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Prebiotics and Probiotics

By Carol Witte, RDN, Director of Nutrition Services and Centers

Prebiotics and probiotics are found in functional foods. Functional foods are specific foods that provide a positive effect on health more than the basic vitamins, minerals and nutrients found in the item. These foods may help reduce the risk of heart disease and cancer and could also help improve overall health.

Prebiotics are non-digestible food items which are typically high in fiber and help nourish good microorganisms. Prebiotics include fructooligosaccharides, such as inulin and galacto-oligosaccharides. You can obtain these by including more fruits, vegetables and whole grains. Examples include bananas, onions, garlic, leeks, asparagus, artichokes, soybeans and whole-wheat foods.

Probiotics are foods or supplements that contain live microorganisms that help to improve the good bacteria in the body. These live cultures, or good bacteria, are found in a healthy intestine serving to balance the intestinal system. They have been found to help treat diseases like irritable bowel syndrome, lactose intolerance, varied causes of diarrhea (including traveler’s diarrhea and anti-biotic associated diarrhea) certain infectious diseases, immune disorders and neurological disorders.

Probiotics were noticed centuries ago when people started making and eating fermented foods. The fermentation process is one in which microorganisms such as bacteria, yeast or fungi change carbohydrates (sugars and starches) into alcohol or acids. These were initially used to preserve foods in the days before modern refrigeration. They also helped certain food items to become more digestible as well as causing the taste to change to a more sour or tangy flavor. Today, those foods are coming back in popularity and include some of the following:

  • Fermented vegetables, sauerkraut, olives and pickles (Exercise caution with these items as they are also very high in sodium.)
  • Miso—a paste made from fermented soybeans and barley or rice malt and used in Japanese cooking (One tablespoon has at least 600mg of sodium.)
  • Kefir—a sour-tasting drink make from cow’s milk fermented with certain bacteria and fermented cheese
  • Yogurt, but only those with live cultures which include lactobacillus
  • Kimchi—made with cut cabbage, radish, scallions and a seasoned paste of red pepper, garlic, ginger, sugar, and fish sauce, salted shrimp, or kelp powder (Very high in sodium)
  • Wine
  • Sourdough bread

Probiotics and prebiotics are added to some foods and are available as dietary supplements. Research is ongoing into the relationship of the gut microflora to disease. At this time they are showing many benefits and side effects are rare. Future research may lead to advanced probiotics with greater potential to improve health. Supplements are costly and if you’re considering taking them, check with your doctor to be sure they’re right for you. There are many recipes on the internet regarding fermenting your own vegetables. Please make sure you are following good practices for food safety, as you would with preserving any produce. Here are a few safety tips:

  • Start with fresh vegetables, grown using good safety practices
  • Wash all surfaces and containers with hot water
  • Use only food grade material for canning or fermenting
  • Avoid containers that may react with acid (Avoid metal and any containers with cracks.)
  • You cannot decrease the amount of salt in the recipe. It is essential for the fermentation process. Realize there is a lot of sodium found in fermented food items!
  • For the fermentation process to take place, they have to be stored in sealed containers at 70-75°F. If mold develops, you do not want to use them.
  • After fermenting, food must be stored in the refrigerator, or should be properly canned.

It is all about balance. Although you won’t find FDA health claims on all products that provide probiotics, you may see claims such as “promotes a healthy digestive system.” Include more fruits and vegetables and whole grains for beneficial prebiotics and try some foods like yogurt for probiotics. Be cautious with portion size of fermented foods and read labels to view the sodium content. The latest USDA guidelines recommend limiting sodium to less than 2000mg per day.