species as their cultures may be beneficial, assuming they contain the same dose of bacteria. So if general digestive benefits like regular bowel movements are what you’re after, don’t let marketers trick you into thinking that their expensive products are necessarily better for you.
Having said that, some companies (particularly manufacturers of probiotic supplements, like VSL #3) do make the effort to test specific bacterial strains so that they can make specific claims about what conditions their probiotics will benefit. If you have a specific
health concern beyond just improving your overall regularity or counteracting the impact of a recent course of antiobiotics, seeking out these types of products may be worth the time and money for you. For example, VSL #3 (which must be refrigerated, so ask for it at the pharmacy counter of your drugstore) contains a combination of 8 specific strains of lactobacillus bacteria that have demonstrated clinical benefits in patients with Ulcerative Colitis, Irritable Bowel Syndrome and prevention of “pouchitis” (inflammation of an ileal pouch in people who have had intestinal resection surgeries.) Be aware, however, that they company claims it contains trace amounts of gluten if that’s a concern for you. The strain of bacteria used in Align appears to have a small amount of scientific data behind it supporting its benefit in reducing the symptoms of Irritable Bowel Syndrome. Other products, including supplements like Culturelle (Culturelle for Kids is gluten-free) or probiotic beverages like GoodBelly (note to celiacs: only the powdered drink, GoodBelly ToGo, is 100% gluten-free), can only make more general claims about “improving digestive health” based on the available scientific evidence, but if an ocassional bout of diarrhea is an issue for you, particularly if it results from recent use of antiobiotics or an infectious agent, these types of products may help do the trick just fine.
Probiotic supplements are considered safe for most people, though if you are immunocomprimised due to a disease or medical treatment (e.g., radiation or chemo), you are advised to confer with a doctor before initiating a probiotic supplment regimen.
Additionally, people who must follow low-tyramine diets due to a potential interaction with a medication they take (e.g., MAO Inhibitors) should avoid fermented foods in particular.
As far as other foods go, be very wary of dry, shelf-stable foods like cereals (e.g., Kashi Vive, recently discontinued) or granola bars that claim to contain probiotics. Since probiotics are living bacteria, they need the same things that other living bacteria need to stay alive: namely, water, and a specific temperature range. It is highly unlikely that enough of the probiotic bacteria contained in a breakfast cereal will have survived their long, hot, dry journey from the factory to distribution warehouse to storage room to supermarket shelf alive enough to do your intestines any good.
Scouting Out Live-Culture Foods
- Hit the dairy aisle: Yogurt and kefir are among the easist, most portable sources of live, beneficial bacteria available. There are plenty of dairy free options available as well; cultured soy or coconut milk yogurts are widely available, for example.
- Have a cultured smoothie: Use cultured low-fat Buttermilk instead of regular milk in your favorite fruit smoothie recipe (essentially, this is what a “Lassi” is at Indian restaurants)
- Go Asian: Munch on kimchi (a spicy Korean condiment), miso soup (Japanese) or seek out other traditional Asian fermented soy foods like Natto or Tempeh (note: the latter, widely sold under the brand name Lightlife, is not gluten-free).
- Make Your Own: My fermenting friends-in-the-know swear by Sandor Katz’s (a.ka. “Sandorkraut”) book, Wild Fermentation, for recipes and inspiration. (Click here for a list of recipes featured in his book to get an idea for what types of foods it features.) One such friend, Vered M., shared her recipe for Radish Kimchi elsewhere on the web.
- Invite some Microscopic Friends to your Lunch: Have some sauerkraut on your sandwich, or look for products by a small Pennsylvania-based company called Zukay, which sells condiments such as relishes and salad dressings that contain live cultures.