Betty Kovacs, MS, RD
Betty is a Registered Dietitian who earned her B.S. degree in Food and Nutrition from Marymount College of Fordham University and her M.S. degree in Clinical Nutrition from New York University. She is the Co-Director and Director of nutrition for the New York Obesity Research Center Weight Loss Program.
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
In this Article
- What are probiotics?
- What are prebiotics and synbiotics?
- What are microbes and their role in our health?
- What are the health benefits of probiotics?
- What are the different types of probiotics?
- What foods contain probiotics?
- What are the side effects and risks of probiotics?
- How should people take probiotics?
What foods contain probiotics?
The discovery of the benefits of probiotics began with sour milk. Today we have many other options to get various bacteria from our foods, although it's not as simple as just adding them to the food. For there to be health benefits, the microorganism has to be able to survive the passage through the gastrointestinal tract, survive the food manufacturing process, and grow and survive during the ripening or storage period. Also, the bacteria must not negatively affect product quality and be included on the Generally Recognized as Safe (GRAS) list.
Most bacteria are included through the fermentation process. Fermentation helps extend the shelf life of perishable foods. It is a slow decomposition process of organic substances induced by microorganisms or enzymes that essentially convert carbohydrates to alcohols or organic acids. The lactic acid supplies the bacteria that then add the health benefits to the food. You can purchase foods that are fermented or ferment them yourself.
- Kefir: This could be the most ideal probiotic dairy product because it contains both bacteria and yeast working together to provide the numerous health benefits. In a recent eight-week study, people with diabetes were given kefir milk containing Lactobacillus casei, Lactobacillus acidophilus, and bifidobacteria vs. conventional fermented milk. The hemoglobin A1C levels were significantly lower in the group consuming the kefir.
- Kimchi: This fermented vegetable is made from Chinese cabbage (beachu), radish, green onion, red pepper powder, garlic, ginger, and fermented seafood (jeotgal). Many bacteria have been found to be present and can include any of the following: Leuconostoc mesenteroides and Lactobacillus plantarum, L. mesenteroides, L. citreum, L. gasicomitatum, L. brevis, L. curvatus, L. plantarum, L. sakei, L. lactis, Pediococcus pentosaceus, Weissella confusa, and W. koreensis. A recent review linked the health benefits of kimchi to anticancer, antiobesity, anticonstipation, colon health promotion, cholesterol reduction, antioxidative and antiaging properties, brain health promotion, immune promotion, and skin health promotion.
- Yogurt: It can contain Streptococcus thermophilus, Lactobacillus bulgaricus, L. acidophilus, and Bifidobacterium bifidum. Research has shown links with yogurt to have positive effects on the gut microbiota and is associated with a reduced risk for gastrointestinal disease and improvement of lactose intolerance (especially among children), type 2 diabetes, cardiovascular disease, allergies and respiratory diseases, as well as improved dental and bone health.
- Sweet acidophilus milk: L. acidophilus and L. acidophilus plus bifidobacteria are added to make this milk.
- Other foods without substantial research: miso (fermented soybean paste); tempeh; sauerkraut; aged soft cheese; sourdough bread; sour pickles; gundruk (nonsalted, fermented, and acidic vegetable product); sinki (indigenous fermented radish tap root food); khalpi (fermented cucumber); inziangsang (traditional fermented leafy vegetable product prepared from mustard leaves); soidonis (widespread fermented product prepared from the tip of mature bamboo shoots)
What are the side effects and risks of probiotics?
Supplements play an important role when the diet is not adequate to supply our needs. In the case of probiotics, one's diet is the ideal source for probiotics. These are live bacteria and need to be carefully monitored, stored, and combined for the health benefits that one would be taking them for. At this time, supplements are not monitored in the U.S. the way that food or medication is. They fall under the Dietary Supplement Health and Education Act of 1994 (DSHEA). This requires that the dietary supplement or dietary ingredient manufacturer be responsible for ensuring that a dietary supplement or ingredient is safe before it is marketed. The only time that the U.S. Food and Drug Administration (FDA) may get involved is if action is needed to be taken against a manufacturer after the supplement is marketed and then found to be unsafe. This means that as much as we may know about probiotics, we can't be certain of the safety or content of the supplements available to us.
There is one Voluntary Certification Program by which a supplement manufacturer can choose to be evaluated. ConsumerLab.com (CL) is the leading provider of independent test results and information to help consumers and health-care professionals identify the best quality health and nutrition products. Products that have passed their testing for identity, strength, purity, and disintegration can print the CL Seal of Approval on their product. This is one step toward being confident that one is getting the amount and type of probiotic promised by the manufacturer.
Caution needs to be taken by everyone who chooses to take these supplements, but this is especially true for children, pregnant women, elderly people, and people with compromised immune systems. For people with compromised immune systems due to disease or treatment for a disease (such as cancer chemotherapy), taking probiotics may actually increase one's chances of getting sick. It has been shown that the use of various probiotics for immunocompromised patients or patients with a leaky gut has resulted in infections and sepsis (infection of the bloodstream). One case of bacteremia (bacteria in the bloodstream) was recently found when someone with active severe inflammatory bowel diseases with mucosal disruption was given Lactobacillus GG. Always speak with a doctor before taking any supplement under these circumstances.
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