By Allison Tannis
Probiotics 101
As probiotic foods are starting to appear on Canadian shelves, it is evident that good bacteria are becoming big news in health food. Despite their microscopic size, the story behind probiotics is enormous.
Similar to cholesterol, bacteria may be good or bad, helpful or harmful. The human intestinal tract is home to over 400 species of bacteria. The average adult carries about four pounds of bacteria in their intestinal tract. In a healthy digestive system, the ratio of good bacteria (probiotics) to bad bacteria (pathogens) is typically about 85 percent to 10 percent. However, for some, these percentages are in reverse, leading to poor health.
Health benefits
Despite their simplicity, the healthy effects of probiotics reach almost every aspect of the body. Since the discovery of their potential health benefits in 1908 (which won the Nobel Prize), probiotics have been explored by scientists around the world. Today, research suggests that probiotics may be beneficial to those with irritable bowel syndrome, eczema, lactose intolerance, diarrhea, and may play a role in disease prevention. Most importantly, research has discovered that probiotics greatly support the immune system and are therefore vital to good health.
Common probiotics
The most common probiotic species in intestinal flora are lactic acid bacteria, which include lactobacilli and bifidobacteria. Lactobacilli are most commonly found in the small intestine, while bifidobacteria are located in the colon. There are many different lactobacilli species found in humans including Lactobacillus acidophilus and Lactobacillus rhamnosus. The main bifidobacteria species found in humans include Bifidobacterium bifidum and Bifidobacterium infantis.
How do they work?
Lactic acid bacteria are able to help protect their host against pathogenic bacteria such as E. coli and salmonella. This is why we are able to consume small numbers of these microbes without ill effects. How a lactic acid bacterium elicits these healthy effects is multifaceted. When a probiotic supplement is consumed, billions of live, active cells enter the intestines where they reach their receptor sites. Once adhered to their receptor sites, a probiotic serves as a protective shield, inhibiting both the ability of harmful pathogens to adhere and the ability of those already attached to grow. Since a probiotic is a living organism, it consumes nutrients, which reduces the amount of nutrients available to harmful pathogens. Lastly, probiotics produce bacteriocins which have antimicrobial activities that restrain the growth of harmful pathogens.
Probiotic products
Store shelves contain a variety of probiotics. Probiotic yogurts and milks are available in the food department, but it may be the supplement department that offers the greatest potential for health using probiotics. Probiotics are living bacteria and have to make it past the acidity of the stomach and the harsh basic pancreatic bile before they reach their destination in the small intestine. As such, probiotics in capsules are better protected and more likely to be alive when they arrive in the small intestine. Enteric-coated probiotic capsules protect probiotics from the stomach acid because they only release in the small intestine.
Each probiotic species elicits a unique set of health benefits on the body. Scientists have not uncovered all there is to know about various species’ abilities. As a result, many experts recommend the use of a probiotic with a wide variety of species in order to mimic the natural diversity found in the intestines. This diverse approach increases the likelihood that the bacteria taken can create the health effect desired.
Scientists have confirmed that as we age, natural changes occur in our intestinal flora. As infants, the predominant strains of bifidobacteria present are Bifidobacterium infantis and Bifidobacterium breve, which are both rarely found in adults. When we reach adulthood and begin to age, the concentration of bifidobacteria declines. Probiotic supplements are available for every age to meet the changing requirements. Infant formulas should contain L. infantis since it is one of the most prevalent species in that age group. Kid’s chewable formulas contain probiotics that are likely to make it through the stomach without a protective capsule. Adult formulas should offer a wide diversity of species and be present in high quantities (more than one million). Elderly formulas should focus on bifidobacteria.
Why take probiotics?
Probiotics have been shown to support the immune system, inhibit harmful pathogens from living in the intestines and improve many chronic conditions. They are also very useful after antibiotic use. Antibiotics kill all types of bacteria in the body, not just the pathogenic (bad) bacteria. As a result, the populations of good bacteria are greatly reduced. Probiotic supplementation can help restore healthy flora in the intestines after antibiotic use.
One of the most studied probiotics, Lactobacillus reuteri, has the ability to speed up recovery after an infection of a harmful pathogen in the intestines. In particular, L. reuteri is effective at speeding recovery in rotavirus infections, which are one of the most common causes of diarrhea in children. L. reuteri’s beneficial effects are likely due to its ability to produce a particular antimicrobial, called reuterin. Isolated from human breast milk, L. reuteri is naturally adapted to inhabiting the human gastrointestinal tract, unlike other species of probiotics that are more transient (temporary inhabitants). Look for more fascinating research on L. reuteri and other probiotic species in the future as scientists around the world try to uncover all of the benefits of these healthy bacteria.
What is CFU?
Colony forming units (CFU) is a measurement of how many probiotics are available in a supplement. According to current research, the CFU of a probiotic supplement must, at minimum, be one million for sufficient colonization of the probiotics in the intestine to occur. Some probiotic supplements guarantee the CFU at time of manufacture while others at time of expiry. Be savvy about this point because it can greatly affect the number of probiotics you’re actually getting.
When to take probiotics?
Probiotics should be taken on a full stomach. To restore healthy levels of probiotics in the body, it is commonly recommended that a quality supplement be taken three times per day. To maintain healthy levels, one daily dosage is recommended.
Probiotics are the biggest nutritional category to hit North America since essential fatty acids. Their health benefits are far reaching, the research extensive and growing. With health benefits for people of every age, gender and race, probiotics may be one of the most important nutritional breakthroughs this century. How healthy is your gut?
Allison Tannis
Allison Tannis, BSc, MSc is a nutritional scientist and educator. She is the author of Vitality: Quest for a Healthy Diet, and loving aunt to three school-aged, flu-catching boys.
