Food components and immune function

This is the authors' abstract. We don't add key points for this paper.

Purpose of review Enhancing immune function or alternatively dampening inflammatory processes by specific food components has received a lot of interest. The purpose of this review is to summarize recent findings with the emphasis on underlying mechanisms. Recent findings Dietary β-glucans are relatively new candidates in the field of immune modulation by diet. In-vitro and animal studies suggest that β-glucans shift inflammatory profiles to a Th1 type, which may enhance resistance against bacterial and parasitic infections. Regarding polyunsaturated fatty acids, there is evidence that n-3 fatty acids from fish oils (eicosapentaenoic acid and docosahexaenoic acid) dampen inflammatory responses. Whether eicosapentaenoic acid or docosahexaenoic acid is responsible for this phenomenon remains controversial. It is also inconclusive whether the plant-derived n-3 fatty acid α-linolenic acid has the same antiinflammatory effects as observed for fish oils. Saturated fatty acids may activate toll-like receptors and consequently the inflammatory pathway. The effect of total fat intake is controversial, since high-fat diets have been found to suppress immune function, while also improving intestinal barrier function. Finally, Gingko biloba was found to lower nuclear factor κB and activator protein 1 activation, possibly due to its high content of polyphenols. Summary In this review we discuss the nutritional components able to enhance immune function or show antiinflammatory effects. It can be concluded that diet certainly has the potential to direct immune responses. Apart from studies on fish oils, however, evidence from human studies is limited. Abbreviations AP-1: activator protein 1; CLA: conjugated linoleic acid; DHA: docosahexaenoic acid; EPA: eicosapentaenoic acid; LTB4: leukotriene B4; NF-κB: nuclear factor kappa B; PBMC: peripheral blood mononuclear cells; PGE2: prostaglandin E2; PPAR: peroxisome proliferator-activated receptor; SAFA: saturated fatty acid; TLR: toll-like receptor; TNF: tumor necrosis factor; VCAM: vascular cell adhesion molecule.