October 2011 Issue

A Healthful Dose of Bacteria — Yogurt Is the Best Probiotic Source, but Clients Do Have Other Options
By Lindsey Getz
Today’s Dietitian
Vol. 13 No. 10 P. 46

There’s a good chance most of your clients have heard of probiotics. And because of television commercials, print ads, and other media sources, they probably associate these “good” or “friendly” bacteria with yogurt. That’s not a bad thing since yogurt is a great addition to any healthful diet and one of the best sources for probiotics. But it’s not the only source. Though there’s some controversy surrounding the number of live cultures in products other than yogurt, there are other potential avenues to receiving a probiotic boost.

The National Center for Complementary and Alternative Medicine defines probiotics as live microorganisms—usually bacteria, but they also can include microbes such as yeast—that people can ingest to increase the population of desirable bacteria in the gut. “The term probiotic literally means ‘for life,’” says Linda Antinoro, RD, who works in the Nutrition Consultation Service at Brigham and Women’s Hospital in Boston. “One of the better known benefits of probiotics is that it helps with gastrointestinal problems like constipation, diarrhea, bloating, and gas. Helping to enhance the immune system and cancer risk reduction as well as weight management is less [conclusive], but there’s some speculation [probiotics] may help.”

Probiotic Sources
Yogurt is by far the most commonly known and widely available probiotic food in the United States. While it’s not the only way to get your probiotics, there’s good reason yogurt and other dairy foods are the best way to get these friendly bacteria into your system. “Dairy foods and beverages are the best probiotic delivery vehicles since probiotics have a short shelf life and are easily destroyed by heat and acidic environments,” explains Carol Ann Brannon, MS, RD, LD, a nutrition and feeding therapist based in Georgia. “Dairy foods have a short shelf life and buffer stomach acid and bile. In addition, dairy foods and probiotics appear to have synergy. In vitro studies indicate that lactoferrin in dairy foods may enhance bifidobacteria growth.”

“It’s critical that the organisms in yogurt are alive and active during its shelf life in order to ensure that the health benefits are received from the yogurt,” Brannon says. “Pasteurization, partial sterilization using heat, often results in the death of many microorganisms. For this reason, organic yogurts are preferable.”

Antinoro agrees that while there are other sources claiming to contain probiotics, nothing tops yogurt. But there are a few other dairy sources that fit the bill, such as smoothies, cottage cheese, and kefir. Kefir is relatively new in American grocery stores, Brannon says. But this creamy fermented milk product is nothing brand new. It originated centuries ago in the Eastern European Caucasus Mountains. “The longevity of the Caucasus Mountain people was associated with their consumption of kefir,” Brannon says. “Kefir contains several major strains of friendly bacteria, such as Lactobacillus Caucasus, Leuconostoc, Acetobacter species, and Streptococcus species, as well as some beneficial yeasts that aren’t found in yogurt.”

And although yogurt may be a more well-known source of probiotics, many contend that kefir is the better choice. Kefir is made by adding kefir grains to milk, which causes a unique fermenting process to occur. While both yogurt and kefir are cultured milk products, they contain different strains of bacteria, and kefir’s combination seems more powerful. “Kefir is probably a better source [of probiotics] because of the sheer potency,” Antinoro says. “A popular brand called Lifeway has 12 species or cultures.”

For some clients, especially those who are picky eaters or struggle with change, making the switch from milk to kefir may be difficult. But Antinoro says that although the flavor is more tart than milk—similar to a yogurt drink—it comes in many flavors, including blueberry and strawberry, which add some sweetness. Blending kefir with fruit to make a smoothie or pouring it over cereal, rather than drinking it plain, may help your clients accept it. In addition, adding kefir doesn’t mean forgoing milk. It’s just a possible substitution that can boost the amount of probiotics your clients are getting.

For the lactose intolerant set, adding kefir to the diet may be a welcome change. Though it contains lactose, the live cultures in it act to “predigest” the sugar, making kefir better tolerated, Antinoro says. You can easily find kefir in grocery stores, and it’s comparable to the price of milk.

Beyond Dairy
Besides cultured milk products, there are other food sources that may offer probiotic power. However, many experts, like Antinoro, stress that sources other than yogurt and kefir aren’t necessarily ideal. “Beyond yogurt and kefir, everything else is rather questionable,” she says. “It’s pretty unclear how much probiotic potency is really in foods.”

If you have clients who don’t like yogurt or kefir—or are tired of eating it all of the time—there’s no harm in suggesting they try other sources. Foods that use lactic acid bacteria for the fermentation process are thought to have live probiotic cultures. That includes pickled vegetables such as the Korean specialty kimchi. Kimchi consists of spicy fermented vegetables including cabbage and carrot, mixed with seasonings such as hot pepper flakes, ginger, and salt. Since this condiment is known to be hot, it’s often used atop other dishes in smaller quantities.

Like kimchi, sauerkraut (fermented cabbage but without the spicy kick) is considered to be a source of probiotics. In addition, it’s a great source of vitamin C and digestive enzymes. Many of your clients may not like pickled vegetables as a stand-alone dish, but there are ways to incorporate them into a meal. “Sauerkraut is great in toasted sandwiches, on top of pizzas, or added to soups with onions, beans, and low-sodium vegetable broth,” suggests Vashti Timmermans, BSc, RD, a dietitian at the St. Paul’s Hospital Diabetes Centre in Vancouver, British Columbia, and a private practitioner. “It’s low-calorie but high in sodium, so use smaller amounts, and aim to include no more than 1/4 cup per serving.”

