PREBIOTICS, different from PROBIOTICS, are found in certain foods and provide nourishment to probiotic bacteria.  In other words, prebiotics are food for the beneficial bacteria living in your gut.  In addition to stimulating growth and/or activity of beneficial bacteria, prebiotics have many health benefits for the host (YOU!).  The most well-known prebiotic is fiber, which is important in maintaining a healthy digestive tract.  Prebiotics are found in many fruits, vegetables, oats, legumes and even dark chocolate.

How do prebiotics keep me healthy?

The components in food that your body cannot digest, such as fiber, can be broken down by the bacteria in your gut and used as fuel.  Prebiotics also function as a selective antibiotic, inhibiting the growth of certain bad bacteria that may find their way into your digestive tract.  When probiotics feed off prebiotics, they produce a byproduct called short chain fatty acids (SCFA).  These SCFAs have the ability to slow the growth of non-probiotic bacteria such as E. coli. 

Fiber:  Soluble vs. Insoluble

There are two categories of fiber: soluble and insoluble.  While both have benefits, such as contributing to our feeling full and lowering cholesterol, soluble fiber will give you the most benefit as a prebiotic.  Soluble fiber absorbs water and turns into a gel-like substance in our bodies.  Our friendly bacteria love to break down soluble fiber, which allows them to grow more quickly than any unfriendly bacteria lurking around. 

Why are prebiotics being added to infant formulas?

Human breast milk is not only a source of nutrition for breastfed infants but also a source of prebiotics.  Some formula makers are enriching their products with prebiotics in an effort to more closely mimic human milk. However, no formula is entirely equivalent to breastmilk and more research is needed to know if prebiotics add real value. Adding soluble fiber, oligosaccharides, and milk protein GMP (glycomacropeptide) to formula, appear to influence the composition of bacteria in the gut.  Research has indicated that babies consuming infant formula containing prebiotics have similar amounts of Bifidobacterium (beneficial bacteria) in their guts compared to breastfed babies; however, more research is needed.

How can I eat more prebiotics?

If you are consuming a diet rich in fruits and vegetables and fiber, you are probably already getting some benefit from prebiotics.  Some of the best sources include:  oats, herbs/spices, legumes (beans, peas and lentils), tea (green and black), fruits and vegetables (with skin), nuts, seeds, red wine and dark chocolate.  If you do not normally consume much fiber and then begin eating it in large quantities, you may experience some gas and bloating as your body adjusts.  Try introducing fiber more slowly into your diet. 

Bottom line

Prebiotics are part of a healthy diet and healthy bacterial population in your digestive tract that may help prevent future disease.