Probiotics and Prebiotics – what’s the difference?

In terms of digestive health prebiotics and probiotics are often recommended, but it can be confusing to understand what they are and why both are necessary. Let’s start with the easy one, probiotics, as most people have heard of them. Probiotics provide new good bacteria to populate our digestive system. These good bacteria are incredibly tiny one-celled organisms that reside in our intestine – there are ten times more of them than there are cells in our body! There are over 400 different species and they live on the mucosal lining of our digestive system.

These bacteria are critical for many functions in the body such as protecting the digestive system from invading bacteria and to help manage the populations of less desirable bacteria and yeasts that also reside in the digestive system. They ferment indigestible fibre and produce enzymes that help create important vitamins such as B group vitamins and vitamin K. They help to breakdown certain substances excreted the liver into the digestive system for removal such as oestrogens, cholesterol and certain prescription drugs. Probiotics are an important part of the immune system, and act as an early warning system, by sensing an infectious agent. They then send a signal to the immune system to be wary of foreign invaders. This helps to prevent the immune system from becoming suddenly swamped without any warning. Finally if that was not enough, good bacteria also affect our brain chemistry. Gut bacteria produce hundreds of neurochemicals that the brain uses to regulate processes such as learning, memory and mood. For example it makes about 95 percent of the body's supply of serotonin, a chemical which helps us feel relaxed, happy and helps with sleep.

Good bacteria can by depleted by many things such as antibiotics, other medicines such as the oral contraceptive pill, poor diet, stress, invading bacteria and food intolerances. So from time to time we may need to top up their numbers by supplementing with probiotics and eating fermented foods. However in order to help these ingested bacterial strains, or to help our existing good bacteria to thrive and replicate, we need prebiotics. Prebiotics come from indigestible fibre and feed good bacteria to selectively encourage their growth. Oligosaccharides are simple sugar molecules that act as prebiotics. One example is galactoglucomannan, an indigestible fibre found in kiwifruit, which feeds the good bacteria and helps to provide fibre to improve bowel regulation. Other good sources are bananas, asparagus, chicory, apples, garlic, the onion family (leeks, spring onion, brown onions), blueberries, pears, watermelon and nectarines. Another type of prebiotic is inulin, which is also found in similar sorts of fruit and vegetables as well as many herbs. So you can see a good diet of fresh fruit and vegetables will greatly help to increase your populations of beneficial good bacteria.

A final benefit for this great prebiotic/ probiotic combination is that good bacteria ferment prebiotics into short-chain fatty acids, which provide energy for the cells lining the gut wall, the liver and other tissues in the body. These short chained fatty acids are being studied for their overall protective effects for the body, but also colon health.  Who would have guessed our probiotics and prebiotics could have such far reaching health benefits.

By Jane Cronin

Clinicians Naturopath