By Sangeeta Pradhan
INDIA New England Clumnist
Jumping on the probiotic bandwagon: As we saw last month in the post, ” What’s your gut instinct?? A must read on how your gut bacteria, can impact your health! Part I, with the gut quickly emerging as one of the most exciting frontiers in medicine today, probiotics and fermented drinks have become the latest buzzword in the media, with food companies scrambling to jump on this bandwagon, and finding novel ways to harness the power of probiotics in a pill, or powder. Some are incorporating these probiotics into the ubiquitous, functional foods like granola bars, cheeses, and even some beverages that compete for space at your local grocery!
While the little critters called gut bacteria have co-existed with human beings since time immemorial, it is only in the last decade that the microbial community that we all harbor, has come under intense scientific scrutiny.
Are probiotic product claims valid?: Although there are some blinded, placebo controlled trials that support the role of probiotics in maintaining health or preventing disease, the science of probiotics continues to brew and ferment. Hence, further, well designed studies are required to establish the proposed benefits. In some cases, general health claims are made that are not valid for the specific strains and levels being used, and as a savvy consumer you do not want to be misled by such claims.
While an altered microbiota or dysbiosis as discussed in the last post has been implicated in obesity, the metabolic syndrome, non-alcoholic fatty liver, inflammatory bowel disease, irritable bowel syndrome (IBS), atherosclerosis, type 1 diabetes, autism, allergy, asthma and celiac disease, a cause-and-effect relationship per se, has not yet been described.
So what can consumers do to help tap into the health promoting potential of probiotics, while ensuring that they make informed decisions when it comes to choosing products, commercial or otherwise? Do you use probiotics? Had you heard of prebiotics before? Read on for the science behind this…
What exactly are probiotics?:
There is no legal definition for the term “probiotic”, which could be why some commercial products that do not meet the minimal criteria to be termed probiotics, may still make unsubstantiated claims. The International Scientific Association for Probiotics and Prebiotics defines probiotics as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Probiotics are live microbes that can be formulated into many different types of products, including foods, drugs, and dietary supplements. However strictly speaking, probiotics are live microbes that have been shown in controlled human studies to impart health benefits.
What do probiotics do for you?
- Fermentation of carbohydrates: Friendly bacteria such as Bifidobacterium and Lactobacilli in the colon ferment the non-digestible carbohydrates arriving from the upper part of your digestive tract. These bugs do not produce toxins, and instead produce a variety of organic acids. While the acidic environment is a boon for the Bifidobacteria and Lactobacilli, as it turns out, it is a curse for disease producers, as it inhibits their growth, effectively protecting us from an invasion by these microbes. Friendly bacteria also benefit the host by interacting with your immune system.
- Barrier function: One of the by-products of this fermentation, butyrate, is an organic acid associated with maintaining the integrity of the intestinal barrier in your digestive tract. There is some evidence that shows that the loss of butyrate producing microbes, may be linked with colitis and inflammatory bowel disease. The gastrointestinal mucosa forms a barrier between the body and the intestinal lumen. This lumen or cavity within your digestive tract, not only contains nutrients obtained from digested foods, but may also contain potentially antagonistic bacteria and toxins that have also been accidentally ingested. The challenge is to allow efficient transport of nutrients across the epithelium into the bloodstream, from where they will get transported to various organs and tissues, while ensuring that harmful bacteria and their toxins are barred from entering. These exclusionary properties of the gastric and intestinal mucosa are referred to as the “gastrointestinal barrier” and butyrate production by friendly bacteria, has been linked with helping maintain this very crucial barrier function.
- Anti-microbial substances: Probiotics may produce anti-microbial compounds called bacteriocins that prevent disease producers from getting a foothold in your GI or gastrointestinal epithelium in the first place, thus preventing their proliferation.
What exactly are prebiotics?
Prebiotics: precursors of probiotics :Prebiotics are certain types of fibers that serve as “precursors” of probiotics or good bacteria by being selectively fermented by these probiotic or beneficial bacteria, allowing the latter to grow and thrive, thus conferring benefits to the health of the host. Simply put, prebiotics provide “fuel” for helpful bugs in your gut.
Inoculate your gut: By supporting the growth of good bacteria, prebiotics help establish a healthy ecosystem in the colon by creating a favorable ratio between health-promoting microbiota and opportunistic pathogens. While we all harbor some friendly microbes, “inoculating” the gut with probiotics gives the host (us), an added edge by increasing the proportions of beneficial bacteria, and favorably manipulating the overall composition of the gut microbiota.
Feed your gut: “Feeding” your gut prebiotics in turn, allows beneficial bacteria to thrive and flourish. One of the key, established, prebiotics includes complex carbohydrates called fructo-oligosaccharides (FOS), such as inulin. Fructooligosaccharides (FOS) are smaller chain complex carbs of the sugar fructose. Studies in human beings have confirmed that prebiotics are selectively fermented by, and increase the proportion of Bifidobacteria and Lactobacilli in the gut, while having no quantifiable effects on other groups of bacteria. Emerging research shows that an increased proportion of Bifidobacteria and Lactobacilli constitute a healthier microbiota, that is linked to potential health benefits such as decreased colon pH, a decrease in putrefactive nitrogenous end products, that may be associated with ingestion of meat based diets, and improved mineral absorption, improved glucose tolerance, decreased appetite, improved weight regulation and immune response.