Fermented soybean products like tempeh, miso, and natto are also sources of probiotics, says Megan Tempest, RD, a freelance nutrition writer based in Boulder, Colo. For many, these foods may seem exotic and your clients may be unfamiliar with how to use them, so be prepared to offer some suggestions. For instance, you can use tempeh as a meat substitute. It can be lightly steamed, marinated, or grilled, Tempest says. “And it can add a delicious nutty flavor to salads, rice, pasta, or sandwiches.”

Tempeh is firmer than tofu, which gives it additional appeal for some clients, Timmermans says. “You can use tempeh like chicken,” she adds. “Try cutting tempeh into strips and stir frying it with vegetables, or mix tempeh cubes with celery, bell peppers, scallions, light mayo, lemon juice, and parsley to make a tempeh ‘chicken’ salad sandwich. It’s a great source of protein and calcium and is low in sodium.”

Miso, a staple seasoning in Japanese kitchens, also may contain probiotics. While it’s most often used in miso soup—made by stirring some miso seasoning into water with tofu and seaweed—there are other ways to incorporate this protein-rich seasoning into meals. “Miso paste is an extremely versatile product that can be used as an ingredient in sauces for fish or chicken,” Tempest suggests. “You also can use it to make delicious homemade salad dressings that can be far healthier than most store-bought dressings.”

Of the three suggested soybean-based foods, natto may be the least well-known to Americans, but it’s a staple in Japan—typically mixed with rice and served for breakfast. And like all soybean-based foods, natto is high in plant protein. These distinct-tasting beans can be tossed into salads or mashed into burritos. “Natto is an acquired taste with its strong smell and somewhat slimy texture,” Timmermans says. She suggests mixing it into the ingredients of an omelet.

While these fermented foods are part of a daily diet in countries like Japan or Korea, it’s important to remember that many of them are high in sodium. Timmermans suggests always keeping in mind the sodium content and limiting those foods that contain high levels.

Brannon adds that kombucha tea, made by placing a kombucha mushroom in sweetened black tea, is a traditional medicinal food believed to be a good source of probiotics. “The bacteria and yeast of the mushroom cause the tea to ferment,” she explains. “Kombucha tea is an acidic, sharp-tasting beverage that tastes best after being refrigerated. It’s available in the refrigerated section of selected U.S. grocery stores such as Whole Foods.”

Caveat Emptor
Ever since probiotics has become such a powerful buzzword in the consumer nutrition world, there have been many big name brands that have wanted to get in on the action. That’s led to some trouble over strong claims manufacturers couldn’t fully substantiate.

Despite these issues, brands continue to tout the probiotic buzzword, and new products containing “added probiotics” continue to crop up. While dietitians may appreciate the increased interest in the health benefits of probiotics, many also want clients to be wary of claims. “More and more products are marketed as having probiotics but confirming whether those products contain viable organisms is a challenge,” Timmermans admits. “The shelf life of refrigerated probiotics is three to six weeks and about 12 months for freeze-dried probiotic supplements. Furthermore, the number of viable organisms likely will decrease over that timeframe.

“A Canadian study in 2004 measured the viable organisms in 10 brands of probiotic preparations and none matched the amount on their labels, with eight brands having only 10% of the stated number and two having no viable probiotics whatsoever. Dietitians should inform clients that many products may not have viable probiotics, and that they need to be wary of advertising.”

Antinoro agrees. “I’d be cautious or at least skeptical about how much probiotics are really in a food product,” she says. “For instance, a report from Consumerlab.com, an independent evaluator of nutrition and health products, found that some supplements didn’t contain the number of viable organisms listed on their labels. Yet even though they delivered fewer than listed, they still may provide an amount that might offer a health benefit. The same is most likely true for food products.”

Today, probiotics are being added to everything from nutrition bars to pizza crusts to various drinks. Even more surprising, some brands of gum are now trumpeting the power of probiotics. But these unlikely “probiotic foods” require extra consideration before purchasing. Clients may be led to think foods are more healthful than they actually are simply because the word “probiotics” is on the wrapper, but even a dose of healthful bacteria can’t overshadow unhealthful ingredients. For instance, some of the probiotic-enriched fruit drinks on the market contain a hefty amount of sugar. And though Antinoro believes that wellness bars like Attune have decent strains, the Attune bar is not free of saturated fat. Her advice for clients? “When choosing foods, look for strains from lactobacillus or bifidobacterium species, but remember what the food source is to begin with,” she advises. “Probiotics added to a chocolate bar, for instance, doesn’t negate the other ingredients that may not be so healthy in that chocolate bar.”

There’s one more thing to keep in mind when talking about probiotics with patients. Though obtaining probiotics from food sources and supplements is generally safe since probiotic bacteria are found naturally in the digestive tract, probiotic supplementation typically should be reserved for healthy individuals, Tempest says. “There may be risks to using probiotic supplements in individuals with a weakened or immature immune system, such as infants, the critically ill, and the elderly for whom probiotics may potentially do more harm than good,” she says. “Health professionals should use great discretion when recommending probiotic supplements.”

Timmermans adds that individuals allergic to cow’s milk should be cautious about taking probiotics since cow’s milk proteins are a common growth substrate and may be present even in small amounts of some probiotic supplements or probiotic-containing products. “Even a juice with probiotics may have traces of milk proteins.”

In the end, the best thing you can do is help your clients navigate the many food choices out there. Though several new probiotic options may emerge, it’s important to ensure the research is keeping up with the claims. Currently, it’s safe to say that yogurt and kefir are the ideal delivery vehicles for a healthful dose of probiotics. But as research continues, we may learn even more about these friendly bacteria and how we can get more into our system.

— Lindsey Getz is a freelance writer based in Royersford, Pa.