Minerals prevent the oxidation of lipids in the cell membrane,
which can reduce oxidative stress affecting immune cells. For
instance, selenium is indispensable to the function of reducing
enzymes such as glutathione peroxidase and thioredoxin
reductase, and is needed to stimulate cell-mediated immune
functions (156). Furthermore, zinc may be required for the
translocation and binding of NF-B to DNA (157).
Long-chain PUFAs in foods can modulate immune functions.
Dietary n-3 PUFAs alter the lipid composition of the cell
membrane and regulate the function of immune cells. Antigenpresenting
cells from mice and humans fed n-3 PUFAs
exhibited the capacity to suppress excessive activation of
T cells (158,159). As a result, n-3 PUFAs can act as antiinflammatory
agents.
Major food-derived substances and their immune-modulating
functions are summarized in Table 2.