Load up on prebiotic rich foods: Since prebiotics are found in many plant foods such as onions, chicory root, garlic, asparagus, bananas, artichokes and leeks, among many others, loading up on a diverse variety of plant-based foods is a good strategy to tap into the benefits of prebiotic rich foods.
Prebiotics are indigestible fibers, but all indigestible fibers are not prebiotics: That being said, most folks have a tendency to lump prebiotics and fiber together. Although like fiber, prebiotics are resistant to the action of human digestive enzymes, and like fiber are fermented in the colon, established prebiotics are selectively fermented by good bacteria, not by the bad bacteria in the colon. Hence if you want a thriving colony of good bacteria, you would need to specifically target prebiotic rich foods in your diet, not just foods high in fiber.
Fortify your gut: Take high quality probiotic supplements with Lactobacillus or Bifidobacterium species. But how do you know that the probiotic actually lives up to it’s name??!
Evaluation criteria for probiotics: What you see is not always what you get!
- Not all probiotics are created equal: Bear in mind that the benefits of probiotics may be strain specific, so that the results seen with one strain may not necessarily be reproducible with another strain even in the same species. Look for products that contain the specific strain(s) of bacteria at the same levels as used in published research, conducted in human beings. Check product Web sites to see study results.
- Ask questions: Specific questions about probiotic content which are not answered on product labels or web sites may be directly addressed to the manufacturer.
- Viability through the end of shelf-life: Ensure that the cultures are viable through the end of shelf life, not just at the time of packing. The live cultures in probiotics are sensitive to heat and moisture. They must also survive a host of damaging factors such as the harsh acidic stomach environment, digestive enzymes and digestive juices that they will encounter during their journey down the digestive tract. In order for a probiotic supplement to be truly effective in the body, it must be packaged in a delivery vehicle that protects these live bugs from such damage.
- Dose: The required dose varies from strain to strain with no specific “magic number for an optimal count” for all probiotics. The scientific literature has documented health benefits for products ranging from 50 million to more than 1 trillion “Colony Forming Units” per day. High numbers of bacteria may not necessarily make a product superior. Products with lower levels of probiotics, but with proven benefits are more important than counts alone
- Safety profile: Commercial products are generally safe in healthy individuals, but it would be prudent to check with your physician, regardless. Traditional lactic acid bacteria, have been used for food fermentation since the dawn of time, and are generally considered safe for oral consumption as part of foods and supplements for the generally healthy population, but may not be considered safe in immune-compromised individuals.
- Resources: For additional information, refer to this table for products with documented health benefits and this site for a consumer’s guide to making smart choices when it comes to prebiotics.
Daily dose of microbes from diet: Although it is certainly advantageous to ingest probiotics that have been associated with proven health benefits, since we all have to eat food, without exception every day, it makes sense to try to get our daily dose of live and active bacteria from one’s diet. According to this article, published in the Journal of the Academy of Nutrition and Dietetics, although such diets have not been evaluated strictly, they could be recommended based upon the emerging body of research demonstrating the benefits of probiotics.
Will all fermented foods give me probiotics?: Many of the commercially available fermented foods in the United States may not contain live and active cultures in the finished products, which could be partly related to processing. While traditional, fermented foods made in small batches such as kimchi and it’s cousin, sauerkraut (both made from fermented cabbage), or tempeh made from fermented soy beans may contain large numbers of beneficial bacteria, many commercially prepared foods may not. For e.g., if sauerkraut is pasteurized, as is true with supermarket sauerkraut, the pasteurization process wipes out live bacteria, thus wiping out any potential benefits, whereas raw, naturally fermented sauerkraut should contain beneficial bacteria.
While yogurt, kefir and cheeses contain live and active bacteria, specifically Lactobacillus, evidence-based use recommendations should be obtained from the manufacturer if not disclosed on the label. Products with established benefits in published human studies include B infantis 35264 found in align capsules shown to be effective against Irritable Bowel Syndrome, while L casei DN 114001 found in Dan active fermented milk is effective against antibiotic associated diarrhea. Please go to this site as well as usprobiotics.org for more info.
What’s in a yogurt? Federal regulations stipulate that all “yogurts” must contain the lactic acid producing bacteria, Lactobacillus bulgaricus and Streptococcus Thermophilus. However, in an attempt to increase shelf stability, some companies may heat-treat yogurt, thus killing any beneficial bacteria. To ensure that the yogurt you pick contains viable cultures, look for the “live and active” cultures seal created by the National Yogurt Association for refrigerated yogurt products that contain at least 100 million cultures per gram at the time of manufacture. What is interesting is that bacterial counts begin to drop, the longer the product sits on the shelf, hence choosing fresh yogurt or organic yogurt may be your best bet to ensure you are reaping the probiotic benefits!
A tale of 2 probiotics: While yogurt is a more well-known probiotic source, kefir, the relatively “new kid on the block”, is beginning to get some media attention as it begins to pop up on more supermarket shelves. Is one superior over the other? While both are cultured milk products, rich in calcium, protein, potassium, phosphorous and B vitamins, kefir is made from a complex mixture of yeasts and about 10 different types of bacteria, or more, depending upon the brand, thus making it slightly more potent than yogurt and giving it a slight edge over it’s rival.
Either way, if you do your homework on probiotics, you should get a plethora of nutrients, along with a healthful dose of friendly bacteria to boot!
Disclaimer: This blog is strictly for informational purposes only and should not be construed as medical advice. Please consult your physician or registered dietitian for recommendations tailored to your specific needs.