Chemistry Reference
In-Depth Information
compared to 129 patients supplemented with a cellulose-based placebo. No statisti-
cal difference was demonstrated between the groups in the incidence of ventilator-
associated pneumonia (VAP) (9 and 13 percent,
P
= 0.31), the rate of VAP per 1,000
ventilator days (13 and 14.6,
p
= 0.73), and hospital mortality (27 and 33 percent,
p
= 0.32).
113
8.12 ChoICE oF lACTIC ACID bACTErIA As ProbIoTICs
Only a few probiotic strains have thus far shown ability to eliminate or reduce
unwanted proinflammatory molecules, such as AGE, ALE, glutenoids, and heterocy-
clic amines, from food. Furthermore, only a minority of several hundred tested pro-
biotic strains have demonstrated ability to suppress inflammation in the body, when
supplemented. Especially desirable strains are those that improve immune function
by increasing the number of IgA-producing plasma cells, improve phagocytosis, and
the proportion of Th1 cells and NK cells.
114
The genetic differences between differ-
ent LAB are large, said by some to be larger than those between fish and humans.
The choice of probiotics for clinical use is critical, especially as strains that carry
the same name have often different and sometimes opposite effects. A recent study
selected 46 strains of
Lactococcus lactis
from about 2,600 LAB and compared their
ability to induce production of cytokines.
115
Even if the different strains carry the
same name, their ability to produce pro- and antiinflammatory cytokines varies
widely, which seems to underline the importance of a meticulous choice for clini-
cal studies and use. Some strains, however, are more likely to have strong clinical
effects; among them are such strains as
Lactobacillus paracasei
subsp
paracasei,
L. plantarum,
and
Pediococcus pentosaceus.
Especially
L. paracasei
has a solid
record. It has been shown to induce cellular immunity and stimulate production of
suppressive cytokines, such as transforming growth factor beta (TGF-β) and Il-10
and to suppress Th2 activity and CD4 T cells,
116,117
to suppress splenocyte prolif-
eration,
118
and to decrease antigen-specific IgE and IgG
1
.
119
Lactobacillus paracasei
was also shown to be the strongest inducer of Th1 and repressor of Th2 cytokines
when more than 100 were compared.
120
A recent study in rats compared the ability
of four different strains:
L. paracasei
,
L. johnsonii
,
B. longum
, or
B. lactis
to control
Trichinella spiralis-
induced infection; only
L. paracasei
but not the other LAB was
able to reduce the infection-associated Th2 response, muscle levels of TGF-β, COX-
2, and PGE2, and attenuate infection-induced muscle hypercontractility.
121
An even
more recent study compared three probiotic strains—
B. lactis
NCC362,
L. johnsonii
NCC533, and
L. paracasei
NCC2461—and their effects on stress-induced changes
in gut permeability and on sensitivity to colorectal distension. Again, only
L. para-
casei
but not the other LAB significantly prevented visceral hyperalgesia, reduced
visceral pain, and restored normal gut permeability.
122
However,
L. plantarum
also
has an excellent record. When the ability of 50 different LAB to control 23 differ-
ent
Clostridium difficile
strains
was studied, only
L. paracasei
and
L. plantarum
were effective in eliminating all
C. difficile
strains; more than half of the tried LAB
strains were totally ineffective, and some against only a few.
123
Some LAB can be
