Our bodies are maintained in constant health conditions by the nervous, endocrine, and immune
systems (homeostasis). The immune system can be impaired by stress, poor nutrition, and aging.
Infectious disease is the leading cause of death in the elderly, indicating that the immune system
is compromised in the elderly. There are individual differences in the decline
of immune function (Reference 6). CP is a safe food ingredient with a long food experience. If its
intake ameliorates immune function, CP can improve the quality of life (QOL) of the elderly and the
homeostasis of people with immune function impaired due to severe stress.
Therefore, we conducted a randomized, double-blind, placebo-controlled, clinical trial to evaluate
immune function in Japanese males and females in their 30s to 50s who feel tired
easily. They took 10 g of CP or placebo (dextrin) daily for 8 weeks (Reference 7). Immune function
was evaluated using the method of Hirokawa et al.*2 (Reference 6). The number of immune
cells (T cells,
CD4+ T cells, CD8+ T cells, naive T cells, memory T cells, CD8+
CD28+ T cells, B cells, and NK cells)
in peripheral blood was counted (Table 1). The values of seven parameters (T cell count, a ratio of
CD4+/CD8+ T cell count, naive T cell count, a ratio of naive/memory T cell
count, CD8+ CD28+ T cell
count, B cell count, and NK cell count) were then scored according to the database of healthy
individuals, respectively (1: low, 2: moderate, and 3: high). The sum of the seven scores is the
scoring of immunological vigor (SIV), an overall indicator of an individual immune function (Figure
9). The SIV is classified into three immunological grades according to the database of healthy
individuals, defined as I: critical zone, II: warning zone, III: observation zone, IV: safety zone,
and V:
sufficiently high *3 (Figure 9). Number of CD8+ CD28+ T cells is
known to decrease with age.
“T-lymphocyte age” was calculated by matching CD8+ CD28+ T cell
count to a database of
healthy
individuals (Figure 10). Questionnaires were administered using the Likert scale to assess
subjective
feelings about physical conditions.
*2: As of April 2015, this evaluation method is used by more than 50 medical institutions in Japan
to assess immune function.
*3: The grade I (SIV of 9 or less) indicates the possibility of having some disease (critical zone).
Therefore, subjects were selected from immunological grade II (warning zone) or III (observation
zone).
In the intra-group comparison before and after 8 weeks of the intervention, significant changes were
observed
in 3 parameters (CD8+ T cell count, naive/memory T cell ratio, and B cell count) in the
placebo
group, possibly due to seasonal variations, placebo effects, or the effect of dextrin as a placebo.
On the other hand, the CP group showed significant increases in the SIV, T cell count, memory T cell
count, CD8+CD28+ T cell count, and NK cell count, and significant decreases in
T lymphocyte age and
CD4+ CD8+ T cell ratio, in addition to these three measurements (Table 2).
The inter-group comparison
showed that the SIV was significantly higher (P = 0.030) in the CP group (16.2 ± 1.6) than in
the
placebo group (15.6 ± 1.8), indicating that immune function improved after daily intake of CP
(Table
3). Furthermore, no inter-group differences in the immunological grade were between the two groups
before and after 8 weeks of the intervention. However, the number of warning zone was lower, and the
number of safety zone was higher in the CP group than in the placebo group after the
intervention (Figure 11). Regarding subjective feelings of physical conditions, "diarrhea" and "lack
of
appetite" were improved in only the CP group. These results indicate that when people feel easily
fatigued with a weak immune system, CP intake can ameliorate the immune system and improve
subjective symptoms.
Figure 9. Methods of assessing immune function (1).
The following shows the method using the immunological score and grade.
[Scoring of Immunological Vigor (SIV)] The values of the seven parameters (colored cells) are
compared
with the database of healthy individuals and converted into a score (1: low, 2: medium, and 3:
high), which are then summed up.
[Immunological Grade] The SIV is compared with the database of healthy individuals and classified
into five levels: I: critical zone, II: warning zone, III: observation zone, IV: safety zone, and V:
sufficiently high.
The score and grade are indicators of an individual overall immune status.
Figure 10. Methods of assessing immune function (2).
“T lymphocyte age” is calculated by matching CD8+CD28+T cell
count, which
decreases with age, to a
database of healthy individuals.
 
Figure 11. Change in the immunological grade.
Before and after 8 weeks of intake, there was no inter-group difference in the immunological grade.
However, after the intake, the number of the warning zone was lower, and the number of the safety
zone was higher in the CP group than in the placebo group.
Table 1. The immunological parameters
The parameters used to evaluate immunological function are below.
Table 2. Intra-group variation of the immunological parameters
Statistical analysis of the changes before and after intake in the CP group is shown. In addition to
the three parameters that changed significantly in the two groups (CD8+ T cell count,
naive/memory T
cell ratio, and B cell count), the parameters changed significantly only in the CP group in
colored cells. n=25/group, Mean ± SD.
Table 3. Inter-group comparison of the immunological parameters
Statistical analysis of the difference between the two groups is shown. The SIV was significantly
higher in the CP group than in the placebo group. n=25/group, Mean ± SD.
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