Acidophilus is an “umbrella” name for a category
of probiotics. These probiotics, as defined by
the Food and Agricultural Organization of the
United Nations, are “live microorganisms which,
when administered in adequate amounts, confer a
health benefit on the host.” (1) One of the main
functions of probiotics in the acidophilus group
is to provide aid in the digestion process. Some
of these bacteria include: Lactobacillus (L.)
acidophilus, L. bulgaricus and L. fermentum.
Lactobacillus acidophilus is found naturally in humans in
the mouth, the intestines and the vagina.
Classified as “healthy” bacteria, L. acidophilus
helps guard against infections and disease.
There are a number of ways in which L.
acidophilus performs. It assists in the
breakdown of foods and thereby produces hydrogen
peroxide, lactic acid and other substances that
create an acidic, unfriendly environment for
harmful organisms. L. acidophilus also creates
lactase, which is an enzyme that converts
lactose (milk sugar) into a simple sugar.
Because of this latter capability, ingestion of
L. acidophilus may be useful for people who
suffer from lactose intolerance.
Scientists began to use Lactobacillus acidophilus for its
probiotic benefits as far back as the early 20th
century. Russian scientist and Nobel laureate Elie Metchnikoff, studying the helpful
properties of yogurt, speculated that the lactic
acid produced during yogurt fermentation could
conquer decaying gut microbes. Metchnikoff
proposed that when the probiotics found their
way into the intestines, they would prevent the
formation of the harmful microbes. While
investigating the diets of people living in the
Balkans and the Near East, Metchnikoff came to
believe in a connection between long-term
consumption of yogurt and longevity.(2)
In the 1920s, acidophilus milk was administered
to treat diarrhea as well as constipation. (3)
Dannon, a leading manufacturer of yogurt
products, began producing yogurt for delivery to
pharmacies in the early 1920s. In the 1970s, the
company produced a television commercial (the
first ever filmed in the then-Soviet Union) that
featured a purportedly 89-year-old man from
Soviet Georgia eating his yogurt with his
mother, allegedly 114 years old, smiling in the
background. The campaign sparked sales of Dannon
yogurt, and helped create awareness of yogurt
among a new generation of users.
In addition to being present in yogurt,
acidophilus is available as a supplement, in the
form of tablets, liquids and powders.
Lactobacillus Acidophilus Benefits
Helps Prevent Yeast Infections
Urogenital infections such as bacterial
vaginosis, yeast vaginitis and urinary tract
infections affect millions of women. In many
instances, the affliction recurs, particularly
due to a buildup in resistance to certain
antimicrobial therapies. L. acidophilus may
prove to be effective in inhibiting the growth
of candida albicans, which is the fungus
responsible for many of these infections. An
abstract from a 2003 article in the Post
Graduate Medical Journal of the British Medical
Journal states: “daily oral intake of probiotic
strains Lactobacillus rhamnosus GR-1 and
Lactobacillus fermentum RC-14, resulted in some
asymptomatic bacterial vaginosis patients
reverting to a normal lactobacilli dominated
vaginal microflora.” (4, 5) “When lactobacilli
are introduced vaginally … there will be an
impact on the subject’s microflora. If this is
dominated by yeast, Gram-negative coliforms and
anaerobes, or gram-positive cocci, then the
outcome might significantly benefit the
Assists in the Absorption of Nutrients
Microflora such as Lactobacillus acidophilus are also
necessary for the body’s assimilation of
nutrients. They assist in the production of key
enzymes, and increase the rate at which vitamins
are absorbed. Some of the nutrients best
absorbed with L. acidophilus are the vitamins K
and B, calcium, lactase and fatty acids.
Helps Reduce Lactose Intolerance
A 1984 study demonstrated that lactose is
absorbed more effectively in yogurt and products
containing L. acidophilus than in milk, and the
other items sampled, which include sweet
acidophilus milk, pasteurized yogurt and
cultured milk. (7) The study also showed that
pasteurization greatly inhibited the body’s
ability to digest lactose and significantly
decreased yogurt’s natural lactase activity.
Decreases Antibiotic Side Effects
Antibiotics kill bacteria in the body, both the
good and the bad. While antibiotics are a
crucial therapy for many illnesses, they can
cause the demise of “friendly” flora. They can
also produce unpleasant side effects such as
diarrhea. Ingestion of L. acidophilus can reduce
the likelihood of these side effects. A study
conducted among healthy volunteers taking 400 mg
of erythromycin showed that those who ate yogurt
containing Lactobacillus probiotics exhibited
fewer instances of diarrhea than those who
ingested pasteurized yogurt. (8) Diarrhea is
sometimes reported as a side effect among
infants and young children who have been
administered antibiotics for respiratory
infections. L. acidophilus, when used as a
prophylactic, decreases the likelihood of
diarrhea among these young subjects. (9)
Safety of Acidophilus
Few negative effects have been reported with
appropriate use of this probiotic. During
initial use, there may be a period of excessive
gassiness and flatulence. These conditions will
decrease in frequency as the body becomes
accustomed to the presence of Lactobacillus acidophilus.
(1) FAO/WHO: Health and Nutritional Properties
of Probiotics in Food including Powder Milk with
Live Lactic Acid Bacteria. Report of the Joint
Food and Agriculture Organization (FAO) of the
United Nations/World Health Organization (WHO)
Expert Consultation on Evaluation of Health and
Nutritional Properties of Probiotics in Food
Including Powder Milk with Live Lactic Acid
(2) Metchnikoff O. Life of Elie Metchnikoff 1921
Houghton Mifflin Co., Boston, MA.
(3) Kopeloff N. "Lactobacillus Acidophilus"
Williams and Wilkins Co., 1926.
(4) Reid G, Bruce AW, Fraser N, et al. Oral
probiotics can resolve urogenital infections.
FEMS Immunology and Medical Microbiology
(5) Reid G, Charbonneau D, Erb J, et al. Oral
use of Lactobacillus rhamnosus GR-1 and L
fermentum RC-14 significantly alters vaginal
flora: randomized, placebo-controlled trial in
64 healthy women. FEMS Immunology and Medical
Microbiology 2003;35: 131−4.
(6) Burton JP, Cadieux P, Reid G. Improved
understanding of the bacterial vaginal
microflora of women before and after probiotic
instillation. Applied Environmental Microbiology
(7) DA Savaiano, A AbouElAnouar, DE Smith and MD
Levitt. Lactose malabsorption from yogurt,
pasteurized yogurt, sweet acidophilus milk, and
cultured milk in lactase-deficient individuals.
American Journal of Clinical Nutrition, 1984,
Vol. 40, 1219-1223.
(8) Effect of Lactobacillus GG Yoghurt in
Prevention of Antibiotic Associated Diarrhoea.
Annals of Medicine, 1990, Vol. 22, No. 1, Pages
(9) Arvola T, Laiho K, Torkkeli S, et al.
Prophylactic Lactobacillus GG reduces
antibiotic-associated diarrhea in children with
respiratory infections: a randomized study.
Pediatrics 1999; 104(5): e64.
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