Americans spend millions of dollars on anti-bacterial soap, sponges,
moisturizers, disinfectants and a whole array of cleaning products to kill
germs, yet microbes -- far from being public enemy number one -- actually
provide essential health benefits. The concept that tiny organisms, such as
bacteria and fungi, can have health benefits is not new. For thousands of years,
people have benefited from foods, such as yogurt and cheese, that are rich with
microorganisms. Only recently however, has modern nutrition come to understand
the health benefits of certain microorganisms when added to foods or taken as
The human intestinal tract is a complex ecosystem of microbes, many of which
live in harmony with their human hosts and do not promote disease or illness.
Microbes that are health-enhancing are called "probiotics." Probiotics maintain
the health of the cells lining the small and large intestine, which boosts the
digestive tract's ability to absorb nutrients and fight unwanted toxins. Medical
researchers are now looking into the various uses of probiotics to prevent and
treat gastrointestinal disorders such as antibiotic-induced diarrhea, irritable
bowel syndrome, "traveler's diarrhea," and other bacterial and viral infections.
A recent issue of the Journal of the American Medical Association
highlighted information from the World Congress on Pediatric
Gastroenterology, Hepatology and Nutrition on the use of probiotics to improve
health and fight disease.
Lactobacillus acidophilus (L. acidophilus) is a probiotic that has been well
studied by scientists. L. acidophilus lives in the intestines and vagina and
prevents bacterial disease, partly through the production of lactic acid. It
also produces lactase, the enzyme that breaks down milk sugar (lactose) into
simple sugars. People with lactose intolerance may benefit from the lactase
produced by the microbes.
The primary dietary sources of L. acidophilus include the
- Acidophilus milk
- Yogurt (with live L. acidophilus)
- Fermented dairy products
- L. acidophilus is also available in freeze-dried granules, powders,
capsules, and liquid form.
To be health-enhancing, orally ingested probiotics must endure a tough ordeal
-- they have to survive the digestive process, implant in the gut, and multiply.
Unfortunately, most yogurts and fermented milks contain a strain of probiotics
that are lucky to make it out of the digestive process alive. If they do
survive, their effects are rarely long lasting. This is why the most effective
probiotics are taken as dietary supplements, such as lactic acid bacteria
bifidobacterium sp. and lactobacillus sp.
Part of the mutual benefit between microbes and humans is the ability of the
lactobacilli in the colon to break down carbohydrates, such as insulin and
fructoliogsaccharide (FOS) to short-chain fatty acids, which provides fuel for
the cells in the colon. Carbohydrates like FOS are called prebiotics and serve
as food for the "friendly bacteria." Sources of prebiotics include onions,
bananas, tomatoes, honey, barley, garlic and wheat.
Prebiotics should be taken along with the probiotics, as food or in a capsule
form. It is important to note however, that adverse interactions between
medications and some supplements are common. For example vitamins and minerals
that exceed recommended dietary allowances may be harmful. Some common foods,
including nuts, dairy products, fish, and eggs, may trigger allergic reactions,
which may require emergency medical care. If you are considering taking dietary
supplements or dramatically changing your diet, it is important to first consult
with your healthcare provider or nutritionist.
For more information on nutrition, including a helpful a rating guide to
nutrition sites on the Internet, contact the Tufts University Nutrition
Navigator at www.navigator.tufts.edu. Another helpful source is the American
Dietetic Association in Chicago, Illinois at 800-877-1600 or visit them on the
web at www.eatright.org.
Friedrich MJ. A bit of culture for children: probiotics may improve health
and fight disease. JAMA. 2000;284(11):1365-1366.