Interesting article on probiotics

[Guest guest]

Alternative Medicine Review, Nov, 2003 by E.

Investigators are building evidence that childhood infections reduce the

probability of

chronic diseases in adults. According to this hypothesis, exposure to infectious

antigens

during infancy and early childhood builds immunity and prevents autoimmune

diseases.

(38) Several environmental factors may affect susceptibility to infectious and

allergenic

agents and play a role in mucosal immunity. In developing countries where large

family

size is common and children of all ages mingle with each other, adults,

livestock, and

pets, the number and variety of endogenous gut flora increase, providing a

wealth of

stimuli for the developing immune system and the maintenance of balanced

immunity.

Such populations have much lower incidences of atopic allergies, asthma, and

autoimmune diseases than their counterparts in the developed nations. (38)

Paradoxical as

it may seem, treatment based on this hypothesis, with colonization by commensal

bacteria

in early childhood combined with the avoidance of the overuse of antibiotics,

may promote

lifelong health. (40)

The elderly may also benefit from probiotic supplementation. Aging appears to

alter

gastric mucosal responses and there is increased proliferative activity of the

gastrointestinal mucosa in older people, which may contribute to carcinogenesis

and an

increased incidence of inflammatory bowel disease. (36) Arunachalam demonstrated

even

short-term consumption of Bifidobacterium improved interferon production and

increased

phagocytic capacity. (41) These findings suggest a role for prebiotic,

probiotic, and soil

organisms in the treatment of allergic and autoimmune diseases. According to the

hygiene

hypothesis, the human immune system evolved elaborate mechanisms to accommodate

a

certain number of infectious agents, coevolute with microbes--both commensal and

pathogenic--and allow for homeostasis within the organism.

Natural Compounds for Restoration of Mucosal Immunity

A large number of natural compounds are potentially useful in restoring mucosal

immunity, including vitamins and minerals, amino acids, pre- and probiotics,

soil-derived

organisms, colostrums-derived nutrients, and herbal medications. Perhaps more

fundamentally, the link between diet and immunity has been well demonstrated,

confirming that nutrient deficiencies lead to an increased incidence of

infection. It is well-

known that infection and malnutrition aggravate each other, but even moderate

deficiencies of individual nutrients such as zinc, iron, selenium, and vitamins

A, B6, B12,

C, and E lead to weakened immunity and increased susceptibility to infections.

(42-44)

Viruses can also mutate and alter their virulence, depending on the nutritional

status of

the host at the time of infection. (45) Generally, improving antiviral immunity

and

restoring mucosal immune integrity begins with a diet composed of adequate

protein,

sufficient fiber, high nutrient density foods like fruits and vegetables,

moderate amounts

of complex carbohydrates, avoidance of refined carbohydrates, appropriate

amounts of

essential fatty acids, and the addition of nutritional supplements. (46) Dietary

intervention

for the treatment of inflammatory bowel disease has been well-addressed by other

authors. (47)

Functional foods (a food for which a health claim has been authorized), like

yogurt, inulin,

oligofructose, and soluble dietary fiber (often termed " prebiotics " ), have shown

considerable positive influence on restoring healthy commensal populations.

(48-50)

Supplementing the substrate with functional foods and prebiotics promotes

recolonization

of the microenvironment and helps maintain normal inflammatory responses in the

gastrointestinal mucosa.

Yogurt, derived from the fermentation of lactic acid in milk by Lactobacillus

bulgaricus,

Streptococcus thermophilus, and other bacteria, exerts a nonspecific

immunostimulatory

effect on host defenses due to changes in the gastrointestinal microenvironment.

The

therapeutic benefits of yogurt and lactic acid bacteria are well-documented.

