What’s your gut feeling about bacteria? We often think of bad bacteria as the cause of infection that needs antibiotic treatment. But good bacteria are diminished as well when we use antibiotics. Probiotics, the “friendly” bacteria, can help you replenish good intestinal bacteria that are vital to digestive health.

The most prominent indigenous bacteria in our gut are lactobacilli (lactic acid bacteria). Of these, acidophilus, officially known as Lactobacillus acidophilus, is perhaps the most well-known “good” bacteria. The live microbes in probiotics maintain these and the more than 400 other species of bacteria that colonize our intestines.

How Does Acidophilus Work?

Probiotics, like L. acidophilus, attach to the walls of the intestine and alter the condition of both the mucus layer of the intestines and the systemic immune system. Acidophilus produces antimicrobial compounds and enhances the immune system to inhibit growth of bad bacteria such as Escherichia coli (E. coli) and Salmonella typhimurium, as well as Candida albicans yeast. Thus probiotic intake results in a change in the flora population in favour of good bacteria like lactobacillus and bifidus.

Beating Bad Bacteria

Bad bacteria increase flatulence, are associated with irritable bowel syndrome, and can cause infection. A 1999 study published in the Journal of Infectious Diseases found that 78 percent of the 60 women studied had an overgrowth of bad bacteria in the vagina, which increases risk of developing a yeast infection, bladder infection, and bacterial vaginosis. Probiotics have been found to reduce the frequency of these types of infections by preventing colonization of bad bacteria.

Bad bacteria also produce enzymes that create carcinogenic compounds in the colon. Thus, the ability of acidophilus to reduce the presence of bad bacteria may decrease the risk of colon cancer.

Acidophilus has been widely studied and has also been found to decrease toxic amines in the blood of kidney dialysis patients, help in the treatment of pediatric diarrhea, facilitate lactose digestion in lactose-intolerant people, and possibly play a role in inhibiting cholesterol assimilation.

The ability of probiotics to affect the systemic immune system has researchers wondering if probiotics may be a multipurpose immune enhancer. In fact, in 2001 the British Medical Journal reported that children taking lactobacillus had fewer respiratory illnesses. Researchers recommended further research into this beneficial use, however.

Bringing It Home

Not surprisingly, acidophilus is the most common probiotic used in supplements to date. This is partially because studies have confirmed that Lactobacillus acidophilus survives gastrointestinal tract transit in both healthy and diseased populations. An enteric coating appears to aid this process. Also, researchers have found that probiotics need to be taken repeatedly and regularly in dosages between one to ten billion organisms daily to result in a positive effect.

Based on current knowledge, L. acidophilus appears to be a beneficial probiotic to enhance immune function, inhibit bad bacteria colonization in the gut, and reduce the risk of yeast, bladder, and vaginal infections, as well as the risk of colon cancer. In addition, probiotics, including acidophilus, have an excellent safety record. So, don’t be afraid of bacteria. The good ones can help.

Allison Tannis, MSc, is a nutritional researcher, educator, and author of Vitality: Quest for a Healthy Diet (2005). www.allisontannis.com.

Source: alive #278, December 2005