November 29, 2015
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What are probiotics?

The idea that bacteria are beneficial can be tough to understand. We take antibiotics to kill harmful bacterial infections and use antibacterial soaps and lotions more than ever. The wrong bacteria in the wrong place can cause problems, but the right bacteria in the right place can have benefits. This is where probiotics come in. Probiotics are live microorganisms that may be able to help prevent and treat some illnesses. Promoting a healthy digestive tract and a healthy immune system are their most widely studied benefits at this time. These are also commonly known as friendly, good, or healthy bacteria. Probiotics can be supplied through foods, beverages, and dietary supplements.

The root of the word probiotic comes from the Greek word pro, meaning "promoting," and biotic, meaning "life." The discovery of probiotics came about in the early 20th century, when Elie Metchnikoff, known as the "father of probiotics," had observed that rural dwellers in Bulgaria lived to very old ages despite extreme poverty and harsh climate. He theorized that health could be enhanced and senility delayed by manipulating the intestinal microbiome with host-friendly bacteria found in sour milk. Since then, research has continued to support his findings along with suggesting even more benefits.

In October 2013, the International Scientific Association for Probiotics and Prebiotics (ISAPP) organized a meeting of clinical and scientific experts on probiotics (with specialties in gastroenterology, pediatrics, family medicine, gut microbiota, microbiology of probiotic bacteria, microbial genetics, immunology, and food science) to reexamine the concept of probiotics. They define probiotics as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host." They also differentiated between products containing probiotics and those containing live or active cultures and established the following criteria:

  • Live or active cultures criteria:
    • Any food with fermentation microbe(s)
    • Proof of viability at a minimum level reflective of typical levels seen in fermented foods, suggested to be 1 × 109 CFU per serving
    • No specific research or evidence is needed to make this claim.
  • Probiotics criteria for products that do not make a health claim:
    • A member(s) of a safe species, which is supported by sufficient evidence of a general beneficial effect in humans or a safe microbe(s) with a property (for example, a structure, activity, or end product) for which there is sufficient evidence for a general beneficial effect in humans
    • Proof of viability at the appropriate level used in supporting human studies
  • Probiotics criteria for products that make a health claim:
    • Defined probiotic strain(s)
    • Proof of delivery of viable strain(s) at efficacious dose at the end of shelf life
    • Convincing evidence needed for specific strain(s) or strain combination in the specified health indication

Our body normally has what we would call good or helpful bacteria and bad or harmful bacteria. Maintaining the correct balance between these bacteria is necessary for optimal health. Age, genetics, and diet may influence the composition of the bacteria in the body (microbiota). An imbalance is called dysbiosis, and this has possible links to diseases of the intestinal tract, including ulcerative colitis, irritable bowel syndrome, celiac disease, and Crohn's disease, as well as more systemic diseases such as obesity and type 1 and type 2 diabetes. How do you know if you need probiotics? This article will help you decide.

What are prebiotics and synbiotics?

The prebiotic comes before and helps the probiotic, and then the two can combine to have a synergistic effect, known as synbiotics. A prebiotic is actually a nondigestible carbohydrate that acts as food for the probiotics and bacteria in your gut. The definition of the effect of prebiotics is the selective stimulation of growth and/or activity(ies) of one or a limited number of microbial genus(era)/species in the gut microbiota that confer(s) health benefits to the host. The health benefits have been suggested to include acting as a remedy for gastrointestinal (GI) complications such as enteritis, constipation, and irritable bowel disease; prevention and treatment of various cancers; decreasing allergic inflammation; treatment of nonalcoholic fatty liver disease (NAFLD), and fighting immune deficiency diseases. There has also been research showing that the dietary intake of particular food products with a prebiotic effect has been shown, especially in adolescents, but also tentatively in postmenopausal women, to increase calcium absorption as well as bone calcium accretion and bone mineral density. The benefits for obesity and type 2 diabetes are growing as recent data, both from experimental models and from human studies, have shown particular food products with prebiotics have influences on energy homeostasis, satiety regulation, and body weight gain.

Most of the prebiotics identified are oligosaccharides. They are resistant to the human digestive enzymes that work on all other carbohydrates. This means that they pass through the upper GI system without being digested. They then get fermented in the lower colon and produce short-chain fatty acids that will then nourish the beneficial microbiota that live there. Oligosaccharides can be synthesized or obtained from natural sources. These sources include asparagus, artichoke, bamboo shoots, banana, barley, chicory, leeks, garlic, honey, lentils, milk, mustards, onion, rye, soybean, sugar beet, sugarcane juice, tomato, wheat, and yacón. The health benefits from these oligosaccharides is a topic of ongoing research.

What are microbes and their role in our health?

Microbes are tiny organisms (bacteria, viruses, parasites, or fungi) -- so tiny that millions can fit into the eye of a needle -- that are so powerful that an imbalance in the body is related to numerous diseases. These microorganisms can be found in almost every part of the human body, living on the skin, in the nose, and in the gut. There are trillions of these microorganisms in our bodies. They outnumber human cells by 10 to one, but due to their small size, they only make up 1%-3% of a body's total mass.

The National Institute of Health (NIH) is sponsoring the Human Microbiome Project (HMP), which is developing research resources to enable the study of the microbial communities that live in and on our bodies and the roles they play in human health and disease. The NIH has funded many more medical studies using HMP data and techniques, including the role of the gut microbiome in Crohn's disease, ulcerative colitis, and esophageal cancer; skin microbiome in psoriasis, atopic dermatitis, and immunodeficiency; urogenital microbiome in reproductive and sexual history and circumcision; and a number of childhood disorders, including pediatric abdominal pain, intestinal inflammation, and necrotizing enterocolitis, a severe condition in premature infants in which the intestine tissue dies due to lack of oxygen.

Medically Reviewed by a Doctor on 9/10/2015


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