(51) In vitro

and in vivo studies provide evidence that yogurt stimulates phagocytosis, (52)

mobilizes

antibody including sIgA, increases cytokine levels involved in the inflammatory

response

and antiviral immunity (IL- 1[beta], IL-6, IL-10, TNF-[alpha] (53) and

IFN-[gamma]), exerts

an antitumor effect, (54,55) mitigates against IgE-mediated hypersensitivity,

improves

gastrointestinal disorders, and reduces asthma. (56) In order to accomplish

these

immunological effects, dosages of whole organic milk yogurt in patients who are

not dairy

intolerant should be at least 200 grams daily. (57)

Inulin (a heterogeneous blend of fructose polymers) and oligofructose (a

subgroup of

inulin) are natural substances widely distributed in nature and commonly found

in the diet.

(58) The average U.S. diet contains insufficient amounts of prebiotic

substances, with only

an estimated 2.6 grams of inulin and 2.5 grams of oligofructose consumed daily.

However,

since the average U.S. diet contains large amounts of refined and processed

foods, and

because the amount of prebiotics consumed may be too low for the maintenance of

gastrointestinal homeostasis, several authors propose supplementing inulin and

oligofructose to improve gastrointestinal function, modulate gut microflora, and

stimulate

mucosal immunity. (59,60) Studies suggest daily prebiotic dosages of 8-40 grams

per day

are necessary to stimulate growth of Bifidobacteria strains. (61)

Although probiotics do not appear to have specific antiviral properties, taken

orally they

demonstrate enhanced nonspecific host immunity, increased sIgA response,

increased

TNF-[alpha] production, enhanced IL-2, -5, and -6, and prevention of pathogenic

transmission at the epithelia. (62-64) All of these actions improve mucosal

integrity and

indirectly protect against viral infection. Commercial probiotic supplements

include

Lactobacillus acidophilus, Bifidobacterium bifidum, L. sporogenes. L. casei, L.

brevi,

Streptococcus thermophilus, Saccharomyces boulardii, and others. Daily dosing of

probiotics range from 1-10 billion viable units of live organisms. (65)

In addition to the indirect immune benefits from restoring friendly intestinal

bacterial

species, several species of microflora enhance sIgA, which is important in the

prevention

of viral attachment. Saccharomyces boulardii, a nonpathogenic yeast useful to

protect

against antibiotic-induced colitis, (66) has been shown in experimental models

to

stimulate sIgA production and enhance phagocytosis. (67) These and similar

findings

suggest Saccharomyces probiotic supplementation may modulate host immune

responses

and therefore have indirect antiviral benefits.

Medicinal soils such as Luvos Heilerde from Germany, a finely ground dried soil

that

protects the gastrointestinal mucosa, and microorganisms derived from soil like

Bacillus

subtilis, a common gram-positive bacteria with antifungal properties, hold

promise in

restoring normal gastrointestinal function and enhancing mucosal immunity. (68)

An

experimental recombinant form of Bacillus subtilis (Subalin 2335 strain) has

been shown

to increase interferon synthesis and exert antiviral activity. (69) In addition,

laboratory

grown, commercially prepared, homeostatic soil organism (HSO) blends have been

used

for the treatment of inflammatory bowel conditions and autoimmune diseases. (70)

Preliminary research suggests HSO blends have antifungal, antimicrobial, and

immunomodulating properties. (71) There are no clinical standards for dosing

these

compounds and recommended amounts are dependent on manufacturer guidelines.

Although some dietary proteins can activate mucosal inflammation, the individual

amino

acids glutamine and arginine act to moderate inflammation and promote repair

mechanisms in the gastrointestinal tract. Glutamine is considered to be a

non-essential

amino acid; nevertheless, the body synthesizes large amounts, accounting for

30-35

percent of the amino acid-bound nitrogen in plasma, with the gastrointestinal

tract using

the majority of glutamine to promote growth, metabolism, structure, and function

of the

intestinal mucosa. (772,73) L-arginine has immunostimulatory properties and

serves as a

protective nutrient for the gastrointestinal tract. (74,75) Absorbed in the gut

and

transported into the circulation by intestinal cells, it is involved in immune

function and

nitric oxide (NO) synthesis. Uptake of L-arginine by the small intestine plays

an important

role in regulating NO synthesis and thereby immune activity. (76) Daily dosages

of L-

glutamine range from 1-8 g and L-arginine from 1-6 g, although some sources

suggest

considerably higher amounts.