Probiotics, the live microbial food constituents that enhance bodily functions, have come under close scrutiny by scientists in recent years. Now that some benefits have been verified, probiotics normally found only in fermented milk products are being introduced into other foods, which are often referred to as functional foods. The creation of functional foods, which offer benefits such as aiding in digestion, is transforming the American food supply, say Eleanor Whitney and Sharon Rolfes in "Understanding Nutrition."
History
Folklore for ages has espoused the healing powers of yogurt, but for centuries no one understood how it provided benefits, according to Whitney and Rolfes. Soured milk and cultured dairy products were used medicinally before microorganisms were recognized. In 1907, Elie Metchnikoff, a Russian Nobel Prize winner, suggested that fermented milk products established a normal balance between pathogenic and nonpathogenic bacteria in the intestine. The term probiotic, in contrast to antibiotic, became popular in the 1970s.
Identification
Probiotics are live microorganisms such as bacteria or yeast in a person's digestive tract that provide a health benefit to their host. These friendly bacteria degrade toxic and allergenic substances in the intestine and colon. The human body contains well over a trillion bacteria weighing more than 3 lbs. in all. The digestive tract contains nearly 500 bacteria species, according to Probiotics.org.
Function
Probiotics aid digestion in several specific ways. The friendly bacteria Lactobacillus acidophilus helps with the absorption of the B vitamins and vitamin K, along with fatty acids and minerals such as calcium. Probiotics also reduce the inflammatory response to dairy products and help the body digest lactose.
Probiotics also promote beneficial bacteria and discourage the proliferation of unfriendly bacteria by producing organic acids that inhibit their growth. Probiotic bacteria lower the pH of the intestine, making it a hostile environment for certain other bacteria, according to Kathleen Mahan and Sylvia Escott-Stump in "Krause's Food, Nutrition & Diet Therapy."
In the text "Nutrition and Immune Function," authors P.C. Calder, C.J. Field and H.S. Gill indicate that certain strains of probiotic bacteria also help regulate cholesterol and triglyceride absorption.
Significance
Nearly 70 percent of people in the world suffer lactose intolerance. Some friendly bacteria, such as Lactobacillus bulgaricus, produce the enzyme bacterial lactase, which helps digest the lactose in milk. These friendly bacteria help people who are lactose-intolerant incorporate some dairy products in their diet.
Lactobacillus rhamnosus in some milks helps reduce the inflammatory response that occurs in people who are lactose-intolerant when they consume milk. Probiotics also enhance the immune system, according to "Nutrition and Immune Function."
Considerations
The primary food source of probiotics in America is dairy products, although supplements provide an additional source. Saccharomyces boulardii, a yeast strain, helps control diarrhea. A particularly difficult strain of unfriendly bacteria, Clostridium difficile, tends to proliferate in the colon after antibiotics have killed other microorganisms and upsets the balance of friendly and unfriendly bacteria. Saccharomyces boulardii helps check the growth of Clostridium difficile, according to MayoClinic.com.
References
- "Understanding Nutrition, Ninth Edition"; Eleanor Noss Whitney and Sharon Rady Rolfes; 2002.
- Probiotics.org: Probiotic Strains
- "Krause's Food, Nutrition & Diet Therapy, 10th Edition"; Mahan and Escott-Stump; 2000
- "Nutrition and Immune Function"; P.C. Calder, C.J. Field and H.S. Gill; 2002
- MayoClinic.com: Pseudomembranous Colitis Definition
